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

Federal RegisterOct 12, 2005

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 9, 63, 260, 264, 265, 266, 270 and 271

[FRL-7971-8]

RIN 2050-AE01

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

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

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

The HAP emitted by HWCs 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 to the lung, skin, and mucus membranes, effects on the central nervous system, kidney damage, and cancer. The adverse health effects associated with exposure to these specific HAP are further described in the preamble. For many HAP, these findings have only been shown with concentrations higher than those typically in the ambient air.

This action also presents our decision regarding the February 28, 2002 petition for rulemaking submitted by the Cement Kiln Recycling Coalition, relating to EPA's implementation of the so-called omnibus permitting authority under section 3005(c) of the Resource Conservation and Recovery Act (RCRA). That section requires that each permit issued under RCRA contain such terms and conditions as permit writers determine to be necessary to protect human health and the environment. In that petition, the Cement Kiln Recycling Coalition requested 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:

The final rule is effective December 12, 2005. The incorporation by reference of Method 0023A into § 63.14 is approved by the Director of the Federal Register as of December 12, 2005.

ADDRESSES:

The official public docket is the collection of materials that is available for public viewing at the Office of Air and Radiation Docket and Information Center (Air Docket) in the EPA Docket Center, Room B-102, 1301 Constitution Ave., NW., Washington, DC.

FOR FURTHER INFORMATION CONTACT:

For more information concerning applicability and rule determinations, contact your State or local representative or appropriate EPA Regional Office representative. For information concerning rule development, contact Michael Galbraith, Waste Treatment Branch, Hazardous Waste Minimization and Management Division, (5302W), U.S. EPA, 1200 Pennsylvania Avenue, NW., Washington DC 20460, telephone number (703) 605-0567, fax number (703) 308-8433, electronic mail address

galbraith.michael@epa.gov.

SUPPLEMENTARY INFORMATION:

Regulated Entities

The promulgation of the final 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 final rule

562211

4953

Incinerator, hazardous waste

327310

3241

Cement manufacturing, clinker production

327992

3295

Ground or treated mineral and earth manufacturing

325

Chemical Manufacturers

324

Petroleum Refiners

331

Primary Aluminum

333

Photographic equipment and supplies

488, 561, 562

Sanitary Services, N.E.C.

421

Scrap and waste materials

422

Chemical and Allied Products, N.E.C

512, 541, 561, 812

Business Services, N.E.C.

512, 514, 541, 711

Services, N.E.C.

924

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 entities 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.

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

μg/dscm micrograms per dry standard cubic meter

U.S.C. United States Code

Table of Contents

Part One: Background and Summary

I. What Is the Statutory Authority for this Standard?

II. What Is the Regulatory Development Background of the Source Categories in the Final Rule?

A. Phase I Source Categories

B. Phase II Source Categories

III. How Was the Final Rule Developed?

IV. What Is the Relationship Between the Final Rule and Other MACT Combustion Rules?

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

Part Two: Summary of the Final Rule

I. What Source Categories and Subcategories Are Affected by the Final Rule?

II. What Are the Affected Sources and Emission Points?

III. What Pollutants Are Emitted and Controlled?

IV. Does the Final Rule Apply to Me?

V. What Are the Emission Limitations?

VI. What Are the Testing and Initial Compliance Requirements?

A. Compliance Dates

B. Testing Requirements

C. Initial Compliance Requirements

VII. What Are the Continuous Compliance Requirements?

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

IX. What Is the Health-Based Compliance Alternative for Total Chlorine, and How Do I Demonstrate Eligibility?

A. Overview

B. HCl-Equivalent Emission Rates

C. Eligibility Demonstration

D. Assurance that the 1-Hour HCl-Equivalent Emission Rate Will Not Be Exceeded

E. Review and Approval of Eligibility Demonstrations

F. Testing Requirements

G. Monitoring Requirements

H. Relationship Among Emission Rates, Emission Rate Limits, and Feedrate Limits

I. Changes

X. Overview on Floor Methodologies

Part Three: What Are the Major Changes Since Proposal?

I. Database

A. Hazardous Burning Incinerators

B. Hazardous Waste Cement Kilns

C. Hazardous Waste Lightweight Aggregate Kilns

D. Liquid Fuel Boilers

E. HCl Production Furnaces

F. Total Chlorine Emissions Data Below 20 ppmv

II. Emission Limits

A. Incinerators

B. Hazardous Waste Burning Cement Kilns

C. Hazardous Waste Burning Lightweight Aggregate Kilns

D. Solid Fuel Boilers

E. Liquid Fuel Boilers

F. Hydrochloric Acid Production Furnaces

G. Dioxin/Furan Testing for Sources Not Subject to a Numerical Standard

III. Statistics and Variability

A. Using Statistical Imputation to Address Variability of Nondetect Values

B. Degrees of Freedom when Imputing a Standard Deviation Using the Universal Variability Factor for Particulate Matter Controlled by a Fabric Filter

IV. Compliance Assurance for Fabric Filters, Electrostatic Precipitators, and Ionizing Wet Scrubbers

V. Health-Based Compliance Alternative for Total Chlorine

Part Four: What Are the Responses to Major Comments?

I. Database

A. Revisions to the EPA's Hazardous Waste Combustor Data Base

B. Use of Data from Recently Upgraded Sources

C. Correction of Total Chlorine Data to Address Potential Bias in Stack Measurement Method

D. Mercury Data for Cement Kilns

E. Mercury Data for Lightweight Aggregate Kilns

F. Incinerator Database

II. Affected Sources

A. Area Source Boilers and Hydrochloric Acid Production Furnaces

B. Boilers Eligible for the RCRA Low Risk Waste Exemption

C. Mobile Incinerators

III. Floor Approaches

A. Variability

B. SRE/Feed Methdology

C. Air Pollution Control Technology Methodologies for the Particulate Matter Standard and for the Total Chlorine Standard for Hydrochloric Acid Production Furnaces

D. Format of Standards

E. Standards Can Be No Less Stringent Than the Interim Standards

F. How Can EPA's Approach to Assessing Variability and its Ranking Methodologies be Reasonable when they Result in Standards Higher than the Interim Standards?

IV. Use of Surrogates

A. Particulate Matter as Surrogate for Metal HAP

B. Carbon Monoxide/Hydrocarbons and DRE as Surrogates for Dioxin/Furan

C. Use of Carbon Monoxide and Total Hydrocarbons as Surrogate for Non-Dioxin Organic HAP

V. Additional Issues Relating to Variability and Statistics

A. Data Sets Containing Nondetects

B. Using Statistical Imputation to Address Variability of Nondetect Values

C. Analysis of Variance Procedures to Assess Subcategorization

VI. Emission Standards

A. Incinerators

B. Cement Kilns

C. Lightweight Aggregate Kilns

D. Liquid Fuel Boilers

E. General

VII. Health-Based Compliance Alternative for Total Chlorine

A. Authority for Health-Based Compliance Alternatives

B. Implementation of the Health-Based Standards

C. National Health-Based Standards for Cement Kilns.

VIII. Implementation and Compliance

A. Compliance Assurance Issues for both Fabric Filters and Electrostatic Precipitators (and Ionizing Wet Scrubbers)

B. Compliance Assurance Issues for Fabric Filters

C. Compliance Issues for Electrostatic Precipitators and Ionizing Wet Scrubbers

D. Fugitive Emissions

E. Notification of Intent to Comply and Compliance Progress Report

F. Startup, Shutdown, and Malfunction Plan

G. Public Notice of Test Plans

H. Using Method 23 Instead of Method 0023A

I. Extrapolating Feedrate Limits for Compliance with the Liquid Fuel Boiler Mercury and Semivolatile Metal Standards

J. Temporary Compliance with Alternative, Otherwise Applicable MACT Standards

K. Periodic DRE Testing and Limits on Minimum Combustion Chamber Temperature for Cement Kilns

L. One Time Dioxin and Furan Test for Sources Not Subject to a Numerical Limit for Dioxin and Furan

M. Miscellaneous Compliance Issues

IX. Site-Specific Risk Assessment under RCRA

A. What Is the Site-Specific Risk Assessment Policy?

B. Why Might SSRAs Continue To Be Necessary for Sources Complying With Phase 1 Replacement Standards and Phase 2 Standards?

C. What Changes Are EPA Finalizing With Respect To the Site-Specific Risk Assessment Policy?

D. How Will the New SSRA Regulatory Provisions Work?

E. What Were Commenters' Reactions to EPA's Proposed Decision Not to Provide National Criteria for Determining When an SSRA Is or Is Not Necessary?

F. What Are EPA's Responses to the Cement Kiln Recycling Coalition's Comments on the Proposal and What is EPA's Final Decision on CKRC's Petition?

X. Permitting

A. What is the Statutory Authority for the RCRA Requirements Discussed in this Section?

B. Did Commenters Express any Concerns Regarding the Current Permitting Requirements?

C. Are There Any Changes to the Proposed Class 1 Permit Modification Procedure?

D. What Permitting Approach Is EPA Finalizing for New Units?

E. What Other Permitting Requirements Were Discussed In the Proposal?

Part Five: What Are the CAA Delegation Clarifications and RCRA State Authorization Requirements?

I. Authority for this Rule.

II. CAA Delegation Authority.

III. Clarifications to CAA Delegation Provisions for Subpart EEE.

A. Alternatives to Requirements.

B. Alternatives to Test Methods.

C. Alternatives to Monitoring.

D. Alternatives to Recordkeeping and Reporting.

E. Other Delegation Provisions

IV. RCRA State Authorization and Amendments To the RCRA Regulations.

Part Six: Impacts of the Final 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. What Are the Economic Impacts?

A. Market Exit Estimates

B. Waste Reallocations

VI. What Are the Social Costs and Benefits of the Final Rule?

A. Combustion Market Overview

B. Baseline Specification

C. Analytical Methodology and Findings—Social Cost Analysis

D. Analytical Methodology and Findings—Benefits Assessment

Part Seven: How Does the Final Rule Meet the RCRA Protectiveness Mandate?

I. Background

II. Evaluation of Protectiveness

Part Eight: Statutory and Executive Order Reviews

I. Executive Order 12866: Regulatory Planning and Review

II. Paperwork Reduction Act

III. Regulatory Flexibility Act

IV. Unfunded Mandates Reform Act of 1995

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 Risks and Safety Risks

VIII. Executive Order 13211: Actions Concerning Regulations 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

Part One: Background and Summary

I. 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).

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). Hazardous waste incinerators, Portland cement plants, clay products manufacturing (including 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 these sources may reasonably be anticipated to emit one or more of the 186 listed HAP in quantities sufficient to designate them as major sources.

II. What Is the Regulatory Development Background of the Source Categories in the Final Rule?

Today's notice finalizes standards for controlling emissions of HAP from hazardous waste combustors: incinerators, cement kilns, lightweight aggregate kilns, boilers, process heaters

, and hydrochloric acid production furnaces that burn hazardous waste. 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.

A process heater meets the RCRA definition of a boiler. Therefore, process heaters that burn hazardous wastes are covered under subpart EEE as boilers, and are discussed as such in subsequent parts of the preamble.

A. 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 hazardous waste burning 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 assure control necessary to protect human health and the environment, the applicable RCRA standard. See RCRA section 3004 (a) and (q).

The Phase I source categories also are subject to standards under the Clean Air Act. We promulgated standards for Phase I sources on September 30, 1999 (64 FR 52828). This final rule is referred to in this preamble 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 on a source-by-source basis in a RCRA permit if necessary 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 granted portions of the Sierra Club's petition for review and vacated the challenged portions of the standards.

Cement Kiln Recycling Coalition

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, for new sources, (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.

. 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 adverse consequences that would result from the regulatory gap resulting from no standards being in place. Id. at 6793, 6795-96; see also 69 FR at 21217 (April 20, 2004). EPA also entered into a settlement agreement, enforceable by the Court of Appeals, to issue final standard conforming to the Court's mandate by June 14, 2005. That date has since been extended to September 14, 2005.

B. 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 also have entered into a judicially enforceable consent decree with Sierra Club that requires EPA to promulgate MACT standards for the Phase II sources by June 14, 2005, since extended to September 14, 2005—the same date that (for independent reasons) is required for the replacement standards for Phase I sources.

III. How Was the Final Rule Developed?

We proposed standards for HWCs on April 20, 2004 (69 FR 21197). The public comment period closed on July 6, 2004. In addition, on February 4, 2005, we requested certain key commenters to comment by email on a limited number of issues arising from public comments on the proposed rule. The comment period for those issues closed on March 7, 2005.

We received approximately 100 public comment letters on the proposed rule and the subsequent direct request for comments. Comments were submitted by owner/operators of HWCs, trade associations, state regulatory agencies and their representatives, and environmental groups. Today's final rule reflects our consideration of all of the comments and additional information we received. Major public comments on the proposed rule along with our responses, are summarized in this preamble.

IV. What Is the Relationship Between the Final Rule and Other MACT Combustion Rules?

The amendments to the Subpart EEE, Part 63, standards for hazardous waste combustors 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 final rule, however, also amends 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. 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).

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 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, 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.

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 and/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.

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).

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

Hydrochloric acid production furnaces that combust hazardous waste are also 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 emission standards or operating limits 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.

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

Today's final 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 final rule show that metals, 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.

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 an antimony processing facilities. Similar effects on the heart, lungs, and reproductive system have been observed in laboratory animals.

EPA 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.

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, the International Agency for Research on Cancer in an earlier evaluation, concluded that antimony trioxide is “possibly carcinogenic to humans” (Group 2B).

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

Arsenic

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

Chronic inhalation exposure of humans to high levels of beryllium has been reported to cause chronic beryllium disease (berylliosis), in which granulomatous (noncancerous) lesions develop in the lung. Inhalation exposure to high levels of beryllium has been demonstrated to cause lung cancer in rats and monkeys. Human studies are limited, but suggest a causal relationship between beryllium exposure and an increased risk of lung cancer. We have classified beryllium as a Group B1, probable human carcinogen, when inhaled; data are inadequate to determine whether beryllium is carcinogenic when ingested.

Cadmium

Chronic 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

Chlorine is an 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. No information is available on the carcinogenic effects of chlorine in humans from inhalation exposure. A National Toxicology Program (NTP) study showed no evidence of carcinogenic activity in male rats or male and female mice, and equivocal evidence in female rats, from ingestion of chlorinated water. The EPA has not classified chlorine for potential carcinogenicity. In the absence of specific scientific evidence to the contrary, it is the Agency's policy to classify noncarcinogenic effects as threshold effects. RfC development is the default approach for threshold (or nonlinear) effects.

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 inhalation exposures. Bronchitis, decreases pulmonary function, pneumonia, and other respiratory effects have been noted from chronic high does exposure in occupational settings due to chromium VI. 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, especially copper. Cobalt has been widely reported to cause respiratory effects in humans exposed by inhalation, including respiratory irritation, wheezing, asthma, and pneumonia. Cardiomyopathy (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 as a vital component of vitamin B

, 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 (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 has classified cobalt as a confirmed animal carcinogen with unknown relevance to humans (category A3). An EPA assessment concludes that under EPA's cancer guidelines, cobalt would be considered likely to be carcinogenic to humans.

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. This is a provisional EPA assessment that has been externally peer reviewed but has not yet been incorporated in IRIS.

Dioxins and Furans

Exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and related compounds at levels 10 times or less above those modeled to approximate average background exposure have resulted in adverse non-cancer health effects in animals. This statement is based on assumptions about the toxic equivalent for these compounds, for which there is acknowledged uncertainty. 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.

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.

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.

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

The chemical and environmental stability of dioxins and their tendency to accumulate in fat have resulted in their detection within many ecosystems. In the United States and elsewhere, accidental contamination of the environment by 2,3,7,8-TCDD has resulted in deaths in many species of wildlife and domestic animals.

High residues of this compound in fish have resulted in closing rivers to fishing. Laboratory studies with birds, mammals, aquatic organisms, and other species have demonstrated that exposure to 2,3,7,8-TCDD can result in acute and delayed mortality as well as carcinogenic, teratogenic, mutagenic, histopathologic, immunotoxic, and reproductive effects, depending on dose received, which varied widely in the experiments.

This does not necessarily apply in regard to laboratory testing, which tend to use 2,3,7,8 TCDD as the test compound.

Eisler, R. 1986. Dioxin hazards to fish, wildlife, and invertebrates: a synoptic review. U.S. Fish and Wildlife Service Biological Report. 85(1.8).

Hydrogen chloride/hydrochloric acid

Hydrogen chloride, also called hydrochloric acid, is corrosive to the eyes, skin, and mucous membranes. 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. In the absence of specific scientific evidence to the contrary, it is the Agency's policy to classify noncarcinogenic effects as threshold effects. RfC development is the default approach for threshold (or nonlinear) effects.

Lead

Lead can cause a variety of effects at low dose levels. Chronic exposure to high levels of lead in humans results in effects on the blood, central nervous system, 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 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 effects. Visual reaction time, hand steadiness, and eye-hand coordination were affected in chronically-exposed workers. 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.

Chronic exposure to elemental mercury in humans also affects the central nervous system, with effects such as increased excitability, irritability, excessive shyness, and tremors. The EPA has not classified elemental mercury with respect to cancer.

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 an essential element in some animal species, and it has been suggested it may be essential for human nutrition. Nickel dermatitis, consisting of itching of the fingers, hand and forearms, is the most common effect in humans from chronic exposure to nickel. Respiratory effects have also been reported in humans from inhalation exposure to nickel. No information is available regarding the reproductive of developmental effects of nickel in humans, but animal studies have reported such effects, although a consistent dose-response relationship has not been seen. Nickel forms released from industrial boilers include soluble nickel compounds, nickel subsulfide, and nickel carbonyl. Human and animal studies have reported an increased risk of lung and nasal cancers from exposure to nickel refinery dusts and nickel subsulfide. Animal studies of soluble nickel compounds i.e., nickel carbonyl) have reported lung tumors. The EPA has classified nickel refinery subsulfide as a Group A, human carcinogen and nickel carbonyl as a Group B2, probable human carcinogen.

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. Organic HAP also 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

Atmospheric particulate matter (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.

Exposure to particles can lead to a variety of serious health effects. The largest particles do not get very far into the lungs, so they tend to cause fewer harmful health effects. Fine particles pose the greatest problems because they can get deep into the lungs. Scientific studies show links between these small particles and numerous adverse health effects. Epidemiological studies have shown a significant correlation between elevated PM levels and premature mortality. Other important effects associated with PM exposure include aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions, emergency room visits, absences from school or work, and restricted activity days), lung disease, decreased lung function, asthma attacks, and certain cardiovascular problems. Individuals particularly sensitive to PM exposure include older adults and people with heart and lung disease.

This is only a partial summary of adverse health and environmental effects associated with exposure to PM. Further information is found in the 2004 Criteria Document for PM (“Air Quality Criteria for Particulate Matter,” EPA/600/P-99/002bF) and the 2005 Staff Paper for PM (EPA, “Review of the National Ambient Air Quality Standards for Particulate Matter, Policy Assessment of Scientific and Technical Information: OAQPS Staff Paper,” (June 2005)).

Selenium

Selenium is a naturally occurring substance that is toxic at high concentrations but is also a nutritionally essential element. Studies of humans chronically exposed to high levels of selenium in food and water have reported discoloration of the skin, pathological deformation and loss of nails, loss of hair, excessive tooth decay and discoloration, lack of mental alertness, and listlessness. The consumption of high levels of selenium by pigs, sheep, and cattle has been shown to interfere with normal fetal development and to produce birth defects. Results of human and animal studies suggest that supplementation with some forms of selenium may result in a reduced incidence of several tumor types. One selenium compound, selenium sulfide, is carcinogenic in animals exposed orally. We have classified elemental selenium as a Group D, not classifiable as to human carcinogenicity, and selenium sulfide as a Group B2, probable human carcinogen.

Part Two: Summary of the Final Rule

I. What Source Categories and Subcategories Are Affected by the Final Rule?

Today's rule promulgates standards for controlling emissions of HAP from hazardous waste combustors: incinerators, cement kilns, lightweight aggregate kilns, boilers, and hydrochloric acid production furnaces that burn hazardous waste. A description of each source category can be found in the proposed rule (see 69 FR at 21207-08).

Hazardous waste burning incinerators, cement kilns, and lightweight aggregate kilns are currently subject to 40 CFR part 63, subpart EEE, National Emission Standards for Hazardous Air Pollutants (NESHAP). Today's rule revises the emissions limits and certain compliance and monitoring provisions of subpart EEE for these

source categories. The definitions of hazardous waste incinerator, hazardous waste cement kiln, and hazardous waste lightweight aggregate kiln appear at 40 CFR 63.1201(a).

Boilers that burn hazardous waste are also affected sources under today's rule. The rule uses the RCRA definition of a boiler under 40 CFR 260.10 and includes industrial, commercial, and institutional boilers as well as thermal units known as process heaters. Hazardous waste burning boilers will continue to comply with the emission standards found under 40 CFR part 266, subpart H (i.e., the existing RCRA rules) until they demonstrate compliance with the requirements of 40 CFR part 63, subpart EEE, and, for permitted sources, subsequently remove these requirements from their RCRA permit.

Finally, hydrochloric acid production furnaces that burn hazardous waste are affected sources under today's rule. These furnaces are a type of halogen acid furnace included in the definition of “industrial furnace” defined at § 260.10. Hydrochloric acid production furnaces that burn hazardous waste will continue to comply with the emission standards found under 40 CFR part 266, subpart H, until they demonstrate compliance with 40 CFR part 63, subpart EEE, and, for permitted sources, subsequently remove these requirements from their RCRA permit.

II. What Are the Affected Sources and Emission Points?

Today's rule apply to each major and area source incinerator, cement kiln, lightweight aggregate kiln, boiler, and hydrochloric acid production furnace that burns hazardous waste.

We note that only major source boilers and hydrochloric acid production furnaces are subject to the full suite of subpart EEE emission standards.

The emissions limits apply to each emission point (e.g., stack) where gases from the combustion of hazardous waste are discharged or otherwise emitted into the atmosphere. For facilities that have multiple combustion gas discharge points, the emission limits generally apply to each emission point. A cement kiln, for example, could be configured to have dual stacks where the majority of combustion gases are discharged though the main stack and other combustion gases emitted through a separate stack, such as an alkali bypass stack. In that case, the emission standards would apply separately to each of these stacks.

A major source emits or has the potential to emit 10 tons per year of any single hazardous air pollutant or 25 tons per year or greater of hazardous air pollutants in the aggregate. An area source is a source that is not a major source.

See Part Four, Section II.A for a discussion of the standards that are applicable to area source boilers and hydrochloric acid production furnaces.

We note that there is a provision that allows cement kilns with dual stacks to average emissions on a flow-weighted basis to demonstrate compliance with the metal and chlorine emission standards. See §§ 63.1204(e) and 63.1220(3).

III. What Pollutants Are Emitted and Controlled?

Hazardous waste combustors emit dioxin/furans, sometimes at high levels depending on the design and operation of the emission control equipment, and, for incinerators, depending on whether a waste heat recovery boiler is used. All hazardous waste combustors can also 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. Hazardous waste burning hydrochloric acid production furnaces, however, generally feed and emit low levels of metal HAP.

All of these HAP metals (except for the volatile metal mercury) are emitted as a portion of the particulate matter emitted by these sources. Hazardous waste combustors can also emit high levels of particulate matter, except that hydrochloric acid production furnaces generally feed hazardous wastes with low ash content and consequently emit low levels of particulate matter. A majority of particulate matter emissions from hazardous waste combustors are in the form of fine particulate. Particulate emissions from incinerators and liquid fuel-fired boilers depend on the ash content of the hazardous 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 fine raw material entrained in the combustion gas. Thus, particulate emissions from kilns depends on operating conditions that effect entrainment of raw material, and the design and operation of the emission control equipment.

IV. Does the Final Rule Apply to Me?

The final rule applies to you if you own or operate a hazardous waste combustor—an incinerator, cement kiln, lightweight aggregate kiln, boiler, or hydrochloric acid production facility that burns hazardous waste. The final rule does not apply to a source that meets the applicability requirements of § 63.1200(b) for reasons explained at 69 FR at 21212-13.

V. What Are the Emission Limitations?

You must meet the emission limits in Tables 1 and 2 of this preamble for your applicable source category and subcategory. Standards are corrected to 7 percent oxygen. As noted at proposal, we previously promulgated requirements for carbon monoxide, total hydrocarbon, and destruction and removal efficiency standards under subpart EEE for incinerators, cement kilns, and lightweight aggregate kilns. We view these standards as unaffected by the Court's vacature of the challenged regulations in its decision of July 24, 2001. We are therefore not re-promulgating and reopening consideration of these standards in today's final rule, but are summarizing these standards in Tables 1 and 2 for reader's convenience.

See 69 FR at 21221, 21248, 21261 and 21274.

We are also republishing these standards, for reader's convenience only, in the new replacement standard section for these source categories. See § 63.1219, § 63.1220 and § 673.1219.

Liquid fuel boilers equipped with dry air pollution control devices are subject to different dioxin/furan emission standards than liquid fuel boilers that are not equipped with dry air pollution control devices.

Liquid fuel boilers processing hazardous waste with a heating value less than 10,000 BTU/lb must comply with the emission concentration-based standards (expressed as mass of total HAP emissions per volume of stack gas emitted) for mercury, semivolatile metals, low volatile metals, and total chlorine. Liquid fuel boilers processing hazardous waste with heating values greater than 10,000 BTU/lb must comply with thermal emissions-based standards (expressed as mass of HAP emissions attributable to the hazardous waste per million BTU input from the hazardous waste) for those same pollutants. Low volatile metal standards for liquid fuel boilers apply only to emissions of chromium, whereas the low volatile metal standard for the other source categories applies to the combined emissions of chromium, arsenic, and beryllium. Semivolatile metal standards apply to the combined emissions of lead and cadmium.

Liquid fuel boilers equipped with a wet air pollution control device followed by a dry air pollution control device do not meet the definition of a dry air pollution device.

For any of the source categories except hydrochloric acid production

furnaces, you may elect to comply with an alternative to the total chlorine standard under which you would establish site-specific, health-based emission limits for hydrogen chloride and chlorine based on national exposure standards. This alternative chlorine standard is discussed in part two, section IX and part four, section VII.

Incinerators and liquid and solid fuel boilers may elect to comply with an alternative to the particulate matter standard that would limit emissions of all the semivolatile metal HAPs and low volatile metal HAPs. Under this alternative, the numerical emission limits for semivolatile metal and low volatile metal emission HAP are identical to the limitations included in Tables 1 and 2. However, for semivolatile metals, the alternative standard applies to the combined emissions of lead, cadmium, and selenium; for low volatile metals, the standard applies to the combined emissions of chromium, arsenic, beryllium, antimony, cobalt, manganese, and nickel. See § 63.1219(e).

Table 1.—Summary of Emission Limits for Existing Sources

Incinerators

Cement kilns

Lightweight aggregate kilns

Solid fuel-fired boilers

Liquid fuel-fired boilers

Hydrochloric acid production furnaces

Dioxin/Furans (ng TEQ/dscm)

0.20 or 0.40 and temperature control < 400°F at APCD inlet

0.20 or rapid quench below 400°F at kiln exit

CO or HC and DRE standard as a surrogate

0.40 for dry APCD sources; CO or HC and DRE standard as surrogate for others

CO or HC and DRE standard as surrogate.

Mercury

130 μg/dscm

Hazardous waste feed restriction of 3.0 ppmw and 120 μg/dscm MTEC

; or 120 μg/dscm total emissions

120 hazardous waste MTEC

feed restriction or 120 μg/dscm total emissions

11 μg/dscm

4.2E-5lb/MMBtu

or 19 μg/dscm

; depending on BTU content of hazardous waste

Total chlorine standard as surrogate.

Particulate Matter

0.013 gr/dscf

0.028 gr/dscf and 20% opacity

0.025 gr/dscf

0.030 gr/dscf

0.035 gr/dscf

Total chlorine standard as surrogate.

Semivolatile Metals (lead + cadmium)

230 μg/dscm

7.6 E-4 lbs/MMBtu

and 330 μg/dscm

3.0E-4 lb/MMBtu

and 250 μg/dscm

180 μg/dscm

8.2 E-5 lb/MMBtu

or 150 μg/dscm

; depending on BTU content of hazardous waste

Total chlorine standard as surrogate.

Low Volatile Metals (arsenic + beryllium + chromium)

92 μg/dscm

2.1 E-5 lbs/MMBtu

and 56 μg/dscm

9.5E-5 lb/MMBtu

and 110 μg/dscm

380 μg/dscm

1.26E-4 lbMMBtu

or 370 μg/dscm

; depending on BTU content of hazardous waste

Total chlorine standard as surrogate.

Total Chlorine (hydrogen chloride + chlorine gas)

32 ppmv

120 ppmv

600 ppmv

440 ppmv

5.08E-2 lb/MMBtu

or 31 ppmv

; depending on BTU content of hazardous waste

150 ppmv or 99.923% system removal efficiency.

Carbon Monoxide (CO) or Hydrocarbons (HC)

100 ppmv CO

or 10 ppmv HC

See Note # 10 below

100 ppmv CO

or 20 ppmv HC

(2) 100 ppmv CO

or 10 ppmv HC

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:

Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards for solid and liquid fuel boilers apply only to major sources. Particulate matter, semivolatile and low volatile metal standards for hydrochloric acid production furnaces apply only to major sources, although area sources must still comply with the surrogate total chlorine standard to control mercury emissions.

Standard is based on normal emissions data, and is therefore expressed as an annual average emission limitation.

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

Low volatile metal standard for liquid fuel-fired boilers is for chromium only.

Standards expressed as mass of pollutant contributed by hazardous waste per million BTU contributed by the hazardous waste.

APCD means “air pollution control device”.

Sources may elect to comply with site-specific risk-based emission limits for hydrogen chloride and chlorine gas

Sources may elect to comply with an alternative to the particulate matter standard.

Sources that elect to comply with the CO standard must demonstrate compliance with the HC standard during the comprehensive performance test that demonstrates compliance with the destruction and removal efficiency requirement.

Kilns without a bypass: 20 ppmv HC or 100 ppmv CO

. Kilns with a bypass/mid-kiln sampling system: 10 ppmv HC or 100 ppmv CO9 in the bypass duct, mid-kiln sampling system or bypass stack.

MTEC means “maximum theoretical emission concentration”, and is equivalent to the feed rate divided by gas flow rate

The opacity standard does not apply to a source equipped with a bag leak detection system under 63.1206(c)(8) or a particulate matter detection system under 63.1206(c)(9).

Emission concentration-based standards apply to sources processing hazardous waste with energy content less than 10,000 BTU/lb; thermal emission standards apply to sources processing hazardous waste with energy content greater than 10,000 btu/lb.

Table 2.—Summary of Emission Limits for New or Reconstructed Sources

Incinerators

Cement kilns

Lightweight aggregate kilns

Solid fuel boilers

Liquid fuel boilers

Hydrochloric acid production furnaces

Dioxin/Furans (ng TEQ/dscm)

0.11 for dry APCD and/or WHB

sources; 0.20 for other sources

0.20 or 0.40 and temperature control <400 °F at APCD inlet

0.20 or rapid quench <400 °F at kiln exit

CO or HC and DRE standard as a surrogate

0.40 for sources with dry APCD; CO or HC and DRE standard as a surrogate for other sources

CO or THC and DRE standard as a surrogate.

Mercury

8.1 μg/dscm

Hazardous waste feed restriction of 1.9 ppmw and 120 μg/dscm MTEC

; or 120 μg/dscm total emissions

120 hazardous waste MTEC

feed restriction or 120 μg/dscm total emissions

11 μg/dscm

1.2E-6 lb/MMBtu

or 6.8 μg/dscm

; depending on BTU content of hazardous waste

TCl as surrogate.

Particulate matter (gr/dscf)

0.0015

0.0023 and 20% opacity

0.0098

0.015

0.0087

TCl as surrogate.

Semivolatile Metals (lead + cadmium)

10 μg/dscm

6.2E-5 lb/MMBtu

and 180 μg/dscm

3.7 E-5 lb/MMBtu

and 43 μg/dscm

180 μg/dscm

6.2 E-6 lb/MMBtu

or 78 μg/dscm

; depending on BTU content of hazardous waste

TCl as surrogate.

Low Volatile Metals (arsenic + beryllium + chromium)

23 μg/dscm

1.5E-5 lb/MMBtu

and 54 μg/dscm

3..3E-5 lb/MMBtu

and 110 μg/dscm

190 μg/dscm

1.41E-5lb/MMBtu

or 12 μg/dscm

; depending on BTU content of hazardous waste

TCl as surrogate.

Total Chlorine (Hydrogen chloride + chlorine gas)

21 ppmv

86 ppmv

600 ppmv

73 ppmv

5.08E-2 lb/MMBtu

or 31 ppmv

; depending on BTU content of hazardous waste

25 ppmv or 99.987% SRE.

Carbon monoxide (CO) or Hydrocarbons (HC)

100 ppmv CO

or 10 ppmv HC

See note #9 below

100 ppmv CO

or 20 ppmv HC

100 ppmv CO

or 10 ppmv HC

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:

Standard is based on normal emissions data, and is therefore expressed as an annual average emission limitation.

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.

Standards expressed as mass of pollutant contributed by hazardous waste per million BTU contributed by the hazardous waste.

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

Sources may elect to comply with risk-based emission limits for hydrogen chloride and chlorine gas.

Sources may elect to comply with an alternative to the particulate matter standard.

Sources that elect to comply with the CO standard must demonstrate compliance with the THC standard during the comprehensive performance test that demonstrates compliance with the destruction and removal efficiency requirement.

Greenfield kilns without a bypass: 20 ppmv HC or 100 ppmv CO

and 50 ppmv HC. Greenfield kilns with a bypass/mid kiln sampling system: Main stack standard of 50 ppmv HC and 10 ppmv HC or 100 ppmv CO

in the bypass duct, mid-kiln sampling system or bypass stack. Greenfield kilns with a bypass/mid-kiln sampling system: 10 ppmv HC or 100 ppmv CO

in the bypass duct, mid-kiln sampling system or bypass stack; Non-greenfield kilns without a bypass: 20 ppmv HC or 100 ppmv CO

. A greenfield kiln is a kiln whose construction commenced after April 19, 1996 at a plant site where a cement kiln (whether burning hazardous waste or not) did not previously exist.

MTEC means “maximum theoretical emission concentration”, and is equivalent to the feed rate divided by gas flow rate.

The opacity standard does not apply to a source equipped with a bag leak detection system under 63.1206(c)(8) or a particulate matter detection system under 63.1206(c)(9).

VI. What Are the Testing and Initial Compliance Requirements?

The testing and initial compliance requirements we promulgate today for solid fuel boilers, liquid fuel boilers, and hydrochloric acid production furnaces are identical to those that are applicable to incinerators, cement kilns, and lightweight aggregate kilns at §§ 63.1206, 63.1207, and 63.1208. We note, however, that today's final rule revises some of these requirements as they apply to all or specific HWCs (

e.g.

, one-time dioxin/furan test for sources not subject to a numerical dioxin/furan standard; dioxin/furan stack test method; hydrogen chloride and chlorine stack test methods)

We also discuss compliance and testing dates for incinerators, cement kilns, and lightweight aggregate kilns as well. Even though we are not repromulgating the compliance and testing requirements for those source categories, those sources must demonstrate compliance with the replacement emission standards promulgated today.

A. Compliance Dates

The time-line for testing and initial compliance requirements is as follows:

1. The compliance date is October 14, 2008;

See 69 FR at 21313 for rationale. We received no adverse comments at proposal.

2. You must submit a comprehensive performance test plan to the permitting authority for review and approval 12 months prior to commencing the test.

3.You must submit an eligibility demonstration for the health-based compliance alternative to the total chlorine emission standard 12 months before the compliance date if you elect to comply with § 63.1215;

4. You must place in the operating record a Documentation of Compliance by the compliance date identifying the operating parameter limits that, using available information, you have determined will ensure compliance with the emission standards;

5. For boilers and hydrochloric acid production furnaces, you must commence the initial comprehensive performance test within 6 months after the compliance date;

6. For incinerators, cement kilns, and lightweight aggregate kilns, you must commence the initial comprehensive performance test within 12 months after the compliance date;

7. You must complete the initial comprehensive performance test within 60 days of commencing the test; and

8. You must submit a Notification of Compliance within 90 days of completing the test documenting compliance with emission standards and continuous monitoring system requirements.

B. Testing Requirements

All hazardous waste combustors must commence the initial comprehensive performance test under the time lines discussed above. The purpose of the comprehensive performance test is to document compliance with the emission standards of the final rule and establish operating parameter limits to maintain compliance with those standards. You must also conduct periodic comprehensive performance testing every five years.

If your source is subject to a numerical dioxin/furan emission standard (i.e., incinerators, cement kilns, lightweight aggregate kilns that comply with the 0.2 ng TEQ/dscm standard, and liquid fuel boilers equipped with a dry air pollution control device), you must conduct a dioxin/furan confirmatory performance test no later than 2.5 years after each comprehensive performance test (i.e., midway between comprehensive performance tests). If your source is not subject to a numerical dioxin/furan emission standard (e.g., solid fuel boilers, lightweight aggregate kilns that comply with the 400 °F temperature limit at the kiln exit, liquid fuel boilers equipped with wet or no air pollution control system, and hydrochloric acid production furnaces), you must conduct a one-time dioxin/furan test to enable the Agency to evaluate the effectiveness of the carbon monoxide/hydrocarbon standard and the destruction and removal efficiency standard in controlling dioxin/furan emissions for those sources. Previous dioxin/furan emission tests may be used to meet this requirement if the combustor operated under the conditions required by the rule and if design and operation of the combustor has not changed since the test in a manner that could increase dioxin/furan emissions. The Agency will use those emissions data when reevaluating the MACT standards under CAA section 112(d)(6), when determining whether to develop residual risk standards for these sources pursuant to section 112(f)(2), and when determining whether the source's RCRA Permit is protective of human health and the environment.

You must use the following stack test methods to document compliance with the emission standards: (1) Method 29 for mercury, semivolatile metals, and low volatile metals; and (2) Method 26/26A, Methods 320 or 321, or ASTM D 6735-01 for hydrogen chloride and chlorine;

(3) either Method 0023A or Method 23 for dioxin/furans; and (4) either Method 5 or 5i for particulate matter.

Note that you may be required to use other test methods to document emissions of hydrogen chloride and chlorine if you elect to comply with the alternative, health-based emission limits for total chlorine under § 63.1215. See § 63.1208(b)(5).

C. Initial Compliance Requirements

The initial compliance requirements for solid fuel boilers, liquid fuel boilers, and hydrochloric acid production furnaces include:

These same requirements currently apply to incinerators, cement kilns, and lightweight aggregate kilns.

1. You must place in the operating record a Documentation of Compliance by the compliance date identifying the operating parameter limits that, using available information, you have determined will ensure compliance with the emission standards;

2. You must develop and comply with a startup, shutdown, and malfunction plan;

3. You must install an automatic waste feed cutoff system that links the operating parameter limits to the waste feed cutoff system;

4. You must control combustion system leaks;

5. You must establish and comply with an operator training and certification program;

6. You must establish and comply with an operation and maintenance plan;

7. If your source is equipped with a baghouse, you must install either a bag leak detection system or a particulate matter detection system;

and

A major difference between a bag leak detection system and a particulate matter detection system is the way the alarm level is established. The alarm level for a bag leak detection system is established using concepts in the Agency's bag leak detection system guidance document while the alarm level for a particulate matter detection system is established based on the detector response during the comprehensive performance test. The ash feedrate limit for incinerators and boilers is waived if you use a particulate matter detection system but not if you use a bag leak detection system because the bag leak detection system alarm level may not provide reasonable assurance of continuous compliance with the particulate matter emission standard.

8. If your source is equipped with an electrostatic precipitator or ionizing wet scrubber, you must either establish site-specific control device operating parameter limits which limits are linked to the automatic waste feed cutoff system, or install a particulate matter detection system and take corrective measures when the alarm level is exceeded.

VII. What Are the Continuous Compliance Requirements?

The continuous compliance requirements for solid fuel boilers, liquid fuel boilers, and hydrochloric acid production furnaces are identical to those applicable to incinerators, cement kilns, and lightweight aggregate kilns. See § 63.1209. We note, however, that today's final rule revises some of these requirements as they apply to all or specific HWCs (e.g., bag leak detection system requirements; optional particulate matter detection system requirements; compliance assurance for thermal emissions-based standards).

You must 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 standards.

You must also establish limits (as applicable) on the feedrate of metals, chlorine, and ash, key combustor operating parameters, and key operating

parameters of the air pollution control device based on operations during the comprehensive performance test. You must continuously monitor these parameters with a continuous monitoring system.

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

The notification, recordkeeping, and reporting requirements that we promulgate today for solid fuel boilers, liquid fuel boilers, and hydrochloric acid production furnaces are identical to those that are applicable to incinerators, cement kilns, and lightweight aggregate kilns. See §§ 63.1210 and 63.1211. We note, however, that today's final rule revises some of these requirements as they apply to all or specific HWCs.

You must submit notifications including the following to the permitting authority in addition to those required by the NESHAP General Provisions, subpart A of 40 CFR part 63:

1. Notification of changes in design, operation, or maintenance (§ 63.1206(b)(5)(i));

2. Notification of performance test and continuous monitoring system evaluation, including the performance test plan and continuous monitoring system performance evaluation plan (§ 63.1207(e));

3. Notification of compliance, including results of performance tests and continuous monitoring system evaluations (§§ 63.1210(b), 63.1207(j); 63.1207(k), and 63.1207(l)); and

4. Various notifications if you request or elect to comply with alternative requirements at § 63.1210(a)(2).

You must submit the following reports to the permitting authority in addition to those required by the NESHAP General Provisions, subpart A of 40 CFR part 63:

1. Startup, shutdown, and malfunction plan, if you elect to comply with § 63.1206(c)(2)(ii)(B));

2. Excessive exceedances report (§ 63.1206(c)(3)(vi)); and

3. Emergency safety vent opening reports (§ 63.1206(c)(4)(iv)).

Finally, you must keep records documenting compliance with the requirements of Subpart EEE. Recordkeeping requirements are prescribed in § 63.1211(b), and include requirements under the NESHAP General Provisions, subpart A of 40 CFR

IX. What Is the Health-Based Compliance Alternative for Total Chlorine, and How Do I Demonstrate Eligibility?

A. Overview

The rule allows you to establish and comply with health-based compliance alternatives for total chlorine for hazardous waste combustors other than hydrochloric acid production furnaces in lieu of the MACT technology-based emission standards established under §§ 63.1216, 63.1217, 63.1219, 63.1220, and 63.1221. See § 63.1215. To identify and comply with the limits, you must:

(1) Identify a total chlorine emission rate for each on-site hazardous waste combustor. You may select total chlorine emission rates as you choose to demonstrate eligibility for the health-based limits, except the total chlorine emission rate limits for incinerators, cement kilns, and lightweight aggregate kilns cannot result in total chlorine emission concentrations exceeding the Interim Standards provided by §§ 63.1203, 63.1204, and 63.1205;

Note that the final rule sunsets the Interim Standards on the compliance date of today's rule but codifies the Interim Standards for total chlorine under § 63.1215(b)(7).

(2) Calculate the HCl-equivalent emission rate for the total chlorine emission rates you select, considering long-term exposure and using Reference Concentrations (RfCs) as the health threshold metric. This emission rate is called the annual average HCl-equivalent emission rate;

(3) Perform an eligibility demonstration to determine if your annual average HCl-equivalent emission rate meets the national exposure standard (i.e., Hazard Index not exceeding 1.0 considering the maximum annual average ambient concentration of hydrogen chloride and chlorine at an off-site receptor location which concentrations are attributable to all on-site hazardous waste combustors) and thus is below the annual average HCl-equivalent emission rate limit;

(4) Calculate the HCl-equivalent emission rate for the total chlorine emission rates you select, considering short-term exposure and using acute Reference Exposure Levels (aRELs) as the health threshold metric. This emission rate is called the 1-hour average HCl-equivalent emission rate.

(5) Determine whether your 1-hour HCl-equivalent emission rate may exceed the national exposure standard (i.e., Hazard Index not exceeding 1.0 considering the maximum 1-hour average ambient concentration of hydrogen chloride and chlorine at an off-site receptor location which concentrations are attributable to all on-site hazardous waste combustors) and thus may exceed the 1-hour average HCl-equivalent emission rate limit when complying with the annual average HCl-equivalent emission rate limit, absent an hourly rolling average limit on the feedrate of total chlorine and chloride.

(6) Submit your eligibility demonstration, including your determination of whether the 1-hour average HCl-equivalent emission rate limit may be exceeded absent an hourly rolling average limit on the feedrate of total chlorine and chloride, for review and approval;

(7) Document during the comprehensive performance test the total chlorine system removal efficiency for each combustor and use this system removal efficiency to calculate chlorine feedrate limits. Also, document that total chlorine emissions during the test do not exceed the 1-hour average HCl-equivalent emission rate limit during any run of the test. In addition, establish operating limits on the emission control device based on operations during the comprehensive performance test; and

(8) Comply with the requirements for changes in the design, operation, or maintenance of the facility which could affect the HCl-equivalent emission rate limits or system removal efficiency for total chlorine, and changes in the vicinity of your facility over which you do not have control (e.g., new receptors locating proximate to the facility).

B. HCl-Equivalent Emission Rates

You must express total chlorine emission rates (lb/hr) from each on-site hazardous waste combustor, including hydrochloric acid production furnaces

, as an annual average HCl-equivalent emission rate and a 1-hour average HCl-equivalent emission rate. See § 63.1215(b). The annual average HCl-equivalent emission rate equates chlorine emission rates to hydrogen chloride (HCl) emission rates using Reference Concentrations (RfCs) as the health risk metric for long-term exposure. The 1-hour average HCl-equivalent emission rate equates chlorine emission rates to HCl emission rates using 1-hour Reference Exposure

Levels (aRELs) as the health risk metric for acute exposure.

Although hydrochloric acid production furnaces are not eligible for the health-based total chlorine emission limits (because control of total chlorine is a surrogate for control of metal HAP), you must consider total chlorine emissions from hydrochloric acid production furnaces when demonstrating that total chlorine emissions from all on-site hazardous waste combustors will not exceed the Hazard Index limit of 1.0 at an off-site receptor location.

To calculate HCl-equivalent emission rates, you must apportion total chlorine emissions (ppmv) between chlorine and HCl using the volumetric ratio of chlorine to hydrogen chloride (Cl

/HCl).

• To calculate the annual average HCl-equivalent emission rate (lb/hr) and the emission rate limit, you must use the historical average Cl

/HCl volumetric ratio from all regulatory compliance tests and the gas flowrate (and other relevant parameters) from the most recent RCRA compliance test or MACT performance test.

• To calculate the 1-hour average HCl-equivalent emission rate (lb/hr) and emission rate limit, you must use the highest Cl

/HCl volumetric ratio from all regulatory compliance tests and the gas flowrate from the most recent RCRA compliance test or MACT performance test.

• If you believe that the Cl

/HCl volumetric ratio for one or more historical compliance tests is not representative of the current ratio, you may request that the permitting authority allow you to screen those ratios from the analysis of historical ratios.

• If the permitting authority believes that too few historical Cl

/HCl ratios are available to establish a representative average ratio and a representative maximum ratio, the permitting authority may require you to conduct periodic testing to establish representative ratios.

• You must include the Cl

/HCl volumetric ratio demonstrated during each performance test in your data base of historical Cl

/HCl ratios to update the ratios for subsequent calculations of the annual average and 1-hour average HCl-equivalent emission rates (and emission rate limits).

C. Eligibility Demonstration

You must perform an eligibility demonstration to determine whether the total chlorine emission rates you select for each on-site hazardous waste combustor meet the national exposure standard (i.e., the Hazard Index of 1.0 cannot be exceeded at an off-site receptor location considering maximum annual average ambient concentrations attributable to all on-site hazardous waste combustors and the RfCs for HCl and chlorine) using either a look-up table analysis or a site-specific compliance demonstration.

Eligibility for the health-based total chlorine standard is determined by comparing the annual average HCl-equivalent emission rate for the total chlorine emission rate you select for each combustor to the annual average HCl-equivalent emission rate limit.

The total chlorine emission rates (lb/hr) for incinerators, cement kilns, and lightweight aggregate kilns cannot result in total chlorine emission concentrations (ppmv) exceeding the Interim Standards provided by §§ 63.1203, 63.1204, and 63.1205. The final rule sunsets the Interim Standards on the compliance date of today's rule but codifies the Interim Standards for total chlorine under § 63.1215(b)(7).

The annual average HCl-equivalent emission rate limit is the HCl-equivalent emission rate, determined by equating the toxicity of chlorine to HCl using RfCs as the health risk metric for long-term exposure, which ensures that maximum annual average ambient concentrations of HCl equivalents do not exceed a Hazard Index of 1.0, rounded to the nearest tenths decimal place (0.1) and considering all on-site hazardous waste combustors. See § 63.1215(b)(2).

Your facility is eligible for the health-based compliance alternatives for total chlorine if either: (1) The annual average HCl-equivalent emission rate for each on-site hazardous waste combustor is below the HCl-equivalent emission rate limit determined from the appropriate value for the emission rate limit in the applicable look-up table and the proration procedure for multiple combustors discussed below; or (2) the annual average HCl-equivalent emission rate for each on-site hazardous waste combustor is below the annual average HCl-equivalent emission rate limit you calculate based on a site-specific compliance demonstration.

1. Look-Up Table Analysis

Look-up tables for the eligibility demonstration are provided as Tables 1 and 2 to § 63.1215. Table 1 presents annual average HCl-equivalent emission rate limits for sources located in flat terrain. For purposes of this analysis, flat terrain is terrain that rises to a level not exceeding one half the stack height within a distance of 50 stack heights.

Table 2 presents annual average HCl-equivalent emission rate limits for sources located in simple elevated terrain. For purposes of this analysis, simple elevated terrain is terrain that rises to a level exceeding one half the stack height, but that does not exceed the stack height within a distance of 50 stack heights.

If your facility is not located in either flat or simple elevated terrain, you must conduct a site-specific compliance demonstration.

To determine the annual average HCl-equivalent emission rate limit for a source from the look-up table, you must use the stack height and stack diameter for your hazardous waste combustors and the distance between the stack and the property boundary. If any of these values for stack height, stack diameter, and distance to nearest property boundary do not match the exact values in the look-up table, you must use the next lowest table value. If you have more than one hazardous waste combustor on site, you must adjust the emission rate limits provided by the tables such that the sum of the ratios for all combustors of the adjusted emission rate limit to the emission rate limit provided by the table cannot exceed 1.0. See § 63.1215 (c)(3)(v).

2. Site-Specific Compliance Demonstration

You may use any scientifically-accepted peer-reviewed risk assessment methodology for your site-specific compliance demonstration to calculate an annual average HCl-equivalent emission rate limit for each on-site hazardous waste combustor. An example of one approach for performing the demonstration for air toxics can be found in the EPA's “Air Toxics Risk Assessment Reference Library, Volume 2, Site-Specific Risk Assessment Technical Resource Document,” which may be obtained through the EPA's Air Toxics Web site at

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

To determine the annual average HCl-equivalent emission rate limit for each on-site hazardous waste combustor, your site-specific compliance demonstration must, at a minimum: (1) estimate long-term inhalation exposures through the estimation of annual or multi-year average ambient concentrations; (2) estimate the inhalation exposure for the actual individual most exposed to the facility's emissions from hazardous waste combustors, considering locations where people reside and where people congregate for work, school, or recreation; (3) use site-specific, quality-assured data wherever possible; (4) use health-protective default assumptions wherever site-specific data are not available, and: (5) contain adequate documentation of the data and methods used for the assessment so that it is transparent and can be reproduced by an experienced risk assessor and emissions measurement expert.

To establish the annual average HCl-equivalent emission rate limit for each combustor, you may apportion as you elect among the combustors the annual average HCl-equivalent emission rate limit for the facility, which limit ensures that the RfC-based Hazard Index of 1.0 is not exceeded.

D. Assurance That the 1-Hour HCl-Equivalent Emission Rate Will Not Be Exceeded

The long-term, RfC-based Hazard Index will always be higher than the short-term, aREL-based Hazard Index for a constant HCl-equivalent emission rate because the health threshold levels for short-term exposure are orders of magnitude higher than the health threshold levels for long-term exposure.

Even though maximum 1-hour average ambient concentrations are substantially higher than maximum annual average concentrations, the higher short-term ambient concentrations do not offset the much higher health threshold levels for short-term exposures. Thus, the long-term, RfC-based Hazard Index will always govern regarding whether a source can make an eligibility demonstration. Accordingly, eligibility for the health-based emission limits is based solely on whether a source can comply with the annual average HCl-equivalent emission rate limit.

USEPA, “Technical Support Document for HWC MACT Standards, Volume III: Selection of MACT Standards,” September 2005, Section 24.2.

Nonetheless, some sources may have highly variably chlorine feedrates (and corresponding highly variable HCl-equivalent emission rates) such that they may feed chlorine at very high levels for short periods of time and still remain in compliance with the chlorine feedrate limit established to ensure compliance with the annual average HCl-equivalent emission rate limit.

To ensure that the 1-hour HCl-equivalent emission rate limit will not be exceeded during these periods of peak emissions, you must establish a 1-hour average HCl-equivalent emission rate and 1-hour average HCl-equivalent emission rate limit for each combustor and consider site-specific factors including prescribed criteria to determine if the 1-hour average HCl-equivalent emission rate limit may be exceeded absent an hourly rolling average limit on chlorine feedrate. If the 1-hour average HCl-equivalent emission rate limit may be exceeded, you must establish an hourly rolling average feedrate limit on chlorine.

See discussion below in Section F regarding the requirement to establish chlorine feedrate limits.

You must calculate the 1-hour average HCl-equivalent emission rate from the total chlorine emission rate you select for each source.

You must establish the 1-hour average HCl-equivalent emission rate limit for each affected source using either a look-up table analysis or site-specific analysis. Look-up tables are provided for 1-hour average HCl-equivalent emission rate limits as Table 3 and Table 4 to this section. Table 3 provides limits for facilities located in flat terrain. Table 4 provides limits for facilities located in simple elevated terrain. You must use the Tables to establish emission rate limits in the same manner as you use Tables 1 and 2 to establish annual average HCl-equivalent emission rate limits.

If you conduct a site-specific analysis to establish a 1-hour average HCl-equivalent emission rate limit, you must follow the risk assessment procedures you used to establish an annual average HCl-equivalent emission rate limit. The 1-hour HCl-equivalent emission rate limit, however, is the emission rate than ensures that the Hazard Index associated with maximum 1-hour average exposures is not greater than 1.0.

You must consider criteria including the following to determine if a source may exceed the 1-hour HCl-equivalent emission rate limit absent an hourly rolling average chlorine feedrate limit: (1) The ratio of the 1-hour average HCl-equivalent emission rate based on the total chlorine emission rate you select for each hazardous waste combustor to the 1-hour average HCl-equivalent emission rate limit for the combustor; and (2) the potential for the source to vary total chlorine and chloride feedrates substantially over the averaging period for the feedrate limit you establish to ensure compliance with the annual average HCl-equivalent emission rate limit.

If you determine that a source may exceed the 1-hour average HCl-equivalent emission rate limit, you must establish an hourly rolling average chlorine feedrate limit as discussed below in Section G.

You must include the following information in your eligibility demonstration to document your determination whether an hourly rolling average feedrate limit is needed to maintain compliance with the 1-hour HCl-equivalent emission rate limit: (1) Determination of the Cl2/HCl volumetric ratio established for 1-hour average HCl-equivalent emission rate determinations as provided by § 63.1215(b)(6)(ii); (2) determination of the 1-hour average HCl-equivalent emission rate calculated from the total chlorine emission rate you select for the combustor; (3) determination of the 1-hour average HCl-equivalent emission rate limit; (4) determination of the ratio of the 1-hour average HCl-equivalent emission rate to the 1-hour HCl-equivalent emission rate limit for the combustor; and (5) determination of the potential for the source to vary chlorine feedrates substantially over the averaging period for the long-term feedrate limit (

i.e.

, 12-hours, or up to annually) established to maintain compliance with the annual average HCl-equivalent emission rate limit.

E. Review and Approval of Eligibility Demonstrations

The permitting authority will review and approve your eligibility demonstration. Your eligibility demonstration must contain, at a minimum, the information listed in § 63.1215(d)(1).

1. Review and Approval for Existing Sources

If you operate an existing source, you must submit the eligibility demonstration to your permitting authority for review and approval not later than 12 months prior to the compliance date. You must also submit a separate copy of the eligibility demonstration to: U.S. EPA, Risk and Exposure Assessment Group, Emission Standards Division (C404-01), Attn: Group Leader, Research Triangle Park, North Carolina 27711, electronic mail address

REAG@epa.gov

Your permitting authority should notify you of approval or intent to disapprove your eligibility demonstration within 6 months after receipt of the original demonstration, and within 3 months after receipt of any supplemental information that you submit. A notice of intent to disapprove your eligibility demonstration will identify incomplete or inaccurate information or noncompliance with prescribed procedures and specify how much time you will have to submit additional information or to comply with the MACT total chlorine standards. If your eligibility demonstration is disapproved, the permitting authority may extend the compliance date of the total chlorine standard to allow you to make changes to the design or operation of the combustor or related systems as quickly as practicable to enable you to achieve compliance with the MACT standard for total chlorine.

If your permitting authority has not approved your eligibility demonstration by the compliance date, and has not issued a notice of intent to disapprove your demonstration, you may nonetheless begin complying, on the compliance date, with the annual average HCl-equivalent emission rate limits you present in your eligibility demonstration.

If your permitting authority issues a notice of intent to disapprove your eligibility demonstration after the

compliance date, the authority will identify the basis for that notice and specify how much time you will have to submit additional information or to comply with the MACT total chlorine standards. The permitting authority may extend the compliance date of the total chlorine standard to allow you to make changes to the design or operation of the combustor or related systems as quickly as practicable to enable you to achieve compliance with the MACT standard for total chlorine.

2. Review and Approval for New and Reconstructed Sources

The procedures for review and approval of eligibility demonstrations applicable to existing sources discussed above also apply to new or reconstructed sources, except that the date you must submit the eligibility demonstration is as discussed below.

If you operate a new or reconstructed source that starts up by April 12, 2007, or a solid fuel-fired boiler or liquid fuel-fired boiler that is an area source that increases its emissions or its potential to emit such that it becomes a major source of HAP before April 12, 2007, you must either: (1) Submit an eligibility demonstration for review and approval by April 12, 2006 and comply with the HCl-equivalent emission rate limits and operating requirements you establish in the eligibility demonstration; or (2) comply with the final total chlorine emission standards under §§ 63.1216, 63.1217, 63.1219, 63.1220, and 63.1221, by October 12, 2005, or upon startup, whichever is later, except for a standard that is more stringent than the standard proposed on April 20, 2004 for your source. If a final standard is more stringent than the proposed standard, you may comply with the proposed standard until October 14, 2008, after which you must comply with the final standard.

If you operate a new or reconstructed source that starts up on or after April 12, 2007, or a solid fuel-fired boiler or liquid fuel-fired boiler that is an area source that increases its emissions or its potential to emit such that it becomes a major source of HAP on or after April 12, 2007, you must comply with either of the following. You may submit an eligibility demonstration for review and approval 12 months prior to startup. Alternatively, you may comply with the final total chlorine emission standards under §§ 63.1216, 63.1217, 63.1219, 63.1220, and 63.1221 upon startup. If the final standard is more stringent than the standard proposed for your source on April 20, 2004, however, and if you start operations before October 14, 2008, you may comply with the proposed standard until October 14, 2008, after which you must comply with the final standard.

F. Testing Requirements

You must comply with the requirements for comprehensive performance testing under § 63.1207.

1. Test Methods for Stack Gas Containing Alkaline Particulate

If you operate a cement kiln or a combustor equipped with a dry acid gas scrubber, you must use EPA Method 320/321 or ASTM D 6735-01, or an equivalent method, to measure hydrogen chloride, and the back-half (caustic impingers) of Method 26/26A, or an equivalent method, to measure chlorine.

2. Test Methods for Stack Gas Containing High Levels of Bromine or Sulfur

If you operate an incinerator, boiler, or lightweight aggregate kiln and your feedstreams contain bromine or sulfur during the comprehensive performance test at the levels indicated below, you must use EPA Method 320/321 or ASTM D 6735'01, or an equivalent method, to measure hydrogen chloride, and Method 26/26A, or an equivalent method, to measure chlorine and hydrogen chloride combined. You must determine your chlorine emissions to be the higher of: (1) The value measured by Method 26/26A, or an equivalent method; or (2) the value calculated by the difference between the combined hydrogen chloride and chlorine levels measured by Method 26/26a, or an equivalent method, and the hydrogen chloride measurement from EPA Method 320/321 or ASTM D 6735-01, or an equivalent method.

These procedures apply if you feed during the comprehensive performance test bromine at a bromine/chlorine ratio in feedstreams greater than 5 percent by mass, or sulfur at a sulfur/chlorine ratio in feedstreams greater than 50 percent by mass.

USEPA, “Technical Support Document for HWC MACT Standards, Volume IV: Compliance with the HWC MACT Standards,” September 2005, Chapter 15.1.2.

Finally, you should precondition the M26/26A filter for one hour prior to beginning the performance test to minimize the potential for a low bias caused by adsorption/absorption of hydrogen chloride on the filter.

G. Monitoring Requirements

You must establish and comply with limits on the same operating parameters that apply to sources complying with the MACT standard for total chlorine under § 63.1209(o), except that feedrate limits on total chlorine and chloride must be established as described below.

1. Feedrate Limit to Ensure Compliance with the Annual Average HCl-Equivalent Emission Rate Limit

For sources subject to the feedrate limit for total chlorine and chloride under § 63.1209(n)(4) to ensure compliance with the semivolatile metals standard, the feedrate limit (and averaging period) for total chlorine and chloride to ensure compliance with the annual average HCl-equivalent emission rate limit is the same as required by that paragraph. Thus, the chlorine feedrate limit is the average of the run averages during the comprehensive performance test, and is established as a 12-hour rolling average.

That chlorine feedrate limit cannot exceed the numerical value (i.e., not considering the averaging period) of the feedrate limit that ensures compliance with the annual average HCl-equivalent emission rate limit, however. Therefore, the numerical value of the total chlorine and chloride feedrate limit must not exceed the value you calculate as the annual average HCl-equivalent emission rate limit (lb/hr) divided by [1 − system removal efficiency]. You must calculate a total chlorine system removal efficiency for each test run of the comprehensive performance test as [1 − total chlorine emission rate (g/s)/chlorine feedrate (g/s)], and calculate the average system removal efficiency of the test run averages. If your source does not control total chlorine, you must assume zero system removal efficiency. If emissions during the comprehensive performance test exceed the annual average HCl-equivalent emission rate limit, eligibility for the health-based emission limits is not affected. This is because the emission rate limit is an annual average limit. Compliance is based on a 12-hour rolling average chlorine feedrate limit (rather than an (up to) an annual averaging period) for sources subject to the 12-hour rolling average feedrate limit for total chlorine and chloride under § 63.1209(n)(4) to ensure compliance with the semivolatile metals standard given that the more stringent feedrate limit (i.e., the feedrate limit with the shorter averaging period) would apply.

For sources exempt from the feedrate limit for total chlorine and chloride under § 63.1209(n)(4) because they comply with § 63.1207(m)(2) (which allows compliance with the semivolatile metals emission standard absent emissions testing by assuming all metals fed are emitted), the feedrate limit for total chlorine and chloride to ensure

compliance with the annual average HCl-equivalent emission rate must be established as follows:

• You must establish an average period for the feedrate limit that does not exceed an annual rolling average;

• You must calculate a total chlorine system removal efficiency for each test run of the comprehensive performance test as [1 − total chlorine emission rate (g/s)/chlorine feedrate (g/s)], and calculate the average system removal efficiency of the test run averages. If your source is not equipped with a control system that consistently and reproducibly controls total emissions (e.g., wet or dry scrubber), you must assume zero system removal efficiency. If emissions during the comprehensive performance test exceed the annual average HCl-equivalent emission rate limit, eligibility for emission limits under this section is not affected. The emission rate limit is an annual average limit and compliance is based on an annual average feedrate limit on total chlorine and chloride (or a shorter averaging period if you so elect under paragraph (g)(2)(ii)(A) of this section); and

• You must calculate the feedrate limit for total chlorine and chloride as the annual average HCl-equivalent emission rate limit (lb/hr) divided by [1 − system removal efficiency] and comply with the feedrate limit on the averaging period you establish.

2. Feedrate Limit To Ensure Compliance With the 1-Hour Average HCl-Equivalent Emission Rate Limit

You must establish an hourly rolling average feedrate limit on total chlorine and chloride to ensure compliance with the 1-hour average HCl-equivalent emission rate limit unless you determine that the hourly rolling average feedrate limit is waived as discussed under Section D above. If required, you must calculate the hourly rolling average feedrate limit for total chlorine and chloride as the 1-hour average HCl-equivalent emission rate limit (lb/hr) divided by [1 − system removal efficiency] using the system removal efficiency demonstrated during the comprehensive performance test.

H. Relationship Among Emission Rates, Emission Rate Limits, and Feedrate Limits

We summarize here the relationship among: (1) the total chlorine emission rate you select in your eligibility demonstration; (2) the annual average and 1-hour average HCl-equivalent emission rates you present in your eligibility demonstration; (3) the annual average and 1-hour average emission rate limits you present in your eligibility demonstration; (4) performance test emission rates for total chlorine and HCl-equivalent emissions; and (5) long-term and hourly rolling average chlorine feedrate limits.

1. Total Chlorine Emission Rate, Annual Average HCl-Equivalent Emission Rate, and Annual Average HCl-Equivalent Emission Rate Limit

For the eligibility demonstration, you must select a total chlorine emission concentration (ppmv) for each combustor, determine the Cl

/HCl volumetric ratio, calculate the annual average HCl-equivalent emission rate (lb/hr), and document that the emission rate does not exceed the annual average HCl-equivalent emission rate limit.

You select a total chlorine (

i.e.

, HCl and chlorine combined) emission concentration (ppmv) for each hazardous waste combustor expressed as chloride (Cl

(-)

) equivalent. For incinerators, cement kilns, and lightweight aggregate kilns, this emission concentration cannot exceed the Interim Standards for total chlorine. You then determine the average Cl

/HCl volumetric ratio considering all historical regulatory emissions tests and apportion total chlorine emissions between Cl

and HCl accordingly. You use these apportioned volumetric emissions to calculate the Cl

and HCl emission rates (lb/hr) using the average gas flowrate (and other relevant parameters) for the most recent RCRA compliance test or MACT performance test for total chlorine. Finally, you use these Cl

and HCl emission rates to calculate an annual average HCl-equivalent emission rate, which cannot exceed the annual average HCl-equivalent emission rate limit that you establish as discussed below.

To establish the annual average HCl-equivalent emission rate limit, you may either use Tables 1 or 2 in § 63.1215 to look-up the limit, or conduct a site-specific risk analysis. Under the site-specific risk analysis option, the annual average HCl-equivalent emission rate limit would be the highest emission rate that the risk assessment estimates would result in a Hazard Index not exceeding 1.0 for the actual individual most exposed to the facility's emissions considering off-site locations where people reside and where people congregate for work, school, or recreation.

If you have more than one on-site hazardous waste combustor, and if you use the look-up tables to establish the annual average HCl-equivalent emission rate limits, the sum of the ratios for all combustors of the annual average HCl-equivalent emission rate to the annual average HCl-equivalent emission rate limit cannot not exceed 1.0. This will ensure that the RfC-based Hazard Index of 1.0 is not exceeded, a principle criterion of the eligibility demonstration.

If you use site-specific risk analysis to demonstrate that a Hazard Index of 1.0 is not exceeded, you would generally identify for each combustor the maximum annual average HCl-equivalent emission rate that the risk assessment estimates would result in an RfC-based Hazard Index of 1.0 at any off-site receptor location (i.e., considering locations where people reside and where people congregate for work, school, or recreation.

This emission rate would be the annual average HCl-equivalent emission rate limit for each combustor.

Note again, however, that the total chlorine emission concentration (ppmv) is capped by the Interim Standards for incinerators, cement kilns, and lightweight aggregate kilns.

2. 1-Hour Average HCl-Equivalent Emission Rate and Emission Rate Limit

As discussed in Section D above, you must determine in your eligibility demonstration whether the 1-hour HCl-equivalent emission rate limit may be exceeded absent an hourly rolling average chlorine feedrate limit. To make this determination, you must establish a 1-hour average HCl-equivalent emission rate and a 1-hour average HCl-equivalent emission rate limit.

You calculate the 1-hour average HCl-equivalent emission rate from the total chlorine emission rate, established as discussed above, using the equation in § 63.1215(b)(3).

You establish the 1-hour average HCl-equivalent emission rate limit by either using Tables 3 or 4 in § 63.1215 to look-up the limit, or conducting a site-specific risk analysis. Under the site-specific risk analysis option, the 1-hour average HCl-equivalent emission rate limit would be the highest emission rate that the risk assessment estimates would result in an aREL-based Hazard Index not exceeding 1.0 at any off-site receptor location (i.e., considering locations where people reside and where people congregate for work, school, or recreation).

3. Performance Test Emissions

During the comprehensive performance test, you must demonstrate a system removal efficiency for total chlorine as [1 − TCl emitted (lb/hr)/chlorine fed (lb/hr)]. During the test, however, the total chlorine emission rate you select for each combustor and the annual average HCl-equivalent

emission rate limit can exceed the levels you present in the eligibility demonstration. This is because those emission rates are annual average rates and need not be complied with over the duration of three runs of the performance test, which may be nominally only 3 hours.

The 1-hour average HCl-equivalent emission rate limit cannot be exceeded during any run of the comprehensive performance test, however. This limit is based on an aREL Hazard Index of 1.0; an exceedance of the limit over a test run with a nominal 1-hour duration would result in a Hazard Index of greater than 1.0.

4. Chlorine Feedrate Limits

To maintain compliance with the annual average HCl-equivalent emission rate limit, you must establish a long-term average chlorine feedrate limit. In addition, if you determine under § 63.1205(d)(3) that the 1-hour average HCl-equivalent emission rate may be exceeded (i.e., because your chlorine feedrate may vary substantially over the averaging period for the long-term chlorine feedrate limit), you must establish an hourly rolling average chlorine feedrate limit.

Long-Term Chlorine Feedrate Limit.

The chlorine feedrate limit to maintain compliance with the annual average HCl-equivalent emission rate is either: (1) The chlorine feedrate during the comprehensive performance test if you demonstrate compliance with the semivolatile metals emission standard during the test (see § 63.1209(o)); or (2) if you comply with the semivolatile metals emission standard under § 63.1207(m)(2) by assuming all metals in the feed to the combustor are emitted, the HCl-equivalent emission rate limit divided by [1 − system removal efficiency] where you demonstrate the system removal efficiency during the comprehensive performance test.

If you establish the chlorine feedrate limit based on the feedrate during the performance test to demonstrate compliance with the semivolatile metals emission standard, the averaging period for the feedrate limit is a 12-hour rolling average. If you establish the chlorine feedrate limit based on the system removal efficiency during the performance test, the averaging period is up to an annual rolling average. See discussion in Part Four, Section VII.B of this preamble.

If you comply with the semivolatile metals emission standard under § 63.1207(m)(2), however, the long-term chlorine feedrate limit is based on the system removal efficiency during the comprehensive performance test rather than the feedrate during the performance test. This is because the averaging period for this chlorine feedrate limit (that ensures compliance with the annual average HCl-equivalent emission rate limit) is up to an annual rolling average. See § 63.1215(g)(2). Thus, the chlorine feedrate, and total chlorine emissions, can be higher than the limit during the relatively short duration of the comprehensive performance tests.

Hourly Rolling Average Chlorine Feedrate Limit.

If you determine under § 63.1205(d)(3) that the 1-hour average HCl-equivalent emission rate limit may be exceeded, you must establish an hourly rolling average chlorine feedrate limit. That feedrate limit is established as the 1-hour HCl-equivalent emission rate limit divided by [1 − system removal efficiency]. The hourly rolling average chlorine feedrate limit is not established based on feedrates during the performance test because performance test feedrates may be substantially lower than the feedrate needed to ensure compliance with the 1-hour average HCl-equivalent emission rate. Note, however, that the hourly rolling average feedrate limit cannot be exceeded during any run of the comprehensive performance test. This chlorine feedrate limit is based on the 1-hour average HCl-equivalent emission rate limit, which is based on an aREL Hazard Index of 1.0. Thus, an exceedance of the hourly rolling average feedrate limit (and the 1-hour lHCl-equivalent emission rate limit) over a test run with a nominal 1-hour duration would result in a Hazard Index of greater than 1.0.

I. Changes

Your requirements will change in response to changes that affect the HCl-equivalent emission rate or HCl-equivalent emission rate limit for a source.

1. Changes Over Which You Have Control

Changes That Affect HCl-Equivalent Emission Rate Limits.

If you plan to change the design, operation, or maintenance of the facility in a manner that would decrease the annual average or 1-hour average HCl-equivalent emission rate limit (

e.g.

, reduce the distance to the property line; reduce stack gas temperature; reduce stack height), prior to the change you must submit to the permitting authority a revised eligibility demonstration documenting the lower emission rate limits and calculations of reduced total chlorine and chloride feedrate limits.

If you plan to change the design, operation, or maintenance of the facility in a manner than would increase the annual average or 1-hour average HCl-equivalent emission rate limit, and you elect to increase your total chlorine and chloride feedrate limits, prior to the change you must submit to the permitting authority a revised eligibility demonstration documenting the increased emission rate limits and calculations of the increased feedrate limits prior to the change.

Changes That Affect System Removal Efficiency.

If you plan to change the design, operation, or maintenance of the combustor in a manner than could decrease the system removal efficiency, you are subject to the requirements of § 63.1206(b)(5) for conducting a performance test to reestablish the combustor's system removal efficiency. You also must submit a revised eligibility demonstration documenting the lower system removal efficiency and the reduced feedrate limits on total chlorine and chloride.

If you plan to change the design, operation, or maintenance of the combustor in a manner than could increase the system removal efficiency, and you elect to document the increased system removal efficiency to establish higher feedrate limits on total chlorine and chloride, you are subject to the requirements of § 63.1206(b)(5) for conducting a performance test to reestablish the combustor's system removal efficiency. You must also submit a revised eligibility demonstration documenting the higher system removal efficiency and the increased feedrate limits on total chlorine and chloride.

2. Changes Over Which You Do Not Have Control

If you use site-specific risk assessment in lieu of the look-up tables to establish the HCl-equivalent emission rate limit, you must review the documentation you use in your eligibility demonstration every five years from the date of the comprehensive performance test and submit for review and approval with the comprehensive performance test plan either a certification that the information used in your eligibility demonstration has not changed in a manner that would decrease the annual average HCl-equivalent emission rate limit, or a revised eligibility demonstration. Examples of changes beyond your control that may decrease the annual average HCl-equivalent emission rate limit (or 1-hour average HCl-equivalent emission rate limit) are construction of residences at a location exposed to higher ambient

concentrations than evaluated during your previous risk analysis, or a reduction in the RfCs or aRELs.

If, in the interim between the dates of your comprehensive performance tests, you have reason to know of changes that would decrease the annual average HCl-equivalent emission rate limit, you must submit a revised eligibility demonstration as soon as practicable but not more frequently than annually.

If you determine that you cannot demonstrate compliance with a lower annual average HCl-equivalent emission rate limit (dictated by a change over which you do not have control) during the comprehensive performance test because you need additional time to complete changes to the design or operation of the source or related systems, you may request that the permitting authority grant you additional time to make those changes as quickly as practicable.

X. Overview on Floor Methodologies

The most contentious issue in the rulemaking involved methodologies for determining MACT floors, namely, which sources are best performing, and what is their level of performance. Superficially, these questions have a ready answer: the best performers are the lowest emitters as measured by compliance tests, and those tests fix their level of performance. But compliance tests are snapshots which do not fully capture sources' total operating variability. Since the standards must be met at all times, picking lowest compliance test data to set the standard results in standards best performing sources themselves would be unable to meet at all times.

To avoid this impermissible result, EPA selected approaches that reasonably estimate best performing sources' total variability. Certain types of variability can be quantified statistically, and EPA did so here (using standard statistical approaches) in all of the floor methodologies used in the rule. There are other components of variability, however, which cannot be fully quantified, but nonetheless must be accounted for in reasonably estimating best performing sources' performance over time. EPA selected ranking methodologies which best account for this total variability.

Where control of the feed of HAP is feasible and technically assessable (the case for HAP metals and for total chlorine), EPA used a methodology that ranked sources by their ability to best control both HAP feed and HAP emissions. This methodology thus assesses the efficiency of control of both the HAP inputs to a hazardous waste combustion unit, and the efficiency of control of the unit's outputs. This methodology reasonably selects the best performing (and for new sources, best controlled) sources, and reasonably assesses their level of performance. When HAP feed control is not feasible, notably where HAP is contributed by raw material and fossil fuel inputs, EPA determined best performers and their level of performance using a methodology that selects the lowest emitters using the best air pollution control technology. This methodology reasonably estimates the best performing sources' level of performance, and better accounts for total variability in emissions levels of the best performing sources.

EPA carefully examined approaches selecting lowest emitters as best performers. Examination of other test conditions from the same best performing sources shows, however, that this approach results in standards not achievable even by the best performers. Indeed, in order to meet such standards, even “best performing” sources (lowest emitting in individual tests) would have to add additional air pollution control technology. EPA views this result as an end run around the section 112(d)(2) beyond-the-floor process, because floor standards would force industry-wide technological changes without consideration of the factors (cost and energy in particular) which Congress mandated for consideration when establishing beyond-the-floor standards.

Part Three: What Are the Major Changes Since Proposal?

I. Database

A. Hazardous Burning Incinerators

Five incinerators have been removed from the database because they have initiated or completed RCRA closure.

Two incinerators have been added to the list of sources used to calculate the floor levels.

Emissions data from source 3015 has been excluded for purposes of calculating the particulate matter floor because the source was processing an atypical waste stream from a particulate matter compliance perspective. See part four, section I.F. We have excluded the most recent mercury and dioxin/furan emissions data from source 327, and have instead used data from an older test condition to represent this source's emissions because the source encountered problems with its carbon injection system during the most recent test. See part four, section I.F. Emissions data from source 3006 has been excluded for purposes of calculating the semivolatile metal standard because this source did not measure cadmium emissions during its emissions test. See part four, section I.F. We have added mercury emissions data from source 901 (DSSI) to the incinerator mercury database because this source (which is otherwise subject to standards for liquid fuel boilers) is burning a waste which is unlike that burned by any other liquid fuel boiler with respect to mercury concentration and waste provenance, but typical of waste burned by incinerators with respect to those factors. See part four, section VI.D.1. This change correspondingly affects the liquid fuel boiler standard by removing that data from the liquid fuel boiler database.

See “Final Technical Support Document for HWC MACT Standards, Volume II: HWC Database” for a list of the sources that have initiated or completed RCRA closure.

We noticed the data from these sources but did not include them in the MACT standard calculations at proposal. Note that inclusion of these sources did not affect any of the calculated MACT standards. See “Final Technical Support Document for HWC MACT Standards, Volume II: HWC Database” for more discussion.

B. Hazardous Waste Cement Kilns

1. Use of Emissions Data From Ash Grove Cement Company

The emissions data from Ash Grove Cement Company, which operates a recently constructed preheater/precalciner kiln located in Chanute, Kansas, are considered when calculating MACT floors for new hazardous waste burning cement kilns. In the proposal, we did not consider their emissions data in the floor analyses for existing sources because Ash Grove Cement used the data to demonstrate compliance with the new source interim standards, and did not address the data for purposes of new source standards. See 69 FR at 21217 n. 35. Consistent with our position on use of post-1999 emissions data, we are including Ash Grove Cement's emissions data in the floor analyses for new sources. See also Part Four, Section I.B of the preamble.

2. Removal of Holcim's Emissions Data From EPA's HWC Data Base

Following cessation of hazardous waste operations in 2003, we are removing all emissions data from both wet process cement kilns at Holcim's Holly Hill, South Carolina, plant from our hazardous waste combustor data base. This is consistent with our approach in both this rule and the 1999 rule to base the standards only on performance of sources that actually are operating (i.e., burning hazardous waste). See also Part Four, Section I.A and 64 FR at 52844.

3. Use of Mercury Data

As discussed below, we are using a commenter-submitted dataset as the basis of the mercury standards for existing and new cement kilns. This comprehensive dataset documents the day-to-day levels of mercury in hazardous waste fired to all cement kilns for a three year period covering 1999 to 2001. We have determined that the commenter-submitted data are more representative than data used at proposal. See Part Four, Section I.D of the preamble for our rationale.

C. Hazardous Waste Lightweight Aggregate Kilns

We are incorporating mercury data submitted by a commenter into the MACT floor analysis for existing and new lightweight aggregate kilns. These data document the day-to-day levels of mercury in hazardous waste fired to lightweight aggregate kilns located at Solite Corporation's Arvonia plant between October 2003 and June 2004. We have determined that the commenter-submitted data are more representative than the data used at proposal. See Part Four, Section I.E of the preamble for our rationale.

D. Liquid Fuel Boilers

In the proposed rule, we classified liquid fuel boilers as one category. The final rule classifies them into two for purposes of the mercury, semivolatile metals, chromium, and total chlorine standards: one for liquid fuel boilers burning lower heating value hazardous waste (hazardous waste with a heating value less than 10,000 Btu/lb), and another for liquid fuel boilers burning higher heating value hazardous waste (hazardous waste with a heating value of 10,000 Btu/lb or greater).

We also made other, minor changes to the data base because some sources have initiated closure, were misclassified as other sources in the proposed rule, or were inadvertently not considered in the floor calculations although the sources' test reports were in the docket at proposal.

E. HCl Production Furnaces

Six of the 17 hydrochloric acid production furnaces have ceased burning hazardous waste since proposal. Consequently, we do not use emissions data from these sources to establish the final standards. All six of these sources were equipped with waste heat recovery boilers and had relatively high dioxin/furan emissions. In addition, we reclassified source #2020 as a boiler based on comments received at proposal.

F. Total Chlorine Emissions Data Below 20 ppmv

We corrected all the total chlorine measurements in the data base that were below 20 ppmv to account for potential systemic negative biases in the Method 0050 data in response to comments on the proposed rule. See the discussion in Part Four, Section I.C.1 below.

To account for the bias, we corrected all total chlorine emissions data that were below 20 ppmv to 20 ppmv. We accounted for within-test condition emissions variability for the corrected data by imputing a standard deviation that is based on a regression analysis of run-to-run standard deviation versus emission concentration for all data above 20 ppmv. This approach of using a regression analysis to impute a standard deviation is similar to the approach we used to account for total variability (i.e., test-to-test and within test variability) of PM emissions for sources that use fabric filters.

II. Emission Limits

A. Incinerators

The changes in the incinerator standards for existing sources since proposal are:

Standard

Proposed limit

Final limit

Dioxin/Furans (ng TEQ/dscm)

Sources with dry air pollution control systems or waste heat boilers: 0.28; For others: 0.2 or 0.4 and temperature control at inlet of air pollution control device < 400 °F

For all sources, 0.20 or 0.40 and temperature control < 400 °F at the air pollution control device inlet.

Particulate Matter (gr/dscf)

0.015

0.013.

Semivolatile Metals (μg/dscm)

230.

Low Volatile Metals (μg/dscm)

92.

Total Chlorine (ppmv)

1.5

32.

Alternative to the particulate matter standard: Combined emissions of lead, cadmium and selenium (μg/dscm)

230.

Alternative to the particulate matter standard: Combined emissions of arsenic, berrylium, chrome, antimony, cobalt, manganese, and nickel (μg/dscm)

92.

The changes in the incinerator standards for new sources since proposal are:

Standard

Proposed limit

Final limit

Particulate Matter (gr/dscf)

0.0007

0.0015

Mercury (μg/dscm)

8.0

8.1

Semivolatile Metals (μg/dscm)

6.5

Low Volatile Metals (μg/dscm)

8.9

Total Chlorine (ppmv)

0.18

Alternative to the particulate matter standard: Combined emissions of lead, cadmium and selenium (μg/dscm)

6.5

Alternative to the particulate matter standard: Combined emissions of arsenic, berrylium, chrome, antimony, cobalt, manganese, and nickel (μg/dscm)

8.9

Hazardous Waste Burning Cement Kilns

The changes in the standards for existing cement kiln since proposal are:

Standard

Proposed limit

Final limit

Mercury (μg/dscm)

Both 3.0 ppmw

and either 120 μg/dscm (stack emissions) or 120 μg/dscm (expressed as a hazardous waste MTEC)

Particulate matter

0.028 gr/dscf

and

20% opacity

Semivolatile metals

4.0E-04 lb/MMBtu

7.6E-04 lb/MMBtu

and

330 μg/dscm.

Low volatile metals

1.4E-05 lb/MMBtu

2.1E-05 lb/MMBtu

and

56 μg/dscm.

Total chlorine (ppmv)

110

120.

The proposed mercury standard was an annual limit.

Feed concentration of mercury in hazardous waste as-fired.

HW MTEC means maximum theoretical emissions concentration of the hazardous waste and MTEC is defined at § 63.1201(a).

The opacity standard does not apply to a source equipped with a bag leak detection system under § 63.1206(c)(8) or a particulate matter detection system under § 63.1206(c)(9).

Standard is expressed as mass of pollutant stack emissions attributable to the hazardous waste per million British thermal unit heat input of the hazardous waste.

Combined standard, reported as a chloride (Cl

(-)

) equivalent.

The changes in the standards for new cement kilns since proposal are:

Standard

Proposed limit

Final limit

Mercury (μg/dscm)

Both 1.9 ppmw

and either 120 μg/dscm (stack emissions) or 120 μg/dscm (expressed as a hazardous waste MTEC)

Particulate matter

0.0058 gr/dscf

0.0023 gr/dscf and 20% opacity

Semivolatile metals

6.2E-05 lb/MMBtu

and

180 μg/dscm.

Low volatile metals

1.4E-05 lb/MMBtu

1.5E-05 lb/MMBtu

and

54 μg/dscm.

Total chlorine (ppmv)

86.

The proposed mercury standard was an annual limit.

Feed concentration of mercury in hazardous waste as-fired.

HW MTEC means maximum theoretical emissions concentration of the hazardous waste and MTEC is defined at § 63.1201(a).

The opacity standard does not apply to a source equipped with a bag leak detection system under § 63.1206(c)(8) or a particulate matter detection system under § 63.1206(c)(9).

Standard is expressed as mass of pollutant stack emissions attributable to the hazardous waste per million British thermal unit heat input of the hazardous waste.

Combined standard, reported as a chloride (Cl

(-)

) equivalent.

C. Hazardous Waste Burning Lightweight Aggregate Kilns

The changes in the standards for existing lightweight aggregate kilns since proposal are:

Standard

Proposed limit

Final limit

Dioxins and furans (ng TEQ/dscm)

0.40

0.20

rapid quench of the flue gas at the exit of the kiln to less than 400 °F.

Mercury (μg/dscm)

120 μg/dscm (stack emissions) or 120 μg/dscm (expressed as a hazardous waste MTEC)

Semivolatile metals

3.1E-04 lb/MMBtu

and

250 μg/dscm

3.0E-04 lb/MMBtu

and

250 μg/dscm.

The proposed mercury standard was an annual limit.

HW MTEC means maximum theoretical emissions concentration of the hazardous waste and MTEC is defined at § 63.1201(a).

Standard is expressed as mass of pollutant stack emissions attributable to the hazardous waste per million British thermal unit heat input of the hazardous waste.

The changes in the standards for new lightweight aggregate kilns since proposal are:

Standard

Proposed limit

Final limit

Dioxins and furans (ng TEQ/dscm)

0.40

0.20

rapid quench of the flue gas at the exit of the kiln to less than 400 °F.

Particulate matter

0.0099 gr/dscf

0.0098 gr/dscf.

Mercury (μg/dscm)

120 μg/dscm (stack emissions) or 120 μg/dscm (expressed as a hazardous waste MTEC)

Semivolatile metals

2.4E-05 lb/MMBtu

and

43 μg/dscm

3.7E-05 lb/MMBtu

and

43 μg/dscm.

The proposed mercury standard was an annual limit.

HW MTEC means maximum theoretical emissions concentration of the hazardous waste and MTEC is defined at § 63.1201(a).

Standard is expressed as mass of pollutant stack emissions attributable to the hazardous waste per million British thermal unit heat input of the hazardous waste.

D. Solid Fuel Boilers

The changes in the solid fuel boiler standards for existing sources since proposal are:

Standard

Proposed

limit

Final

limit

Mercury (μg/dscm)

Semivolatile Metals (μg/dscm)

170

180

Low Volatile metals (μg/dscm)

210

380

Alternative to the particulate matter standard: Combined emissions of lead, cadmium and selenium (μg/dscm)

170

180

Alternative to the particulate matter standard: Combined emissions of arsenic, beryllium, chromium, antimony, cobalt, manganese, and nickel (μg/dscm)

210

380

The changes in the solid fuel boiler standards for new sources since proposal are:

Standard

Proposed

limit

Final

limit

Mercury (μg/dscm)

Semivolatile Metals (μg/dscm)

170

180

Low Volatile metals (μg/dscm)

210

380

Alternative to the particulate matter standard: Combined emissions of lead, cadmium and selenium (μg/dscm)

170

180

E. Liquid Fuel Boilers

We redefined the liquid fuel boiler subcategory into two separate boiler subcategories based on the heating value of the hazardous waste they burn: Those that burn waste below 10,000 Btu/lb, those that burn hazardous waste with a heating value of 10,000 Btu/lb or greater. See Part Four, Section VI.D.2 of today's preamble for a complete discussion.

The additional changes to the liquid fuel boiler standards for existing sources since proposal are:

Standard

Proposed

limit

Final limit

HW Fuel < 10,000 Btu/lb

HW Fuel ≥ 10,000 Btu/lb

Mercury (lb/MM Btu)

3.7E-6

19 μg/dscm

4.2E-5

Particulate matter (gr/dscf)

0.032

0.035

Semivolatile metals (lb/MM Btu)

1.1E-5

150 μg/dscm

8.2E-5

Chromium (lb/MM Btu)

1.1E-4

370 μg/dscm

1.3E-4

Total chlorine (Lb/MM Btu)

2.5E-2

31 ppmv

5.1E-2

Alternative to the particulate matter standard: Combined emissions of lead, cadmium and selenium (lb/MM Btu)

1.1E-5

150 μg/dscm

8.2E-5

Alternative to the particulate matter standard: Combined emissions of arsenic, beryllium, chromium, antimony, cobalt, manganese, and nickel (lb/MM Btu)

1.1E-4

370 μg/dscm

1.3E-4

The changes in the liquid fuel boiler standards for new sources since proposal are:

Standard

Proposed limit

Final limit

HW fuel < 10,000 Btu/lb

HW fuel > 10,000 Btu/lb

Dioxin and Furan, dry APCD (ng TEQ/dscm)

0.015 or temp control <400F for dry APCD

0.40

Mercury (lb/MM Btu)

3.8E-7

6.8 μg/dscm

1.2E-6

Particulate matter (gr/dscf)

0.0076

0.0087

Semivolatile metals (lb/MM Btu)

4.3E-6

78 μg/dscm

6.2E-6

Chromium (lb/MM Btu)

3.6E-5

12 μg/dscm

1.4E-5

Total chlorine (lb/MM Btu)

7.2E-4

31 μg/dscm

5.1E-2

Alternative to the particulate matter standard: Combined emissions of lead, cadmium and selenium (lb/MM Btu)

4.3E-6

78 μg/dscm

6.2E-6

Alternative to the particulate matter standard: Combined emissions of arsenic, beryllium, chromium, antimony, cobalt, manganese, and nickel (lb/MM Btu)

3.6E-5

12 μg/dscm

1.4E-5

New or reconstructed liquid fuel boilers that process residual oil or liquid feedstreams that are neither fossil fuel nor hazardous waste and that operate pursuant to the alternative to the particulate matter standard must comply with the alternative emission concentration standard of 4.7 μg/dscm, which is applicable to lead, cadmium and selenium emissions attributable to all feedstreams (hazardous and nonhazardous).

New or reconstructed liquid fuel boilers that process residual oil or liquid feedstreams that are neither fossil fuel nor hazardous waste that operate pursuant to the alternative to the particulate matter standard must comply with the alternative emission concentration standard of 12 μg/dscm, which is applicable to arsenic, beryllium, chrome, antimony, cobalt, manganese, and nickel emissions attributable to all feedstreams (hazardous and nonhazardous).

F. Hydrochloric Acid Production Furnaces

The changes in the hydrochloric acid production furnace standards for existing sources since proposal are:

Standard

Proposed limit

Final limit

Dioxin and Furans

0.4 ng TEQ/dscm

Carbon Monoxide/Total Hydrocarbons and DRE standards as surrogates.

Total chlorine

14 ppmv or 99.9927% system removal efficiency

150 ppmv or 99.923% system removal efficiency.

The changes in the hydrochloric acid production furnace standards for new sources since proposal are:

Standard

Proposed limit

Final limit

Dioxin and Furans

0.4 ng TEQ/dscm

Carbon Monoxide/Total Hydrocarbons and DRE standards as surrogates

Total chlorine

1.2 ppmv or 99.9994% system removal efficiency

25 ppmv or 99.987% system removal efficiency

G. Dioxin/Furan Testing for Sources Not Subject to a Numerical Standard

Today's final rule requires that all sources not subject to a numerical dioxin and furan standard perform a one time test to determine their dioxin and furan emissions. See the discussion in Part Four, Section VII.L.

In the proposed rule, this requirement was limited to solid fuel boilers and those liquid fuel boilers with a wet or no air pollution control system. The final rule expands this requirement to include hydrochloric acid production furnaces and those lightweight aggregate kilns that elect to comply with the temperature limit at the kiln exit in lieu of the 0.20 ng TEQ/dscm dioxin/furan standard. Those sources are not subject to a numerical dioxin/furan standard under the final rule for reasons explained in Volume III of the Technical Support Document, Sections 12 and 15. We note that sources not subject to a numerical dioxin/furan emission standard are subject to the carbon monoxide or hydrocarbon standards and the DRE standard as surrogates.

We are making no changes to the implementation of this requirement. See the proposed rule at 69 FR at 21307 for more information.

III. Statistics and Variability

A. Using Statistical Imputation To Address Variability of Nondetect Values

In the final rule, we use a statistical approach to impute the value of nondetect emissions and feedrate measurements to avoid dampening of the variability of data sets when nondetect measurements are assumed to be present at the detection limit.

At proposal, we assumed that nondetects (i.e., HAP levels in stack emissions below the level of detection of the applicable analytic method) are invariably present at the detection limit. Commenters on the proposed rule stated, however, that assuming nondetects are present at the detection limit dampens emissions variability—a consideration necessary to reasonably ascertain sources' performance over time. This could have significant practical consequence for those data sets (such as the data base for liquid fuel boilers) dominated by nondetected values. We agree with these commenters, and instead of making the arbitrary assumption that all nondetected values are identical (which

in fact is highly unlikely), we are using a statistical methodology to impute the value of nondetect measurements.

The imputation approach assigns a value for each nondetect measurement in a data set within the possible range of values that results in maximizing the 99th percentile upper prediction limit for the data set. For example, the possible range of values for a measurement that is 100% nondetect is between zero and the detection limit.

On February 4, 2005 we distributed a direct request for comments on the imputation approach to major stakeholders. We respond to the comments we received in Part Four, Section IV.D of today's notice.

B. Degrees of Freedom When Imputing a Standard Deviation Using the Universal Variability Factor for Particulate Matter Controlled by a Fabric Filter

The use of the universal variability factor to impute a standard deviation for particulate emissions from sources controlled with a fabric filter takes advantage of the empirical observation that the standard deviation of particulate emissions from sources is positively correlated to the average particulate emissions of sources. Based on this observation, we use regression analysis to determine the best fitting curve to explain the relationship of average value to standard deviation.

In the final rule, we use the actual sample size, rather than an assumed sample size of nine used at proposal, to determine the degrees of freedom for the t-statistic to calculate the floor using the standard deviation imputed from the universal variability factor for particulate matter controlled by a fabric filter.

At proposal, we used eight degrees of freedom to identify the t-statistic to account for within-test condition variability (i.e., run-to-run variability) for standard deviations imputed from the universal variability factor regression.

This is because, on average, about three test conditions with nine individual test runs are associated with each source used to develop the regression curve.

USEPA, “Draft Technical Support Document for HWC MACT Standards, Volume III: Selection of MACT Standards,” March 2004, p. 5-4.

A commenter states, however, that this approach can dramatically understate variability when imputing a standard deviation for a source with only three runs because the t-statistic is substantially higher for 2 degrees of freedom than 8 degrees of freedom.

We agree with the commenter. Moreover, using the actual number of runs to identify the t-statistic rather than assuming nine runs is appropriate given that the true test condition average is less certain for sources with only three runs, and thus there is less certainty in the imputed standard deviation. The higher t-statistic associated with a three-run data set reflects this uncertainty.

In addition, we include emissions data classified as “normal” in the regression analysis for the final rule. At proposal, we used only data classified as CT (i.e., highest compliance test condition in a test campaign) or IB (i.e., a compliance test condition that achieved lower emissions than another compliance test condition in the test campaign). We conclude that normal data (i.e., emissions data that were not used to establish operating limits and thus do not reflect variability in controllable operating parameters) should also be considered in the regression analysis because particulate matter emissions are relatively insensitive to baghouse inlet loading and operating conditions.

Including normal emissions in the analysis provides additional data to better quantify these devices' performance variability.

USEPA, “Technical Support Document for HWC MACT Standards, Volume III: Selection of MACT Standards,” September 2005, Section 5.3. See also Part Four, Section III.C of this preamble.

IV. Compliance Assurance for Fabric Filters, Electrostatic Precipitators, and Ionizing Wet Scrubbers

The final rule provides additional requirements to clarify how you determine the duration of periods of operation when the alarm set point has been exceeded for a bag leak detection system or a particulate matter detection system:

1. You must keep records of the date, time, and duration of each alarm, the time corrective action was initiated and completed, and a brief description of the cause of the alarm and the corrective action taken.

2. You must record the percent of the operating time during each 6-month period that the alarm sounds.

3. In calculating the operating time percentage, if inspection of the fabric filter, electrostatic precipitator, or ionizing wet scrubber demonstrates that no corrective action is required, no alarm time is counted.

4. If corrective action is required, each alarm shall be counted as a minimum of 1 hour.

The final rule also establishes revised procedures for establishing the alarm set point if you elect to use a particulate matter detector system in lieu of site-specific operating parameter limits for compliance assurance for sources equipped with electrostatic precipitators and ionizing wet scrubbers. The rule explicitly allows you to maximize controllable operating parameters during the comprehensive performance test to account for variability by, for example, detuning the APCD or spiking ash. To establish the alarm set-point, you may either establish the set-point as the average of the test condition run average detector responses during the comprehensive performance test or extrapolate the detector response after approximating the correlation between the detector response and particulate matter emission concentrations. You may extrapolate the detector response up to a response value that corresponds to 50% of the particulate matter emission standard or 125% of the highest particulate matter concentration used to develop the correlation, whichever is greater. To establish an approximate correlation of the detector response to particulate matter emission concentrations you should use as guidance Performance Specification-11 for PM CEMS (40 CFR Part 60, Appendix B), except that you need conduct only 5 runs to establish the initial correlation rather than a minimum of 15 runs required by PS-11.

The final rule also notes that an exceedance of a detector response that corresponds to the particulate matter emission standard is not evidence that the standard has been exceeded because the correlation is an approximate correlation used for the purpose of compliance assurance to determine when corrective measures must be taken. The correlation, however, does not meet the requirements of PS-11 for compliance monitoring.

In addition, if you elect to use a particulate matter detection system in lieu of site-specific control device operating parameter limits on the electronic control device, the ash feedrate limit for incinerators and boilers under § 63.1209(m)(3) is waived. The ash feedrate limit is waived because the particulate matter detection system continuously monitors relative particulate matter emissions and the alarm set point provides reasonable assurance that emissions will not exceed the standard.

Note that if your incinerator or boiler is equipped with a fabric filter and you elect under § 63.1206(c)(8)(i) to use a particulate matter detection system in lieu of a bag leak detection system for compliance assurance, the ash feedrate limit is waived. The ash feedrate limit is not waived if you use a bag leak detection system, however, because the alarm level may not ensure compliance with the emission standard when you follow the

concepts in the Agency's guidance document on bag leak detection systems to establish the alarm level.

Finally, you must submit an excessive exceedance notification within 30 days of the date that the alarm set-point is exceeded more than 5 percent of the time during any 6-month block period of time, or within 30 days after the end of the 6-month block period, whichever is earlier. The proposed rule would have required you to submit that notification within 5 days of the end of the 6-month block period.

V. Health-Based Compliance Alternative for Total Chlorine

The final rule includes the following major changes to the proposed health-based compliance alternative for total chlorine:

(1) You must use 1-hour Reference Exposure Levels (aRELs) rather than 1-hour acute exposure guideline levels (AEGL-1) as the acute health risk threshold metric when calculating 1-hour HCl-equivalent emission rates;

(2) You must establish a long-term average chlorine feedrate limit (i.e., 12 hour rolling average or an (up to) annual rolling average) as the annual average HCl-equivalent emission rate limit divided by [1 − system removal efficiency]. You establish the total chlorine system removal efficiency during the comprehensive performance test. The proposed rule would have required you to establish the long-term average chlorine feedrate limit as the average of the test run averages of the comprehensive performance test.

Note that, as a practical matter, most sources must establish the chlorine feedrate limit as the average of the test run average feedrate limit during the comprehensive performance test to demonstrate compliance with the semivolatile emission standard. This is because chlorine feedrate is a compliance assurance parameter for the semivolatile metal emission standard. That feedrate limit is based on a 12-hour rolling average. To ensure compliance with the annual average HCl-equivalent emission rate limit, however, that feedrate limit cannot exceed the value calculated as the annual average HCl-equivalent emission rate limit divided by [1 − system removal efficiency], where you demonstrate the total chlorine system removal efficiency during the performance test.

(3) At proposal, we requested comment on whether and how to establish a short-term chlorine feedrate limit to ensure that the acute exposure Hazard Index of 1.0 is not exceeded. See 69 FR at 21304. We conclude for the final rule that a 1-hour rolling average feedrate limit may be needed for some situations (i.e., if chlorine feedrates can vary substantially during the averaging period for the long-term feedrate limit and potentially result in an exceedance of the 1-hour average HCl-equivalent emission rate limit). Accordingly, although your eligibility for the health-based compliance alternatives is based on annual average HCl-equivalent emissions, you must determine considering prescribed criteria whether your 1-hour HCl-equivalent emission rate may exceed the national exposure standard (i.e., Hazard Index not exceeding 1.0 considering the maximum 1-hour average ambient concentration of hydrogen chloride and chlorine at an off-site receptor location

) and thus may exceed the 1-hour average HCl-equivalent emission rate limit absent an hourly rolling average limit on the feedrate of chlorine. If the acute exposure standard may be exceeded, you must establish an hourly rolling average chlorine feedrate limit as the 1-hour HCl-equivalent emission rate limit divided by [1 − system removal efficiency]. You establish the system removal efficiency during the comprehensive performance test.

Under the site-specific risk assessment approach to demonstrate eligibility, you must consider locations where people reside and where people congregate for work, school, or recreation.

(4) When calculating HCl-equivalent emission rates, rather than partitioning total chlorine emissions between chlorine and HCl (i.e., the Cl

/HCl volumetric ratio) based on the comprehensive performance test as proposed, you must establish the Cl

/HCl volumetric ratio used to calculate the annual average HCl-equivalent emission rate based on the historical average ratio from all regulatory compliance tests. You must establish the Cl

/HCl volumetric used to calculate the 1-hour average HCl-equivalent emission rate as the highest of the historical ratios from all regulatory compliance tests. The rule allows you to exclude ratios from historical compliance tests where the emission data may not be representative of the current Cl

/HCl ratio for reasons such as changes to the design or operation of the combustor or biases in measurement methods. The rule also explicitly allows the permitting authority to require periodic emissions testing to obtain a representative average and maximum ratio;

(5) The look-up table analysis has been refined by presenting annual average and 1-hour HCl-equivalent emission rate limits as a function of stack height, stack diameter, and distance to property line. In addition, separate look-up tables are presented for flat terrain and simple elevated terrain;

(6) The proposed rule required approval of the eligibility demonstration before you could comply with the alternative health-based emission limits for total chlorine. Under the final rule, if your permitting authority has not approved your eligibility demonstration by the compliance date, and has not issued a notice of intent to disapprove your demonstration, you may nonetheless begin complying, on the compliance date, with the annual average HCl-equivalent emission rate limits you present in your eligibility demonstration. In addition, if your permitting authority issues a notice of intent to disapprove your eligibility demonstration, the authority will identify the basis for that notice and specify how much time you will have to submit additional information or to comply with the MACT total chlorine standards. The permitting authority may extend the compliance date of the total chlorine standards to allow you to make changes to the design or operation of the combustor or related systems as quickly as practicable to enable you to achieve compliance with the MACT total chlorine standards;

(7) We have revised the approach for determining chlorine emissions if you feed bromine or sulfur during the comprehensive performance test at levels higher than those specified in § 63.1215(e)(3)(ii)(B). Under the final rule, you must use EPA Method 320/321 or ASTM D 6735'01, or an equivalent method, to measure hydrogen chloride, and Method 26/26A, or an equivalent method, to measure chlorine and hydrogen chloride. You must determine your chlorine emissions to be the higher of: (1) The value measured by Method 26/26A, or an equivalent method; or (2) the value calculated by difference between the combined hydrogen chloride and chlorine levels measured by Method 26/26a, or an equivalent method, and the hydrogen chloride measurement from EPA Method 320/321 or ASTM D 6735-01, or an equivalent method; and

(8) The proposed rule would have required you to conduct a new comprehensive performance test if you planned to make changes to the facility that would lower the annual average HCl-equivalent emission rate limit. Under the final rule, you would be required to conduct a performance test as a result of a planned change only for a change to the design, operation, or maintenance of the combustor that could affect the system removal efficiency for total chlorine if the change could reduce the system removal efficiency, or if the change would increase the system removal efficiency and you elect to increase the feedrate limits on total chlorine and chloride.

Part Four: What Are the Responses to Major Comments?

I. Database

A. Revisions to the EPA's Hazardous Waste Combustor Data Base

Comment:

Several commenters identify sources which have ceased operations as a hazardous waste combustor and should be removed from EPA's data base.

Response:

We agree with commenters that data and information from sources no longer burning hazardous waste should not be included in our hazardous waste combustor data base and should not be used to calculate the MACT standards. We consider any source that has initiated RCRA closure procedures and activities as a source that is no longer burning hazardous waste. This data handling decision is consistent with the approach we used in the 1999 final rule. See 64 FR at 52844. As we stated in that rule, ample emissions data remain to support calculating the MACT standards without using data from sources that no longer burn hazardous waste.

As a result, we removed the following former hazardous waste combustors from the data base: the Safety-Kleen incinerator in Clarence, New York, the Dow Chemical Company incinerators in Midland, Michigan, and LaPorte, Texas, the two Holcim wet process cement kilns in Holly Hill, South Carolina, the Dow Chemical Company liquid fuel-fired boiler in Freeport, Texas, the Union Carbide liquid fuel-fired boilers in Hahnville, Louisiana, and Texas City, Texas, and six Dow Chemical Company hydrochloric production furnaces in Freeport, Texas.

We are retaining, however, Solite Corporation's lightweight aggregate facility in Cascade, Virg

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