# National Emission Standards for Hazardous Air Pollutants: Proposed Standards for Hazardous Air Pollutants for Hazardous Waste Combustors (Phase I Final Replacement Standards and Phase II)

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URL: https://www.frixlaw.com/law-library/documents/fr%3A04-7858

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** April 20, 2004
- **Citation:** 69 FR 21198

## Text

ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 63, 264, 265, 266, 270, and 271
[FRL-7644-1]
RIN 2050-AE01
National Emission Standards for Hazardous Air Pollutants: Proposed Standards for Hazardous Air Pollutants for Hazardous Waste Combustors (Phase I Final Replacement Standards and Phase II)

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

This action proposes national emission standards for hazardous air pollutants (NESHAP) for hazardous waste combustors. These combustors include hazardous waste burning incinerators, cement kilns, lightweight aggregate kilns, industrial/commercial/institutional boilers and process heaters, and hydrochloric acid production furnaces, known collectively as hazardous waste combustors (HWCs). EPA has identified these HWCs as major sources of hazardous air pollutant (HAP) emissions. These proposed standards will, when final, implement section 112(d) of the Clean Air Act (CAA) by requiring hazardous waste combustors to meet HAP emission standards reflecting the application of the maximum achievable control technology (MACT).

The HAP emitted by facilities in the incinerator, cement kiln, lightweight aggregate kiln, industrial/commercial/institutional boiler, process heater, and hydrochloric acid production furnace source categories include arsenic, beryllium, cadmium, chromium, dioxins and furans, hydrogen chloride and chlorine gas, lead, manganese, and mercury. Exposure to these substances has been demonstrated to cause adverse health effects such as irritation on the lung, skin, and mucus membranes, effects on the central nervous system, kidney damage, and cancer. The adverse health effects associated with the exposure to these specific HAP are further described in the preamble. In general, these findings have only been shown with concentrations higher than those typically in the ambient air.

This action also presents our tentative decision regarding the February 28, 2002, petition for rulemaking submitted by the Cement Kiln Recycling Coalition to the Administrator, relating to EPA's implementation of the so-called omnibus permitting authority under section 3005(c) of the Resource Conservation and Recovery Act (RCRA), which requires that each permit issued under RCRA contain such terms and conditions as are determined necessary to protect human health and the environment. In that petition, the Cement Kiln Recycling Coalition requests that we repeal the existing site-specific risk assessment policy and technical guidance for hazardous waste combustors and that we promulgate the policy and guidance as rules in accordance with the Administrative Procedure Act if we continue to believe that site-specific risk assessments may be necessary.

DATES:

Submit comments on or before July 6, 2004.

ADDRESSES:

Submit your comments, identified by Docket ID No. OAR-2004-0022 by one of the following methods:

• Federal eRulemaking Portal:
http://www.regulations.gov
. Follow the on-line instructions for submitting comments.

• Agency Web site:
http://www.epa.gov/edocket
. EDOCKET, EPA's electronic public docket and comment system, is EPA's preferred method for receiving comments. Follow the on-line instructions for submitting comments.

• E-mail:
http://www.epa.gov/edocket
.

• Fax: 202-566-1741.

• Mail: OAR Docket, Environmental Protection Agency, Mailcode: B102, 1200 Pennsylvania Ave., NW., Washington, DC 20460. Please include a total of 2 copies.

• Hand Delivery: EPA/DC, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions:
Direct your comments to Docket ID No. OAR-2004-0022. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at
http://www.epa.gov/edocket
, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through EDOCKET, regulations.gov, or e-mail. The EPA EDOCKET and the federal regulations.gov Web sites are “anonymous access” systems, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through EDOCKET or regulations.gov, your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about EPA's public docket visit EDOCKET on-line or see the
Federal Register
of May 31, 2002 (67 FR 38102).

For additional instructions on submitting comments, go to unit II of the
SUPPLEMENTARY INFORMATION
section of this document.

Docket:
All documents in the docket are listed in the EDOCKET index at
http://www.epa.gov/edocket
. Although listed in the index, some information is not publicly available,
i.e.
, CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in EDOCKET or in hard copy at the OAR Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the OAR Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

For general information, call the RCRA Call Center at 1-800-424-9346 or TDD 1-800-553-7672 (hearing impaired). Callers within the Washington Metropolitan Area must dial 703-412-9810 or TDD 703-412-3323 (hearing impaired). The RCRA Call Center is open Monday-Friday, 9 a.m. to 4 p.m., eastern standard time. For more information about this proposal, contact Michael Galbraith at 703-605-0567, or
galbraith.michael@epa.gov
.

SUPPLEMENTARY INFORMATION:

I. Regulated Entities

The promulgation of the proposed rule would affect the following North

American Industrial Classification System (NAICS) and Standard Industrial Classification (SIC) codes:

Category
NAICS code
SIC code
Examples of potentially regulated entities

Any industry that combusts hazardous waste as defined in the proposed rule
562211
4953
Incinerator, hazardous waste.

327310
3241
Cement manufacturing, clinker production.

327992
3295
Ground or treated mineral and earth manufacturing.

325
28
Chemical Manufacturers.

324
29
Petroleum Refiners.

331
33
Primary Aluminum.

333
38
Photographic equipment and supplies.

488, 561, 562
49
Sanitary Services, N.E.C.

421
50
Scrap and waste materials.

422
51
Chemical and Allied Products, N.E.C.

512, 541, 561, 812
73
Business Services, N.E.C.

512, 514, 541, 711
89
Services, N.E.C.

924
95
Air, Water and Solid Waste Management.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. This table lists examples of the types of entries EPA is now aware could potentially be regulated by this action. Other types of entities not listed could also be affected. To determine whether your facility, company, business, organization, etc., is regulated by this action, you should examine the applicability criteria in Part II of this preamble. 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.

II. What Should I Consider as I Prepare My Comments for EPA?

1.
Submitting CBI.
Do not submit this information to EPA through EDOCKET, regulations.gov or e-mail. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as CBI and then identify electronically within the disk or CD-ROM the specific information that is claimed as CBI). In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

2.
Tips for Preparing Your Comments.
When submitting comments, remember to:

A. Identify the rulemaking by docket number and other identifying information (subject heading,
Federal Register
date and page number).

B. Follow directions—The agency may ask you to respond to specific questions or organize comments by referencing a Code of Federal Regulations (CFR) part or section number.

C. Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes.

D. Describe any assumptions and provide any technical information and/or data that you used.

E. If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

F. Provide specific examples to illustrate your concerns, and suggest alternatives.

G. Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

H. Make sure to submit your comments by the comment period deadline identified.

Outline

Part One: Background and Summary

I. Background Information

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

B. What Is the Regulatory Development Background of the Source Categories in the Proposed Rule?

C. What Is the Statutory Authority for this Standard?

D. What Is the Relationship Between the Proposed Rule and Other MACT Combustion Rules?

E. What Are the Health Effects Associated with Pollutants Emitted by Hazardous Waste Combustors?

II. Summary of the Proposed Rule

A. What Source Categories Are Affected by the Proposed Rule?

B. What HAP Are Emitted?

C. Does Today's Proposed Rule Apply to My Source?

D. What Emissions Limitations Must I Meet?

E. What Are the Testing and Initial Compliance Requirements?

F. What Are the Continuous Compliance Requirements?

G. What Are the Notification, Recordkeeping, and Reporting Requirements?

Part Two: Rationale for the Proposed Rule

I. How Did EPA Determine Which Hazardous Waste Combustion Sources Would Be Regulated?

A. How Are Area Sources Regulated?

B. What Hazardous Waste Combustors Are Not Covered by this Proposal?

C. How Would Sulfuric Acid Regeneration Facilities Be Regulated?

II. What Subcategorization Considerations Did EPA Evaluate?

A. What Subcategorization Options Did We Consider for Incinerators?

B. What Subcategorization Options Did We Consider for Cement Kilns?

C. What Subcategorization Options Did We Consider for Lightweight Aggregate Kilns?

D. What Subcategorization Options Did We Consider for Boilers?

E. What Subcategorization Options Did We Consider for Hydrochloric Acid Production Furnaces?

III. What Data and Information Did EPA Consider to Establish the Proposed Standards?

A. Data Base for Phase I Sources

B. Data Base for Phase II Sources

C. Classification of the Emission Data

D. Invitation to Comment on Data Base

IV. How Did EPA Select the Format for the Proposed Rule?

A. What Is the Rationale for Generally Selecting an Emission Limit Format Rather than a Percent Reduction Format?

B. What Is the Rationale for Selecting a Hazardous Waste Thermal Emissions Format for Some Standards, and an Emissions Concentration Format for Others?

C. What Is the Rationale for Selecting Surrogates to Control Multiple HAP?

D. What Is the Rationale for Requiring Compliance with Operating Parameter Limits to Ensure Compliance with Emission Standards?

V. How Did EPA Determine the Proposed Emission Limitations for New and Existing Units?

A. How Did EPA Determine the Proposed Emission Limitations for New Units?

B. How Did EPA Determine the Proposed Emission Limitations for Existing Units?

VI. How Did EPA Determine the MACT Floor for Existing and New Units?

A. What MACT Methodology Approaches Are Used to Identify the Best Performers for the Proposed Floors, and When Are They Applied?

B. How Did EPA Select the Data to Represent Each Source When Determining Floor Levels?

C. How Did We Evaluate Whether It Is Appropriate to Issue Separate Emissions Standards for Various Subcategories?

D. How Did We Rank Each Source's Performance Levels to Identify the Best Performing Sources for the Three MACT Methodologies?

E. How Did EPA Calculate Floor Levels That Are Achievable for the Average of the Best Performing Sources?

F. Why Did EPA Default to the Interim Standards When Establishing Floors?

G. What Other Options Did EPA Consider?

VII. How Did EPA Determine the Proposed Emission Standards for Hazardous Waste Burning Incinerators?

A. What Are the Proposed Standards for Dioxin and Furan?

B. What Are the Proposed Standards for Mercury?

C. What Are the Proposed Standards for Particulate Matter?

D. What Are the Proposed Standards for Semivolatile Metals?

E. What Are the Proposed Standards for Low Volatile Metals?

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

H. What Are the Standards for Destruction and Removal Efficiency?

VIII. How Did EPA Determine the Proposed Emission Standards for Hazardous Waste Burning Cement Kilns?

A. What Are the Proposed Standards for Dioxin and Furan?

B. What Are the Proposed Standards for Mercury?

C. What Are the Proposed Standards for Particulate Matter?

D. What Are the Proposed Standards for Semivolatile Metals?

E. What Are the Proposed Standards for Low Volatile Metals?

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

H. What Are the Standards for Destruction and Removal Efficiency?

IX. How Did EPA Determine the Proposed Emission Standards for Hazardous Waste Burning Lightweight Aggregate Kilns?

A. What Are the Proposed Standards for Dioxin and Furan?

B. What Are the Proposed Standards for Mercury?

C. What Are the Proposed Standards for Particulate Matter?

D. What Are the Proposed Standards for Semivolatile Metals?

E. What Are the Proposed Standards for Low Volatile Metals?

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

H. What Are the Standards for Destruction and Removal Efficiency?

X. How Did EPA Determine the Proposed Emission Standards for Hazardous Waste Burning Solid Fuel-Fired Boilers?

A. What Is the Rationale for the Proposed Standards for Dioxin and Furan?

B. What Is the Rationale for the Proposed Standards for Mercury?

C. What Is the Rationale for the Proposed Standards for Particulate Matter?

D. What Is the Rationale for the Proposed Standards for Semivolatile Metals?

E. What Is the Rationale for the Proposed Standards for Low Volatile Metals?

F. What Is the Rationale for the Proposed Standards for Total Chlorine?

G. What Is the Rationale for the Proposed Standards for Carbon Monoxide or Hydrocarbons?

H. What Is the Rationale for the Proposed Standard for Destruction and Removal Efficiency?

XI. How Did EPA Determine the Proposed Emission Standards for Hazardous Waste Burning Liquid Fuel-Fired Boilers?

A. What Are the Proposed Standards for Dioxin and Furan?

B. What Is the Rationale for the Proposed Standards for Mercury?

C. What Is the Rationale for the Proposed Standards for Particulate Matter?

D. What Is the Rationale for the Proposed Standards for Semivolatile Metals?

E. What Is the Rationale for the Proposed Standards for Chromium?

F. What Is the Rationale for the Proposed Standards for Total Chlorine?

G. What Is the Rationale for the Proposed Standards for Carbon Monoxide or Hydrocarbons?

H. What Is the Rationale for the Proposed Standard for Destruction and Removal Efficiency?

XII. How Did EPA Determine the Proposed Emission Standards for Hazardous Waste Burning Hydrochloric Acid Production Furnaces?

A. What Is the Rationale for the Proposed Standards for Dioxin and Furan?

B. What Is the Rationale for the Proposed Standards for Mercury, Semivolatile Metals, and Low Volatile Metals?

C. What Is the Rationale for the Proposed Standards for Total Chlorine?

D. What Is the Rationale for the Proposed Standards for Carbon Monoxide or Hydrocarbons?

E. What Is the Rationale for the Proposed Standard for Destruction and Removal Efficiency?

XIII. What Is the Rationale for Proposing An Alternative Risk-Based Standard for Total Chlorine in Lieu of the MACT Standard?

A. What Is the Legal Authority to Establish Risk-Based Standards?

B. What Is the Rationale for the National Exposure Standards?

C. How Would You Determine if Your Total Chlorine Emission Rate Meets the Eligibility Requirements Defined by the National Exposure Standards?

D. What Is the Rationale for Caps on the Risk-Based Emission Limits?

E. What Would Your Risk-Based Eligibility Demonstration Contain?

F. When Would You Complete and Submit Your Eligibility Demonstration?

G. How Would the Risk-Based HCl-Equivalent Emission Rate Limit Be Implemented?

H. How Would You Ensure that Your Facility Remains Eligible for the Risk-Based Emission Limit?

I. Request for Comment on an Alternative Approach: Risk-Based National Emission Standards

XIV. How Did EPA Determine Testing and Monitoring Requirements for the Proposed Rule?

A. What Is the Rationale for the Proposed Testing Requirements?

B. What Are the Dioxin/Furan Testing Requirements for Boilers that Would Not Be Subject to a Numerical Dioxin/Furan Emission Standard?

C. What Are the Proposed Test Methods?

D. What Is the Rationale for the Proposed Continuous Monitoring Requirements?

E. What Are the Averaging Periods for the Operating Parameter Limits, and How Are Performance Test Data Averaged to Calculate the Limits?

F. How Would Sources Comply with Emissions Standards Based on Normal Emissions?

G. How Would Sources Comply with Emission Standards Expressed as Hazardous Waste Thermal Emissions?

H. What Happens if My Thermal Emissions Standard Limits Emissions to Below the Detection Limit of the Stack Test Methods?

I. Are We Concerned About Possible Negative Biases Associated With Making Hydrogen Chloride Measurements in High Moisture Conditions?

J. What Are the Other Proposed Compliance Requirements?

XV. How Did EPA Determine Compliance Times for this Proposed Rule?

XVI. How Did EPA Determine the Required Records and Reports for the Proposed Rule?

A. Summary of Requirements Currently Applicable to Incinerators, Cement Kilns, and Lightweight Aggregate Kilns and that Would Be Applicable to Boilers and Hydrochloric Acid Production Furnaces

B. Why Is EPA Proposing Notification of Intent to Comply and Compliance Progress Report Requirements?

XVII. What Are the Title V and RCRA Permitting Requirements for Phase I and Phase II Sources?

A. What Is the General Approach to Permitting Hazardous Waste Combustion Sources?

B. How Will the Replacement Standards Affect Permitting for Phase I Sources?

C. What Permitting Requirements Is EPA Proposing for Phase II Sources?

D. How Would this Proposal Affect the RCRA Site-Specific Risk Assessment Policy?

XVIII. What Alternatives to the Particulate Matter Standard Is EPA Proposing or Requesting Comment On?

A. What Alternative to the Particulate Matter Standard Is EPA Proposing for Incinerators, Liquid Fuel-Fired Boilers, and Solid Fuel-Fired Boilers?

B. What Alternative to the Particulate Matter Standard Is EPA Requesting Comment On?

XIX. What Are the Proposed RCRA State Authorization and CAA Delegation Requirements?

A. What Is the Authority for this Rule?

B. Are There Any Changes to the CAA Delegation Requirements for Phase I Sources?

C. What Are the Proposed CAA Delegation Requirements for Phase II Sources?

Part Three: Proposed Revisions to Compliance Requirements

I. Why Is EPA Proposing to Allow Phase I Sources to Conduct the Initial Performance Test to Comply with the Replacement Rules 12 Months After the Compliance Date?

II. Why Is EPA Requesting Comment on Requirements Promulgated as Interim Standards or as Final Amendments?

A. Interim Standards Amendments to the Startup, Shutdown, and Malfunction Plan Requirements

B. Interim Standards Amendments to the Compliance Requirements for Ionizing Wet Scrubbers

C. Why Is EPA Requesting Comment on the Fugitive Emission Requirements?

D. Why Is EPA Requesting Comment on Bag Leak Detector Sensitivity?

E. Final Amendments Waiving Operating Parameter Limits during Testing without an Approved Test Plan

III. Why Is EPA Requesting Comment on Issues and Amendments that Were Previously Proposed?

A. Definition of Research, Development, and Demonstration Source

B. Identification of an Organics Residence Time that Is Independent of, and Shorter than, the Hazardous Waste Residence Time

C. Why Is EPA Not Proposing to Extend APCD Controls after the Residence Time Has Expired when Sources Operate under Alternative Section 112 or 129 Standards?

D. Why Is EPA Proposing to Allow Use of Method 23 as an Alternative to Method 0023A for Dioxin/Furan?

E. Why Is EPA Not Proposing the “Matching the Profile” Alternative Approach to Establish Operating Parameter Limits?

F. Why Is EPA Not Proposing to Allow Extrapolation of OPLs?

G. Why Is EPA Proposing to Delete the Limit on Minimum Combustion Chamber Temperature for Dioxin/Furan for Cement Kilns?

H. Why Is EPA Requesting Additional Comment on Whether to Add a Maximum pH Limit for Wet Scrubbers to Control Mercury Emissions?

I. How Is EPA Proposing to Ensure Performance of Electrostatic Precipitators, Ionizing Wet Scrubbers, and Fabric Filters?

IV. Other Proposed Compliance Revisions

A. What Is the Proposed Clarification to the Public Notice Requirement for Approved Test Plans?

B. What Is the Proposed Clarification to the Public Notice Requirement for the Petition to Waive a Performance Test?

Part Four: Impacts of the Proposed Rule

I. What Are the Air Impacts?

II. What Are the Water and Solid Waste Impacts?

III. What Are the Energy Impacts?

IV. What are the Control Costs?

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

VI. What are the Economic Impacts?

A. Market Exit Estimates

B. Quantity of Waste Reallocated

C. Employment Impacts

VII. What Are the Benefits of Reductions in Particulate Matter Emissions?

VIII. What are the Social Costs and Benefits of the Proposed Rule?

A. Combustion Market Overview

B. Baseline Specification

C. Analytical Methodology and Findings—Social Cost Analysis

D. Analytical Methodology and Findings—Benefits Assessment

IX. How Does the Proposed Rule Meet the RCRA Protectiveness Mandate?

A. Background

B. Assessment of Risks

Part Five: Administrative Requirements

I. Executive Order 12866: Regulatory Planning and Review

II. Paperwork Reduction Act

III. Regulatory Flexibility Act

IV. Unfunded Mandates Reform Act

V. Executive Order 13132: Federalism

VI. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments

VII. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks

VIII. Executive Order 13211: Actions that Significantly Affect Energy Supply, Distribution, or Use

IX. National Technology Transfer and Advancement Act

X. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations

XI. Congressional Review

Abbreviations and Acronyms Used in This Document

acfm—actual cubic feet per minute

Btu—British thermal units

CAA—Clean Air Act

CFR—Code of Federal Regulations

DRE—destruction and removal efficiency

dscf—dry standard cubic foot

dscm—dry standard cubic meter

EPA—Environmental Protection Agency

FR—
Federal Register

gr/dscf—grains per dry standard cubic foot

HAP—hazardous air pollutant(s)

ICR—Information Collection Request

kg/hr—kilograms per hour

kW-hour—kilo Watt hour

MACT—Maximum Achievable Control Technology

mg/dscm—milligrams per dry standard cubic meter

MMBtu—million British thermal unit

ng/dscm—nanograms per dry standard cubic meter

NESHAP—national emission standards for HAP

ng—nanograms

POHC—principal organic hazardous constituent

ppmv—parts per million by volume

ppmw—parts per million by weight

Pub. L.—Public Law

RCRA—Resource Conservation and Recovery Act

SRE—system removal efficiency

TEQ—toxicity equivalence

ug/dscm—micrograms per dry standard cubic meter

U.S.C.—United States Code

Part One: Background and Summary

I. Background Information

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

1. What Information Is Covered in This Preamble and How Is It Organized?

In this preamble, EPA summarizes the important features of these proposed standards that apply to hazardous waste burning incinerators, cement kilns, lightweight aggregate kilns, boilers, and hydrochloric acid production furnaces, known collectively as HWCs. This preamble describes: (1) The environmental, energy, and economic impacts of these proposed standards; (2) the basis for each of the decisions made regarding the proposed standards; (3) requests public comments on certain issues; and (4) discusses administrative requirements relative to this action.

2. Where in the Code of Federal Regulations Will These Standards Be Codified?

The Code of Federal Regulations (CFR) is a codification of the general and permanent rules published in the
Federal Register
by the Executive departments and agencies of the Federal Government. The code is divided into 50 titles that represent broad areas subject to Federal regulation. These proposed rules would be published in Title 40, Protection of the Environment, Part 63, Subpart EEE: National Emission Standards for Hazardous Air Pollutants From Hazardous Waste Combustors.

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

Section 112 of the Clean Air Act (CAA) requires EPA to promulgate regulations for the control of HAP emissions from each source category listed by EPA under section 112(c). The statute requires the regulations to reflect the maximum degree of reduction in emissions of HAP that is achievable taking into consideration the cost of achieving the emission reduction, any nonair quality health and environmental impacts, and energy requirements. This level of control is commonly referred to as MACT (
i.e.,
maximum achievable control technology). The MACT regulation can be based on the emission reductions achievable through application of measures, processes, methods, systems, or techniques including, but not limited to: (1) Reducing the volume of, or eliminating emissions of, such pollutants through process changes, substitutions of materials, or other modifications; (2) enclosing systems or processes to eliminate emissions; (3) collecting, capturing, or treating such pollutants when released from a process, stack, storage or fugitive emission point; (4) design, equipment, work practices, or operational standards as provided in subsection 112(h); or (5) a combination of the above.
See
section 112(d)(2) of the CAA.

For new sources, MACT standards cannot be less stringent than the emission control achieved in practice by the best-controlled similar source.
See
section 112(d)(3) of the Act. 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 for categories and subcategories with 30 or more sources, or the best-performing 5 sources for categories or subcategories with fewer than 30 sources.
Id.
This level of control is usually referred to as the MACT “floor”, the term used in the Legislative History.

In essence, MACT standards ensure that all major sources of air toxic (
i.e.,
HAP) emissions achieve the level of control already being achieved by the better-controlled and lower-emitting sources in each category. This approach provides assurance to citizens that each major source of toxic air pollution will be required to effectively control its emissions of air toxics. At the same time, this approach provides a level playing field, ensuring that facilities that employ cleaner processes and good emission controls are not disadvantaged relative to competitors with poorer controls.

B. What Is the Regulatory Development Background of the Source Categories in the Proposed Rule?

Today's notice proposes standards for controlling emissions of HAP from hazardous waste combustors. Hazardous waste combustors comprise several categories of sources that burn hazardous waste: incinerators, cement kilns, lightweight aggregate kilns, boilers and hydrochloric acid production furnaces. We call incinerators, cement kilns, and lightweight aggregate kilns Phase I sources because we have already promulgated standards for those source categories. We call boilers and hydrochloric acid production furnaces Phase II sources because we intended to promulgate MACT standards for those source categories after promulgating MACT standards for Phase I sources. The regulatory background of Phase I and Phase II source categories is discussed below.

1. Phase I Source Categories

Phase I combustor sources are regulated under the Resource Conservation and Recovery Act (RCRA), which establishes a “cradle-to-grave” regulatory structure overseeing the safe treatment, storage, and disposal of hazardous waste. We issued RCRA rules to control air emissions from incinerators in 1981, 40 CFR parts 264 and 265, subpart O, and from cement kilns and lightweight aggregate kilns that burn hazardous waste in 1991, 40 CFR part 266, subpart H. These rules rely generally on risk-based standards to achieve the RCRA protectiveness mandate.

The Phase I source categories are also subject to standards under section 112(d) of the Clean Air Act. We promulgated standards for Phase I sources on September 30, 1999 (64 FR 52828). This final rule is referred to as the Phase I rule or 1999 final rule. These emission standards created a technology-based national cap for hazardous air pollutant emissions from the combustion of hazardous waste in these devices. The rule regulates emissions of numerous hazardous air pollutants: dioxin/furans, other toxic organics (through surrogates), mercury, other toxic metals (both directly and through a surrogate), and hydrogen chloride and chlorine gas. Where necessary, section 3005(c)(3) of RCRA provides the authority to impose additional conditions in a RCRA permit to protect human health and the environment.

A number of parties, representing interests of both industrial sources and of the environmental community, sought judicial review of the Phase I rule. On July 24, 2001, the United States Court of Appeals for the District of Columbia Circuit (the Court) granted portions of the Sierra Club's petition for review and vacated the challenged portions of the standards.
Cement Kiln Recycling Coalition
v.
EPA,
255 F. 3d 855 (D.C. Cir. 2001). The Court held that EPA had not demonstrated that its calculation of MACT floors met the statutory requirement of being no less stringent than (1) the average emission limitation achieved by the best performing 12 percent of existing sources and (2) the emission control achieved in practice by the best controlled similar source for new sources. 255 F.3d at 861, 865-66. As a remedy, the Court, after declining to rule on most of the issues presented in the industry petitions for review, vacated the “challenged regulations,” stating that: “[W]e have chosen not to reach the bulk of industry petitioners' claims, and leaving the regulations in place during remand would ignore petitioners' potentially meritorious challenges.”
Id.
at 872. Examples of the specific challenges the Court indicated might have merit were provisions relating to compliance during start up/shut down and malfunction events, including emergency safety vent openings, the dioxin/furan standard for lightweight aggregate kilns, and the semivolatile metal standard for cement kilns.
Id.
However, the Court stated, “[b]ecause this decision leaves EPA without standards regulating [hazardous waste combustor] emissions, EPA (or any of the parties to this proceeding) may file a motion to delay issuance of the mandate to request either that the current standards remain in place or that EPA be allowed reasonable time to develop interim standards.”
Id.

Acting on this invitation, all parties moved the Court jointly to stay the issuance of its mandate for four months to allow EPA time to develop interim standards, which would replace the vacated standards temporarily, until final standards consistent with the Court's mandate are promulgated. The interim standards were published on February 13, 2002 (67 FR 6792). EPA did not justify or characterize these standards as conforming to MACT, but rather as an interim measure to prevent the adverse environmental and other consequences that would result from the regulatory gap resulting from no standards being in place.
Id.
at 6795-96.

The motion also indicates that EPA will issue final standards which comply

with the Court's opinion by June 14, 2005, and it indicates that EPA and Petitioner Sierra Club intend to enter into a settlement agreement requiring us to promulgate final rules by that date, and that date be judicially enforceable. EPA and Sierra Club entered into that settlement agreement on March 4, 2002.

The joint motion also details other actions we agreed to take, including issuing a one-year extension to the September 30, 2002, compliance date (66 FR 63313, December 6, 2001), and promulgating several of the compliance and implementation amendments to the rule which we proposed on July 3, 2001 (66 FR 35126). These final amendments were published on February 14, 2002 (67 FR 6968).

2. Phase II Source Categories

Phase II combustors—boilers and hydrochloric acid production furnaces—are also regulated under the Resource Conservation and Recovery Act (RCRA) pursuant to 40 CFR part 266, subpart H, and (for reasons discussed below) are also subject to the MACT standard setting process in section 112(d) of the CAA. We delayed promulgating MACT standards for these source categories pending reevaluation of the MACT standard setting methodology following the Court's decision to vacate the standards for the Phase I source categories. We have also entered into a judicially enforceable consent decree with Sierra Club which requires EPA to promulgate MACT standards for the Phase II sources by June 14, 2005—the same date that (for independent reasons) is required for the replacement standards for Phase I sources.

C. What Is the Statutory Authority for This Standard?

Section 112 of the Clean Air Act requires that the EPA promulgate regulations requiring the control of HAP emissions from major and certain area sources. The control of HAP is achieved through promulgation of emission standards under sections 112(d) and (in a second round of standard setting) (f) and, in appropriate circumstances, work practice standards under section 112(h).

EPA's initial list of categories of major and area sources of HAP selected for regulation in accordance with section 112(c) of the Act was published in the
Federal Register
on July 16, 1992 (57 FR 31576). Incinerators, cement kilns, lightweight aggregate kilns, industrial/commercial/institutional boilers and process heaters, and hydrochloric acid production furnaces are among the listed 174 categories of sources. The listing was based on the Administrator's determination that they may reasonably be anticipated to emit several of the 188 listed HAP in quantities sufficient to designate them as major sources.

D. What Is the Relationship Between the Proposed Rule and Other MACT Combustion Rules?

The proposed amendments to the subpart EEE, part 63, standards for hazardous waste combustors would apply to the source categories that are currently subject to that subpart—incinerators, cement kilns, and lightweight aggregate kilns that burn hazardous waste. Today's proposed rule, however, would also amend subpart EEE to establish MACT standards for the Phase II source categories—those boilers and hydrochloric acid production furnaces that burn hazardous waste.

Generally speaking, you are an affected source pursuant to subpart EEE if you combust, or have previously combusted, hazardous waste in an incinerator, cement kiln, lightweight aggregate kiln, boiler, or hydrochloric acid production furnace. You continue to be an affected source until you cease burning hazardous waste and initiate closure requirements pursuant to RCRA. See § 63.1200(b). If you never previously combusted hazardous waste, or have ceased burning hazardous waste and initiated RCRA closure requirements, you are not subject to subpart EEE. Rather, EPA has promulgated or proposed separate MACT standards for sources that do not burn hazardous waste within the following source categories: commercial and industrial solid waste incinerators (40 CFR part 60, subparts CCCC and DDDD); Portland cement manufacturing facilities (40 CFR part 63, subpart LLL); industrial/commercial/institutional boilers and process heaters (40 CFR part 63, proposed subpart DDDDD); and hydrochloric acid production facilities (40 CFR part 63, subpart NNNNN). In addition, EPA considered whether to establish MACT standards for lightweight aggregate manufacturing facilities that do not burn hazardous waste, and determined that they are not major sources of HAP emissions. Thus, EPA has not established MACT standards for lightweight aggregate manufacturing facilities that do not burn hazardous waste.

Note that non-stack emissions points are not regulated under subpart EEE.
1

Emissions attributable to storage and handling of hazardous waste prior to combustion (
i.e.,
emissions from tanks, containers, equipment, and process vents) would continue to be regulated pursuant to either RCRA subpart AA, BB, and CC or an applicable MACT that applies to the before-mentioned material handling devices. Emissions unrelated to the hazardous waste operations may be regulated pursuant to other MACT rulemakings. For example, Portland cement manufacturing facilities that combust hazardous waste are subject to both subpart EEE and subpart LLL, and hydrochloric acid production facilities that combust hazardous waste may be subject to both subpart EEE and subpart NNNNN.
2

In these instances subpart EEE controls HAP emissions from the cement kiln and hydrochloric acid production furnace stack, while subparts LLL and NNNNN would control HAP emissions from other operations that are not directly related to the combustion of hazardous waste (
e.g.,
clinker cooler emissions for cement production facilities, and hydrochloric acid product transportation and storage for hydrochloric acid production facilities).

1
Note, however, that fugitive emissions attributable to the combustion of hazardous waste from the combustion device are regulated pursuant to subpart EEE.

2
Hydrochloric acid production furnaces that combust hazardous waste would also be affected sources subject to subpart NNNNN if they produce a liquid acid product that contains greater than 30% hydrochloric acid.

Note that if you temporarily cease burning hazardous waste for any reason, you remain an affected source and are still subject to the applicable Subpart EEE requirements. However, even as an affected source, the proposed emission standards or operating limits derived from the hazardous waste combustors do not apply if: (1) Hazardous waste is not in the combustion chamber and you elect to comply with other MACT (or CAA section 129) standards that otherwise would be applicable if you were not burning hazardous waste,
e.g.,
the nonhazardous waste burning Portland Cement Kiln MACT (subpart LLL); or (2) you are in a startup, shutdown, or malfunction mode of operation.

E. What Are the Health Effects Associated With Pollutants Emitted by Hazardous Waste Combustors?

Today's proposed rule protects air quality and promotes the public health by reducing the emissions of some of the HAP listed in section 112(b)(1) of the CAA. Emissions data collected in the development of this proposed rule show that metals, particulate matter, hydrogen chloride and chlorine gas, dioxins and furans, and other organic compounds are emitted from hazardous waste combustors. The HAP that would

be controlled with this rule are associated with a variety of adverse health affects. These adverse health effects include chronic health disorders (
e.g.,
irritation of the lung, skin, and mucus membranes and effects on the blood, digestive tract, kidneys, and central nervous system), and acute health disorders (
e.g.,
lung irritation and congestion, alimentary effects such as nausea and vomiting, and effects on the central nervous system). Provided below are brief descriptions of risks associated with HAP that are emitted from hazardous waste combustors. Note that a more detailed discussion of the risks associated with these emissions is included in Part Four.

Antimony

Antimony occurs at very low levels in the environment, both in the soils and foods. Higher concentrations, however, are found at antimony processing sites, and in their hazardous wastes. The most common industrial use of antimony is as a fire retardant in the form of antimony trioxide. Chronic occupational exposure to antimony (generally antimony trioxide) is most commonly associated with “antimony pneumoconiosis,” a condition involving fibrosis and scarring of the lung tissues. Studies have shown that antimony accumulates in the lung and is retained for long periods of time. Effects are not limited to the lungs, however, and myocardial effects (effects on the heart muscle) and related effects (
e.g.,
increased blood pressure, altered EKG readings) are among the best-characterized human health effects associated with antimony exposure. Reproductive effects (increased incidence of spontaneous abortions and higher rates of premature deliveries) have been observed in female workers exposed in antimony processing facilities. Similar effects on the heart, lungs, and reproductive system have been observed in laboratory animals.

EPA recently assessed the carcinogenicity of antimony and found the evidence for carcinogenicity to be weak, with conflicting evidence from inhalation studies with laboratory animals, equivocal data from the occupational studies, negative results from studies of oral exposures in laboratory animals, and little evidence of mutagenicity or genotoxicity.
3

As a consequence, EPA concluded that insufficient data are available to adequately characterize the carcinogenicity of antimony and, accordingly, the carcinogenicity of antimony cannot be determined based on available information. However, IARC (International Agency for Research on Cancer) in an earlier evaluation, concluded that antimony trioxide is “possibly carcinogenic to humans” (Group 2B).

3

See
“Evaluating the Carcinogenicity of Antimony,” Risk Assessment Issue Paper (98-030/07-26-99), Superfund Technical Support Center, National Center for Environmental Assessment, July 26, 1999.

Arsenic

Acute (short-term) high-level inhalation exposure to arsenic dust or fumes has resulted in gastrointestinal effects (nausea, diarrhea, abdominal pain), and central and peripheral nervous system disorders. Chronic (long-term) inhalation exposure to inorganic arsenic in humans is associated with irritation of the skin and mucous membranes. Human data suggest a relationship between inhalation exposure of women working at or living near metal smelters and an increased risk of reproductive effects, such as spontaneous abortions. Inorganic arsenic exposure in humans by the inhalation route has been shown to be strongly associated with lung cancer, while ingestion or inorganic arsenic in humans has been linked to a form of skin cancer and also to bladder, liver, and lung cancer. EPA has classified inorganic arsenic as a Group A, human carcinogen.

Beryllium

Beryllium is a hard, grayish metal naturally found in minerals, rocks, coal, soil, and volcanic dust. Beryllium dust enters the air from burning coal and oil. This beryllium dust will eventually settle over the land and water. It enters water from erosion of rocks and soil, and from industrial waste. Some beryllium compounds will dissolve in water, but most stick to particles and settle to the bottom. Most beryllium in soil does not dissolve in water and remains bound to soil. Beryllium does not accumulate in the food chain.

Beryllium can be harmful if you breathe it. The effects depend on how much you are exposed to and for how long. If beryllium air levels are high enough, an acute condition can result. This condition resembles pneumonia and is called acute beryllium disease. Long-term exposure to beryllium can increase the risk of developing lung cancer.

Cadmium

The acute (short-term) effects of cadmium inhalation in humans consist mainly of effects on the lung, such as pulmonary irritation. Chronic (long-term) inhalation or oral exposure to cadmium leads to a build-up of cadmium in the kidneys that can cause kidney disease. Cadmium has been shown to be a developmental toxicant in animals, resulting in fetal malformations and other effects, but no conclusive evidence exists in humans. An association between cadmium exposure and an increased risk of lung cancer has been reported from human studies, but these studies are inconclusive due to confounding factors. Animal studies have demonstrated an increase in lung cancer from long-term inhalation exposure to cadmium. EPA has classified cadmium as a Group B1, probable carcinogen.

Chlorine Gas

Acute exposure to high levels of chlorine in humans can result in chest pain, vomiting, toxic pneumonitis, and pulmonary edema. At lower levels chlorine is a potent irritant to the eyes, the upper respiratory tract, and lungs. Chronic exposure to chlorine gas in workers has resulted in respiratory effects including eye and throat irritation and airflow obstruction. Animal studies have reported decreased body weight gain, eye and nose irritation, nonneoplastic nasal lesions, and respiratory epithelial hyperplasia from chronic inhalation exposure to chlorine. No information is available on the carcinogenic effects of chlorine in humans from inhalation exposure. We have not classified chlorine for potential carcinogenicity.

Chromium

Chromium may be emitted in two forms, trivalent chromium (chromium III) or hexavalent chromium (chromium VI). The respiratory tract is the major target organ for chromium VI toxicity, for acute (short-term) and chronic (long-term) inhalation exposures. Shortness of breath, coughing, and wheezing have been reported from acute exposure to chromium VI, while perforations and ulcerations of the septum, bronchitis, decreased pulmonary function, pneumonia, and other respiratory effects have been noted from chronic exposure. Limited human studies suggest that chromium VI inhalation exposure may be associated with complications during pregnancy and childbirth, while animal studies have not reported reproductive effects from inhalation exposure to chromium VI. Human and animal studies have clearly established that inhaled chromium VI is a carcinogen, resulting in an increased risk of lung cancer. EPA has classified chromium VI as a Group A, human carcinogen.

Chromium III is less toxic than chromium VI. The respiratory tract is also the major target organ for

chromium III toxicity, similar to chromium VI. Chromium III is an essential element in humans, with a daily intake of 50 to 200 micrograms per day recommended for an adult. The body can detoxify some amount of chromium VI to chromium III. EPA has not classified chromium III with respect to carcinogenicity.

Cobalt

Cobalt is a relatively rare metal that is produced primarily as a by-product during refining of other metals, primarily copper. Cobalt has been widely reported to cause respiratory effects in humans exposed by inhalation, including respiratory irritation, wheezing, asthma, and pneumonia. Cardiomyopathy (or damage to the heart muscle) has also been reported, although this effect is better known from oral exposure. Other effects of oral exposure in humans are polycythemia (an abnormally high number of red blood cells) and the blocking of uptake of iodine by the thyroid. In addition, cobalt is a sensitizer in humans by any route of exposure. Sensitized individuals may react to inhalation of cobalt by developing asthma or to ingestion or dermal contact with cobalt by developing dermatitis. Cobalt is a vital component of vitamin B
12
, though there is no evidence that intake of cobalt is ever limiting in the human diet.

A number of epidemiological studies have found that exposures to cobalt are associated with an increased incidence of lung cancer in occupational settings. The International Agency for Research on Cancer (IARC, part of the World Health Organization) classifies cobalt and cobalt compounds as “possibly carcinogenic to humans” (Group 2B). The American Conference of Governmental Industrial Hygienists (ACGIH) has classified cobalt as a confirmed animal carcinogen with unknown relevance to humans (category A3). An EPA assessment concludes that under EPA's 1986 guidelines, cobalt would be classified as a probable human carcinogen (group B1) based on limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in animals, as evidenced by an increased incidence of alveolar/bronchiolar tumors in recent studies of both rats and mice. Under EPA's proposed cancer guidelines, cobalt is considered likely to be carcinogenic to humans.
4

4
See “Derivation of a Provisional Carcinogenicity Assessment for Cobalt and Compounds,” Risk Assessment Issue Paper (00-122/1-15-02), Superfund Technical Support Center, National Center for Environmental Assessment, January 15, 2002.

Dioxins and Furans

Exposures to 2,3,7,8-tetrachlorodibenzo-
p
-dioxin (2,3,7,8-TCDD) at levels 10 times or less above those modeled to approximate average background exposure have resulted in adverse non-cancer health effects in animals. These effects include changes in hormone systems, alterations in fetal development, reduced reproductive capacity, and immunosuppression. Effects that may be linked to dioxin and furan exposures at low dose in humans include changes in markers of early development and hormone levels. Dioxin and furan exposures are associated with altered liver function and lipid metabolism changes in activity of various liver enzymes, depression of the immune system, and endocrine and nervous system effects. EPA in its 1985 dioxin assessment classified 2,3,7,8-TCDD as a probable human carcinogen. The International Agency for Research on Cancer (IARC) concluded in 1997 that the overall weight of the evidence was sufficient to characterize 2,3,7,8-TCDD as a known human carcinogen.
5

In 2001 the U.S. Department of Health and Human Services National Toxicology Program in their 9th Report on Carcinogens classified 2,3,7,8-TCDD as a known human carcinogen.
6

5
IARC (International Agency for Research on Cancer). (1997) IARC monographs on the evaluation of carcinogenic risks to humans. Vol. 69. Polychlorinated dibenzo-para-dioxins and polychlorinated dibenzofurans. Lyon, France.

6
The U.S. Department of Health and Human Services, National Toxicology Program 9th Report on Carcinogens, Revised January 2001.

Hydrogen Chloride/Hydrochloric Acid

Hydrogen chloride, also called hydrochloric acid, is corrosive to the eyes, skin, and mucous membranes. Acute (short-term) inhalation exposure may cause eye, nose, and respiratory tract irritation and inflammation and pulmonary edema in humans. Chronic (long-term) occupational exposure to hydrochloric acid has been reported to cause gastritis, bronchitis, and dermatitis in workers. Prolonged exposure to low concentrations may also cause dental discoloration and erosion. No information is available on the reproductive or developmental effects of hydrochloric acid in humans. In rats exposed to hydrochloric acid by inhalation, altered estrus cycles have been reported in females and increased fetal mortality and decreased fetal weight have been reported in offspring. EPA has not classified hydrochloric acid for carcinogenicity.

Lead

Lead is a very toxic element, causing a variety of effects at low dose levels. Brain damage, kidney damage, and gastrointestinal distress may occur from acute (short-term) exposure to high levels of lead in humans. Chronic (long-term) exposure to lead in humans results in effects on the blood, central nervous system (CNS), blood pressure, and kidneys. Children are particularly sensitive to the chronic effects of lead, with slowed cognitive development, reduced growth and other effects reported. Reproductive effects, such as decreased sperm count in men and spontaneous abortions in women, have been associated with lead exposure. The developing fetus is at particular risk from maternal lead exposure, with low birth weight and slowed postnatal neurobehavioral development noted. Human studies are inconclusive regarding lead exposure and cancer, while animal studies have reported an increase in kidney cancer from lead exposure by the oral route. EPA has classified lead as a Group B2, probable human carcinogen.

Manganese

Health effects in humans have been associated with both deficiencies and excess intakes of manganese. Chronic (long-term) exposure to low levels of manganese in the diet is considered to be nutritionally essential in humans, with a recommended daily allowance of 2 to 5 milligrams per day (mg/d). Chronic exposure to high levels of manganese by inhalation in humans results primarily in central nervous system (CNS) effects. Visual reaction time, hand steadiness, and eye-hand coordination were affected in chronically-exposed workers. Manganism, characterized by feelings of weakness and lethargy, tremors, a mask-like face, and psychological disturbances, may result from chronic exposure to higher levels. Impotence and loss of libido have been noted in male workers afflicted with manganism attributed to inhalation exposures. EPA has classified manganese in Group D, not classifiable as to carcinogenicity in humans.

Mercury

Mercury exists in three forms: elemental mercury, inorganic mercury compounds (primarily mercuric chloride), and organic mercury compounds (primarily methyl mercury). Each form exhibits different health effects. Various sources may release elemental or inorganic mercury; environmental methyl mercury is

typically formed by biological processes after mercury has precipitated from the air.

Acute (short-term) exposure to high levels of elemental mercury in humans results in central nervous system (CNS) effects such as tremors, mood changes, and slowed sensory and motor nerve function. High inhalation exposures can also cause kidney damage and effects on the gastrointestinal tract and respiratory system. Chronic (long-term) exposure to elemental mercury in humans also affects the CNS, with effects such as increased excitability, irritability, excessive shyness, and tremors. EPA has not classified elemental mercury with respect to cancer.

Acute exposure to inorganic mercury by the oral route may result in effects such as nausea, vomiting, and severe abdominal pain. The major effect from chronic exposure to inorganic mercury is kidney damage. Reproductive and developmental animal studies have reported effects such as alterations in testicular tissue, increased embryo resorption rates, and abnormalities of development. Mercuric chloride (an inorganic mercury compound) exposure has been shown to result in forestomach, thyroid, and renal tumors in experimental animals. EPA has classified mercuric chloride as a Group C, possible human carcinogen.

Nickel

Nickel is a commonly used industrial metal, and is frequently associated with iron and copper ores. Contact dermatitis is the most common effect in humans from exposure to nickel, whether via inhalation, oral, or dermal exposure. Cases of nickel-contact dermatitis have been reported following occupational and non-occupational exposure, with symptoms of itching of the fingers, wrists, and forearms. Many studies have also demonstrated dermal effects in sensitive humans from ingested nickel, invoking an eruption or worsening of eczema. Chronic inhalation exposure to nickel in humans results in direct respiratory effects, such as asthma due to primary irritation, or an allergic response and an increased risk of chronic respiratory tract infections.

Animal studies have reported a variety of inflammatory effects on the lungs, as well as effects on the kidneys and immune system from inhalation exposure to nickel. Significant differences in inhalation toxicity among the various forms of nickel have been documented, with soluble nickel compounds being more toxic to the respiratory tract than less soluble compounds (
e.g.,
nickel oxide). Animal studies have also reported effects on the respiratory and gastrointestinal systems, heart, blood, liver, kidney, and body weight from oral exposure to nickel, as well as to the fetus.

EPA currently classifies nickel refinery dust and nickel subsulfide (a major component of nickel refinery dust) as class A human carcinogens based on increased risks of lung and nasal cancer in human epidemiological studies of occupational exposures to nickel refinery dust, increased tumor incidences in animals by several routes of administration in several animal species, and positive results in genotoxicity assays. More recently, a pair of inhalation studies performed under the auspices of the National Toxicology Program (NTP) of the National Institutes of Health concluded that there was no evidence of carcinogenic activity of soluble nickel salts in rats or mice and that there was some evidence of carcinogenic activity of nickel oxide in male and female rats based on increased incidence of alveolar/bronchiolar adenoma or carcinoma and increased incidence of benign or malignant pheochromocytoma (a tumor of the adrenal gland) and equivocal evidence in mice based on marginally increased incidence of alveolar/bronchiolar adenoma or carcinoma in females and no evidence in males. The Tenth Annual Report on Carcinogens classifies nickel compounds as “known to be human carcinogens.”
7

This is consistent with the International Agency for Cancer Research (IARC) which classifies nickel compounds as Group 1 human carcinogens.

7
Report on Carcinogens, Tenth Edition; U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program, December 2002.

Organic HAP

Organic HAPs include halogenated and nonhalogenated organic classes of compounds such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Both PAHs and PCBs are classified as potential human carcinogens, and are considered toxic, persistent and bioaccumulative. They include compounds such as benzene, methane, propane, chlorinated alkanes and alkenes, phenols and chlorinated aromatics. Adverse health effects of HAPs include damage to the immune system, as well as neurological, reproductive, developmental, respiratory and other health problems.

Particulate Matter
8

8
The discussion of PM effects is drawn from the executive summary of the “Fourth External Review Draft of Air Quality Criteria for Particulate Matter,” National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, EPA/600/P-99/002aD, June, 2003.

Atmospheric PM is composed of sulfate, nitrate, ammonium, and other ions, elemental carbon, particle-bound water, a wide variety of organic compounds, and a large number of elements contained in various compounds, some of which originate from crustal materials and others from combustion sources. Combustion sources are the primary origin of trace metals found in fine particles in the atmosphere. Ambient PM can be of primary or secondary origin.
9

9
Secondary PM is not emitted directly but is formed in the atmosphere by gas phase or aqueous phase reactions of emissions of various precursor compounds.

A large body of evidence exists from epidemiological studies that demonstrates a relationship between ambient particulate matter (PM) and mortality and morbidity in the general population and, when combined with evidence from other studies (
e.g.,
clinical and animal studies), indicates that exposure to PM is a probable contributing cause to the adverse human health effects that have been observed. For example, many different studies report that increased cardiovascular and respiratory-related mortality risks are significantly associated with various measures (both long-term and short-term) of ambient PM. Some studies suggest that a portion of the increased mortality may be associated with concurrent exposures to PM and other criteria pollutants, such as SO
2
. Much evidence exists of positive associations between ambient PM concentrations and increased respiratory-related hospital admissions, emergency room, and other medical visits. Additional findings implicate PM as likely associated with an increased occurrence of chronic bronchitis and a contributing factor in the exacerbation of asthmatic conditions. Recent reports from prospective cohort studies of long-term ambient PM exposures provide substantial evidence of an association between increased risk of lung cancer and PM, especially exposure to fine PM or its components.

PM has other effects, beyond the health effects to human beings. The major effect of atmospheric PM on ecosystems is indirect and occurs through the deposition of nitrates and sulfates and the acidifying effects of the associated hydrogen ions contained in

wet and dry deposition.
10

Acidification of surface waters can have long-term adverse effects on aquatic ecosystems, including effects on fish populations, macro invertebrates, species richness, and zooplankton abundance. In the soil environment, acid deposition has the potential to inhibit nutrient uptake, alter the ecological processes of energy flow and nutrient cycling, change ecosystem structure, and affect ecosystem biodiversity. In addition, ambient fine particles are well known as the major cause of visibility impairment. Visibility impairment (or haziness) is widespread in the U.S. and is greatest in the eastern United States and southern California. In addition, PM exerts important effects on materials, such as soiling, corrosion, and degradation of surfaces, and accelerates weathering of man-made and natural materials.

10
Nitrates and sulfates in PM are derived primarily from emissions of SO
X
and NO
X
.

A large body of evidence exists from epidemiological studies that demonstrates a relationship between ambient particulate matter (PM) and mortality and morbidity in the general population and, when combined with evidence from other studies (
e.g.
, clinical and animal studies), indicates that exposure to PM is a probable contributing cause to the adverse human health effects that have been observed. For example, many different studies report that increased cardiovascular and respiratory-related mortality risks are significantly associated with various measures (both long-term and short-term) of ambient PM. Some studies suggest that a portion of the increased mortality may be associated with concurrent exposures to PM and other criteria pollutants, such as SO
2
. Much evidence exists of positive associations between ambient PM concentrations and increased respiratory-related hospital admissions, emergency room, and other medical visits. Additional findings implicate PM as likely associated with an increased occurrence of chronic bronchitis and a contributing factor in the exacerbation of asthmatic conditions. Recent reports from prospective cohort studies of long-term ambient PM exposures provide substantial evidence of an association between increased risk of lung cancer and PM, especially exposure to fine PM or its components.

PM has other effects, beyond the health effects to human beings. The major effect of atmospheric PM on ecosystems is indirect and occurs through the deposition of nitrates and sulfates and the acidifying effects of the associated hydrogen ions contained in wet and dry deposition.
11

Acidification of surface waters can have long-term adverse effects on aquatic ecosystems, including effects on fish populations, macro invertebrates, species richness, and zooplankton abundance. In the soil environment, acid deposition has the potential to inhibit nutrient uptake, alter the ecological processes of energy flow and nutrient cycling, change ecosystem structure, and affect ecosystem biodiversity. In addition, ambient fine particles are well known as the major cause of visibility impairment. Visibility impairment (or haziness) is widespread in the U.S. and is greatest in the eastern United States and southern California. In addition, PM exerts important effects on materials, such as soiling, corrosion, and degradation of surfaces, and accelerates weathering of man-made and natural materials.

11
Nitrates and sulfates in PM are derived primarily from emissions of SO
X
and NO
X
.

Selenium

Selenium occurs naturally in soils, is associated with copper refining, and several industrial processes, and has been used in pesticides. It is an essential element and bioaccumulates in certain plant species, and has been associated with toxic effects in livestock (blind staggers syndrome). Soils containing high levels of selenium (seleniferous soils can lead to high concentration of selenium in certain plants, and pose a hazard to livestock and other species. Bioaccumulation and magnification of selenium has also been observed in aquatic organisms and has been shown to be toxic to piscivorous fish. In humans, selenium partitions to the kidneys and liver, and is excreted through the urine and feces. Selenium intoxication in humans causes a syndrome known as selenosis. The condition is characterized by chronic dermatitis, fatigue, anorexia, gastroenteritis, hepatic degeneration, enlarged spleen and increased concentrations of Se in the hair and nails. Clinical signs of selenosis include a characteristic “garlic odor” of excess selenium excretion in the breath and urine, thickened and brittle nails, hair and nail loss, lowered hemoglobin levels, mottled teeth, skin lesions and CNS abnormalities (peripheral anesthesia, acroparesthesia and pain in the extremities). Aquatic birds are extremely sensitive to selenium; toxic effects include teratogenesis. Based on available data, both aquatic birds and aquatic mammals are sensitive ecological receptors.

II. Summary of the Proposed Rule

A. What Source Categories Are Affected by the Proposed Rule?

1. Incinerators That Burn Hazardous Waste

A hazardous waste burning incinerator is defined under § 63.1201(a) as a device that meets the definition of an incinerator in 40 CFR part 260.10 and that burns hazardous waste at any time. Hazardous waste incinerators are currently subject to the emission standards of part 63, subpart EEE.
12

Hazardous waste incinerator design types include rotary kilns, liquid injection incinerators, fluidized bed incinerators, and fixed hearth incinerators. Most incinerators have air pollution control equipment to capture particulate matter (and nonvolatile metals) and scrubbing equipment for the capture of acid gases. At least four incinerators are equipped with activated carbon injection systems or carbon beds to control dioxin/furan emissions (as well as other HAP emissions).

12
Incinerators that burn hazardous waste will also remain subject to the RCRA hazardous waste incinerator emission limitations pursuant to § 264 subpart O until they demonstrate compliance with the interim MACT standards and remove the emission limitations from their RCRA permit. See § 270.42 appendix I, section a.8 and introductory paragraph to § 270.62.

Incinerators can be further classified as either commercial or onsite. Commercial incinerators accept and treat, for a tipping fee, wastes that have been generated off-site. The purpose of commercial incinerators is to generate profit from treating hazardous wastes. On-site facilities treat only wastes that have been generated at the facility to avoid the costs of off-site treatment. In 2003, there were approximately 107 hazardous waste incinerators in operation, 15 of which were commercial facilities, the remaining being on-site facilities.

2. Cement Kilns That Burn Hazardous Waste

A hazardous waste burning cement kiln is defined under § 63.1201(a). Cement kilns that burn hazardous waste are currently subject to the emission standards of part 63, subpart EEE.
13

Cement kilns are long, cylindrical, slightly inclined rotating furnaces that are lined with refractory brick to protect the steel shell and retain heat within the

kiln. Cement kilns are designed to calcine, or expel carbon dioxide by roasting, a blend of raw materials such as limestone, shale, clay, or sand to produce Portland cement. The raw materials enter the kiln at the elevated end, and the combustion fuels generally are introduced into the lower end of the kiln where the clinker product is discharged. The materials are continuously and slowly moved to the lower end by rotation of the kiln. As they move down the kiln, the raw materials are changed to cementitious minerals as a result of increased temperatures within the kiln.

13
Cement kilns that burn hazardous waste will also remain subject to the RCRA Boilers and Industrial Furnace emission limitations pursuant to § 266 subpart H until they demonstrate compliance with the interim MACT standards and remove the emission limitations from their RCRA permit. See § 270.42 appendix I, section a.8 and introductory paragraph to § 270.66.

Portland cement is a fine powder, usually gray in color, that consists of a mixture of minerals comprising primarily calcium silicates, aluminates, and aluminoferrites, to which small amounts of gypsum have been added during the finish grinding operations. Portland cement is the key ingredient in Portland cement concrete, which is used in almost all construction applications.

Cement kilns covered by this proposal burn hazardous waste-derived fuels to replace some or all of normal fossil fuels, typically coal. Most kilns burn liquid waste; however, cement kilns also may burn solids and small containers containing viscous or solid hazardous waste fuels. The annual hazardous waste fuel replacement rate varies considerably across sources from approximately 25 to 85 percent.

In 2003, there were 14 Portland cement plants in nine states operating a total of 25 hazardous waste burning kilns. All cement kilns use either bag houses or electrostatic precipitators to control particulate matter emissions.

3. Lightweight Aggregate Kilns That Burn Hazardous Waste

A hazardous waste burning lightweight aggregate kiln is defined under § 63.1201(a). Lightweight aggregate kilns that burn hazardous waste are currently subject to the emission standards of part 63, subpart EEE.
14

Raw materials such as shale, clay, and slate are crushed and introduced at the upper end of the rotary kiln. In passing through the kiln, the materials reach temperatures of 1,900-2,100 ° F. Heat is provided by a burner at the lower end of the kiln where the product is discharged. As the raw material is heated, it melts into a semi-plastic state and begins to generate gases that serve as the bloating or expanding agent. As temperatures reach their maximum, the semi-plastic raw material becomes viscous and entraps the expanding gases. This bloating action produces small, unconnected gas cells, which remain in the material after it cools and solidifies. Lightweight aggregate kilns are designed to expand the raw material by thermal processing into a coarse aggregate used in the production of lightweight concrete products such as concrete block, structural concrete, and pavement.

14
Lightweight aggregate kilns that burn hazardous waste will also remain subject to the RCRA Boilers and Industrial Furnace emission limitations pursuant to § 266 subpart H until they demonstrate compliance with the interim MACT standards and remove the emission limitations from their RCRA permit. See § 270.42 appendix I, section a.8 and introductory paragraph to § 270.66.

The lightweight aggregate kilns affected by this proposal burn hazardous waste-derived fuels to replace some or all of normal fossil fuels. Two of the facilities burn only liquid hazardous wastes, while the third facility burns both liquid and solid wastes. The annual hazardous waste fuel replacement rate is 100 percent.

In 2003, there were three lightweight aggregate kiln facilities in two states operating a total of seven hazardous waste-fired kilns. All lightweight aggregate kilns use baghouses to control particulate matter and one facility also uses a venturi scrubber to control acid gas emissions.

4. Boilers That Burn Hazardous Waste

Boilers that burn hazardous waste are currently regulated under RCRA at part 266, subpart H. We propose to use the RCRA definition of boiler under 40 CFR 260.10 for purposes of today's rulemaking for simplicity and continuity. This definition includes industrial, commercial, and institutional boilers as well as thermal units known in industry as process heaters. We propose to subcategorize boilers based on the type of fuel that is burned, which would result in separate emission standards for solid fuel-fired boilers and liquid fuel-fired boilers. We discuss subcategorization options in more detail in Part Two, Section II.

Boilers are typically described by either their design or type of fuel burned. Hazardous waste burning boilers comprise two basic different boiler designs—watertube and firetube. The choice of which design to use depends on factors such as the desired steam quality, thermal efficiency, size, economics, fuel type, and responsiveness. Watertube boilers are those that flow the water through tubes running the length of the boiler. The hot combustion gas surrounds these tubes, causing the water inside to get hot. Most hazardous waste burning boilers use this design. Watertube boilers can also burn a variety of fuel types including coal, oil, gas, wood, and municipal or industrial wastes. Firetube boilers are similar to watertube type, except the placement of the water and combustion gas is reversed. Here the hot combustion gas flows through the tubes, while the water surrounds the tubes. This design does have some disadvantages, however, in that they work well with only gas and liquid fuels.

Process heaters are similar to boilers (as conventionally defined), except they heat a fluid other than water. This fluid is often an oil or some other fluid with more suitable heating properties. Process heaters are often used in circumstances where the amount of heat needed is greater than what can be delivered by steam. For the purposes of this rulemaking and consistent with current RCRA regulations, process heaters would be classified as boilers.

Descriptions of liquid and solid fuel-fired boilers that burn hazardous waste are provided below.

a. Liquid Fuel-Fired Boilers. A liquid fuel-fired boiler is a device that meets the definition of a boiler under 40 CFR 260.10 and that burns any combination of liquid and gas fuels, but no solids. See proposed definition in § 63.1201(a). A liquid fuel is defined as a fuel that is pumpable (
e.g.
, liquid wastes, sludges, or slurries). Most liquid hazardous waste burning boilers co-fire natural gas, fuel oil, or process gases to achieve the proper combustion temperatures and a consistent steam supply.

There are approximately 104 liquid fuel-fired boilers that burn hazardous waste, 85 of which have not installed back-end air pollution control equipment. The rest of the liquid boilers use either a wet scrubber, electrostatic precipitator, or fabric filter. These boilers co-fire liquid hazardous waste with either natural gas or heating oil at heat input rates of 10% to 100%.

b. Solid Fuel-Fired Boilers. A solid fuel-fired boiler is a device that meets the definition of a boiler under 40 CFR 260.10 and that burns solid fuels, including both pulverized and stoker coal.
15

See proposed definition in § 63.1201(a). Boilers that co-fire solid fuel with liquid or gaseous fuels are solid fuel-fired boilers.

15
Please note that the RCRA definition of boiler includes devices defined under part 63 as boilers and process heaters.

There are 12 solid fuel-fired boilers that burn hazardous waste. These boilers co-fire liquid hazardous waste with coal at heat input rates of 6% to 33%. Nine of these boilers are stoker-fired, and three burn pulverized coal. Two boilers are equipped with fabric filters to control particulate matter and

metals, and 10 are equipped with electrostatic precipitators.

5. Hydrochloric Acid Production Furnaces That Process Hazardous Waste

Hydrochloric acid production furnaces that burn hazardous waste are currently regulated under RCRA at part 266, subpart H. We propose to use the RCRA definition of hydrochloric acid production furnace under 40 CFR 260.10 for purposes of today's rulemaking for simplicity and continuity. See proposed definition in § 63.1201(a).

Hydrochloric acid production furnaces burn chlorinated hazardous wastes to make an aqueous hydrochloric acid for on-site use as an ingredient in a manufacturing process. The hazardous waste feedstocks have a chlorine content of over 20% by weight. The hydrochloric acid produced by burning the chlorinated byproducts dissolves in the scrubber water to produce an acid product containing hydrochloric acid greater than 3% by weight. There are 17 hazardous waste burning hydrochloric acid production furnaces currently in operation.

Chlorine-bearing feedstreams, wastes, and auxiliary fuels (usually natural gas) are burned in these hydrochloric acid production furnaces in a refractory lined chamber similar to a liquid waste incinerator chamber. Combustion is maintained at a high temperature, with adequate excess hydrogen to ensure the conversion of chlorine in the feedstreams to hydrogen chloride in the combustion gases. Many furnaces also have waste heat boilers, similar to those used by some incinerators, to recover heat and return it to the production process. Others use a water spray quench to cool the combustion gases.

The cooled combustion flue gas is routed to an acid recovery system, consisting of multiple wet scrubbing absorption units. These units are usually packed tower or film tray scrubbers which operate with an acidic scrubbing solution. The scrubbing solution is recycled to concentrate the acid until it reaches the desired concentration level, at which point it is recovered for use as a valuable product. A final polishing scrubber, operated with a caustic liquid solution, is used to control emissions of hydrogen chloride and chlorine gas.

B. What HAP Are Emitted?

Incinerators, cement kilns, lightweight aggregate kilns, and hydrochloric acid production furnaces that burn hazardous waste can emit high levels of dioxin/furans depending on the design and operation of the emission control equipment, and, for incinerators, whether a waste heat recovery boiler is used. Our data base shows that boilers that burn hazardous waste generally do not emit high levels of dioxin/furans.

All hazardous waste combustors can emit high levels of other organic HAP if they are not designed, operated, and maintained to operate under good combustion conditions.

Hazardous waste combustors can also emit high levels of metal HAP, depending on the level of metals in the waste feed and the design and operation of air emissions control equipment. Hydrochloric acid production furnaces, however, generally feed and emit low levels of metal HAP.

Hazardous waste combustors can also emit high levels of particulate matter, except that hydrochloric acid production furnaces generally feed wastes with low ash content and emit low levels of particulate matter.
16

The majority of particulate matter emissions from hazardous waste combustors is in the form of fine particulate (
i.e.
, 50% or more of the particulate matter emitted is 2.5 microns in diameter or less).
17

Particulate emissions from incinerators and liquid fuel-fired boilers depend on the ash content of the waste feed and the design and operation of air emission control equipment. Particulate emissions from cement kilns and lightweight aggregate kilns are not significantly affected by the ash content of the hazardous waste fuel because uncontrolled particulate emissions are attributable primarily to raw material entrained in the combustion gas. Thus, particulate emissions from kilns depend on operating conditions that affect entrainment of raw material, and the design and operation of the emission control equipment.

16
Emissions of particulate matter are of interest because metal HAP, except notably for mercury, are in the particulate form in stack gas. Thus, controlling particulate matter controls metal HAP.

17
Particulate size distributions are somewhat dependent on the type of combustor. See USEPA “Draft Technical Support Document for HWC MACT Replacement Standards, Volume V: Emission Estimates and Engineering Costs,” March 2004, Chapter 7 for more information.

C. Does Today's Proposed Rule Apply to My Source?

The following sources that burn hazardous waste are considered to be affected sources subject to today's proposed rule: Incinerators, cement kilns, lightweight aggregate kilns, boilers, and hydrochloric acid production furnaces. Affected sources do not include: (1) Sources exempt from regulation under 40 CFR part 266, subpart H, because the only hazardous waste they burn is listed under 40 CFR 266.100(c); (2) research, development, and demonstration sources exempt under § 63.1200(b); and (3) boilers exempt from regulation under 40 CFR part 266, subpart H, because they meet the definition of small quantity burner under 40 CFR 266.108. See § 63.1200(b).

Affected sources also do not include emission points that are unrelated to the combustion of hazardous waste (
e.g.
, cement kiln clinker cooler stack emissions, hydrochloric acid production facility emissions originating from product or waste storage tanks and transfer operations,
etc.
). This is because subpart EEE only controls HAP emission points that are directly related to the combustion of hazardous waste. Under separate rulemakings, the Agency has or will establish MACT standards, where warranted, to control HAP emissions from non-hazardous waste related emission points.

Hazardous waste combustors are affected sources irrespective of whether they are major sources or area sources. As discussed in Part Two, Section I.A, we are proposing to subject area sources of boilers and hydrochloric acid production furnaces to the major source MACT standards for mercury, dioxin/furans, carbon monoxide/hydrocarbons, and destruction and removal efficiency pursuant to section 112(c)(6). As promulgated in the 1999 rule, both area source and major source incinerators, cement kilns, and lightweight aggregate kilns will continue to be subject to the full suite of Subpart EEE emission standards.

D. What Emissions Limitations Must I Meet?

Under today's proposal, you would have to comply with the emission limits in Tables 1 and 2. Note that these emission limitations are discussed in greater detail for each source category (and subcategory) in Part Two, Section VII thru XII. Note also that we are proposing several alternative emission standards: (1) You may elect to comply with an alternative to the particulate matter standard for incinerators and liquid fuel-fired boilers that would limit emissions of total metal HAP; and (2) you may elect to comply with an alternative to the total chlorine standard applicable to all source categories, except hydrochloric acid production furnaces, under which you may establish site-specific, risk-based emission limits for hydrogen chloride and chlorine gas based on national

exposure standards. These alternative standards are discussed in Part Two, Section XVIII and Section XIII, respectively.

Table 1.—Proposed Standards for Existing Sources

Incinerators
Cement kilns
Lightweight aggregate kilns

Solid fuel-fired boilers
1

Liquid fuel-fired boilers
1

Hydrochloric acid production furnaces
1

Dioxin/Furans ( ng TEQ/dscm)

0.28 for dry APCD and WHB sources;
6
0.40 for others

0.20 or 0.40 + 400°F at APCD inlet
0.40
CO or THC standard as a surrogate
0.40 for dry APCD sources; CO or HC standard as surrogate for others
0.40

Mercury
130 ug/dscm

64 ug/dscm
2

67 ug/dscm
2

10 ug/dscm

3.7E-6 lb/MMBtu
2, 5

Total chlorine standard as surrogate

Particulate Matter

0.015 gr/dscf
8

0.028 gr/dscf
0.025 gr/dscf

0.030 gr/dscf
8

0.032 gr/dscf
8

Total chlorine standard as surrogate

Semivolatile Metals (lead + cadmium)
59 ug/dscm

4.0E-4 lbs/MMBtu
5

3.1E-4 lb/MMBtu
5
and 250 ug/dscm
3

170 ug/dscm

1.1E-5 lb/MMBtu
2, 5

Total chlorine standard as surrogate

Low Volatile Metals (arsenic + beryllium + chromium)
84 ug/dscm

1.4E-5 lbs/MMBtu
5

9.5E-5 lbs/MMBtu
5
and 110 ug/dscm
3

210 ug/dscm

1.1E-4 lb/MMBtu
4, 5

Total chlorine standard as surrogate

Total Chlorine (hydrogen chloride + chlorine gas)

1.5 ppmv
7

110 ppmv
7

600 ppmv
7

440 ppmv
7

2.5E-2 lb/MMBtu
5, 7

14 ppmv or 99.9927% system removal efficiency

Carbon Monoxide (CO) or Hydrocarbons HWC
100 ppmv CO or 10 ppmv HWC
See Part Two, Section VIII
100 ppmv CO or 20 ppmv HWC
(2) 100 ppmv CO or 10 ppmv HWC

Destruction and Removal Efficiency (DRE)
99.99% for each principal organic hazardous pollutant. For sources burning hazardous wastes F020, F021, F022, F023, F026, or F027, however, 99.9999% for each principal organic hazardous pollutant.

Notes:

1
Particulate matter, semivolatile metal, low volatile, and total chlorine standards apply to major sources only for solid fuel-fired boilers, liquid fuel-fired boilers, and hydrochloric acid production furnaces.

2
Standard is based on normal emissions data.

3
Sources must comply with both the thermal emissions and emission concentration standards.

4
Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal total for liquid fuel-fired boilers.

5
Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.

6
APCD denotes “air pollution control device”, WHB denotes “waste heat boiler”.

7
Sources may elect to comply with site-specific, risk-based emission limits for hydrogen chloride and chlorine gas based on national exposure standards. See Part Two, Section XIII.

8
Sources may elect to comply with an alternative to the particulate matter standard. See Part Two, Section XVIII.

Table 2.—Proposed Standards for New Sources

Incinerators
Cement kilns
Lightweight aggregate kilns

Solid fuel boilers
1

Liquid fuel boilers
1

Hydrochloric acid production furnaces
1

Dioxin/Furans ( ng TEQ/dscm)

0.11 for dry APCD or WHBs
5
; 0.2 for others

0.20 or 0.40 + 400°F at inlet to particulate matter control device
0.40
Carbon monoxide (CO) or hydrocarbon (HC) as a surrogate
0.015 or 400°F at the inlet to particulate matter control device for dry APCD; CO or HC standard as surrogate for others
0.40

Mercury
8 ug/dscm

35 ug/dscm
2

67 ug/dscm
2

10 ug/dscm

3.8E-7 lb/MMBtu
2, 4

Tcl as surrogate

Particulate matter

0.00070 gr/dscf
7

0.0058 gr/dscf
0.0099 gr/dscf

0.015 gr/dscf
7

0.0076 gr/dscf
7

TCL as surrogate

Semivolatile Metals (lead + cadmium)
6.5 ug/dscm

6.2E-5 lb/MMBtu
4

2.4E-5 lb/MMBtu
4

170 ug/dscm

4.3E-6 lb/MMBtu
2, 4

TCL as surrogate

Low Volatile Metals (arsenic + beryllium + chromium)
8.9 ug/dscm

1.4E-5 lb/MMBtu
4

3.2E-5 lb/MMBtu
4

190 ug/dscm

3.6E-5 lb/MMBtu in HW
3, 4

TCL as surrogate

Total Chlorine (Hydrogen chloride + chlorine gas)

0.18 ppmv
6

78 ppmv
6

600 ppmv
6

73 ppmv
6

7.2E-4 lb/MMBtu
4, 6

1.2 ppmv or 99.99937% SRE

Carbon monoxide CO or Hydrocarbons (HWC)
100 ppmv (CO) or 10 ppmv HWC
See Part Two, Section VIII
100 ppmv CO or 20 ppmv HWC
100 ppmv CO or 10 ppmv HWC

Destruction and Removal Efficiency
99.99% for each principal organic hazardous pollutant. For sources burning hazardous wastes F020, F021, F022, F023, F026, or F027, however, 99.9999% for each principal organic hazardous pollutant.

Notes:

1
Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards apply to major sources only for solid fuel-fired boilers, liquid fuel-fired boilers, and hydrochloric acid production furnaces.

2
Standard is based on normal emissions data.

3
Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal total for liquid fuel-fired boilers.

4
Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.

5
APCD denotes “air pollution control device”, WHB denotes “waste heat boiler”.

6
Sources may elect to comply with site-specific, risk-based emission limits for hydrogen chloride and chlorine gas based on national exposure standards. See Part Two, Section XIII.

7
Sources may elect to comply with an alternative to the particulate matter standard. See Part Two, Section XVIII.

E. What Are the Testing and Initial Compliance Requirements?

We are proposing testing and initial compliance requirements for solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces that are identical to those that are applicable to incinerators, cement kilns, and lightweight aggregate kilns already in place at §§ 63.1206, 63.1207, and 63.1208. Please note also that in Part Three of today's preamble we request comment on, or propose revisions to, several testing and initial compliance requirements. Any amendments to the testing and compliance requirements that we promulgate as a result of those discussions would be applicable to all hazardous waste combustors.

In addition, we are proposing to revise the existing initial compliance requirements for incinerators, cement kilns, and lightweight aggregate kilns. Under the proposed revision, owners and operators of incinerators, cement kilns, and lightweight aggregate kilns would be required to conduct the initial comprehensive performance test to document compliance with the replacement standards proposed today (§§ 63.1219, 63.1220, and 63.1221) within 12 months of the compliance date. Owners and operators of solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces would be required to conduct an initial comprehensive performance test within six months of the compliance date, and periodic comprehensive performance tests every five years. The purpose of the comprehensive performance test is to document compliance with the emission standards, document that continuous monitoring systems meet performance requirements, and establish limits on operating parameters that would be monitored by continuous monitoring systems.

Owners and operators of liquid fuel-fired boilers equipped with a dry air pollution control device and hydrochloric acid production furnaces would be required to conduct a dioxin/furan confirmatory performance test 2.5 years after each comprehensive performance test (
i.e.
, midway between comprehensive performance tests). The purpose of the dioxin/furan confirmatory performance test is to document compliance with the dioxin/furan standard when operating within the range of normal operations. Owners and operators of solid fuel-fired boilers, and liquid fuel-fired boilers that are not subject to a numerical dioxin/furan emission standard (
i.e.
, liquid fuel-fired boilers other than those equipped with an electrostatic precipitator or fabric filter), would be required to conduct a one-time dioxin/furan test to enable the Agency to evaluate the effectiveness of the carbon monoxide/hydrocarbon standard and destruction and removal efficiency standard in controlling dioxin/furan emissions for those sources. The Agency would use those emissions data when reevaluating the MACT standards under section 112(d)(6) and when determining whether to develop residual risk standards for these sources pursuant to CAA section 112(f)(2).

Owners and operators of solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces would be required to use the following stack test methods to document compliance: (1) Method 29 for mercury, semivolatile metals, and low volatile metals; and (2) Method 26A for hydrogen chloride and chlorine gas; (3) either Method 0023A or Method 23 for dioxin/furans; and (4) either Method 5 or 5i for particulate matter.

The following is a proposed time-line for testing and initial compliance requirements for owners and operators of solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces: (1) The compliance date is three years from publication of the final rule; (2) you must place in the operating record a Documentation of Compliance by the compliance date identifying that the operating parameter limits you have determined using available information will ensure compliance with the emission standards; (3) you must commence the initial comprehensive performance test within six months of the compliance date; (4) you must complete the initial comprehensive performance test within 60 days of commencing the test; and (5) you must submit a Notification of Compliance within 90 days of completing the test documenting compliance with emission standards and CMS requirements.

F. What Are the Continuous Compliance Requirements?

We are proposing continuous compliance requirements for solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces that are identical to those already in place at § 63.1209 and applicable to incinerators, cement kilns, and lightweight aggregate kilns. Please note, however, that in Part Three of today's preamble we request comment on, or propose revisions to, several continuous compliance requirements. Any amendments to the continuous compliance requirements that we promulgate as a result of those discussions would be applicable to all hazardous waste combustors.

Owners and operators of solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces would be required to use carbon monoxide or hydrocarbon continuous emissions monitors (as well as an oxygen continuous emissions monitor to correct the carbon monoxide or hydrocarbon values to 7% oxygen) to ensure compliance with the carbon monoxide or hydrocarbon emission limits.

Owners and operators of solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces would also be required to establish limits on the feedrate of metals, chlorine, and (for some source categories) ash, key combustor operating parameters, and key operating parameters of the control device based on operations during the comprehensive performance test. You must continuously monitor these parameters with continuous monitoring systems. See Part Two, Section XIV.C for a discussion of the specific parameters for which you must establish limits.

G. What Are the Notification, Recordkeeping, and Reporting Requirements?

We are proposing notification, recordkeeping, and reporting requirements for solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric acid production furnaces that are identical to those already in place at §§ 63.1210 and 63.1211 and applicable to incinerators, cement kilns, and lightweight aggregate kilns. Please note, however, that we are proposing a new requirement applicable to all hazardous waste combustors that would require you to submit a Notification of Intent to Comply and a Compliance Progress Report. See Part Two, Section XVI.B.

The proposed notification, recordkeeping, and reporting requirements are summarized in Part Two, Section XVI.

Part Two: Rationale for the Proposed Rule

I. How Did EPA Determine Which Hazardous Waste Combustion Sources Would Be Regulated

A. How Are Area Sources Regulated?

We are proposing to subject area source boilers and hydrochloric acid production furnaces to the major source MACT standards for mercury, dioxin/furan, carbon monoxide/hydrocarbons, and destruction and removal efficiency pursuant to section 112(c)(6).
18

Both area source and major source incinerators, cement kilns, and lightweight aggregate kilns will continue to be subject to the full suite of Subpart EEE emission standards.
19

18
We are using carbon monoxide or hydrocarbons and destruction and removal efficiency as surrogates for control of polycyclic organic matter emissions.

19
In support of the 1999 Final Rule, EPA determined incinerators, cement kilns, and lightweight aggregate kilns that are area sources can emit HAP at levels that pose a hazard to human health and the environment. Accordingly, EPA subjected area sources within those source categories to the same emission standards that apply to major sources. See 64 FR at 52837-38.

Section 112(c)(6) of the CAA requires EPA to list and promulgate section 112(d)(2) or (d)(4) standards (
i.e.
, standards reflecting MACT) for categories and subcategories of sources emitting seven specific pollutants. Four of those listed pollutants are emitted by boilers and hydrochloric acid production furnaces: mercury, 2,3,7,8-tetrachlorodibenzofuran, 2,3,7,8-tetrachlorodibenzo-p-dioxin, and polycyclic organic matter. EPA must assure that source categories accounting for not less than 90 percent of the aggregated emissions of each enumerated pollutant are subject to MACT standards. Congress singled out the pollutants in section 112(c)(6) as being of “specific concern” not just because of their toxicity but because of their propensity to cause substantial harm to human health and the environment via indirect exposure pathways (
i.e.
, from the air through other media, such as water, soil, food uptake, etc.). Furthermore, these pollutants have exhibited special potential to bioaccumulate, causing pervasive environmental harm in biota and, ultimately, human health risks.

We estimate that approximately 1,800 pounds of mercury are emitted annually in aggregate from hazardous waste burning boilers in the United States.
20

Also, we estimate that hazardous waste burning boilers and hydrochloric acid production furnaces emit in aggregate approximately 1.1 and 1.6 grams TEQ per year of dioxin/furan, respectively. The Agency has already counted on the control of these pollutants from area sources in the industrial/commercial/institutional boiler source category when we accounted for at least 90 percent of the emissions of these hazardous air pollutants as being subject to standards under section 112(c)(6). See 63 FR 17838; April 10, 1998. Therefore, we are proposing to subject boiler and hydrochloric acid furnace area sources to the major source MACT standards for mercury, dioxin/furan, carbon monoxide/hydrocarbons, and destruction and removal efficiency pursuant to section 112(c)(6).

20
See USEPA “Draft Technical Support Document for HWC MACT Replacement Standards, Volume V: Emission Estimates and Engineering Costs,” March, 2004, Chapter 3.

We are proposing that only major source boilers and hydrochloric acid furnaces would be subject to the full suite of subpart EEE emission standards we propose today. Section 112(c)(3) of the CAA requires us to subject area sources to the full suite of standards applicable to major sources if we find “a threat of adverse effects to human health or the environment” that warrants such action. We cannot make this finding for area source boilers and halogen acid production furnaces.
21

Consequently, area sources in these categories would be subject to the MACT standards for mercury, dioxin/furan, carbon monoxide/hydrocarbons, and destruction and removal efficiency standards only to control the HAP listed under section 112(c)(6). RCRA standards under Part 266, Subpart H for particulate matter, metals other than mercury, and hydrogen chloride and chlorine gas would continue to apply to these area sources unless an area source elects to comply with the major source standards in lieu of the RCRA standards. See proposed § 266.100(b)(3) and the proposed revisions to §§ 270.22 and 270.66.

21
We believe that two or fewer boilers are area sources. We do not believe any hydrochloric acid production furnaces are area sources.

B. What Hazardous Waste Combustors Are Not Covered by This Proposal?

1. Small Quantity Burners

Boilers that are exempt from the RCRA hazardous waste-burning boilers rule under 40 CFR 266.108 because they burn small quantities of hazardous waste fuel would also be exempt from today's proposed rule. Those boilers would be subject, however, to the MACT standards the Agency has proposed for industrial/commercial/institutional boilers. See 68 FR 1660, January 13, 2003.

The type and concentration of HAP emissions from boilers that co-fire small quantities of hazardous waste fuel with other fuels under § 266.108 should be characterized more by the metals and chlorine levels in the primary fuels and the effect of combustion conditions on the primary fuels than by the composition and other characteristics of the hazardous waste fuel. Under § 266.108, boilers that burn small quantities of hazardous waste fuel cannot fire hazardous waste at any time at a rate greater than 1 percent of the

total fuel requirements for the boiler. In addition, a boiler with a stack height of 20 meters or less cannot fire more than 84 gallons of hazardous waste fuel a month, which would equate to an average firing rate of 0.5 quarts per hour. Finally, the hazardous waste fuel must have a heating value of 5,000 Btu/lb to ensure it is a bonafide fuel, and cannot contain hazardous wastes that are listed because they contain chlorinated dioxins/furans. Given these restrictions, we believe that HAP emissions are not substantially related to the hazardous waste fuels these boilers burn. Thus, these boilers are more appropriately regulated under the MACT standards proposed at part 63, subpart DDDDD, than the MACT standards proposed today for hazardous waste combustors.

Boilers that burn small quantities of hazardous waste fuel under § 266.108 would become subject to part 63, subpart DDDDD, three years after publication of the final rule for hazardous waste combustors (
i.e.
, the rules we are proposing today). Subpart DDDDD exempts “a boiler or process heater required to have a permit under section 3005 of the Solid Waste Disposal Act [
i.e.
, RCRA] or covered by 40 CFR part 63, subpart EEE (
e.g.
, hazardous waste combustors).” See 40 CFR 63.7491(d). Boilers that burn small quantities of hazardous waste fuel under § 266.108 are exempt from the substantive emission standards of part 266, subpart H, and the permit requirements of 40 CFR part 270 (establishing RCRA permit requirements). In addition, owners and operators of such boilers would not know whether they are covered by part 63, subpart EEE, until we promulgate the final rule for hazardous waste combustors. Thus, it is appropriate to require that these boilers begin complying with subpart DDDDD three years after we publish the final rule for hazardous waste combustors.

2. Sources Exempt From RCRA Emission Regulation Under 40 CFR Part 266.100(c)

Consistent with the Phase I Hazardous Waste Combustor MACT rule promulgated in 1999, we would not subject boilers and hydrochloric acid production furnaces to today's proposed requirements if the only hazardous waste combusted is exempt from regulation pursuant to § 266.100(c), including certain types of used oil, landfill gas, and otherwise exempt or excluded waste. This is appropriate because HAP emissions from sources that qualify for this exemption would not be significantly impacted by the combustion of hazardous waste. Thus, emissions from these sources would be more appropriately regulated by other promulgated MACT standards that specifically address emissions from these sources.

3. Research, Development, and Demonstration Sources

Consistent with the Phase I Hazardous Waste Combustor MACT rule promulgated in 1999, we would not subject boilers and hydrochloric acid production furnaces that are research, development, and demonstration sources to today's proposed requirements. We explained at promulgation of the Phase I MACT standards that the hazardous waste combustor emission standards may not be appropriate for research, development, and demonstration sources because of their typically intermittent operations and small size. See 64 FR at 52839. Given that emissions from these sources are addressed under RCRA on case-by-case basis pursuant to § 270.65, we continue to believe this is appropriate, and we are today proposing the same exemption for boilers and hydrochloric acid production furnaces.

C. How Would Sulfuric Acid Regeneration Facilities Be Regulated?

Sulfuric acid regeneration facilities burn spent sulfuric acid and sulfur-bearing hazardous wastes or hazardous waste fuel to produce sulfuric acid and are subject to 40 CFR part 266, subpart H, (
i.e.
, the RCRA Boiler and Industrial Furnace Rule) as a listed industrial furnace. We are not proposing MACT standards for these sources because EPA did not list sulfuric acid regeneration facilities as a category of major sources of HAP emissions. See 57 FR 31576 (July 16, 1992). We obtained emissions and other data on these sources and confirmed that they emit very low levels of HAP.
22

Accordingly, these combustors will remain subject to RCRA regulations under part 266, subpart H.

22
See U.S. EPA, “Draft Technical Support Document for HWC MACT Replacement Standards, Volume II: HWC Emissions Data Base,” March 2004.

II. What Subcategorization Considerations Did EPA Evaluate?

CAA section 112(d)(1) allows us to distinguish amongst classes, types, and sizes of sources within a category when establishing floor levels. Subcategorization typically reflects “differences in manufacturing process, emission characteristics, or technical feasibility.” See 67 FR 78058. A classic example, provided in the legislative history to CAA 112(d), is of a different process leading to different emissions and different types of control strategies—the specific example being Soderberg and prebaked anode primary aluminum processes. See “A Legislative History of the Clean Air Act Amendments of 1990,” vol. 1 at 1138-39 (floor debates on Conference Report). If we determine, for instance, that a given source category includes sources that are designed differently such that the type or concentration of HAP emissions are different we may subcategorize these sources and issue separate standards.

We have determined that it is appropriate to subcategorize sources that combust hazardous waste from those sources that do not. EPA published an initial list of categories of major and area sources of HAP selected for regulation in accordance with section 112(c) of the Act on July 16, 1992 (57 FR 31576). Hazardous waste incineration, Portland cement manufacturing, clay products manufacturing (including lightweight aggregate manufacturing), industrial/commercial/institutional boilers and process heaters, and hydrochloric acid production are among the listed 174 categories of sources. Although some cement kilns, lightweight aggregate kilns, boilers and process heaters, and hydrochloric acid production furnaces burn hazardous waste, EPA did not list hazardous waste burning sources as separate source categories. Nonetheless, we generally believe that hazardous waste combustion sources can emit different types or concentrations of HAP emissions because hazardous waste combustors: (1) Have different fuel HAP concentrations; (2) use different control techniques (
e.g.
, feed control); and (3) have a different regulatory history given that their toxic emissions were regulated pursuant to RCRA standards. As a result, we believe it is appropriate to subcategorize each source category listed above to define sources that burn hazardous waste as a separate classes of combustors. We also assessed if further subdividing each class of hazardous waste burning combustors is warranted using both engineering judgement and statistical analysis. In our proposed approach, we first use engineering information and principles to identify potential subcategorization options. We then determine if there is a statistical difference in the emission characteristics between these options. See Part Two, Section VI.C for a discussion of this statistical analysis. Finally, we review the results of the statistical analysis to determine whether they are an appropriate basis for

subcategorization.
23

We describe below the subcategorization options we considered for each source category.

23
For example, although the statistical analysis may find a significant difference in emission levels between potential subcategories, the emission levels may be more a function of the emission control equipment rather than a function of the design and operation of the combustors within the subcategories. If differences in emission levels are attributable to use of different emission control devices, and if there is nothing inherent in the design or operation of sources in both subcategories that would preclude applicability of those control devices, subcategorization would not be warranted.

A. What Subcategorization Options Did We Consider for Incinerators?

We considered whether to propose separate standards for three hazardous waste incinerator subcategory options. First, we assessed whether government-owned incinerator facilities had different emission characteristics when compared to non-government facilities for the mercury, semivolatile metal, low volatile metal, particulate matter, and total chlorine floors. After evaluating the data, we determined that emission characteristics from these two subcategories are not statistically different, and, therefore are not proposing separate emission standards.

Second, we assessed whether liquid injection incinerators emitted significantly different levels of metals and particulate matter compared to incinerators that feed solid wastes (
e.g.
, rotary kilns, fluid bed units, and hearth fired units). We define liquid injection units as those incinerators that exclusively feed pumpable waste streams and solid feed units as those that feed a combination of liquid and solid wastes. We determined that emissions of metal HAP from these potential subcategories are not statistically different.
24

We, therefore, are not proposing separate emission standards for metal HAP. The statistical analysis for particulate matter shows that emissions from liquid feed injection incinerators are higher than emissions from solid feed injection units. However, we believe that separate standards for particulate matter are not warranted because the difference in emissions was more a factor of the types of back-end air pollution devices used by the sources rather than incinerator design. We would expect particulate emissions to be potentially higher for solid feed units, not lower, because solid feed units have higher ash feedrates and air pollution control device inlet particulate matter loadings. Therefore, we must conclude that the difference is the product of less effective back-end air pollution control.

24
USEPA, “Draft Technical Support Document for HWC MACT Replacement Standards, Volume III: Selection of MACT Standards”, March 2004, Chapter 4.

Third, we assessed whether incinerators equipped with dry air pollution control devices and/or waste heat boilers have different dioxin/furan emission characteristics when compared to other sources,
i.e.
, sources with either wet air pollution control or no air pollution control devices. Our statistical analysis determined that dioxin/furan emissions from sources equipped with waste heat boilers and/or dry air pollution control devices are higher.
25

We believe use of wet air pollution control systems (and use of no air pollution control system) can result in different dioxin/furan emission characteristics because they have different post-combustion particle residence times and temperature profiles, which can affect dioxin/furan surface catalyzed formation reaction rates. As a result, we believe that it is appropriate to subcategorize these different types of combustors.

25
USEPA, “Draft Technical Support Document for HWC MACT Replacement Standards, Volume III: Selection of MACT Standards”, March 2004, Chapter 4.

Note that we do not subcategorize based on the type of air pollution control device used. See 69 FR 394 (January 5, 2004). Dioxin/furan emission characteristics are unique in that they are not typically fed into the combustion device, but rather are formed in the combustor or post combustion within ductwork, a heat recovery boiler, or the air pollution control system. Wet and dry air pollution control systems are generally not considered to be dioxin/furan control systems because their primary function is to remove metals and/or total chlorine from the combustion gas. They generally do not remove dioxin/furans from the incinerator flue gas unless they are used in tandem with carbon injection systems or carbon beds. (In contrast, carbon injection systems and carbon beds are considered to be dioxin/furan air pollution control systems). Thus, the differences in dioxin formation here reflect something more akin to a process difference resulting in different emission characteristics, rather than a difference in pollution-capture efficiencies among pollution control devices. We thus are not proposing to subcategorize based on whether a source is equipped with a dioxin/furan control system.

We also considered whether to further subcategorize based on the presence of a waste heat boiler or dry air pollution control device. Our analysis determined that dioxin/furan emissions from incinerators with waste heat boilers are not statistically different from those equipped with dry air pollution control devices.
26

We conclude that further subcategorization is not necessary. See Part Two, Section VII.A for more discussion on the proposed dioxin/furan standards for incinerators.

26
USEPA, “Draft Technical Support Document for HWC MACT Replacement Standards, Volume III: Selection of MACT Standards”, March 2004, Chapter 4.

B. What Subcategorization Options Did We Consider for Cement Kilns?

We considered subdividing hazardous waste burning cement kilns by the clinker manufacturing process: wet process kilns without in-line raw mills versus preheater/precalciner kilns with in-line raw mills. All cement kilns that burn hazardous waste use one of these clinker manufacturing processes. Based on available emissions data, we evaluated design and operating features of each process to determine if the features could have a significant impact on emissions. For the reasons discussed below, we believe that subcategorization is not warranted.

In the wet process, raw materials are ground, wetted, and fed into the kiln as a slurry. Twenty-two of the 25 cement kilns that burn hazardous waste use the wet process to manufacture clinker. In the preheater/precalciner kilns, raw materials are ground dry in a raw mill and fed into the kiln dry. The remaining three of the 25 cement kilns burning hazardous waste use preheater/precalciner kilns with in-line raw mills.

Combustion gases and raw materials move in a counterflow direction inside a cement kiln for both processes. The kiln is inclined, and raw materials are fed into the upper end while fuels are typically fired into the lower end. Combustion gases move up the kiln counter to the flow of raw materials. The raw materials get progressively hotter as they travel down the length of the kiln. The raw materials begin to soften and fuse at temperatures between 2,250 and 2,700 °F to form the clinker product.

Wet process kilns are longer than the preheater/precalciner kilns in order to facilitate evaporation of the water from the slurried raw material. The preheater/precalciner kilns begin the calcining process—heating of the limestone to drive off carbon dioxide to obtain lime (calcium oxide)—before the raw materials are fed into the kiln. This is accomplished by routing the flue gases from the kiln up through the preheater tower while the raw materials are passing down the preheater tower.

The heat of the flue gas is transferred to the raw material as they interact in the preheater tower. The precalciner is a secondary firing system—typically fired with coal—located at the base of the preheater tower.

Though not necessary in a wet process kiln, a preheater/precalciner kiln uses an alkali bypass designed to divert a portion of the flue gas to remove problematic volatile constituents such as alkalies (potassium and sodium oxides), chlorides, and sulfur that, if not removed, can lead to operating problems. In addition, removal of the alkalies is necessary so that their concentrations are below maximum acceptable levels in the clinker. An alkali bypass diverts between 10-30% of the kiln off-gas before it reaches the lower cyclone stages of the preheater tower. Without use of a bypass, the high concentration of volatile constituents at the lower cyclone stage of the preheater tower would create operational problems. Bypass gases are quenched and sent to a dedicated particulate matter control device to capture and remove the volatile constituents.

All preheater/precalciner kilns that burn hazardous waste use the hot flue gases to dry the raw materials as they are being ground in the in-line raw mill. Typically, the raw mill is operating or “on” approximately 85% of the time. The kilns with in-line raw mills must operate both in the “on” mode—gases are routed through the raw mill supporting raw material drying and preparation—and in the “off” mode—necessary down time for raw mill maintenance. Given that there are few preheater/precalciner cement kilns that burn hazardous waste, we had limited emissions data to evaluate to see if there was a significant difference in emissions. Moreover, we do not have any data from a preheater/precalciner kiln operating under similar operating conditions (
e.g.
, metals and chlorine feed concentrations) both for the “on” mode and “off” mode.

We evaluated whether there was a significant difference in HAP emissions b

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A04-7858. Public record. Not legal advice.