National Emission Standards for Hazardous Air Pollutants: Plywood and Composite Wood Products

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[FRL-7419-3]

RIN 2060-AG52

National Emission Standards for Hazardous Air Pollutants: Plywood and Composite Wood Products

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

This action proposes national emission standards for hazardous air pollutants (NESHAP) for the plywood and composite wood products (PCWP) source category. The EPA has determined that the PCWP source category contains major sources of hazardous air pollutants (HAP), including acetaldehyde, acrolein, formaldehyde, methanol, phenol, and propionaldehyde. These HAP are associated with a variety of adverse health effects. These adverse health effects include chronic health disorders (

e.g.

, damage to nasal membranes, reproductive disorders, and problems with pregnancies) and acute health disorders (

e.g.

, irritation of eyes, throat, and mucous membranes, dizziness, headache, and nausea). Three of the HAP have been classified as probable or possible human carcinogens. These proposed standards would implement section 112(d) of the Clean Air Act (CAA) by requiring all major sources subject to the rule to meet HAP emission standards reflecting the application of the maximum achievable control technology (MACT). Implementation of the proposed standards would reduce HAP emissions from the PCWP source category by approximately 9,700 megagrams per year (Mg/yr) (11,000 tons per year (tons/yr)). In addition, the proposed standards would reduce emissions of volatile organic compounds (VOC) by 25,000 Mg/yr (27,000 tons/yr). This action also proposes to add a method to the relevant General Provisions to measure methanol, formaldehyde, and phenol and a method to measure total HAP at PCWP facilities.

DATES:

Comments.

Submit comments on or before March 10, 2003.

Public Hearing.

If anyone contacts the EPA requesting to speak at a public hearing by January 29, 2003, a public hearing will be held on February 10, 2003.

ADDRESSES:

Comments.

Written comments sent by U.S. mail should be submitted (in duplicate if possible) to: Air and Radiation Docket and Information Center (Mail Code 6102T), Attention Docket Number A-98-44, Room B108, U.S. EPA, 1301 Constitution Avenue, NW., Washington, DC 20460. Written comments delivered in person or by courier (

e.g.

, FedEx, Airborne, and UPS) should be submitted (in duplicate if possible) to: Air and Radiation Docket and Information Center (Mail Code 6102T), Attention Docket Number A-98-44, Room B102, U.S. EPA, 1301 Consitution Avenue, NW., Washington, DC 20460. The EPA requests a separate copy also be sent to the contact person listed below (see

FOR FURTHER INFORMATION CONTACT

).

Public Hearing.

If a public hearing is held, it will be held at 10 a.m. at the EPA Office of Administration Auditorium, Research Triangle Park, North Carolina.

Docket.

Docket No. A-98-44 contains supporting information used in developing the standards. The docket is located at the U.S. EPA, 1301 Constitution Avenue, NW., Washington, DC 20460 in room B108, and may be inspected from 8:30 a.m. to 5:30 p.m., Monday through Friday, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT:

General and technical information.

Mary Tom Kissell, Waste and Chemical Processes Group, Emissions Standards Division (C439-03), U.S. EPA, Research Triangle Park, North Carolina 27711, telephone number (919) 541-4516, electronic mail (e-mail) address

kissell.mary@epa.gov

.

Methods, sampling, and monitoring information.

Gary McAlister, Source Measurement Analysis Group, Emission Monitoring and Analysis Division (D243-02), U.S. EPA, Research Triangle Park, North Carolina 27711, telephone number (919) 541-1062, e-mail address

mcalister.gary@epa.gov

.

Economic impacts and benefit analysis.

Larry Sorrels, Innovative Strategies and Economics Group, Air Quality Strategies and Standards Division (C339-01), U.S. EPA, Research Triangle Park, North Carolina 27711, telephone number (919) 541-5041, e-mail address

sorrels.larry@epa.gov

.

SUPPLEMENTARY INFORMATION:

Comments.

Comments and data may be submitted by electronic mail (e-mail) to:

a-and-r-docket@epa.gov.

Electronic comments must be submitted as an ASCII file to avoid the use of special characters and encryption problems and will also be accepted on disks in WordPerfect® version 5.1, 6.1 or Corel 8 file format. All comments and data submitted in electronic form must note the docket number: A-98-44. No confidential business information (CBI) should be submitted by e-mail. Electronic comments may be filed online at many Federal Depository Libraries.

Commenters wishing to submit proprietary information for consideration must clearly distinguish such information from other comments and clearly label it as CBI. Send submissions containing such proprietary information directly to the following address, and not to the public docket, to ensure that proprietary information is not inadvertently placed in the docket: Attention: Mary Tom Kissell, c/o OAQPS Document Control Officer (C404-02), U.S. EPA, Research Triangle Park NC 27711. The EPA will disclose information identified as CBI only the extent allowed by the procedures set forth in 40 CFR part 2. If no claim of confidentiality accompanies a submission when it is received by the EPA, the information may be made available to the public without further notice to the commenter.

Public Hearing.

Persons interested in presenting oral testimony or inquiring as to whether a hearing is to be held should contact JoLynn Collins, Waste and Chemical Processes Group, Emissions Standards Division (C439-03), U.S. EPA, Research Triangle Park, NC 27711, telephone (919) 541-5671 at least 2 days in advance of the public hearing. Persons interested in attending the public hearing must also call JoLynn Collins to verify the time, date, and location of the hearing. The public hearing will provide interested parties the opportunity to present data, views, or arguments concerning these proposed emission standards.

Docket.

The docket is an organized and complete file of all the information considered by the EPA in the development of this rulemaking. The docket is a dynamic file because material is added throughout the rulemaking process. The docketing system is intended to allow members of the public and industries involved to readily identify and locate documents so that they can effectively participate in the rulemaking process. Along with the proposed and promulgated standards and their preambles, the contents of the docket, with certain exceptions, will serve as the record in the case of judicial review. (See section 307(d)(7)(A) of the CAA.) The regulatory text and other materials related to this rulemaking are available for review in the docket or copies may be mailed on request from the Air Docket by calling (202) 566-1742. A reasonable fee may be charged for copying docket materials.

World Wide Web (WWW).

In addition to being available in the docket, an electronic copy of today's proposed rule is also available on the WWW through the Technology Transfer Network (TTN). Following signature, a copy of the rule will be posted on the TTN's policy and guidance page for newly proposed or promulgated rules

http://www.epa.gov/ttn/oarpg.

The TTN provides information and technology exchange in various areas of air pollution control. If more information regarding the TTN is needed, call the TTN HELP line at (919) 541-5384.

Regulated Entities.

Categories and entities potentially regulated by this action include:

Category

SIC

NAICS

Examples of regulated entities

Industry

2421

321999

Sawmills with lumber kilns.

2435

321211

Hardwood plywood and veneer plants.

2436

321212

Softwood plywood and veneer plants.

2493

321219

Reconstituted wood products (Particleboard, medium density fiberboard, hardboard, fiberboard, and oriented strandboard plants).

2439

321213

Structural Wood Members, Not Elsewhere Classified (Engineered wood products plants).

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. To determine whether your facility is regulated by this action, you should examine the applicability criteria in § 63.2231 of the proposed rule. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed in the preceding

FOR FURTHER INFORMATION CONTACT

section.

Outline.

The information presented in this preamble is organized as follows:

I. Introduction

A. What Is the Purpose of This Proposed Rule?

B. What Is the Source of Authority for Development of NESHAP?

C. What Criteria Are Used in the Development of NESHAP?

D. How Was This Proposed Rule Developed?

E. What are the Health effects of the Pollutants Emitted From the PCWP Industry?

F. Incorporation by Reference of NCASI Test Methods

G. Alternative Procedure for Determining Press Enclosure Capture Efficiency

H. Changes to the Scope of a Source Category

II. Summary of Proposed Rule

A. What Process Units Are Subject to This Proposed Rule?

B. What Pollutants Are Regulated by This Proposed Rule?

C. What are the Compliance Options?

D. What Operating Requirements Are in the Proposed Rule?

E. What Are the Work Practice Requirements?

F. When Must I Comply With This Proposed Rule?

G. How Do I demonstrate Initial Compliance With This Proposed Rule?

H. How Do I Demonstrate Continuous Compliance With This Proposed Rule?

III. Rationale for Proposed Rule

A. How Did We Select the Source Category and Any Subcategories?

B. How Did We Define the Affected Source?

C. How Did We Determine the MACT Floor For Existing Sources?

D. How Did We Determine the MACT Floor For New Sources?

E. What Control Options Beyond the MACT Floor Did We Consider?

F. How Did We Select the Format of the Proposed Rule?

G. How Did We Select the Test Methods for Determining Compliance With This Proposed Rule?

H. How Did We Select the Monitoring and Recordkeeping Requirements?

I. How Did We Select the Notification and Reporting Requirements?

IV. Summary of Environmental, Energy and Economic Impacts

A. How Many Facilities Are Impacted by This Proposed Rule?

B. What Are the Air Quality Impacts?

C. What Are the Water Quality Impacts?

D. What Are the Solid Waste Impacts?

E. What Are the Energy Impacts?

F. What Are the Cost Impacts?

G. Can We Achieve the Goals of the Proposed Rule in a Less Costly manner?

H. What Are the Economic Impacts?

I. What Are the Social Costs and Benefits?

V. Relationship to Other Standards and Programs Under the CAA and Other Statutes

A. Wood Building Products Surface Coating NESHAP Proposal

B. Wood Furniture Manufacturing Operations NESHAP (40 CFR Part 63, Subpart JJ)

C. Combustion Related NESHAP

D. New Source Review/Prevention of Significant Deterioration Applicability

E. Interrelationship between MACT Provisions and PSD

F. Effluent Guidelines

VI. Administrative Requirements

A. Executive Order 12866, Regulatory Planning and Review

B. Executive Order 13132, Federalism

C. Executive Order 13175, Consultation and Coordination with Indian Tribal Governments

D. Executive Order 13045, Protection of Children from Environmental Health Risks and Safety Risks

E. Unfunded Mandates Reform Act of 1995

F. Regulatory Flexibility Act (RFA), as amended by the Small Business Regulatory Enforcement Fairness Act (SBREFA) of 1996, 5 U.S.C. 601

et seq.

G. Paperwork Reduction Act

H. National Technology Transfer and Advancement Act of 1995

I. Executive Order 13211, Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use

I. Introduction

A. What Is the Purpose of This Proposed Rule?

The purpose of the proposed rule is to protect the public health by reducing emissions of HAP from PCWP facilities.

B. What Is the Source of Authority for Development of NESHAP?

Section 112 of the CAA requires us to list categories and subcategories of major sources and area sources of HAP and to establish NESHAP for the listed source categories and subcategories. The PCWP source category was originally listed as the plywood and particleboard source category on July 16, 1992 (57 FR 31576). The name of the source category was changed to plywood and composite wood products on November 18, 1999 (64 FR 63025) to more accurately reflect the types of manufacturing facilities covered by the source category. Major sources of HAP are those that have the potential to emit greater than 10 tons/yr of any one HAP or 25 tons per year of any combination of HAP.

Section 112(d) of the CAA directs us to adopt emission standards for categories and subcategories of HAP sources. In cases where emission standards are not feasible, section 112(h) of the CAA allows us to develop design, equipment, work practice and/or operational standards. The collection of compliance options, operating requirements, and work practice requirements in today's proposed rule make up the emission standards and

work practice standards for the PCWP NESHAP.

C. What Criteria Are Used in the Development of NESHAP?

Section 112 of the CAA requires that we establish NESHAP for the control of HAP from both new and existing major sources. The CAA requires the NESHAP to reflect the maximum degree of reduction in emissions of HAP that is achievable. This level of control is commonly referred to as the MACT.

The MACT floor is the minimum control level allowed for NESHAP and is defined under section 112(d)(3) of the CAA. In essence, the MACT floor ensures that the standard is set at a level that assures that all major sources achieve the level of control at least as stringent as that already achieved by the better-controlled and lower-emitting sources in each source category or subcategory. For new sources, the MACT floor cannot be less stringent than the emission control that is achieved in practice by the best-controlled similar source. The MACT standards for existing sources can be less stringent than standards for new sources, but they cannot be less stringent than the average emission limitation achieved by the best-performing 12 percent of existing sources in the category or subcategory (or the best-performing 5 sources for categories or subcategories with fewer than 30 sources).

In developing MACT, we must also consider any control options that are more stringent than the floor. We may establish standards more stringent than the floor based on the consideration of cost of achieving the emissions reductions, any health and environmental impacts, and energy requirements.

D. How Was This Proposed Rule Developed?

We used several resources to develop this proposed rule, including questionnaire responses from industry, emissions test data, site visits to PCWP facilities, telephone contacts, and operating permits. We consulted representatives of the PCWP industry, State and Federal representatives, and emission control device vendors in developing this proposed rule. Industry representatives provided emissions test data, arranged site visits, reviewed draft questionnaires, and identified issues and provided information to help resolve issues in the rulemaking process. State representatives provided emissions test data and copies of permits.

We identified the MACT floor level of control with information obtained from the questionnaire responses, emission test reports, site visits, telephone contacts, and operating permits.

E. What Are the Health Effects of the Pollutants Emitted From the PCWP Industry?

This proposed rule protects air quality and promotes the public health by reducing emissions of some of the HAP listed in section 112(b)(1) of the CAA. The HAP emitted by PCWP facilities include, but are not limited to, acetaldehyde, acrolein, formaldehyde, methanol, phenol, and propionaldehyde. Exposure to these compounds has been demonstrated to cause adverse health effects when present in concentrations higher than those typically found in ambient air.

We do not have the necessary data on each PCWP facility and the people living around each facility to determine the actual population exposures to the HAP emitted from these facilities and the potential health effects. Therefore, we do not know the extent to which the adverse health effects described in the following subsections occur in the populations surrounding these facilities. However, to the extent the adverse effects do occur, today's proposed rule would reduce emissions and subsequent exposures.

1. Acetaldehyde

Acetaldehyde is ubiquitous in the environment and may be formed in the body from the breakdown of ethanol (ethyl alcohol). Acute (short-term) exposure to acetaldehyde results in effects including irritation of the eyes, skin, and respiratory tract. In humans, symptoms of chronic (long-term) exposure to acetaldehyde resemble those of alcoholism. Long-term inhalation exposure studies in animals reported damage to the nasal epithelium and mucous membranes, growth retardation, and increased kidney weight. We have classified acetaldehyde as a probable human carcinogen (Group B2) based on animal studies that have shown nasal tumors in rats and laryngeal tumors in hamsters.

2. Acrolein

Acute (short-term) inhalation exposure to acrolein may result in upper respiratory tract irritation and congestion. The major effects from chronic (long-term) inhalation exposure to acrolein in humans consist of general respiratory congestion and eye, nose, and throat irritation. Acrolein is a strong dermal irritant, causing skin burns in humans. We consider acrolein a possible human carcinogen (Group C) based on limited animal cancer data suggesting an increased incidence of tumors in rats exposed to acrolein in the drinking water.

3. Formaldehyde

Both acute (short-term) and chronic (long-term) exposure to formaldehyde irritates the eyes, nose, and throat, and may cause coughing, chest pains, and bronchitis. Reproductive effects, such as menstrual disorders and pregnancy problems, have been reported in female workers exposed to formaldehyde. Limited human studies have reported an association between formaldehyde exposure and lung and nasopharyngeal cancer. Animal inhalation studies have reported an increased incidence of nasal squamous cell cancer. We consider formaldehyde a probable human carcinogen (Group B2).

4. Methanol

Acute (short-term) or chronic (long-term) exposure of humans to methanol by inhalation or ingestion may result in blurred vision, headache, dizziness, and nausea. No information is available on the reproductive, developmental, or carcinogenic effects of methanol in humans. Birth defects have been observed in the offspring of rats and mice exposed to methanol by inhalation. A methanol inhalation study using rhesus monkeys reported a decrease in the length of pregnancy and limited evidence of impaired learning ability in offspring. We have not classified methanol with respect to carcinogenicity.

5. Phenol

Acute (short-term) inhalation and dermal exposure to phenol is highly irritating to the skin, eyes, and mucous membranes in humans. Oral exposure to small amounts of phenol may cause irregular breathing, muscular weakness and tremors, coma, and respiratory arrest at lethal concentrations. Anorexia, progressive weight loss, diarrhea, vertigo, salivation, and a dark coloration of the urine have been reported in chronically (long-term) exposed humans. Gastrointestinal irritation and blood and liver effects have also been reported. No studies of developmental or reproductive effects of phenol in humans are available, but animal studies have reported reduced fetal body weights, growth retardation, and abnormal development in the offspring of animals exposed to phenol by the oral route. We have classified phenol in Group D, not classifiable as to human carcinogenicity.

6. Propionaldehyde

No information is available on the acute (short-term) effects of propionaldehyde in humans. Animal studies have reported that inhalation exposure to high levels of propionaldehyde results in anesthesia and liver damage. No information is available on the chronic (long-term), reproductive, developmental or carcinogenic effects of propionaldehyde in animals or humans. We have not classified propionaldehyde for carcinogenicity.

F. Incorporation by Reference of NCASI Test Methods

With today's action, we are proposing to amend 40 CFR 63.14 by revising paragraph (f) to incorporate by reference two test methods developed by the National Council of the Paper Industry for Air and Stream Improvement (NCASI): (1) Method CI/WP-98.01, Chilled Impinger Method for Use at Wood Products Mills to Measure Formaldehyde, Methanol, and Phenol; and (2) pending review by EPA, Method IM/CAN/WP-99.01, Impinger/Canister Source Sampling Method for Selected HAPs at Wood Products Facilities. These methods are available from the NCASI, Methods Manual, P.O. Box 133318, Research Triangle Park, NC 27709-3318 or at

http://www.ncasi.org.

They are also available from the docket for this proposed rule (Docket Number A-98-44).

In today's proposed rule, NCASI Method CI/WP-98.01 would be allowed as an alternative to:

• EPA Method 320, Measurement of Vapor Phase Organic and Inorganic Emission by Extractive FTIR, for measuring methanol or formaldehyde;

• EPA Method 0011, Sampling for Selected Aldehyde and Ketone Emissions from Stationary Sources, for measuring formaldehyde;

• EPA Method 316, Sampling and Analysis for Formaldehyde Emissions from Stationary Sources in the Mineral Wool and Wool Fiberglass Industries, for measuring formaldehyde;

• EPA Method 308, Procedure for Determination of Methanol Emission from Stationary Sources, for measuring methanol; and

• NCASI Method IM/CAN/WP-99.01 for measuring formaldehyde or methanol.

The NCASI Method CI/WP-98.01 has been validated using EPA Method 301, Field Validation of Pollutant Measurement Methods from Various Waste Media, for measuring methanol, formaldehyde, and phenol emissions from PCWP facilities. (EPA Method 0011 is available in “Test Methods for Evaluating Solid Waste, Physical/Chemical Methods,” EPA Publication No. SW-846. EPA Methods 301, 308, 316, and 320 are in 40 CFR part 63, appendix A.)

In today's proposed rule, NCASI Method IM/CAN/WP-99.01, which is a self-validating method, would be allowed, pending our review, as an alternative to:

• EPA Method 320, for measuring methanol, formaldehyde, or total HAP;

• EPA Methods 0011 and 316, for measuring formaldehyde;

• EPA Method 308, for measuring methanol; and

• NCASI Method CI/WP-98.01, for measuring formaldehyde or methanol.

G. Alternative Procedure for Determining Press Enclosure Capture Efficiency

We are working with industry representatives to develop a procedure that uses measurement of tracer gas to determine capture efficiency. We are proposing this “tracer gas procedure” today in appendix A to the proposed subpart DDDD.

H. Changes to the Scope of a Source Category

Today's action serves to broaden the PCWP source category to include lumber kilns located at stand-alone kiln-dried lumber manufacturing facilities or at any other type of facility. Wood products industry representatives requested that all lumber kilns (regardless of location) be considered in today's proposed rule so there would be one MACT determination for all lumber kilns nationwide. If lumber kilns at stand-alone kiln-dried lumber manufacturing facilities and other types of facilities are not included in the PCWP NESHAP, kiln-dried lumber manufacturing could be listed as a major source category under section 112(c) of the CAA in the future, requiring a separate section 112(d) rulemaking, and may become separately subject to the provisions of section 112(g) of the CAA as well. Because the design and operation of lumber kilns are essentially the same regardless of whether the kilns are located at a sawmill or are co-located with PCWP or other types of manufacturing operations, we have included lumber kilns in the PCWP source category. Broadening the scope of the PCWP source category to include lumber kilns located at any type of facility is reasonable because based on our information, there are no currently applicable controls at any lumber kilns and it is both more efficient and expeditious to include them in the MACT process now than to separately address them in a rulemaking that would not likely result in meaningful emissions reductions from lumber kilns. Moreover, including all lumber kilns in the PCWP MACT results in placing them on a faster schedule for purposes of future residual risk analysis under CAA section 112(f).

II. Summary of Proposed Rule

A. What Process Units Are Subject to This Proposed Rule?

The proposed rule would regulate HAP emissions from PCWP facilities that are major sources. Plywood and composite wood products are manufactured by bonding wood material (fibers, particles, strands,

etc.

) or agricultural fiber, generally with resin under heat and pressure, to form a structural panel or engineered wood product. Plywood and composite wood products manufacturing facilities also include facilities that manufacture dry veneer and lumber kilns located at any facility. Plywood and composite wood products include (but are not limited to) plywood, veneer, particleboard, oriented strandboard, hardboard, fiberboard, medium density fiberboard, laminated strand lumber, laminated veneer lumber, wood I-joists, kiln-dried lumber, and glue-laminated beams. Table 1 of this preamble lists the process units at PCWP facilities and indicates which process units are subject to the control requirements in today's proposed rule. “Process unit” means equipment classified according to its function such as a blender, dryer, press, former, or board cooler.

Table 1.—Process Units That Are Subject to the Proposed Control Requirements

For the following process units . . .

Does today's proposed rule include control requirements for . . .

Existing

affected

sources?

New affected

sources?

Softwood veneer dryers; tube dryers; strand dryers; green rotary dryers; hardboard ovens; reconstituted wood product presses; and pressurized refiners

Yes

Yes.

Press predryers; fiberboard mat dryers; and board coolers

No

Yes.

Dry rotary dryers; veneer redryers; plywood presses; engineered wood products presses; hardwood veneer dryers; humidifiers; atmospheric refiners; formers; blenders; rotary agricultural fiber dryers; agricultural fiber board presses; sanders; saws; fiber washers; chippers; log vats; lumber kilns; storage tanks; wastewater operations; miscellaneous coating operations; and stand-alone digesters

No

No.

The affected source for this proposed rule is the combination of all PCWP manufacturing operations, including PCWP process units, onsite storage of raw materials, onsite wastewater treatment operations associated with PCWP manufacturing, and miscellaneous coating operations located in a single facility covering a contiguous area under common control that is also a major source. One of the implications of the proposed definition of affected source is that the control requirements or “floor,” as defined in section 112(d)(3), are determined for the entire PCWP facility. Therefore, except for lumber kilns not otherwise located at PCWP facilities, this proposed rule contains the control requirements that represent the MACT level of control for the entire facility. For lumber kilns not otherwise located at PCWP facilities, this proposed rule contains the control requirements that represent the MACT level of control only for lumber kilns.

B. What Pollutants Are Regulated by This Proposed Rule?

The proposed rule would regulate HAP emissions from PCWP facilities. For the purpose of compliance with 40 CFR part 63, subpart DDDD, we defined “total HAP” to be the sum of the emissions of six primary HAP emitted from PCWP manufacturing. For the purpose of determining whether your facility is a major source, you would have to include all HAP as prescribed by rules and guidance pertaining to determination of major source.

The six HAP that define “total HAP” are: Acetaldehyde, acrolein, formaldehyde, methanol, phenol, and propionaldehyde. Other HAP are sometimes emitted and controlled along with these six HAP, but in low quantities that may be difficult to measure. Depending upon which of the compliance alternatives you choose, you could be required to measure emissions of total hydrocarbon (THC), methanol, or formaldehyde as surrogates for measuring total HAP.

C. What Are the Compliance Options?

Today's proposed rule includes a range of compliance options which are summarized in the following subsections. You would have to use one of the compliance options to show compliance with the proposed rule. In most cases, the proposed compliance options would be the same for new and existing sources. Dilution to achieve compliance is prohibited as specified in 40 CFR 63.4.

1. Production-Based Compliance Options

Today's proposed rule includes production-based compliance options which are based on total HAP and vary according to type of process unit. Total HAP emissions are defined in today's proposed rule as the total mass emissions of the following six HAP: Acetaldehyde, acrolein, formaldehyde, methanol, phenol, and propionaldehyde. The production-based compliance options are in units of mass of pollutant per unit of production. Add-on control systems may not be used to meet the production-based compliance options. For pressurized refiners and most dryers, the production-based compliance options are expressed as pounds per oven-dried-ton of wood (lb/ODT). For presses, hardboard ovens, and some dryers, the production-based compliance options are expressed as pounds per thousand square feet of board (lb/MSF), with a reference board thickness.

2. Add-On Control System Compliance Options

If you operate a process unit equipped with an add-on control system, you may use any one of the following six compliance options. “Add-on control system” or “control system” means the combination of capture and control devices used to reduce HAP emissions to the atmosphere.

a. Reduce THC emissions (as carbon, and minus methane if you wish to subtract methane) by 90 percent.

b. Reduce methanol emissions by 90 percent.

c. Reduce formaldehyde emissions by 90 percent.

d. Limit the concentration of THC (as carbon, and minus methane if you wish to subtract methane) in the outlet of the add-on control system to 20 parts per million by volume, dry basis (ppmvd).

e. Limit the concentration of methanol in the exhaust from the add-on control system to 1 ppmvd (can be used only if the concentration of methanol entering the control device is greater than or equal to 10 ppmvd).

f. Limit the concentration of formaldehyde in the exhaust from the add-on control system to 1 ppmvd (can be used only if the concentration of formaldehyde entering the control device is greater than or equal to 10 ppmvd).

In the first three options (a through c), the 90 percent control efficiency represents a total control efficiency. Total control efficiency is defined as the product of the capture efficiency and the control device efficiency. For process units such as rotary strand dryers, capture efficiency is not an issue because the rotary strand dryer has a single exhaust point which is easily captured by the control device. However, for presses and board coolers, the HAP emissions cannot be completely captured without installing an enclosure. If the enclosure meets the criteria for a permanent total enclosure (PTE) as described in EPA Test Method 204 (40 CFR part 51, appendix M), then you could assign the enclosure a capture efficiency of 100 percent. You would have to test other enclosures to determine capture efficiency using EPA Test Methods 204 and 204A through 204F (as appropriate) or the alternative

tracer gas procedure in today's proposed rule. For the three concentration options (d through f), you would need to have an enclosure that either meets the criteria for a PTE or achieves a capture efficiency greater than or equal to 95 percent.

The six compliance options are equivalent ways to express the HAP control levels that represent the MACT floor. Because the compliance options are equivalent for controlling HAP emissions, you would be required to meet only one compliance option for add-on control systems. For example, if you elect to test your control system for THC and formaldehyde and the test results demonstrate compliance with only the THC or only the formaldehyde compliance option, you would still be in compliance with today's proposed rule.

3. Emissions Averaging Compliance Option

The CAA does not limit how we set control requirements beyond requiring that they be applicable to all sources in a category and be at least as stringent as the MACT floor. Therefore, the relevant statutory language does not prohibit us from allowing a source to meet MACT through use of emissions averaging as long as averaging does not cross source category boundaries, and the standard is set at a level at least as stringent as the MACT floor. As explained in this preamble, we believe we have met these criteria. In addition, it should be noted that Congress explicitly provided that cost should be considered in setting the standards. Emissions averaging is a means of achieving the required emissions reductions in a cost effective way. Therefore, if you operate an existing affected source, you could choose to comply with the emissions averaging provisions instead of the production-based compliance options or add-on control system compliance options.

Emissions averaging is a system of debits and credits in which the credits must equal or exceed the debits. “Debit-generating process units” are the PCWP process units required to meet the proposed control requirements that you choose to either not control or under-control. “Credit-generating process units” are the PCWP process units that you choose to control. You may take credit for emissions from debit-generating process units that are under-controlled. Control devices used for credit-generating process units may not be assigned more than 90 percent control efficiency.

Under the emissions averaging provisions, you would determine the required mass removal (RMR) of total HAP from debit-generating process units for a 6-month compliance period. Total HAP is defined in today's proposed rule to include acetaldehyde, acrolein, formaldehyde, methanol, phenol, and propionaldehyde. The RMR would be based on initial total HAP measurements for each debit-generating process unit, your process unit operating hours for a 6-month period, and the required 90 percent control system efficiency. One hundred percent of the RMR for debit-generating process units would have to be achieved or exceeded by the actual mass removal (AMR) of total HAP achieved by credit-generating process units. The AMR is determined based on initial performance tests, the total HAP removal efficiency of the control systems used to control the credit-generating process units, and your process unit operating hours over the 6-month period.

There are some restrictions on use of the emissions averaging provisions in today's proposed rule. You would have to limit emissions averaging to the process units located within your affected source. Emissions averaging could not be used at new affected sources. You could not include in an emissions average those process units that are not operating or that are shut down. You could not include in your emissions average those process units controlled to comply with a State or Federal rule other than today's proposed rule (unless the process unit was included in an emissions average and the control system was installed before the process unit was subject to the other State or Federal rule). Only PCWP process units using add-on control systems may be used to generate credits.

D. What Operating Requirements Are in the Proposed Rule?

The operating requirements in today's proposed rule would apply to add-on control systems used to comply with the proposed rule and to process units that can meet the proposed production-based compliance options. For incineration-based control devices and biofilters, the proposed rule specifies that you would either monitor operating parameters or use a THC continuous emission monitoring system (CEMS) to demonstrate continuous compliance. The proposed operating requirements are summarized below:

• If you operate a thermal oxidizer, such as a regenerative thermal oxidizer (RTO) or a combustion unit that accepts process exhaust into the flame zone, you would be required to maintain the firebox temperature at a level that is greater than or equal to the minimum temperature established during the performance test. You would also be required to maintain the average static pressure at the inlet of the thermal oxidizer within the operating range established during the performance test. You may choose to monitor gas flow rate at the thermal oxidizer stack as an alternative to monitoring static pressure. If you monitor gas flow, you must maintain the gas flow rate below the maximum flow rate established during the performance test. If you operate a combustion unit that accepts process exhaust into the flame zone and that combustion unit has a heat input capacity of greater than or equal to 44 megawatts (MW), you would be exempt from the testing and monitoring requirements described above for thermal oxidizers.

• If you operate a catalytic oxidizer, such as a regenerative catalytic oxidizer (RCO) or thermal catalytic oxidizer (TCO), you would be required to maintain the temperature upstream of the catalyst bed at or above the minimum temperature established during the performance test. You would also be required to maintain the average static pressure at the inlet of the catalytic oxidizer within the operating range established during the performance test. You may choose to monitor gas flow rate at the catalytic oxidizer stack as an alternative to monitoring static pressure. If you monitor gas flow, you must maintain the gas flow rate below the maximum flow rate established during the performance test.

• If you operate a biofilter, you would be required to maintain the temperature of the air stream entering the biofilter, pH of the biofilter effluent, and pressure drop across the biofilter bed within the ranges you specify during the initial performance test or during qualifying previous performance tests using the required test methods. If you use values from previous performance tests to establish the operating parameter ranges, you would have to certify that the biofilter and associated process unit(s) have not been modified subsequent to the date the previous data were collected.

• If you operate an add-on control system not listed in today's proposed rule, you would establish operating parameters to be monitored and parameter values that represent your operating requirements during the performance test, subject to prior written approval by the Administrator.

• If you operate a process unit that can meet the production-based compliance options without an add-on

control device, you would be required to maintain the average process unit inlet or operating temperature (depending on the specific process unit) below the maximum temperature established during the performance test.

• As an alternative to monitoring the operating parameters specified above for thermal oxidizers, catalytic oxidizers, biofilters, other control devices, and process units that meet the compliance options for process units without add-on control systems, you would be allowed to monitor THC concentration in the outlet stack with a THC CEMS. You would be required to maintain the outlet THC concentration below the maximum concentration established during the performance test. You may choose to subtract methane from the THC concentration measured by the CEMS if you wish to do so.

E. What Are the Work Practice Requirements?

The work practice requirements in today's proposed rule apply to veneer dryers, dry rotary dryers, veneer redryers, and hardwood veneer dryers. For veneer dryers, the proposed work practice requirements require you to minimize fugitive emissions from the veneer dryer doors (by applying appropriate operation and maintenance procedures) and from the green end of the dryers (through proper balancing of hot zone exhausts). The proposed work practice requirements also specify parameters that you would monitor to demonstrate that each dry rotary dryer, redryer, and hardwood veneer dryer continuously operates in a manner consistent with the definitions of these process units provided in today's proposed rule, as follows:

• If you operate a dry rotary dryer, you would be required to maintain the inlet dryer temperature at or below 600 °F and maintain the moisture content of the wood particles entering the dryer at or below 30 weight percent, on a dry basis.

• If you operate a veneer redryer, you would be required to maintain the moisture content of the wood veneer entering the dryer at or below 25 percent, by weight.

• If you operate a hardwood veneer dryer, you would be required to process less than 30 percent, by volume, softwood species each year.

F. When Must I Comply With This Proposed Rule?

Existing PCWP facilities must comply within 3 years of the date the promulgated rule is published in the

Federal Register

. New sources that commence construction after today's date must comply immediately upon initial startup or on the effective date of the rule, whichever is later.

G. How Do I Demonstrate Initial Compliance With This Proposed Rule?

The initial compliance requirements in today's proposed rule vary with the different compliance options.

1. Production-Based Compliance Options

If you are complying with the production-based compliance options in today's proposed rule, you would be required to conduct an initial performance test using specified test methods to demonstrate initial compliance. You would be required to test the efficiency of your emissions capture device during the initial compliance test if the process unit is a press or board cooler. The actual emission rate of the press or board cooler would be equivalent to the measured emissions divided by the capture efficiency. You would be required to install process (temperature) monitoring equipment to be used to demonstrate compliance with the operating requirements for process units without add-on control systems or install a THC CEMS and monitor the outlet THC concentration. During the initial compliance test, you would use the process monitoring equipment to establish the parameter value that represents your operating requirement for the process unit.

2. Add-On Control System Compliance Options

If you use the compliance options for add-on control systems, you would be required to conduct an initial performance test using specified test methods to demonstrate initial compliance. With the exception of the 20 ppmvd THC concentration option, you would be required to test at both the inlet and the outlet of the control device. If you use any of the six compliance options for add-on control systems, and the process unit is a press or a board cooler without a PTE, you would also be required to test the capture efficiency of your partial enclosure. Prior to the initial performance test, you would be required to install control device parameter monitoring equipment or THC CEMS to be used to demonstrate compliance with the operating requirements for add-on control systems in today's proposed rule. During the initial compliance test, you would use the control device parameter monitoring equipment or THC CEMS to establish the parameter values that represent your operating requirements for the control systems. If your add-on control system is preceded by a particulate control device, you would only be required to establish operating parameter values for the HAP control system and not for the particulate control device. If your control device is a biofilter, then you may use historical operating records for the biofilter to establish your operating requirements as long as you were in compliance with the emission limits in today's proposed rule when the data were collected, the test data were obtained using the test methods in today's proposed rule, and no modifications were made to the process unit or biofilter subsequent to the date the historical data were collected.

3. Emissions Averaging Compliance Option

If you elect to comply with the emissions averaging compliance option in today's proposed rule, you would be required to submit an Emissions Averaging Plan (EAP) to the Administrator for approval. The EAP would describe the process units you are including in the emissions average. The plan also would specify which process units will be credit-generating units and which process units will be debit-generating units. The EAP would also have to include descriptions of the control systems used to generate emission credits, documentation of the total HAP measurements made to determine the RMR, calculations and supporting documentation to demonstrate that the AMR will be greater than or equal to the RMR, and a summary of the operating parameters that will be monitored for the credit-generating units.

Following approval of your EAP, you would be required to conduct performance tests to determine the total HAP emissions from all process units included in the EAP. The credit-generating process units would be equipped with add-on control systems; therefore, for those process units, you would follow the procedures for demonstrating initial compliance as outlined above for add-on control systems. The emissions averaging provisions would require you to conduct all total HAP measurements and performance test(s) when the process units are operating under representative operating conditions. Today's proposed rule defines “representative operating conditions” as those conditions under which the process unit will be typically operating following the compliance date. Representative conditions would include such things as using a

representative range of materials (

e.g.

, wood material of a typical species mix and moisture content, typical resin formulations) and operating the process unit at typical operating temperature ranges.

4. Work Practice Requirements

The work practice requirements in today's proposed rule do not require you to conduct any initial performance tests. To demonstrate initial compliance with the work practice requirements for dry rotary dryers, you would have to install parameter monitoring devices to continuously monitor the dryer inlet operating temperature and the moisture content (dry basis) of the wood furnish (

i.e.

, wood fibers, particles, or strands used for making board) entering the dryer. You would then use the parameter monitoring devices to continuously monitor and record the dryer temperature and wood furnish moisture content for a minimum of 30 days. If the monitoring data indicate that during the minimum 30-day demonstration period, your dry rotary dryer continuously processed wood furnish with an inlet moisture content less than or equal to 30 percent, and the dryer was continuously operated at an inlet dryer temperature less than or equal to 600 °F, then your dryer would meet the definition of a dry rotary dryer in today's proposed rule. You would submit the monitoring data as part of your notification of compliance status report.

To demonstrate initial compliance with the work practice requirements for hardwood veneer dryers, you would have to calculate the annualized percentage of softwood veneer processed in the dryer by volume, using veneer dryer production records for the 12-month period prior to the compliance date. If the total annual percentage by volume of softwood veneer is less than 30 percent, your veneer dryer would meet the definition of hardwood veneer dryer. You would then submit a summary of the production data for the 12-month period and a statement verifying that the veneer dryer will continue to process less than 30 percent softwoods as part of your notification of compliance status report.

To demonstrate initial compliance with the work practice requirements for softwood veneer dryers, you would have to develop a plan for minimizing fugitive emissions from the veneer dryer green end and heated zones. You would submit the plan with your notification of compliance status report.

To demonstrate initial compliance with the work practice requirements for veneer redryers, you would have to install a device that can be used to continuously monitor the moisture content (dry basis) of veneer entering the dryer. You would then use the moisture monitoring device to continuously monitor and record the inlet moisture content of the veneer for a minimum of 30 days. If the monitoring data indicate that your veneer dryer continuously processed veneer with a moisture content less than or equal to 25 percent during the minimum 30-day demonstration period, then your veneer dryer would meet the definition of a veneer redryer in today's proposed rule. You would submit the monitoring data as part of your notification of compliance status report.

H. How Do I Demonstrate Continuous Compliance With This Proposed Rule?

The continuous compliance requirements in today's proposed rule vary with the different types of compliance options.

1. Production-Based Compliance Options

If you comply with the production-based compliance options, then you would have to install a continuous parameter monitoring system (CPMS) to monitor the process operating parameter(s) used to demonstrate compliance with the operating requirements in today's proposed rule. Your CPMS would have to collect data at least every 15 minutes, and you would need to have at least three data points per hour to have a valid hour of data. You would have to operate the CPMS at all times the process unit is operating. You also would have to conduct proper maintenance of the CPMS and maintain an inventory of necessary parts for routine repairs of the CPMS. Using the data collected with the CPMS, you would calculate and record the 3-hour block average values of each process operating parameter.

The process operating parameter you would monitor for green rotary dryers, tube dryers, and strand dryers is dryer inlet temperature. The process operating parameter you would monitor for hardboard ovens, press predryers, reconstituted wood product presses, fiberboard mat dryer hot zones, and softwood veneer dryer hot zones is operating temperature. You would not be required to monitor process parameters for reconstituted wood product board coolers or pressurized refiners. For each temperature parameter, you would have to continuously maintain the 3-hour block average temperature below the maximum temperature established during the performance test.

Instead of operating a CPMS, you could choose to operate a CEMS for monitoring THC concentration to demonstrate compliance with the operating requirements in today's proposed rule. If you choose to operate a THC CEMS in lieu of a CPMS, you would have to demonstrate continuous compliance as described in the following subsection.

2. Add-On Control System Compliance Options

For add-on control systems, you would have to install a CPMS to monitor the specified control device operating parameter(s) or install a CEMS to monitor THC concentration to demonstrate compliance with the operating requirements in today's proposed rule. If you operate a CPMS, it would have to collect data at least every 15 minutes, and you would need to have at least three data points per hour to have a valid hour of data. You would have to operate the CPMS at all times the process unit is operating. You also would have to conduct proper maintenance of the CPMS and maintain an inventory of necessary parts for routine repairs of the CPMS. Using the data collected with the CPMS, you would calculate and record the average values of each operating parameter according to the specified averaging times.

For thermal oxidizers, you would have to continuously maintain the 3-hour block average firebox temperature at or above the minimum temperature established during the performance test. For catalytic oxidizers, you would have to continuously maintain the 3-hour block average temperature upstream of the catalyst bed at or above the minimum value established during the performance test. For both thermal and catalytic oxidizers, you would also have to continuously maintain the 3-hour block average static pressure at the inlet of the thermal oxidizer within the operating range established during the performance test. As an alternative to monitoring static pressure, you may monitor gas flow rate at the oxidizer stack. If you monitor gas flow, you must maintain the 3-hour block average gas flow rate below the maximum flow rate established during the performance test.

For biofilters, you would have to maintain the gas temperature entering the biofilter, effluent pH, and pressure drop across the biofilter bed within the operating ranges you establish. You would establish your biofilter operating parameter limits, their monitoring frequencies, and their averaging times

based on data collected during the initial performance test or during qualifying previous performance tests using the required test methods. If you use values from previous performance tests to establish the operating parameter ranges, you would have to certify that the biofilter and associated process unit(s) have not been modified subsequent to the date the previous data were collected. If previous performance test data are not available (as would be the case for a new biofilter installation) you would be allowed up to 180 days after the compliance date to gather the necessary information and establish your biofilter operating parameter ranges.

If you choose to operate a CEMS for monitoring THC concentration instead of operating a CPMS, you must install, operate, and maintain the CEMS according to Performance Specification 8 in 40 CFR part 60, appendix B. You would also be required to comply with the CEMS data quality assurance requirements in Procedure 1 of appendix F of 40 CFR part 60. You would be required to conduct a performance evaluation of the CEMS according to 40 CFR 63.8 and Performance Specification 8. The CEMS would have to complete a minimum of one cycle of operation (sampling, analyzing, and data recording) for each successive 15-minute period. Using the data collected with the CEMS, you would calculate and record the 3-hour block average THC concentration. You would have to continuously monitor and maintain the 3-hour block average THC concentration at or below the maximum established during the performance test. You may use a CEMS capable of subtracting methane from the measured THC concentration if you wish to do so.

If you comply with today's proposed rule using an add-on control system, you could request a routine control device maintenance exemption from the Administrator. Your request for a routine control device maintenance exemption would have to document the need for routine maintenance on the control device and the time required to accomplish the maintenance, describe the maintenance activities and the frequency of these activities, explain why the maintenance could not be accomplished during process shutdowns, describe how you plan to minimize emissions to the greatest extent possible during these maintenance activities, and provide any other documentation required by the Administrator. If your request for the routine control device maintenance exemption is approved by the Administrator, it would have to be incorporated into your title V permit. The compliance options and operating requirements would not apply during times when control device maintenance covered under your approved routine control device maintenance exemption is performed. The routine control device maintenance exemption may not exceed 3 percent of annual operating uptime for each green rotary dryer, tube dryer, strand dryer, or pressurized refiner controlled. The routine control device maintenance exemption is limited to 0.5 percent of the annual operating uptime for each softwood veneer dryer, reconstituted wood product press, reconstituted wood product board cooler, hardboard oven, press predryer, or fiberboard mat dryer controlled. If your control device is used to control a combination of equipment with different downtime allowances (

e.g.

, a tube dryer and a press), then the highest (

i.e.

, 3 percent) downtime allowance applies.

3. Emissions Averaging Compliance Option

To demonstrate continuous compliance with the emissions averaging provisions, you would have to continuously comply with the applicable operating requirements for add-on control systems (described in the previous subsection). You also would have to maintain records of your operating hours for each process unit included in the EAP. For each semiannual compliance period, you would have to demonstrate that the AMR equals or exceeds the RMR using your initial (or most recent) total HAP measurements for debit-generating units, initial (or most recent) performance test results for credit-generating units, and the operating hours recorded for the semiannual compliance period.

4. Work Practice Requirements

To demonstrate continuous compliance with the work practice requirements for dry rotary dryers and veneer redryers, you would be required to operate all dry rotary dryers and veneer redryers so that they continuously meet the definitions of these process units in today's proposed rule. For dry rotary dryers, you would have to continuously monitor and maintain the inlet furnish moisture content at or below 30 percent and the inlet dryer operating temperature at or below 600 °F. You would also have to manually measure the moisture content of a representative sample of the inlet wood furnish once per day to verify the readings from the moisture meter. For veneer redryers, you would have to continuously monitor and maintain the inlet veneer moisture content at or below 25 percent.

To demonstrate continuous compliance with the work practice requirements for softwood veneer dryers, you would have to follow the procedures in your operating plan for minimizing fugitive emissions from the green end and heated zones of the veneer dryer and maintain records documenting that you have followed your plan. For hardwood veneer dryers, you would have to continue to process less than 30 percent softwood veneer by volume and maintain records on veneer dryer production.

III. Rationale for Proposed Rule

A. How Did We Select the Source Category and Any Subcategories?

The PCWP source category includes the manufacture of many types of wood products, including (but not limited to) plywood, veneer, particleboard, oriented strandboard, hardboard, fiberboard, medium density fiberboard, laminated strand lumber, laminated veneer lumber, wood I-joists, kiln-dried lumber, and glue-laminated beams. During our review of the available information on this source category, we found that the processes used to produce the different types of wood products were more similar than dissimilar with respect to the types of equipment used and the HAP emitted. Published definitions of the various wood products often group several types of products together or overlap with definitions developed for other similar wood products. As the wood products industry continues its relatively high rate of growth, new and different wood products are coming into the marketplace, some of which are hybrids of existing wood products or modified versions of existing wood products. Because the differences between many of the product lines are already somewhat blurred and the equipment that is used to manufacture wood products cuts across industry sectors, we determined that establishing subcategories based on product type was unwarranted and could seriously hamper applicability determinations. Therefore, today's proposed rule does not establish any subcategories under the PCWP source category.

B. How Did We Define the Affected Source?

In today's proposed rule, the affected source is the collection of process units associated with the manufacturing of PCWP at a plant site. The affected

source includes, but is not limited to, those process units found in green end operations, drying operations, blending and forming operations, pressing and board cooling operations, and miscellaneous finishing operations (such as sanding, sawing, patching, edge sealing, and other finishing operations not subject to other NESHAP). The affected source also includes onsite storage of raw materials used in the manufacture of PCWP, such as resins, onsite wastewater treatment operations specifically associated with PCWP manufacturing, and miscellaneous coating operations. The affected source includes lumber kilns at PCWP manufacturing facilities and at any other facility.

Miscellaneous coating operations are activities such as edge coating of PCWP, labeling and printing on PCWP, application of anti-skid coatings, putty/patching operations at plywood facilities, etc. Only those onsite miscellaneous coating operations at PCWP manufacturing facilities that are listed in § 63.2292 of today's proposed rule are covered by these proposed NESHAP. We specifically excluded these miscellaneous coatings operations from the proposed Wood Building Products Surface Coating NESHAP (40 CFR part 63, subpart QQQQ). We included these sources in the definition of affected source for PCWP because these miscellaneous coating operations are part of the PCWP manufacturing process and are performed at the same location.

To provide compliance flexibility, we defined the affected source as the combination of all of the process units at a PCWP manufacturing facility. Many of the PCWP facilities that already control HAP emissions to the levels that would be required in today's proposed rule do so by first combining emissions from different process units and then controlling the combined emissions in one or more emission control devices. Much of the control device efficiency data used to set the proposed compliance options for add-on control systems was based on control equipment that was used to control emissions from multiple types of process units. As a result, the required level of control would be the same for most types of process units. For example, the control level for new and existing reconstituted wood products presses would be the same as the control level for new and existing tube dryers. We believe that the proposed broad definition of affected source is consistent with the way the industry applies add-on control devices, and that it creates more meaningful opportunities for emissions averaging. The affected source definition we selected is the same for both new and existing sources.

The affected source includes lumber kilns co-located at PCWP manufacturing facilities and lumber kilns at other facilities that do not manufacture PCWP (

i.e.

, stand-alone kiln-dried lumber manufacturing facilities such as sawmills). Wood products industry representatives requested that all lumber kilns (regardless of location) be considered in today's proposed rule so there would be one MACT determination for all lumber kilns nationwide.

If lumber kilns at stand-alone kiln-dried lumber manufacturing facilities are not included in the PCWP NESHAP, those stand-alone facilities could be listed as a major source category under section 112(c) of the CAA in the future and may be subject to the provisions of section 112(g) of the CAA as well. We believe no additional emissions reductions would be accomplished by listing lumber kilns as a separate source category or by having them regulated by case-by-case MACT. We believe this because: (1) The design and operation of lumber kilns are essentially the same regardless of whether the kilns are located at a sawmill or co-located with PCWP manufacturing operations, (2) we know of no lumber kilns that are controlled for HAP, and (3) we know of no cost effective HAP controls for lumber kilns. In addition, we know of no additional recordkeeping or reporting that stand-alone facilities would incur by being part of the PCWP source category since the PCWP source category includes only major sources. Including stand-alone kilns in the PCWP source category will save resources for regulatory agencies and industry and does not forego HAP reductions; therefore, we are proposing stand-alone kilns as part of the PCWP source category.

C. How Did We Determine the MACT Floor for Existing Sources?

Section 112(l)(3) of the CAA specifies that each MACT standard be at least as stringent as the floor for the sources in the relevant source category or subcategory. Today's proposed PCWP rule does not have subcategories; therefore, the average emission limitation achieved by the best-performing 12 percent of all major PCWP facilities represents the MACT floor for the source category. In order to rank the PCWP facilities based on performance, we would need facilitywide uncontrolled emissions data and facilitywide controlled emissions data for each facility to determine the percent reduction in HAP emissions achieved by each facility. We do not have actual facilitywide emissions data; however, we have accurate and complete information on the type and number of individual process units at PCWP facilities. In addition, emissions data are based on process unit data. Therefore, we decided to apply the MACT floor methodology at the process-unit level. Our information is especially accurate and complete for dryers and presses, which are generally the highest-emitting process units and the ones most likely to have add-on control systems that reduce HAP emissions from PCWP facilities. With this approach, the sourcewide MACT floor is represented by the MACT floor level of control established for each process unit group. We believe that applying the MACT floor methodology to process unit groups results in the closest possible approximation of the true sourcewide MACT floor, since it better enables us to take into account process unit-specific emissions data. We do not believe the results from this approach are significantly different from what they would be if facilitywide source-specific data had been available.

We determined the MACT floor control level for existing sources using the following procedure:

• We reviewed available data on pollution prevention techniques and the performance of add-on control devices and identified those add-on control systems that were best at reducing HAP emissions;

• For each process unit group identified in Table 1 of this preamble, we ranked the process units in that group from the best performing to the worst performing based on the type of add-on control system applied to each process unit;

• For each process unit group, we then identified the add-on control system that represented the MACT floor technology; and

• Using available information on the performance of the add-on control systems, we determined the performance level of the add-on control systems.

This procedure is explained in more detail in the following paragraphs. Additional information on how we determined the proposed MACT floor for the PCWP industry is available in the docket for this rule (Docket Number A-98-44).

1. Identifying the Best-Performing Add-On Control Systems

Although we believe that the potential for pollution prevention exists for some

facilities in the PCWP industry, we are not aware of any demonstrated pollution prevention techniques that can be universally applied across the industry. Furthermore, we have no information on the degree of emissions reduction that can be achieved through pollution prevention measures. The PCWP facilities use add-on control devices because there currently are no feasible pollution prevention measures. Therefore, we focused our analysis on the performance of add-on control devices. We reviewed the available data on control device performance to determine which add-on control systems are best at reducing HAP emissions. We focused our analysis on THC, formaldehyde, and methanol because these three pollutants are the most prevalent pollutants emitted from the PCWP industry and represent the majority of the available data on control device performance. The design and operating factors that affect a control system's ability to reduce emissions of formaldehyde, methanol, or THC are generally the same. For example, an RTO designed to reduce THC emissions will also reduce formaldehyde or methanol emissions.

Based on a review of the available control device performance data for the PCWP industry, we concluded that only two types of add-on air pollution control devices (APCD) consistently and continuously reduced HAP emissions: incineration-based controls (including RTOs, RCOs, and incineration of pollutants in onsite process combustion equipment used to control emissions from various PCWP process units) and biofilters (used to control PCWP press emissions). The control device efficiency data showed that APCD installed for particulate matter (PM) abatement had no effect on gaseous HAP or THC emissions. These APCD include cyclones, multiclones (or multicyclones), baghouses (or fabric filters), and electrified filter beds (EFB). The performance data for wet electrostatic precipitators (WESP) and wet scrubbers installed for PM control also showed no effect on HAP and THC emissions. These wet systems may achieve short-term reductions in THC or gaseous HAP emissions, however, the HAP and THC control efficiency data, which range from slightly positive to negative values, indicate that the ability of these wet systems to absorb water-soluble compounds (such as formaldehyde) diminishes as the recirculating scrubbing liquid becomes saturated with these compounds.

The performance data for the incineration-based controls and biofilters showed methanol and formaldehyde emissions reductions equal to or greater than 90 percent, except in those cases where the pollutant loadings of the emission stream entering the control systems were very low. The performance data for THC showed that incineration-based control systems could achieve THC emissions reductions equal to or greater than 90 percent. The THC emissions reductions achieved with biofilters varied somewhat, with an average THC reduction of about 80 percent. Although biofilters are less effective in reducing some of the less water-soluble VOC compounds, such as pinenes, that make up a portion of the THC measurements, they can achieve HAP emissions reductions equal to or greater than 90 percent. These emissions reductions are reported only for biofilters treating emissions from presses at PCWP facilities. No PCWP process units other than presses are currently using biofilters to reduce air pollution. Both incineration-based controls and biofilters can achieve identical formaldehyde and methanol emissions reductions.

2. Ranking of Process Units

We ranked the process units within each process unit group according to the HAP control devices that were applied. Information on the number of process units nationwide and the types of add-on control devices applied to process units was based primarily on responses to a survey of the industry.

When we ranked the process units, we treated process units equipped with any type of incineration-based control system or biofilters as being equivalent with respect to their potential to reduce HAP emissions. We ranked the process units by control device rather than actual unit-specific emissions reductions because we have limited inlet/outlet data on which to calculate control efficiency. Based on available information (

e.g.

, RTO operating temperatures), we are not aware of any significant design or operational differences among each type of control system evaluated that would affect the ranking of process units. Furthermore, we are not aware of factors other than the type of control system used that would significantly affect the ranking of process units.

3. Identifying Control Technologies To Establish the MACT Floor

We established MACT floor control levels by applying the floor procedures to similar process units. We believe that this approach results in the closest approximation of the true sourcewide MACT floor.

With a few exceptions, there were at least 30 process units in each process unit group. As discussed in section I.C, when there are at least 30 sources in the source category, the MACT floor for existing sources is equivalent to the average emission limitation achieved by the best-performing 12 percent of existing sources in that group. Our interpretation of the “average emission limitation” is that it is a measure of central tendency, such as the median. If the median is used when there are at least 30 process units in a process unit group, then the emission level achievable by the process unit and its control system that is at the bottom of the top 6 percent of the best-performing process units (

i.e.

, the 94th percentile) represents the MACT floor control level for that component of the sourcewide floor. For example, there are approximately 303 softwood veneer dryers nationwide, and HAP emissions from approximately 64 of these dryers (21 percent nationwide) are controlled using incineration-based control systems. The HAP emissions from the remainder of the softwood veneer dryers are uncontrolled. In this example, the 94th percentile is represented by the control system applied to the softwood plywood dryer ranked at number 18 (18/303 = 6 percent). However, incineration-based controls are also used by softwood veneer dryers ranked below the 94th percentile. Assuming that there are no significant design or operational differences between the different types of incineration-based control systems that would affect their performance, we would consider the incineration-based control technologies as being equivalent for control of HAP emissions. Thus, all of the softwood veneer dryers equipped with incineration-based control systems would be representative of the MACT floor level of control for softwood veneer dryers.

For those process unit groups where there were fewer than 30 but at least five process units, such as hardboard ovens, the emission level achievable by the process unit and its control system that is the median of the best-performing five sources represents the MACT floor level of control. For example, the MACT floor level of control for fiberboard mat dryers is no emissions reductions because there are ten fiberboard mat dryers nationwide, and emissions from only two of the ten fiberboard mat dryers are controlled (both via incineration). Therefore, the top five fiberboard mat dryers include the two that are controlled, plus three that are uncontrolled. In this example, the

median source (the fiberboard mat dryer ranked “number 3”) is uncontrolled.

When a process unit group had fewer than five process units, we determined the appropriate control technology based on the control technology used by the majority of the process units in the process unit group.

For those process units not required to meet the control requirements in today's proposed rule, we determined that: (1) The MACT floor level of control is no emissions reductions, and beyond the floor control options are too costly to be feasible; or (2) insufficient information is available to conclude that the MACT floor level of control is represented by any emissions reductions (miscellaneous coating operations and wastewater operations). We are requesting comment on whether no emissions reductions for miscellaneous coating operations and for wastewater operations is appropriate. Commenters should submit any information they have on HAP or VOC emissions from miscellaneous coatings and wastewater operations.

4. Determining the Performance Level of MACT Floor Technologies

Using the procedures described above, we determined that the proposed MACT floor level of control for process units was either no emissions reductions or equivalent to the emissions reductions achieved by incineration-based control systems or biofilters. Although some process units are equipped with add-on controls that perform at a level somewhere between zero emissions reductions and the performance level achievable with incineration-based controls and biofilters, none of these control systems were identified as MACT floor control technologies because they either do not reduce organic HAP emissions (bag houses) or do so on an inconsistent and unreliable basis (wet electrostatic precipitators). Therefore, we focused our analysis on incineration-based controls and biofilters.

For the purpose of establishing the performance level of the MACT floor control systems, we decided to group all of the available data on incineration-based controls and biofilters together. We grouped all the data together because the available data for incineration-based controls is incomplete. Without complete data, we could not identify which were the best performing incinerators; therefore, we could not identify the top performing 12 percent. By considering all of the performance data together, we maximized the amount of available data on which we could base the MACT floor level of performance.

The reasons the available data are incomplete are: Multiple emission points are treated, inlet/outlet data are limited, data among pollutants vary, and pollutant loadings are variable. These are discussed below.

Multiple emission points treated.

Some of the control systems treat HAP emissions from multiple types of process units, such as tube dryers, reconstituted panel presses, and board coolers. In those cases, separate determinations of the performance of the control system on emissions from each type of process unit were not possible.

Limited inlet/outlet data.

Limited or no inlet/outlet data were available for the control systems applied to the process units in each group.

Variability in data among pollutants.

In some cases, it was not possible to directly compare the performance of different control systems because data were not available for the same pollutant. For example, for one RTO, we might only have THC emissions data, and for another RTO, we might only have formaldehyde data.

Variability in pollutant loadings.

Our ability to compare the performance of the different types of incineration-based control systems with each other and with biofilters was also hampered by the fact that the uncontrolled emissions being treated by the different control systems varied with respect to pollutant loading (inlet concentration) and pollutant type. For example, the available THC concentration data for the inlet of the control systems ranged from as low as 45 ppmvd to as high as 5,100 ppmvd. With the exception of some control systems with lower pollutant inlet concentrations, the available data for incineration-based controls and biofilters show that these control systems can achieve THC, methanol or formaldehyde emissions reductions greater than or equal to 90 percent.

We considered basing the control system performance level on just one pollutant, such as THC as a surrogate for HAP. Many of the existing PCWP facilities with MACT control systems are already required to meet a specified VOC control efficiency, and these facilities generally measure THC emissions as a surrogate for VOC emissions. Source VOC mass emissions (as required in new source review or prevention of significant deterioration reviews and emission limits for VOC by definition) must be expressed on a mass basis. This requires an adjustment for other compounds, such as formaldehyde, to the measured THC emissions. However, THC emissions data sometimes include methane which is neither a HAP nor a VOC. The THC emissions data also frequently include other non-HAP compounds, such as terpenes, which are associated with processing of softwoods. We also considered basing the control system performance level on HAP, measured as total HAP, or methanol as a surrogate for HAP, or formaldehyde as a surrogate for HAP. Methanol and formaldehyde are the predominant HAP emitted from PCWP process units, and they can be measured directly. However, not all process units emit formaldehyde at detectable levels, and not all process units emit methanol at detectable levels, so basing the performance level only on methanol or only on formaldehyde was not possible. For process units where both the methanol and formaldehyde emissions are low, THC emissions may be the only viable option for defining the control system performance. We rejected basing the control system performance level on total HAP emissions because it seemed overly burdensome to require testing of multiple pollutants at the outlet of a control device when testing of one dominant pollutant would be sufficient for determining control device performance. Furthermore, the total HAP control efficiency could be negatively affected by those measurements for HAP not detected at either the inlet or outlet of the control device (

e.g.

, the method detection limit used in the calculation of total HAP control efficiency may be slightly higher at the inlet than the outlet resulting in decreased total HAP control efficiency).

Another consideration in determining the performance level that represents the MACT floor level of control is the format of this performance level (

e.g.

, percent reduction, outlet concentration level). In general, applying an incineration-based MACT control system to a process unit that emits high concentrations of HAP and THC will result in a greater percentage of emissions reductions than if that same incineration-based MACT control system was applied to a process unit that emits lower concentrations of HAP and THC. Therefore, a performance level solely in the form of a percent reduction in emissions could not adequately characterize the performance level of the MACT floor control technology. In similar MACT rulemakings where incineration-based control technologies represent the MACT floor, we have defined the performance level of the incineration-based control technologies as either a

percent reduction or an outlet concentration, whichever is less stringent, with both forms being considered equivalent to the other. We have recognized in these previous MACT rulemakings that there are practical limits to the ability of incineration-based control systems to treat more dilute emission streams. We consider the practical limit of control of THC via incineration to be approximately 20 ppmvd in the outlet of the control device.

To account for the variability in the type and amount of HAP in the uncontrolled emissions from the various process units and the effect of this variability on control system performance, we decided to base the MACT floor performance level on all three of the pollutants we analyzed and include maximum concentration levels in the outlet of the control systems as an alternative to emissions reductions. The MACT floor performance level is a 90 percent reduction in THC or methanol or formaldehyde emissions. The maximum concentration level in the outlet of the MACT floor control system is 20 ppmvd for THC, or 1 ppmvd for methanol, or 1 ppmvd for formaldehyde. We chose 20 ppmvd as the alternative maximum concentration for THC because 20 ppmvd represents the practical limit of control for THC. We chose 1 ppmvd as the maximum outlet concentration for both methanol and formaldehyde because this concentration is achievable by MACT control systems and the method detection limits for these compounds using the NCASI impinger/canister method (NCASI Method IM/CAN/WP-99.01, proposed to be incorporated by reference in today's proposed rule) are less than 1 ppmvd. Based on the available data for MACT control systems, these six emission levels for add-on control systems are considered equivalent options for defining the performance level of a MACT control system.

D. How Did We Determine the MACT Floor for New Sources?

For new sources, the CAA requires the MACT floor to be based on the degree of emissions reductions achieved in practice by the best-controlled similar source. We believe for most process unit groups that the existing source MACT floor control level also represents the level of control appropriate for new sources because the same types of emission control systems, such as thermal oxidizers and biofilters, are used. In these cases, the existing source MACT floor technology represents the greatest degree of emissions reductions that is achievable under all circumstances within each particular operation regulated by the proposed rule. For a few process units, the MACT floor level of control for new units is more stringent than for existing units. In those cases, we determined the MACT floor control level for existing process units was no emissions reductions, and that the MACT control level for new sources was represented by incineration-based controls or biofilters.

E. What Control Options Beyond the MACT Floor Did We Consider?

The control devices that represent the MACT floor control level achieve the greatest HAP emissions reductions of any available control technologies. There are no controls that achieve greater emissions reductions than the MACT floor control level for process unit groups with MACT floor control levels represented by incineration-based controls or biofilters; therefore, we only looked at beyond the floor options for process unit groups at existing sources where the MACT floor level of control was no emissions reductions. Process units that were inherently lower-emitting, such as sanding and sawing operations, were excluded from the beyond-the-floor analyses because emissions from these process units would not be cost effective to control. Based on a review of the HAP emissions data for process units where the MACT floor level of control was determined to be no emissions reductions, we selected blenders and stand-alone digesters for a beyond-the-floor analysis because these process units emit higher levels of HAP emissions relative to other process units. We also conducted beyond-the-floor analyses for three process unit groups with no emissions reductions at the MACT floor control level for existing sources but requiring control for new sources. These process units included fiberboard mat dryers, press predryers, and board coolers. We determined that the environmental benefits of requiring controls for these process units did not justify the cost. Moreover, many of the existing control devices at well-controlled facilities would not have the additional capacity to treat the emissions from these process units, and thus, these facilities would have to install new controls. Therefore, we decided that the control level for blenders, stand-alone digesters, fiberboard mat dryers, press predryers, and board coolers should be no emissions reductions at existing sources.

F. How Did We Select the Format of the Proposed Rule?

We decided to offer several formats for complying with today's proposed rule. The purpose of multiple formats is to provide you the flexibility to comply in the most cost-effective and efficient manner. We considered the following factors in selecting the format of the proposed rule:

• The format should allow for multiple compliance techniques for the various types of facilities in the industry.

• The format should simplify compliance and ensure that the cost of compliance is not excessive.

• The format must be enforceable.

The format of this proposed rule is based on a combination of production-based compliance options, percent emissions reduction compliance options, pollutant concentration compliance options, and work practice requirements. We are also including emissions averaging as an option for complying with the proposed rule. The following subsections describe the selection of the formats for each compliance option and work practice requirement included in the proposed rule.

1. Production-Based Compliance Options

The production-based total HAP compliance options apply to process unit emissions prior to entering an add-on control system. This option allows for future pollution prevention techniques and cost-effective control of inherently lower-emitting process units. The production-based compliance options were determined by applying a 90 percent reduction to the highest total HAP test for each type of process unit with a controlled MACT floor. A 90 percent reduction was selected because it is equivalent to the emissions reductions achievable through the use of MACT. The 90 percent reduction was applied to the highest tests rather than the average emission factors because the production-based options calculated using the highest tests more closely correlate with actual emissions from process units with MACT control systems. If the average emission factors were used in the calculation of the production-based compliance options, some of the process units with MACT control systems would not be capable of meeting those options. Use of statistical methods for predicting the highest test value likely to be observed for each process unit was also considered. However, the available total HAP test data sets are too small to justify use of

such statistical methods, and the resulting compliance options, in many cases, seemed unreasonably high compared to the actual emissions from process units with MACT control systems. Therefore, statistical methods were not used. We based the production-based compliance options on total HAP emissions, as defined in today's proposed rule, because of the variability in uncontrolled HAP emissions within and among the different types of process units. Total HAP emissions varied less than the emissions of individual HAP and the emissions of THC.

2. Add-On Control System Compliance Options

The six compliance options for add-on control systems in today's proposed rule are based on the performance of incineration-based control systems and biofilters. We included two formats in these compliance options: Emissions reductions (percent) and maximum outlet pollutant concentrations. Many of the well-controlled facilities are already subject to permit limits that are in the form of a percent reduction in emissions. Therefore, we expect that some of those facilities may choose to comply with an emissions reduction option. We are also including outlet concentration options so that sources that have lower inlet pollutant concentrations (and thus, have lesser ability to achieve higher emissions reductions) can demonstrate compliance. We consider the emissions reduction options and the outlet concentration options to be equivalent limits. We are not requiring an oxygen correction to the outlet concentration options because most of our outlet concentration data were measured at ambient oxygen levels due to the relatively dilute emission streams being treated. Dilution to achieve compliance with the proposed PCWP rule is prohibited by 40 CFR 63.4.

We are restricting the use of the formaldehyde and methanol concentration-based options to only those sources with formaldehyde or methanol emissions entering the control device that are greater than 10 ppmvd. We have included this restriction to prevent circumvention of the proposed standards. For example, if a process unit emits primarily formaldehyde and only a very small amount of methanol (slightly less than 1 ppmvd), without the 10 ppmvd restriction, you could demonstrate compliance with the 1 ppmvd methanol concentration option without using a control system or using a control system that does not reduce HAP, such as a baghouse. The 10 ppmvd restriction does not apply to the percent reduction compliance options.

3. Emissions Averaging Compliance Option

Today's proposed rule includes an emissions averaging compliance option because we believe that emissions averaging represents an equivalent, more flexible, and less costly alternative to controlling certain emission points to MACT floor levels. Prior to an industry-sponsored emissions test program carried out by NCASI, the majority of the available emissions test data for the PCWP industry was limited to THC and formaldehyde emissions data for dryers and presses. The industry-sponsored test program provided speciated HAP emissions data for a variety of process units at 29 different PCWP plants. For some of these previously untested process units, the NCASI data represent the only available HAP emissions data for those sources. A few of these process units, such as blenders, may emit quantities of HAP equal to or greater than the quantities emitted from some types of dryers and presses. In addition to emitting more HAP, these other types of process units often have a lower volume of exhaust gas to be treated compared to dryers and presses. The combination of higher pollutant concentrations and lower exhaust gas flow rates may make these other process units more cost effective to control. However, very few PCWP facilities have installed emission control devices on process units other than dryers and presses. Therefore, when determining the MACT floors for existing process units, the process units most likely to have controlled MACT floors have been dryers and presses, with some exceptions. Most other types of process units are largely uncontrolled throughout the industry and based on our MACT analysis, we did not include existing source control requirements for these process units in today's proposed rule. Therefore, emissions from these other types of process units at existing sources would not be controlled under the point-by-point compliance options in today's proposed rule. By allowing emissions averaging across the affected source, which is broadly defined in today's proposed rule, sources can achieve the same environmental gains as point-by-point compliance, but at reduced cost.

The emissions averaging provisions in today's proposed rule are based in part on the emissions averaging provisions in the Hazardous Organic NESHAP (HON). The legal basis and rationale for the HON emissions averaging provisions were provided in the preamble to the final HON (59 FR 19425, April 22, 1994). The rationale for including certain limitations and requirements as part of today's emissions averaging provisions follows the HON and is summarized below.

Emission points allowed in emissions averaging.

Only those emission points (process units) that are part of the affected source (PCWP manufacturing facility), as defined in today's proposed rule, can be included in an emissions average. Therefore, a PCWP facility collocated with a pulp and paper mill, for example, cannot include emission points in the pulp and paper mill as part of the emissions average.

Today's proposed rule also excludes new affected sources from the proposed emissions averaging provisions. Today's proposed rule defines affected sources broadly, such that a new source is essentially a whole new “green field” mill. Therefore, not allowing emissions averaging at new sources does not affect existing sources' ability to use emissions averaging. New sources have historically been held to a stricter standard than existing sources because it is most cost effective to integrate state-of-the-art controls into equipment design and to install the technology during construction of new sources. One reason we allow emissions averaging is to give existing sources flexibility to achieve compliance at diverse points with varying degrees of control already in place in the most cost-effective and technically reasonable fashion. This concern does not apply to new sources which can be designed and constructed with compliance in mind.

Today's proposed rule also excludes from emissions averaging any process units equipped with emission control systems that were installed to comply with a State or Federal rule or statute (other than today's proposed rule). We are including this restriction because credits for controls applied to comply with another rule increase your ability to generate credits, but do not generate any new emissions reductions, thus creating more emissions. However, if a process unit in your approved EAP used to generate emission credits later becomes subject to a State or Federal rule other than the proposed PCWP rule, the process unit can continue to generate credits in the approved plan. Work practice requirements are excluded from emissions averaging because, by definition, the level of emissions reduction achieved by compliance with those requirements is not sufficiently quantifiable.

Limits on credit for control efficiencies.

The proposed emissions averaging provisions limit the value of

the control system efficiency (CD

i

) to 90 percent in the equation for calculating the AMR of total HAP from all process units generating credits. No credit above 90 percent is allowed.

Differences from the HON emissions averaging approach.

Some aspects of the HON emissions averaging approach have not been included in the proposed PCWP rule. Specifically, today's proposed rule does not limit the number of emission points allowed in an emissions average, does not require a hazard or risk analysis, and does not include a discount factor. The HON limited the number of emission points that could be used in an emissions average because of significant enforcement concerns. The HON sources have many emission points, are complex and diverse, and as a result are subject to a more complex set of emissions averaging provisions. The PCWP facilities have fewer emission points within each facility. Therefore, the enforcement concerns arising due to the large number of emission points in each HON facility are minimized for PCWP facilities. As a result, we believe a simpler set of emissions averaging provisions is appropriate for PCWP facilities, and the limitation on the number of points available for averaging was not included in the proposed rule.

The HON requires a hazard and risk study for emission points included in an emissions average largely because of the many pollutants and many emission points at the source. The PCWP facilities have fewer pollutants of concern and are likely to have similar HAP emissions from the emission points that would be used to generate debits and credits. Thus, we believe that averages will achieve a comparable hazard/risk benefit as point-by-point compliance. Although States would still have the discretion to require a PCWP facility that requested approval of an emissions average to conduct a hazard and risk study (or preclude the facility from using emissions averaging altogether), the proposed rule does not require a hazard or risk study.

The HON requires a discount factor of 10 percent in credit calculations to share with the environment some portion of the cost savings due to emissions averaging and to account for uncertainty in emissions estimation. Due to differences between PCWP and HON sources (discussed below), we do not believe it is necessary for the proposed PCWP rule to include a discount factor.

The HON proposal preamble (57 FR 62652, December 31, 1992) and the HON final preamble discuss how cost savings due to emissions averaging should be shared between industry and the environment. For the HON, we decided that it was appropriate that industry share any cost savings realized from emissions averaging and included a discount factor because the costs of controlling different emission points could vary significantly. The HON proposal preamble also discussed the level of uncertainty in estimating emissions reductions that may result from facilities using emissions averaging. For the HON, the uncertainty arose from differing accuracies available for estimating emissions from the number of emission points at a HON facility, the number of HAP emitted from HON facilities, and the different types of emission points.

The PCWP industry differs in almost every relevant factor from the HON. First, HON facilities can cover several square miles and some emission points, such as storage vessels, could be some distance from other emission points making them relatively costly to control. Second, as discussed previously, the number of points that might be included in an emissions average at a PWCP facility is fewer than could be included in a HON average and, therefore, less of a concern. Third, the magnitude of emissions from HON emission points is typically much greater than the emissions from PCWP emission points. Fourth, there are six HAP of primary concern emitted from PCWP facilities compared to over 140 HAP emitted from HON facilities. Fifth, the kinds of emission points found at PCWP facilities are much more similar than those regulated by the HON and, therefore, unlikely to introduce additional uncertainty.

We believe the inclusion of emissions averaging into rules and the decision on how to design an emission averaging approach for a particular source category must be evaluated for each source category. Although the HON and the proposed PCWP rule share the same legal basis for including emission averaging as a compliance option and the same basic system of credits and debits, some of the restrictions reasonable for the HON emissions averaging provisions are unnecessary for the proposed PCWP rule.

4. Work Practice Requirements

Section 112(h) of the CAA states that “* * * if it is not feasible in the judgement of the Administrator to prescribe or enforce an emission standard for control of a hazardous air pollutant or pollutants, the Administrator may, in lieu thereof, promulgate a design, equipment, work practice, or operational standard, or combination thereof * * *” Section 112(h)(2) further defines the phrase “not feasible to prescribe or enforce an emission standard” as any situation in which “* * * a hazardous air pollutant or pollutants cannot be emitted through a conveyance designed and constructed to emit or capture such pollutant, * * * or the application of measurement methodology to a particular class of sources is not practicable * * *”

Today's proposed rule includes work practice requirements for softwood veneer dryers, dry rotary dryers, hardwood veneer dryers, and veneer redryers. The proposed work practice requirements for softwood veneer dryers include a requirement to minimize fugitive emissions from the veneer dryer doors and the green end of the dryer. It is not practical for sources to measure the fugitive emissions from the softwood veneer dryers; therefore, in lieu of establishing an emission limit for fugitive emissions, we are proposing that sources develop a plan for minimizing these emissions and keep records to document they are following their plan.

For dry rotary dryers, hardwood veneer dryers, and veneer redryers, the proposed work practice requirements would establish limits on how these process units are operated and the types of materials processed in these units. The MACT floors for dry rotary dryers, hardwood veneer dryers and veneer redryers are all equivalent to no emissions reductions because none of these process units have add-on control devices. The emissions from these three types of process units are relatively low compared to the emissions from other PCWP process units subject to today's proposed rule. However, if these three types of process units were operated in a manner that was inconsistent with how they are defined in today's proposed rule, the emissions from these process units could increase.

For example, a green rotary dryer, which has proposed compliance options in today's proposed rule, is essentially the same in terms of equipment as a dry rotary dryer. However, a dry rotary dryer emits much less HAP than a green rotary dryer because it dries wood particles that have been previously dried to some extent; thus, much of the HAP present in the wood has already been released. The dry rotary dryers also operate at lower temperatures, which further reduces the amount of HAP emitted. Therefore, the operation of the rotary dryer, and not the equipment design, determines whether it is classified as a green or dry rotary dryer. Because the dry rotary dryers, veneer redryers and hardwood veneer dryers

are defined and classified based on how they are operated, and we made MACT floor determinations based on those classifications, we believe that proposing work practice requirements (such as continuously monitoring dryer temperature and wood moisture content) that ensure that these process units continuously operate as defined in today's proposed rule is more appropriate than proposing compliance options for these process units.

G. How Did We Select the Test Methods for Determining Compliance With the Proposed Rule?

Today's proposed rule would require you to conduct performance tests to demonstrate compliance with the production-based compliance options, compliance options for add-on control devices, and the emissions averaging alternative. Depending upon which compliance option you use, you would be required to measure emissions of methanol, formaldehyde, THC, or total HAP. When determining compliance with compliance options for presses and board coolers, you also would be required to determine the capture efficiency of the enclosures for those presses and board coolers that have enclosures that do not qualify as PTE. For presses and board coolers that have partial enclosures or no enclosures, you must determine the capture efficiency of the emissions capture device by installing a TTE as described in EPA Method 204 or using the tracer gas method as described in Appendix A to today's proposed rule. The test methods you would have to use to measure these pollutants and capture efficiency are discussed below.

We are proposing the use of EPA Method 25A (Determination of Total Gaseous Organic Matter Concentration Using a Flame Ionization Analyzer) for measuring THC emissions because most of the PCWP facilities that are already required to measure THC emissions use this method. Also, most of the available emissions data that we used to establish THC control efficiencies for the various control systems were measured using Method 25A and reported on an “as carbon” basis. Method 25A is better suited than EPA Method 25 (Measurement of Total Gaseous Nonmethane Organic Emissions as Carbon (TGNMO)) for measuring emission streams from PCWP process units which typically have lower THC concentrations (

e.g.

, less than 50 ppm) and relatively high moisture contents. However, unlike Method 25, Method 25A does measure methane as a THC. Because many of the well-controlled PCWP facilities are required by permit to reduce VOC emissions, these facilities generally are allowed to subtract methane emissions from the THC measurement when reporting VOC emissions because methane is not a VOC, according to EPA's definition of VOC. Therefore, we also would allow you to subtract methane emissions from measured THC values using EPA Method 18 (Measurement of Gaseous Organic Compound Emissions by Gas Chromotography). Method 18 is a self-validating method.

We are proposing the use of the NCASI Method (NCASI Method CI/WP-98.01, Chilled Impinger Method for Use at Wood Products Mills to Measure Formaldehyde, Methanol, and Phenol, 1998) for measuring methanol or formaldehyde. We are also proposing the NCASI Chilled Impinger Canister Method (NCASI Method IM/CAN/WP-99.01) for measuring total HAP emissions. Total HAP emissions are defined, for purposes of today's proposed rule, as the sum of the emissions of acetaldehyde, acrolein, formaldehyde, methanol, phenol, and propionaldehyde. The NCASI Chilled Impinger Method (NCASI Method CI/WP-98.01), which we are proposing to incorporate by reference, has been validated (using EPA Method 301 criteria) for measuring formaldehyde, methanol, and phenol from dryers and press vents at PCWP facilities. The NCASI Method IM/CAN/WP-99.01, which we are proposing to incorporate by reference (pending EPA review of the method), is a self-validating method that can be used to measure numerous HAP compounds.

As an alternative to the NCASI methods, we are proposing use of other applicable EPA test methods in order to increase the flexibility of the proposed rule. You could use EPA Method 320 (Measurement of Vapor Phase Organic and Inorganic Emission by Extractive FTIR) to measure emissions of methanol, formaldehyde and total HAP. Method 320 is a self-validating method that uses Fourier transform infrared (FTIR) spectroscopy. You could also use EPA Method 308 (Procedure for Determination of Methanol Emission from Stationary Sources) for measuring emissions of methanol. Method 308 predates the NCASI Chilled Impinger Method and the NCASI Impinger Canister Method and has been used to test PCWP emission sources in the past. You could use EPA Method 0011 (Sampling for Selected Aldehyde and Ketone Emissions from Stationary Sources) or EPA Method 316 (Sampling and Analysis for Formaldehyde Emissions from Stationary Sources in the Mineral Wool and Wool Fiberglass Industries) to measure formaldehyde emissions. Although EPA Method 0011 has not been validated for use in the PCWP industry, it predates the NCASI methods and EPA Method 320 and is frequently used to measure formaldehyde emissions from PCWP process units. A comparison of formaldehyde measurements made using the NCASI methods and EPA Method 0011 showed no significant differences (see Docket number A-98-44); therefore, we would allow you to use EPA Method 0011 as an alternative to the NCASI Methods for measuring formaldehyde. Although EPA Method 316 has not been validated for testing of PCWP process units, it is a relatively new method for measuring formaldehyde concentrations as low as 11 parts per billion. Therefore, it is included as an alternative to the other test methods for formaldehyde in today's proposed rule.

We are proposing the use of EPA Method 204 (Criteria for and Verification of Permanent or Temporary Total Enclosure) and Methods 204A through 204F for determining the capture efficiency of enclosures. Methods 204A through 204F include the following: Method 204A—Volatile Organic Compounds Content In Liquids Input Stream; Method 204B—Volatile Organic Compounds Emissions In Captured Stream; Method 204C—Volatile Organic Compounds Emissions In Captured Stream (Dilution Technique); Method 204D—Volatile Organic Compounds Emissions In Uncaptured Stream From Temporary Total Enclosure; Method 204E—Volatile Organic Compounds Emissions In Uncaptured Stream From Building Enclosure; and Method 204F—Volatile Organic Compounds Content In Liquid Input Stream (Distillation Approach). If the enclosure meets the definition and criteria in EPA Method 204 for a PTE, then you may assume that its capture efficiency is 100 percent. If the enclosure is not a PTE, then you would have to build a total temporary enclosure (TTE) around the process unit that meets the definition of a TTE in EPA Method 204, and you would be required to determine the capture efficiency of the TTE using Methods 204A through 204F (as appropriate). You would then have to measure emissions from both the control device (if applicable) and the TTE and use the combined emissions to determine compliance. If the process unit is uncontrolled, you would have to use the capture efficiency of the TTE in determining the uncontrolled emissions from the process unit.

Industry representatives have expressed concern with using EPA Methods 204 and 204A through F for determining capture efficiency of press enclosures. The industry representatives have indicated that some facilities may have difficulty retrofitting a PTE or TTE that meets the EPA Method 204 criteria. Partial enclosures may be able to achieve high capture. We recognize the need for flexibility in determining capture efficiency for PCWP press enclosures and, therefore, as an alternative to Methods 204 and 204A through F, we are working with PCWP industry representatives to develop and propose a tracer gas procedure that may be used to determine the capture efficiency of PCWP press partial enclosures. This alternative tracer gas procedure is provided as Appendix A to today's proposed rule. This procedure would be applicable for determination of capture efficiency for press enclosures that are not considered to be PTE as defined in EPA Method 204, and the procedure is proposed as an alternative to the construction of TTE. Sulfur hexafluoride (SF6) is used as a tracer gas. This gas is not indigenous to the ambient atmosphere and is nonreactive. The alternative tracer gas procedure provided as Appendix A to today's proposed rule is a “work in progress.” Industry representatives are testing the tracer gas procedure and are expected to provide data and feedback that may be used in revising the procedure if necessary. Discussions with industry representatives regarding development of the proposed alternative tracer gas procedure are documented in Docket A-98-44. We welcome your comments on the proposed alternative tracer gas procedure. We also welcome your comments on additional approaches for determining capture efficiency, such as the use of computational fluid dynamics (CFD) models or other methods that would meet the data quality objective (DQO) or lower confidence limit (LCL) statistical criteria outlined in Appendix A to subpart KK of 40 CFR part 63 (National Emission Standards for the Printing and Publishing Industry). Today's proposed rule would allow facilities to petition the Administrator for use of alternative test methods.

H. How Did We Select the Monitoring and Recordkeeping Requirements?

We are proposing monitoring and recordkeeping requirements based on a combination of general monitoring and recordkeeping requirements in the NESHAP General Provisions (40 CFR part 63, subpart A) and specific monitoring methods already in use at PCWP plants. The proposed monitoring requirements we selected pertain to the operating requirements for control devices and the work practice requirements for various dryers.

The proposed recordkeeping requirements include submitting a copy of each notification and report, as well as documentation supporting any Initial Notification or Notification of Compliance Status, according to the requirements in § 63.10(b)(2)(xiv). You would also have to keep the records specified in § 63.6(e)(3) related to startup, shutdown, and malfunction (SSM), records of performance tests, as required in § 63.7(g)(1), and records for each continuous monitoring system (CMS), including CPMS or CEMS. The records for the CMS would include records of the applicable operating requirements and monitoring data required in today's proposed rule. You also would have to keep records to demonstrate compliance with any work practice requirements that apply to you.

How we selected the specific proposed monitoring and recordkeeping requirements is discussed in the following subsections.

1. Control Device Parameter Monitoring and Recordkeeping Requirements

According to today's proposed rule, you would have the option of either monitoring control device operating parameters or operating a THC CEMS at the control device outlet to demonstrate continuous compliance with the operating requirements. The operating parameters for thermal oxidizers, catalytic oxidizers, and biofilters were selected based on information from the questionnaire responses and information from other source categories regarding the parameters that are currently used as reliable indicators of control device performance.

For thermal oxidizers, we would require monitoring for the temperature in the firebox or in the ductwork immediately downstream of the firebox. A sufficiently high temperature in the firebox helps to ensure complete combustion of pollutants. We also would require you to monitor the static pressure at the inlet of the thermal oxidizer as an indicator of capture efficiency and the process unit exhaust flow rate entering the thermal oxidizer. You may monitor gas flow rate at the thermal oxidizer stack as an alternative to monitoring static pressure. Monitoring of gas flow or static pressure can alert the operator to problems such as plugging of the thermal oxidizer. Parameter monitoring would not be required for combustion units with greater than or equal to 44 MW heat input capacity that accept process exhausts into the flame zone.

For catalytic oxidizers, we would require monitoring of the temperature at the inlet of the catalyst bed. The rate at which pollutants in the exhaust stream are oxidized on the catalyst is greatly affected by temperature, as well as other parameters (such as residence time and turbulence) that are fixed by the design of the catalytic oxidizer. Monitoring of the inlet temperature to the catalytic oxidizer helps to ensure that the system is operating as designed with a temperature high enough to oxidize the pollutants. As for thermal oxidizers, we also would require you to monitor the static pressure at the inlet of the catalytic oxidizer or stack gas flow rate.

If you operate a thermal oxidizer or catalytic oxidizer, you would be required to calculate and record 3-hour block averages of the operating parameter values. We selected the 3-hour averaging time because the initial performance test provisions in today's proposed rule require you to perform a minimum of three 1-hour test runs, and the control device operating requirements would be based on the average values obtained using all test data obtained during the performance test. Each 3-hour average parameter value must remain within the level established during the performance test in order for you to demonstrate continuous compliance with the operating requirement.

The proposed operating parameters for biofilters are based on information about parameters currently monitored for biofilters operated in the PCWP industry and on information supplied by a biofilter vendor. For biofilters, you would be required to monitor the following parameters to demonstrate continuous compliance: (1) Temperature of the air stream entering the biofilter, (2) pressure drop across the media bed, and (3) pH of the effluent. Monitoring temperature and pH help determine the health of the microorganism population. Extremes in either temperature or pH can slow or halt microbial activity. Monitoring the pressure drop across the biofilter can alert the operator to problems such as plugging or drying of the bed media. Because factors that affect the performance of biofilters and biofilter monitoring methods can be site specific, you would be allowed to establish your biofilter operating parameter requirements and their corresponding monitoring methods, monitoring frequencies, and averaging times based on historical biofilter operating records. We allow the use of historical records in setting the biofilter parameter limits

because establishing limits during a 3-hour performance test may not adequately identify acceptable operating ranges for biofilter parameters. Some facilities in the PCWP industry have been operating biofilters for years, and these facilities have learned through experience the most appropriate monitoring methods, monitoring frequencies, and optimal operating ranges for their biofilters. Because historical biofilter operating records may not be available for some biofilters (such as new biofilter installations), today's proposed rule would allow up to 180 days following the compliance date for the necessary operating data to be gathered for use in setting parameter requirements. To ensure compliance, all historical operating data used to establish the operating parameter limits must be accompanied by performance test data for the same time period that show that the biofilter was meeting the emission limits in today's proposed rule, and that the data were collected using the test methods in today's proposed rule. In addition, you would have to certify that no modifications have been made to the biofilter or associated process unit(s) subsequent to the date the historical data were collected. Because there are only a few biofilters operating in the PCWP industry and we have limited information on how changes in biofilter operating parameters affect biofilter performance, we welcome your comments on these proposed monitoring requirements for biofilters.

If you operate a control device other than a thermal oxidizer, catalytic oxidizer, or biofilter, you would be required to petition the Administrator for site-specific operating parameters to indicate proper operation and continued performance of the control device. You would establish the operating parameter values during the performance test and maintain the parameters within the range established during the performance test. The Administrator would determine whether maximum value, minimum value, or a range of operating parameters is appropriate. The Administrator would also determine the appropriate averaging time for each monitoring parameter for the control device.

If you comply with the production-based compliance options, then you would be required to continuously monitor a process operating parameter (temperature). You would monitor dryer inlet temperature for green rotary dryers, tube dryers, or strand dryers. You would monitor operating temperature for hardboard ovens, press predryers, reconstituted wood product presses, fiberboard mat dryer hot zones, and softwood veneer dryer hot zones. You would not be required to monitor process parameters for reconstituted wood product board coolers or pressurized refiners. We request comment on whether the temperature parameters are appropriate for monitoring to show compliance with the production-based compliance options. The production-based compliance options were developed for inherently low-emitting process units or process units using pollution prevention. We believe that process unit HAP emissions are somewhat dependent on dryer or press temperature; however, other factors such as resin HAP content and percent of furnish that enters the plant already dried may also affect HAP emissions. It is not clear what pollution prevention techniques will be used to comply with the production-based compliance options (partly because pollution prevention measures are expected to evolve in the future), therefore, we request your feedback on how facilities that will use pollution prevention could show continuous compliance with the production-based compliance options.

Instead of monitoring process or control system operating parameters for thermal oxidizers, catalytic oxidizers, biofilters, or other control systems, you could choose to monitor THC concentration with a CEMS at the control device outlet to show compliance with the operating requirements. If you use a THC CEMS, you would be required to maintain the average THC concentration at the control device outlet below the maximum THC concentration established during the performance test. The purpose of monitoring THC concentration is to show compliance with the operating requirements (as opposed to the compliance options); thus, you could use the THC CEMS instead of CPMS regardless of whether you demonstrate compliance with the THC, formaldehyde, methanol, or total HAP compliance options. For example, you could conduct a performance test to show that you reduce formaldehyde by 90 percent while simultaneously operating the THC CEMS to determine the maximum 3-hour block outlet THC concentration that would become your parameter value representing your operating requirement. Generally, the same parameters that affect control device formaldehyde, methanol, or total HAP reduction efficiency also impact the THC reduction efficiency; thus, we believe that allowing use of a THC CEMS instead of a operating CPMS to demonstrate continuous compliance with the operating requirements is appropriate. If you choose to do so, you may subtract methane from the THC concentration measured with your THC CEMS (

e.g.

, by using a CEMS that measures TGNMO).

Control device maintenance requirements vary significantly from facility to facility. Although we believe that most of the maintenance activities can be accomplished during scheduled facilitywide or partial shutdowns, we recognize that some facilities may need to perform more maintenance on their control systems than other facilities due to site-specific factors, such as the nature and quantity of particulate entering an RTO or the ability of an RTO to perform online bakeouts (a feature often incorporated into newer RTO designs).

The most widely used add-on control systems at PCWP facilities are RTO, RCO, and biofilters. As with any control device in any industry, these control devices require routine maintenance. Routine maintenance includes activities such as cleaning or replacement of corroded parts, media replacement, bakeouts (RTO and RCO), washouts (RTO and RCO), and cleaning of ducts. Some PCWP drying processes release particulates and salts that can plug and weaken RTO and RCO media beds. Frequent bakeouts and washouts are necessary to combat the particulate and salt buildup. Partial or total media replacement is done when bakeouts and washouts are no longer effective.

Plywood and composite wood products industry representatives have requested that today's proposed rule include a downtime allowance that would allow process units to operate while the control device is offline for routine maintenance. After considering the available data, we included in today's proposed rule a routine control device maintenance exemption. To obtain the exemption, you must explain to the Administrator why you cannot perform routine control device maintenance during process shutdowns and describe how you plan to minimize emissions to the greatest extent possible during the maintenance. The routine control device maintenance exemption may not exceed 3 percent of annual operating uptime for each green rotary dryer, tube dryer, strand dryer, or pressurized refiner controlled. The routine control device maintenance exemption is limited to 0.5 percent of annual operating uptime for each softwood veneer dryer, reconstituted wood product press, reconstituted wood product board cooler, hardboard oven, press predryer, or fiberboard mat dryer

controlled. If your control device is used to control a combination of equipment with different downtime allowances (

e.g.

, a tube dryer and a press), then the highest (

i.e.

, 3 percent) downtime allowance applies. The maximum percentages of operating time allowed for the routine control device maintenance exemption are based on our independent analysis of data from an extensive control device downtime survey conducted by the PCWP industry.

We are requesting comment on the appropriateness of including a routine control device maintenance exemption in today's proposed rule and whether or not the downtime allowance allotted is appropriate as the maximum amount of time per year for such an exemption. Commenters should submit information and data that support their comments such as detailed maintenance records and descriptions of the add-on control systems, sources controlled by the control system, and any particulate removal devices that precede the control system.

2. Monitoring and Recordkeeping Requirements for Process Units Without Add-On Control Devices

If you comply with the production-based compliance options in today's proposed rule without using an add-on control system, then you would be required to monitor and record process unit operating parameters. For most process units, temperature would be the required process monitoring parameter. Although HAP emissions vary within and among process units and no one process parameter is responsible for these variations, we selected temperature as the proposed required process monitoring parameter for most process units. We chose operating temperature because it affects HAP emissions and can be controlled and monitored relatively easily.

As for the control device operating requirements, you could choose to monitor THC concentration using a CEMS at the process unit outlet instead of monitoring process unit temperature. If you use a THC CEMS, you would be required to maintain the average THC concentration at the process unit outlet below the maximum THC concentration established during the performance test.

If you elect to use emissions averaging, you would not be required to monitor process parameters for those uncontrolled process units that are used to generate debits. However, when you determine the total HAP emissions from these uncontrolled process units, you would have to perform the emissions measurements under representative operating conditions, and you would be required to keep records of the hours of operation for these uncontrolled process units.

3. Monitoring and Recordkeeping Requirements for Dry Rotary Dryer Work Practice Requirements

Rotary dryers that meet the definition of “dry rotary dryers” in today's proposed rule would not be subject to the proposed control requirements. Green rotary dryers and dry rotary dryers are essentially the same in terms of equipment design. The differences between the two types of dryers are operational. Green rotary dryers are used to dry green furnish, and dry rotary dryers are used to dry furnish that has been previously dried. Green rotary dryers are defined as dryers that dry wood particles that have a moisture content greater than 30 percent on a dry basis or operate at an inlet dryer temperature greater than 600° F. Conversely, dry rotary dryers dry wood particles that have a moisture content less than or equal to 30 percent on a dry basis and operate at an inlet dryer temperature less than or equal to 600° F. The 30 percent moisture and 600° F values were selected for the definitions of dry and green rotary dryers based on values reported in literature, in the questionnaire responses, and in the emissions test reports.

Because the differences in dry rotary dryers and green rotary dryers are operational, we are including monitoring requirements for dry rotary dryers in today's proposed rule that would ensure that these dryers operate as dry rotary dryers on a continuous basis. If you own or operate a dry rotary dryer, you would be required to continuously monitor, calculate, and record the 24-hour average dryer inlet temperature and the 24-hour average moisture content of the incoming wood particles. In addition to monitoring dryer inlet temperature and furnish moisture, you would be required to take representative grab samples of wood particles at the dryer inlet once each day of dryer operation and manually determine the moisture content of the sample on a dry basis. We have included the grab sampling requirement as a means of checking the accuracy of the correlation between the moisture content measured by the continuous moisture sensor and the dry basis moisture content manually determined using a grab sample. The continuous moisture sensors measure moisture level as the ratio of the weight of water to the volume of wood (in the sensing zone). Today's proposed rule defines moisture content, on a dry basis, as the ratio of the weight of water to the weight of dry wood, multiplied by 100.

The requirements for the continuous moisture sensor and the grab sample requirement are specified in § 63.2268(f). We plan to add performance specifications for the continuous moisture sensor to include such parameters as the amount of drift allowed. We request comment on drift and any other performance specifications that should be added to ensure moisture content is being measured accurately, to ensure flexibility in the type of continuous moisture sensor that can be used by a facility, and to ensure compliance and enforceability. We also plan to add specifications to the grab sample requirements, such as including the period of time a sample must maintain a constant weight. We request comment on what this period of time should be and any other specifications that should be added to ensure accurate and precise results.

However, if you choose or are required by some other regulatory action to install a control device designed to reduce VOC or HAP emissions from a dry rotary dryer, you would be exempted from the process monitoring requirements for dry rotary dryers in today's proposed rule.

4. Monitoring and Recordkeeping Requirements for Veneer Redryer Work Practice Requirements

Veneer dryers that meet the definition of “veneer redryers” in today's proposed rule would not be subject to the proposed control requirements. Like the differences between green and dry rotary particle dryers, the differences between veneer dryers and veneer redryers are operational. Veneer dryers are used to dry green veneer, and veneer redryers are used to redry veneer that has been previously dried but requires some additional moisture reduction. Thus, in today's proposed rule, veneer redryers are defined as veneer dryers with an inlet veneer moisture content of less than 25 percent (by weight, dry basis). The 25 percent value was selected as the criterion for distinguishing between veneer dryers and veneer redryers because 25 percent was the highest reported veneer dryer outlet moisture content in responses to a survey. If you own or operate a veneer redryer, you would be required to continuously monitor, calculate, and record the 24-hour average inlet veneer moisture content to show that you continuously meet the definition of a veneer redryer.

For purposes of today's proposed rule, process units heated by microwaves or

radio frequency that are used to remove moisture from veneer are not considered to be veneer dryers or veneer redryers, although these process units are typically used to redry veneer. Emissions test data from the NCASI sampling program indicate that emissions from radio frequency veneer redryers are minimal compared to the emissions from veneer dryers heated by conventional means (such as direct firing or steam heating). Thus, the monitoring requirements for veneer redryers described above would not apply to process units that dry or redry veneer using microwaves or radio frequency.

5. Monitoring and Recordkeeping Requirements for Hardwood Veneer Dryer Work Practice Requirements

Veneer dryers that meet the definition of “hardwood veneer dryer” in today's proposed rule would not be subject to the proposed control requirements. Hardwood veneer dryers are defined in the proposed rule as veneer dryers that process less than 30 percent softwood species on an annual volume basis. If you own or operate a hardwood veneer dryer, you would be required to keep a record (such as a purchase or production record) of the annual volume percentage of softwood species processed in the dryer to show that your dryer continuously meets the definition of a hardwood veneer dryer.

6. Monitoring and Recordkeeping Requirements for Softwood Veneer Dryer Work Practice Requirements

The proposed work practice requirement for softwood veneer dryers is to minimize fugitive emissions from the dryer doors and green end. If you own or operate a softwood veneer dryer, you would be required to develop a plan for minimizing fugitive emissions from the dryer, and you would have to keep records to document that you are following your plan to show continuous compliance with the work practice requirement.

7. Additional Recordkeeping Requirements for Sources Complying With Emissions Averaging Alternative

If you comply with the emissions averaging provisions, you would be required to keep records of all information necessary to calculate debits and credits, including records of your process unit operating hours, records of total HAP measurements for debit-generating process units, and records of performance tests for credit-generating process units. You would also have to keep monitoring records for add-on control systems used to control credit-generating process units.

I. How Did We Select the Notification and Reporting Requirements?

We selected the proposed notification and reporting requirements based on requirements in the NESHAP General Provisions (40 CFR part 63, subpart A) and specific requirements for the PCWP source category.

The notification requirements that we are proposing include Initial Notifications, notification of performance test, Notification of Compliance Status, and notification dates. These notification requirements are based on requirements in §§ 63.7(b) and (c), 63.8(e) and (f), 63.9(b) through (h), and 63.10(d)(2).

In addition, we selected notification requirements for the emissions averaging provisions. If you comply with the emissions averaging provisions, you would have to submit an EAP to the Administrator for approval at least 1 year prior to the compliance date, or 1 year prior to the date you would begin using an emissions average to comply with the proposed rule, whichever is later. The EAP would have to be submitted prior to the date you would begin using an emissions average so that the Administrator would have time to review and approve or disapprove the plan, and so that you would have time to ensure that the emissions credits would equal or exceed the emissions debits.

The proposed reporting requirements that we selected include semiannual compliance reports, required in § 63.10(e)(3), and immediate SSM reports, required in § 63.10(d)(5)(ii). If there are no deviations from the compliance options, operating requirements, or work practice requirements during the reporting period, then you would only be required to include a statement that there were no deviations in your semiannual compliance report. If there are deviations from the compliance options, operating requirements, or work practice requirements during a reporting period, then you would be required to submit the information required in today's proposed rule in your semiannual compliance report. If you have a startup, shutdown or malfunction during the reporting period, and you take actions consistent with your SSM plan (SSMP), then your compliance report would have to include the information in § 63.10(d)(5)(i). The submittal date for the compliance report is based on information in § 63.10(e)(3)(v).

If there is a startup, shutdown, or malfunction during the reporting period, and you take actions inconsistent with the SSMP, then you would be required to submit an immediate SSM report. The report would have to include the actions taken for the event and the information provided in § 63.10(d)(5)(ii). The submittal date for the immediate SSM report is based on § 63.10(d)(5)(ii). For facilities complying with the emissions averaging provisions, the semiannual compliance report would have to contain calculations showing that the AMR equals or exceeds the RMR in addition to the requirements outlined above for semiannual compliance reports.

We have included a routine control device maintenance exemption in today's proposed rule to provide an allowance for control device downtime associated with routine maintenance such as bakeouts, washouts, and media replacement. We would like to clarify that there will also be instances when a control device is offline for correction of malfunctions such as electrical problems, mechanical problems, utility supply problems, pre-filer upsets, production malfunctions (

e.g.,

dryer fires), and weather-related problems. Because these malfunctions are sudden, infrequent, and not reasonably preventable, they would be covered under the SSM provisions of today's proposed rule. In addition, control device downtime due to process upsets that require shutdown and restarting of equipment would be covered under the SSM provisions.

IV. Summary of Environmental, Energy and Economic Impacts

A. How Many Facilities Are Impacted by This Proposed Rule?

This proposed rule is expected to affect an estimated 223 existing major source facilities that manufacture PCWP. The impacted facilities generally manufacture one or more of the following products: softwood plywood, softwood veneer, medium density fiberboard (MDF), oriented strandboard (OSB), particleboard, hardboard, laminated strand lumber, and laminated veneer lumber. The number of impacted facilities was determined based on the estimated potential to emit (

i.e.,

uncontrolled HAP emissions) from each facility and whether or not the facility already operates control systems necessary to meet the proposed standards. Facilities with estimated potential to emit 25 tons or more of total HAP or 10 or more tons of an individual HAP are major sources of HAP and are

subject to today's proposed rule. Of the estimated 223 facilities affected by this proposed rule, an estimated 166 are expected to install add-on control systems to reduce emissions. The remaining facilities already have installed add-on controls, do not have any process units subject to the compliance options, or are expected to comply with work practice requirements only.

The environmental and cost impacts presented in this preamble represent the estimated impacts for the 223 facilities. The impact estimates were based on the use of RTOs (or in some cases a combination WESP and RTO) because RTOs are the most prevalent HAP emissions control technology used in the PCWP industry. However, technologies other than RTOs could be used to comply with today's proposed standards. For a facility that we believe already achieves the emissions reductions required by today's proposed rule, only recordkeeping cost impacts were estimated.

The number of affected facilities presented above (223) does not include major source facilities with lumber kilns that are not otherwise PCWP facilities. Some of these facilities may be major sources of HAP emissions due to lumber drying operations. Because today's proposed rule contains no control requirements for lumber kilns, we expect there to be no cost, environmental, or energy impacts associated with today's proposed rule for these facilities.

B. What Are the Air Quality Impacts?

We estimate nationwide baseline HAP emissions from the PCWP source category to be 17,000 Mg/yr (19,000 tons/yr) at the current level of control. We estimate that the proposed standards would reduce total HAP emissions from the PCWP source category by about 9,700 Mg/yr (11,000 tons/yr). In addition, we estimate that the proposed standards would reduce VOC emissions (approximated as THC) by about 25,000 Mg/yr (27,000 tons/yr) from a baseline level of 45,000 Mg/yr (50,000 tons/yr).

In addition to reducing emissions of HAP and VOC, the proposed standards would also reduce emissions of criteria pollutants, such as carbon monoxide (CO) from direct-fired emission sources and particulate matter less than 10 microns in diameter (PM

10

). We estimate that the proposed standards would reduce CO emissions by about 10,000 Mg/yr (11,000 tons/yr). We estimate that the proposed standards would reduce PM

10

emissions by about 11,000 Mg/yr (13,000 tons/yr).

Combustion of exhaust gases in an RTO generates some emissions of nitrogen oxides (NO

X

). We estimate that the nationwide increase in NO

X

emissions due to the use of RTOs would be about 4,300 Mg/yr (4,800 tons/yr). This estimated increase in NO

X

emissions may be an overestimate because some plants may select control technologies other than RTOs to comply with the proposed standards.

Indirect air impacts of today's proposed rule would result from increased electricity usage associated with operation of control devices. Assuming that plants will purchase electricity from a power plant, we estimate that the proposed standards may increase secondary emissions of criteria pollutants such as PM

10

, sulfur dioxide (SO

2

), NO

X

, and CO from power plants by about 6,200 Mg/yr (6,900 tons/yr).

C. What Are the Water Quality Impacts?

Wastewater is produced from WESP blowdown, washing out of RTOs, and biofilters. We based all of our impact estimates on the use of RTOs (with or without a WESP upstream depending on the process unit). We estimate that the wastewater generated from WESP blowdown and RTO washouts would increase by about 43 thousand cubic meters per year (m

3

/yr)(11 million gal/yr) as a result of today's proposed rule. Facilities would likely dispose of this wastewater by sending it to a municipal treatment facility, evaporating it onsite, incinerating it in an onsite boiler, reusing it onsite (

e.g.

, in log vats or resin mix), or hauling it offsite for spray irrigation.

D. What Are the Solid Waste Impacts?

Solid waste is produced in the form of solids from WESPs and by RTO or RCO media replacement. We estimate that 4,500 Mg/yr (5,000 tons/yr) of solid waste would be generated as a result of today's proposed rule. This solid material may be disposed of in a landfill or used for other purposes. Some PCWP facilities have been able to use RTO or RCO media as aggregate in onsite roadbeds. Some facilities have also been able to identify a beneficial reuse for wet control device solids (such as giving them away to local farmers for soil amendment).

E. What Are the Energy Impacts?

The overall energy demand (

i.e.

, electricity and natural gas) is expected to increase by about 4.3 million gigajoules per year (GJ/yr) (4.1 trillion British thermal units per year (Btu/yr)) nationwide under the proposed standards. The estimated increase in the energy demand is based on the electricity requirements associated with RTOs and WESPs and the fuel requirements associated with RTOs. Electricity requirements are expected to increase by about 718 gigawatt hours per year (Gwh/yr) under the proposed standards. Natural gas requirements are expected to increase by about 45 million m

3

/yr (1.6 billion cubic feet per year (ft

3

/yr)) under the proposed standards.

F. What Are the Cost Impacts?

The cost impacts estimated for today's proposed rule represent a high-end estimate of costs. Although the use of RTO technology to reduce HAP emissions represents the most expensive compliance option, we based our nationwide cost estimates on the use of RTO technology at all of the impacted facilities because: (1) RTO technology can be used to reduce emissions from all types of PCWP process units; and (2) we could not accurately predict which facilities would use emissions averaging or production-based emissions limits or install less expensive add-on control devices, such as RCO and biofilters. Therefore, our cost estimates are likely to be overstated, as we anticipate that owners and operators of impacted sources will take advantage of available cost saving opportunities.

The high-end estimated total capital costs of today's proposed rule are $479 million. These capital costs apply to existing sources and include the costs to purchase and install both the RTO equipment (and in some cases, a WESP upstream of the RTO) and the monitoring equipment, and the costs of performance tests. Permanent total enclosure costs are also included for reconstituted wood products presses.

The high-end estimated annualized costs of the proposed standards are $142 million. The annualized costs account for the annualized capital costs of the control and monitoring equipment, operation and maintenance expenses, and recordkeeping and reporting costs. Potential control device cost savings and increased recordkeeping and reporting costs associated with today's proposed emissions averaging alternative standard are not accounted for in either the capital or annualized cost estimates.

G. Can We Achieve the Goals of the Proposed Rule in a Less Costly Manner?

We have made every effort in developing this proposal to minimize the cost to the regulated community and allow maximum flexibility in compliance options consistent with our statutory obligations. We recognize, however, that the proposal may still

require some facilities to take costly steps to further control emissions even though those emissions may not result in exposures which could pose an excess individual lifetime cancer risk greater than one in one million, or which exceed thresholds determined to provide an ample margin of safety for protecting public health and the environment from the effects of hazardous air pollutants. We are, therefore, specifically soliciting comment on whether there are further ways to structure the proposed rule to focus on the facilities which pose significant risks and avoid the imposition of high costs on facilities that pose little risk to public health and the environment.

Representatives of the plywood and composite wood products industry provided EPA with descriptions of three mechanisms that they believed could be used to implement more cost-effective reductions in risk. The docket for today's proposed rule contains “white papers” prepared by industry that outline their proposed approaches (see docket number A-98-44, Item # II-D-525). These approaches could be effective in focusing regulatory controls on facilities that pose significant risks and avoiding the imposition of high costs on facilities that pose little risk to public health or the environment, and we are seeking public comment on the utility of each of these approaches with respect to this proposed rule.

One of the approaches, an applicability cutoff for threshold pollutants, would be implemented under the authority of CAA section 112(d)(4); the second approach, subcategorization and delisting, would be implemented under the authority of CAA section 112(c)(1) and (c)(9); and, the third approach, would involve the use of a concentration-based applicability threshold. We are seeking comment on whether these approaches are legally justified and, if so, we ask for information that could be used to support such approaches.

The maximum achievable control technology, or MACT, program outlined in CAA section 112(d) is intended to reduce emissions of HAP through the application of MACT to major sources of toxic air pollutants. Section 112(c)(9) is intended to allow EPA to avoid setting MACT standards for categories or subcategories of sources that pose less than a specified level of risk to public health and the environment. The EPA requests comment on whether the approaches described here appropriately rely on the provisions of CAA section 112. While the approaches focus on assessing the inhalation exposures of HAP emitted by a source, EPA specifically requests comment on the appropriateness and necessity of extending these approaches to account for non-inhalation exposures or to account for adverse environmental impacts. In addition to the specific requests for comment noted in this section, we are also interested in any information or comment concerning technical limitations, environmental and cost impacts, compliance assurance, legal rationale, and implementation relevant to the identified approaches. We also request comment on appropriate practicable and verifiable methods to ensure that sources' emissions remain below levels that protect public health and the environment. We will evaluate all comments before determining whether either of the three approaches will be included in the final rule.

1. Industry Emissions and Potential Health Effects

For the PCWP source category, six HAP make up about 96 percent of the total organic HAP (

i.e.

, does not include metals that are HAP). Those six HAP are methanol, formaldehyde, acetaldehyde, phenol, acrolein, and propionaldehyde. All HAP are not emitted by all sources. However, all of the 223 major sources emit all six of the predominant HAP, with a few exceptions. Some engineered wood plants do not emit phenol; these plants are major sources but would not be affected by the proposed rule because they have no equipment subject to the proposed rule. Also, several particleboard plants do not emit propionaldehyde; these particleboard plants have dry rotary particle dryers (as opposed to green particle dryers), which are not subject to control requirements. (For more information, see section III.C.3).

In accordance with section 112(k), EPA developed a list of 33 HAP which present the greatest threat to public health in the largest number of urban areas. Some of the PCWP HAP are included on this list for the EPA's Urban Air Toxics Program. These HAP include three of the six most predominant PCWP HAP (acetaldehyde, acrolein, and formaldehyde). Additional urban HAP that may be emitted by PCWP facilities include benzene, carbon tetrachloride, chloroform, and methylene chloride.

In November 1998, EPA published “A Multimedia Strategy for Priority Persistent, Bioaccumulative, and Toxic (PBT) Pollutants.” The organic HAP emitted by PCWP facilities do not appear on the published list of PBT compounds referenced in the EPA strategy.

To estimate the potential baseline risks posed by the PCWP source category and the potential impact of applicability cutoffs, EPA performed a “rough” risk assessment for 185 of the 223 facilities in the PCWP source category. The HAP included in the assessment were acetaldehyde, acrolein, benzene, formaldehyde, manganese, methanol, methylene chloride, and phenol. Of these HAP, four are presently not considered to have thresholds for cancer effects: acetaldehyde, benzene, formaldehyde, and methylene chloride.

Of the 185 facilities assessed, 148 facilities were found to pose cancer risks equal to or greater than one in one million to their surrounding population. Forty-six facilities were predicted to pose cancer risks of one in 100,000 or greater, and two PCWP facilities were found to pose cancer risks equal to or greater than one in 10,000.

2. Applicability Cutoffs for Threshold Pollutants Under Section 112(d)(4) of the CAA

The first approach is an “applicability cutoff” for threshold pollutants that is based on EPA's authority under CAA section 112(d)(4) to establish standards for HAP which are “threshold pollutants.” A “threshold pollutant” is one for which there is a concentration or dose below which adverse effects are not expected to occur over a lifetime of exposure. For such pollutants, section 112(d)(4) allows EPA to consider the threshold level, with an ample margin of safety, when establishing emission standards. Specifically, section 112(d)(4) allows EPA to establish emission standards that are not based upon the MACT specified under section 112(d)(2) for pollutants for which a health threshold has been established. Such standards may be less stringent than MACT. Historically, EPA has interpreted section 112(d)(4) to allow categories of sources that emit only threshold pollutants to avoid further regulation if those emissions result in ambient levels that do not exceed the threshold, with an ample margin of safety.

1

1

See

63 FR 18754, 18765-66 (April 15, 1998) (Pulp and Paper Combustion Sources Proposed NESHAP)

A different interpretation would allow us to exempt individual facilities within a source category that meet the section 112(d)(4) requirements. There are three potential scenarios under this interpretation of the section 112(d)(4) provision. One scenario would allow an exemption for individual facilities that emit only threshold pollutants and can demonstrate that their emissions of

threshold pollutants would not result in air concentrations above the threshold levels, with an ample margin of safety, even if the category is otherwise subject to MACT. A second scenario would allow the section 112(d)(4) provision to be applied to both threshold and non-threshold pollutants, using the one in a million cancer risk level for decisionmaking for non-threshold pollutants. A third scenario would allow a section 112(d)(4) exemption at a facility that emits both threshold and non-threshold pollutants. For those emission points where only threshold pollutants are emitted and where emissions of the threshold pollutants would not result in air concentrations above the threshold levels, with an ample margin of safety, those emission points could be exempt from the MACT standard. The MACT standard would still apply to non-threshold emissions from other emission points at the source. For this third scenario, emission points that emit a combination of threshold and non-threshold pollutants that are co-controlled by MACT would still be subject to the MACT level of control. However, any threshold HAP eligible for exemption under section 112(d)(4) that are controlled by control devices different from those controlling non-threshold HAP would be able to use the exemption, and the facility would still be subject to the provisions of the standard that control non-threshold pollutants or that control both threshold and non-threshold pollutants.

Estimation of hazard quotients and hazard indices.

Under the section 112(d)(4) approach, EPA would have to determine that emissions of each of the threshold pollutants emitted by PCWP sources at the facility do not result in exposures which exceed the threshold levels, with an ample margin of safety. The common approach for evaluating the potential hazard of a threshold air pollutant is to calculate a “hazard quotient” by dividing the pollutant's inhalation exposure concentration (often assumed to be equivalent to its estimated concentration in air at a location where people could be exposed) by the pollutant's inhalation Reference Concentration (RfC). An RfC is defined as an estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure that, over a lifetime, likely would not result in the occurrence of adverse health effects in humans, including sensitive individuals. The EPA typically establishes an RfC by applying uncertainty factors to the critical toxic effect derived from the lowest- or no-observed-adverse-effect level of a pollutant.

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A hazard quotient less than one means that the exposure concentration of the pollutant is less than the RfC and, therefore, presumed to be without appreciable risk of adverse health effects. A hazard quotient greater than one means that the exposure concentration of the pollutant is greater than the RfC. Further, EPA guidance for assessing exposures to mixtures of threshold pollutants recommends calculating a “hazard index” by summing the individual hazard quotients for those pollutants in the mixture that affect the same target organ or system by the same mechanism.

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Hazard index (HI) values would be interpreted similarly to hazard quotients; values below one would generally be considered to be without appreciable risk of adverse health effects, and values above one would generally be cause for concern.

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