Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Commercial and Industrial Solid Waste Incineration Units

Federal RegisterMar 21, 2011

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2003-0119; FRL-9273-4]

RIN 2060-AO12

Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Commercial and Industrial Solid Waste Incineration Units

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

This action promulgates EPA's final response to the 2001 voluntary remand of the December 1, 2000, new source performance standards and emission guidelines for commercial and industrial solid waste incineration units and the vacatur and remand of several definitions by the District of Columbia Circuit Court of Appeals in 2007. In addition, this action includes the 5-year technology review of the new source performance standards and emission guidelines required under section 129 of the Clean Air Act. This action also promulgates other amendments that EPA believes are necessary to address air emissions from commercial and industrial solid waste incineration units.

DATES:

The final rule is effective on May 20, 2011. The incorporation by reference of certain publications listed in the final rule are approved by the Director of the Federal Register as of May 20, 2011.

ADDRESSES:

EPA established a single docket under Docket ID Number EPA-HQ-OAR-2003-0119 for this action. All documents in the docket are listed on the

http://www.regulations.gov

Web site. Although listed in the index, some information is not publicly available,

e.g.

, confidential business information or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through

http://www.regulations.gov

, or in hard copy at EPA's Docket Center, Public Reading Room, EPA West Building, Room 3334, 1301 Constitution Avenue, NW., Washington, DC 20004. This Docket Facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the EPA Docket Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

Ms. Toni Jones, Natural Resources and Commerce Group, Sector Policies and Programs Division (E143-03), Environmental Protection Agency, Research Triangle Park, North Carolina 27711; telephone number: (919) 541-0316; facsimile number: (919) 541-3470; e-mail address:

jones.toni@epa.gov

, or Ms. Charlene Spells, Natural Resources and Commerce Group, Sector Policies and Programs Division (E143-03), Environmental Protection Agency, Research Triangle Park, North Carolina 27711; telephone number: (919) 541-5255; facsimile number: (919) 541-3470; e-mail address:

spells.charlene@epa.gov.

SUPPLEMENTARY INFORMATION:

Acronyms and Abbreviations.

The following acronyms and abbreviations are used in this document.

7-PAH 7 Polyaromatic Hydrocarbons

16-PAH 16 Polyaromatic Hydrocarbons

ACI Activated Carbon Injection

ANSI American National Standards Institute

ASME American Society of Mechanical Engineers

ASTM American Society for Testing and Materials

BAT Best Available Technology

CAA Clean Air Act

Cd Cadmium

CDX Central Data Exchange

CEMS Continuous Emissions Monitoring Systems

CFR Code of Federal Regulations

CISWI Commercial and Industrial Solid Waste Incineration

CO Carbon Monoxide

Carbon Dioxide

Catalyst Carbon Monoxide Oxidation Catalyst

The Court U.S. Court of Appeals for the District of Columbia Circuit

CSA Canadian Standards Association

CWA Clean Water Act

D/F Dioxin/Furan

DIFF Dry Sorbent Injection Fabric Filter

dscf Dry Standard Cubic Foot

dscm Dry Standard Cubic Meter

EG Emission Guidelines

EJ Environmental Justice

EMPC Estimated Maximum Possible Concentration

EOM Extractable Organic Matter

ERT Electronic Reporting Tool

ERU Energy Recovery Unit

ESP Electrostatic Precipitator

FF Fabric Filters

HAP Hazardous Air Pollutants

HCl Hydrogen Chloride

Hg Mercury

HMI Hospital, Medical and Infectious

HMIWI Hospital, Medical and Infectious Waste Incineration

HWC Hazardous Waste Combustor

ICR Information Collection Request

ISO International Standards Organization

LBMS Linkageless Burner Management System

LML Lowest Measured Level

MACT Maximum Achievable Control Technology

MDL Method Detection Level

mg/dscm Milligrams per Dry Standard Cubic Meter

mmBtu/hr Million British Thermal Units per Hour

MSW Municipal Solid Waste

MW Megawatts

MWC Municipal Waste Combustor

NAAQS National Ambient Air Quality Standards

NAICS North American Industrial Classification System

ND Nondetect

NESHAP National Emission Standards for Hazardous Air Pollutants

ng/dscm Nanograms per Dry Standard Cubic Meter

Nitrogen Oxides

NSPS New Source Performance Standards

NTTAA National Technology Transfer and Advancement Act

OAQPS Office of Air Quality Planning and Standards

O&M Operations and Maintenance

OMB Office of Management and Budget

OP Office of Policy

OSWI Other Solid Waste Incineration

Pb Lead

PCBs Polychlorinated Biphenyls

PCDD Polychlorinated Dibenzodioxins

PCDF Polychlorinated Dibenzofurans

PM Particulate Matter

POM Polycyclic Organic Matter

ppm Parts Per Million

ppmv Parts Per Million by Volume

ppmvd Parts Per Million by Dry Volume

PRA Paper Reduction Act

PS Performance Specification

QA/QC Quality Assurance/Quality Control

RCRA Resource Conservation and Recovery Act

RFA Regulatory Flexibility Act

RIA Regulatory Impact Analysis

RIN Regulatory Information Number

RTO Regenerative Thermal Oxidizer

SCR Selective Catalytic Reduction

SARU Sulfuric Acid Regeneration Unit

SNCR Selective Noncatalytic Reduction

Sulfur Dioxide

SSI Sewage Sludge Incineration

SSM Startup, Shutdown, and Malfunction

SWDA Solid Waste Disposal Act

TBtu Tera British Thermal Unit

TEF Total Equivalency Factor

TEQ Toxic Equivalency

TMB Total Mass Basis

tpy Tons Per Year

TRI Toxics Release Inventory

TTN Technology Transfer Network

ug/dscm Micrograms per Dry Standard Cubic Meter

UMRA Unfunded Mandates Reform Act

UL Upper Limit

UPL Upper Prediction Limit

UTL Upper Tolerance Limit

VCS Voluntary Consensus Standards

WWW Worldwide Web

Organization of this document.

The information presented in this preamble is organized as follows:

I. General Information

A. Does this action apply to me?

B. Where can I get a copy of this document?

C. Judicial Review

II. Background Information

A. What is the statutory authority for this final rule?

B. What is the history of the CISWI standards?

C. How is the solid waste definition addressed in this final rule?

D. What is the relationship between the final rule and other combustion rules?

E. What is EPA's approach for conducting a 5-year review under CAA section 129(a)(5)?

F. What is the relationship of this final action to section 112(c)(6) of the CAA?

III. Summary of the Final Rule

A. Which units are affected by this final rule?

B. What are the emission limits in the final rule?

C. What are the testing and monitoring requirements?

D. What are the requirements during periods of SSM?

E. How do the rule amendments affect the applicability of the 2000 NSPS and EG?

F. What is the compliance schedule?

G. What is the state plan implementation schedule?

H. What are the requirements for submission of emissions test results to EPA?

I. What are the costs and benefits of this final rule?

IV. Summary of Significant Changes Since Proposal

V. Public Comments

A. Legal and Applicability Issues, Compliance Schedule, and Certification Procedures

B. MACT Floor Analysis

C. Control Technology Assumptions for the Floor and Beyond-the-Floor

D. Rationale for Subcategories

E. Emission Limits

F. New Data/Corrections to Existing Data

G. Testing and Monitoring

H. Startup, Shutdown, and Malfunction Requirements

I. Notification, Recordkeeping and Reporting Requirements

J. Air Curtain Incinerators

K. Role of States

L. Biased Data Collection From Phase II ICR Testing

VI. Impacts of the Action

A. What are the primary air impacts?

B. What are the water and solid waste impacts?

C. What are the energy impacts?

D. What are the secondary air impacts?

E. What are the cost and economic impacts?

F. What are the benefits?

VII. Statutory and Executive Order Reviews

A. Executive Order 12866 and 13563: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks

H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution or Use

I. National Technology Transfer and Advancement Act

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

K. Congressional Review Act

I. General Information

A. Does this action apply to me?

Categories and entities potentially affected by the final action are those that operate CISWI units. The NSPS and EG, hereinafter referred to as “standards,” for CISWI affect the following categories of sources:

Category

NAICS code

Examples of potentially regulated entities

Any industrial or commercial facility using a solid waste incinerator

211, 212, 486

Mining, oil and gas exploration operations; pipeline operators.

221

Utility providers.

321, 322, 337

Manufacturers of wood products; manufacturers of pulp, paper and paperboard; manufacturers of furniture and related products.

325, 326

Manufacturers of chemicals and allied products; manufacturers of plastics and rubber products.

327

Manufacturers of cement; nonmetallic mineral product manufacturing.

333, 336

Manufacturers of machinery; manufacturers of transportation equipment.

423, 44

Merchant wholesalers, durable goods; retail trade.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by the final action. If you have any questions regarding the applicability of the final action to a particular entity, contact the person listed in the preceding

FOR FURTHER INFORMATION CONTACT

section.

B. Where can I get a copy of this document?

In addition to being available in the docket, an electronic copy of the final action will also be available on the WWW through the TTN. Following signature, a copy of the final action will be posted on the TTN's policy and guidance page for newly proposed or promulgated rules at the following address:

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

The TTN provides information and technology exchange in various areas of air pollution control.

C. Judicial Review

Under CAA section 307(b)(1), judicial review of this final rule is available only by filing a petition for review in the Court by May 20, 2011. Section 307(d)(7)(B) of the CAA further provides that “only an objection to a rule or procedure which was raised with reasonable specificity during the period for public comment can be raised during judicial review.” This section also provides a mechanism for us to convene a proceeding for reconsideration, “[i]f the person raising an objection can demonstrate to EPA that it was impracticable to raise such objection within [the period for public comment] or if the grounds for such objection arose after the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule.” Any person seeking to make such a demonstration to us should submit a Petition for Reconsideration to the Office of the Administrator, Environmental Protection Agency, Room 3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC 20004, with a copy to both of the contacts listed in the preceding

FOR FURTHER INFORMATION CONTACT

section, and the Associate General Counsel for the Air and Radiation Law Office, Office of General Counsel (Mail Code 2344A), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20004. Note, under CAA section 307(b)(2), the requirements established by this final rule may not be challenged separately in any civil or criminal proceedings brought by EPA to enforce these requirements.

II. Background Information

A. What is the statutory authority for this final rule?

Section 129 of the CAA, entitled “Solid Waste Combustion,” requires EPA to develop and adopt standards for solid waste incineration units pursuant to CAA sections 111 and 129. Section 129(a)(1)(A) of the CAA requires EPA to establish performance standards, including emission limitations, for “solid waste incineration units” generally and, in particular, for “solid waste incineration units combusting commercial or industrial waste” (CAA section 129(a)(1)(D)). Section 129 of the CAA defines “solid waste incineration unit” as “a distinct operating unit of any facility which combusts any solid waste material from commercial or industrial establishments or the general public” (section 129(g)(1)). Section 129 of the CAA also provides that “solid waste” shall have the meaning established by EPA pursuant to its authority under the RCRA (section 129(g)(6)).

Natural Resources Defense Council

EPA,

489 F.3d 1250 (DC Cir. 2007), the Court vacated the CISWI Definitions Rule (70 FR 55568, September 22, 2005), which EPA issued pursuant to CAA section 129(a)(1)(D). In that rule, EPA defined the term “commercial or industrial solid waste incineration unit” to mean a combustion unit that combusts “commercial or industrial waste.” The rule defined “commercial or industrial waste” to mean waste combusted at a unit that does not recover thermal energy from the combustion for a useful purpose. Under these definitions, only those units that combusted commercial or industrial waste and were not designed to, or did not operate to, recover thermal energy from the combustion, were subject to CAA section 129 standards. In vacating the rule, the Court found that the definitions in the amendments to the CISWI regulations were inconsistent with the CAA. Specifically, the Court held that the term “solid waste incineration unit” in CAA section 129(g)(1) “unambiguously include[s] among the incineration units subject to its standards any facility that combusts any commercial or industrial solid waste material at all—subject to the four statutory exceptions identified [in CAA section 129(g)(1)]”

NRDC

EPA,

489 F.3d at 1257-58.

In response to the Court's vacatur of the CISWI Definitions Rule, EPA initiated a rulemaking to define which non-hazardous secondary materials is “solid waste” for purposes of subtitle D (non-hazardous waste) of RCRA when burned in a combustion unit. See 74 FR 41 (January 2, 2009) soliciting comment on whether certain non-hazardous secondary materials used as alternative fuels or ingredients are solid wastes within the meaning of subtitle D of the RCRA. That definition, once established, will determine the applicability of CAA section 129(a) to commercial and industrial combustion units.

On the same day EPA proposed standards for CISWI units, EPA issued a proposed definition of non-hazardous secondary materials that are solid waste pursuant to subtitle D of RCRA (75 FR 31844, June 4, 2010). In a parallel action to today's final CISWI rule, EPA is promulgating a final definition of solid waste that identifies whether non-hazardous secondary materials burned as fuels in combustion units are solid waste. That action, hereinafter referred to as the “Non-hazardous Solid Waste Definition Rulemaking,” is relevant to this proceeding because some ERUs and waste-burning kilns combust secondary materials in their combustion units which are defined as solid waste under the new definition. Units that combust solid waste (as defined under the new non-hazardous solid waste definition) will be subject to standards in the final CAA section 129 CISWI rules rather than to the standards under CAA section 112 applicable to boilers, process heaters, and cement kilns.

At proposal, we acknowledged that we had incomplete information on the exact nature of the non-hazardous secondary materials that ERUs and waste-burning kilns combust. For example, we indicated that we lacked complete information concerning the provider(s) of the non-hazardous secondary materials, how much processing the non-hazardous secondary materials may have undergone, if any, and other issues potentially relevant in a determination as to whether non-hazardous secondary materials are solid waste, all information relevant not only in this rulemaking but also in developing a definition in the concurrent Non-hazardous Solid Waste Definition Rulemaking.

In developing standards for this final rule, we used best efforts to estimate which units would have been classified as CISWI (i.e., units combusting solid waste) had the final definition of non-hazardous solid waste been in place at the time of the performance testing. The standards (and, necessarily, the pool of best performers establishing the floors for each standard) are based on the performance of this universe of sources.

In evaluating which sources would have been classified as CISWI had the new definition of solid waste been effective, EPA used the information currently available on which non-hazardous secondary materials the sources combust, as supplemented by information obtained from public comment and further information gathered by EPA after the public comment period of this rule.

Section 112(D) MACT standards are based on the performance of sources at a moment in time (or over some demarcated timeframe), and EPA therefore bases those standards on performance of sources classified as part of the source category at the time their performance is evaluated (

i.e.,

the time of performance testing). However, EPA could not use this approach here. Sources combusting non-hazardous secondary materials, the best example being alternative fuels, were not classified as CISWI absent a regulatory definition of solid waste classifying such secondary materials. In order to issue the CISWI standards by the mandated promulgation deadline, EPA thus deviated from its usual practice and based the standards on the performance of devices which would have been classified as CISWI had the final waste definition been in place at the time of the performance testing even though these sources were not CISWI at the time. There was no approach that would be based on the sources' actual status that would have allowed EPA to complete this CISWI rule by the time of the mandated deadline for promulgation.

Energy recovery units (

i.e.,

boilers and process heaters) and waste-burning kilns (

i.e.,

cement kilns) that are burning solid waste (as defined in new section 241) will be subject to today's standards.

Sections 111(b) and 129(a) of the CAA address emissions from new CISWI units (

i.e.,

NSPS) and CAA sections 111(d) and 129(b) address emissions from existing CISWI units (

i.e.,

EG). The NSPS are directly enforceable federal regulations and under CAA section 129(f)(1) become effective 6 months after promulgation. Under CAA section 129(f)(2), the EG become effective and enforceable no later than 3 years after EPA approves a state plan implementing the EG or 5 years after the date they are promulgated, whichever is earlier.

The CAA sets forth a two-stage approach to regulating emissions from solid waste incinerator units. The statute also provides EPA with substantial discretion to distinguish among classes, types, and sizes of incineration units within a category while setting standards. In the first stage of setting standards, CAA section 129(a)(2) requires EPA to establish technology-based emission standards that reflect levels of control EPA determines are achievable for new and existing units, after considering costs, nonair quality health and environmental impacts and energy requirements associated with the implementation of the standards. Section 129(a)(5) of the CAA then directs EPA to review those

standards and revise them as necessary every 5 years. In the second stage, CAA section 129(h)(3) requires EPA to determine whether further revisions of the standards are necessary in order to provide an ample margin of safety to protect public health.

See, e.g., NRDC and LEAN

EPA,

529 F.3d 1077, 1079-80 (D.C. Cir. 2008) addressing the similarly required two-stage approach under CAA sections 112(d) and (f) and upholding EPA's implementation of same.

In setting forth the methodology EPA must use to establish the first-stage technology-based standards for the NSPS and EG, CAA section 129(a)(2) provides that standards “applicable to solid waste incineration units promulgated under section 111 and this section shall reflect the maximum degree of reduction in emissions of [certain listed air pollutants] that the Administrator, taking into consideration the cost of achieving such emission reduction and any nonair quality health and environmental impacts and energy requirements, determines is achievable for new and existing units in each category.” This level of control is referred to as a MACT standard.

In promulgating a MACT standard, EPA must first calculate the minimum stringency levels for new and existing solid waste incineration units in a category, generally based on levels of emissions control achieved or required to be achieved by the subject units. The minimum level of stringency is called the MACT “floor,” and CAA section 129(a)(2) sets forth differing levels of minimum stringency that EPA's standards must achieve, based on whether they regulate new and reconstructed sources, or existing sources. For new and reconstructed sources, CAA section 129(a)(2) provides that the “degree of reduction in emissions that is deemed achievable * * * shall not be less stringent than the emissions control that is achieved in practice by the best controlled similar unit, as determined by the Administrator.” Emissions standards for existing units may be less stringent than standards for new units, but “shall not be less stringent than the average emissions limitation achieved by the best-performing 12 percent of units in the category.”

Maximum Achievable Control Technology analyses involve an assessment of the emissions from the best-performing unit or units in a source category. The assessment can be based on actual emissions data, knowledge of the air pollution control in place in combination with actual emissions data, or on state regulatory requirements that may enable EPA to estimate the actual performance of the regulated units. For each source category, the assessment involves a review of actual emissions data with an appropriate accounting for emissions variability. Other methods of estimating emissions can be used, if the methods can be shown to provide reasonable estimates of the actual emissions performance of a source or sources. Where there is more than one method or technology to control emissions, the analysis may result in a series of potential regulations (called regulatory options), one of which is selected as MACT.

Each regulatory option EPA considers must be at least as stringent as the CAA's minimum stringency “floor” requirements. EPA must examine, but is not necessarily required to adopt, more stringent “beyond-the-floor” regulatory options to determine MACT. Unlike the floor minimum stringency requirements, EPA must consider various impacts of the more stringent regulatory options in determining whether MACT standards are to reflect “beyond-the-floor” requirements. If EPA concludes that the more stringent regulatory options have unreasonable impacts, EPA selects the “floor-based” regulatory option as MACT. However, if EPA concludes that impacts associated with “beyond-the-floor” levels of control are reasonable in light of additional emissions reductions achieved, EPA selects those levels as MACT.

The CAA requires that MACT for new sources be no less stringent than the emissions control achieved in practice by the best-controlled similar unit. Under CAA section 129(a)(2), EPA determines the best control currently in use for a given pollutant and establishes one potential regulatory option at the emission level achieved by that control with an appropriate accounting for emissions variability. More stringent potential beyond-the-floor regulatory options might reflect controls used on other sources that could be applied to the source category in question.

For existing sources, the CAA requires that MACT be no less stringent than the average emissions limitation achieved by the best-performing 12 percent of units in a source category. EPA must determine some measure of the average emissions limitation achieved by the best-performing 12 percent of units to form the floor regulatory option. More stringent beyond-the-floor regulatory options reflect other or additional controls capable of achieving better performance.

B. What is the history of the CISWI standards?

On December 1, 2000, EPA published a notice of final rulemaking establishing the NSPS and EG for CISWI units (60 FR 75338), hereinafter referred to as the 2000 CISWI rule. On August 17, 2001, EPA granted a Request for Reconsideration, pursuant to CAA section 307(d)(7)(B) of the CAA, submitted on behalf of the National Wildlife Federation and the Louisiana Environmental Action Network, related to the definition of “commercial and industrial solid waste incineration unit” and “commercial or industrial waste” in EPA's CISWI rulemaking. In granting the Petition for Reconsideration, EPA agreed to undertake further notice and comment proceedings related to these definitions. On January 30, 2001, Sierra Club filed a petition for review in the Court challenging EPA's final CISWI rule. On September 6, 2001, the Court entered an order granting EPA's motion for a voluntary remand of the CISWI rule, without vacatur. EPA's request for a voluntary remand of the final CISWI rule was taken to allow the EPA to address concerns related to EPA's procedures for establishing MACT floors for CISWI units in light of the Court's decision in

Cement Kiln Recycling Coalition

EPA,

255 F.3d 855 (DC Cir. 2001)(

Cement Kiln

). Neither EPA's granting of the Petition for Reconsideration, nor the Court's order granting a voluntary remand, stayed, vacated, or otherwise influenced the effectiveness of the 2000 CISWI rule. Specifically, CAA section 307(d)(7)(B) provides that “reconsideration shall not postpone the effectiveness of the rule,” except that “[t]he effectiveness of the rule may be stayed during such reconsideration * * * by the Administrator or the Court for a period not to exceed three months.” Neither EPA nor the Court stayed the effectiveness of the final CISWI regulations in connection with the reconsideration petition. In addition, the Court granted EPA's motion for a remand without vacatur; therefore, the remand order had no impact on the implementation of the 2000 CISWI rule.

On February 17, 2004, EPA published a proposed rule soliciting comments on the definitions of “solid waste,” “commercial and industrial waste,” and “commercial and industrial solid waste incineration unit.” On September 22, 2005, EPA published in the

Federal Register

the final rule reflecting our decisions with respect to the CISWI Definitions Rule. The rule was challenged and, on June 8, 2007, the Court vacated and remanded the CISWI

Definitions Rule. In vacating the rule, the Court found that CAA section 129 unambiguously includes among the incineration units subject to its standards, any facility that combusts any solid waste material, subject to four statutory exceptions. While the Court vacated the CISWI Definitions Rule, the 2000 CISWI rule remains in effect.

On June 4, 2010, EPA proposed revised NSPS and EG for CISWI units (75 FR 31938). Today's final action constitutes EPA's response to the voluntary remand of the 2000 CISWI rule and to the 2007 vacatur and remand of the CISWI Definitions Rule. In addition, these amendments address the 5-year technology review that is required under CAA section 129(a)(5).

C. How is the solid waste definition addressed in this final rule?

The RCRA definition of solid waste is integral in defining the CISWI source category. EPA defines the non-hazardous secondary materials that are solid waste under RCRA in the final Non-hazardous Solid Waste Definition Rulemaking. At proposal, the Non-hazardous Solid Waste Definition Rulemaking proposed a definition of solid waste and identified an “alternative approach” for consideration and comment. However, the final solid waste definition does not incorporate the “alternative approach,” and more closely reflects the proposed definition of non-hazardous secondary materials that are solid waste.

D. What is the relationship between the final rule and other combustion rules?

These amendments address the combustion of solid waste materials (as defined by the Administrator under RCRA in the concurrent Non-hazardous Solid Waste Definition Rulemaking) in combustion units at commercial and industrial facilities. If an owner or operator of a CISWI unit permanently ceases combusting solid waste, the affected unit would no longer be subject to this regulation under CAA section 129. Section 112 rules of the CAA, applicable to boilers and process heaters at major sources and boilers at area sources, are being promulgated in parallel actions that are relevant to this action because those standards would apply to subject boilers and process heaters that do not combust solid waste. Boilers and process heaters that combust solid waste are subject to CISWI as ERUs. EPA has also finalized revised CAA section 112 NESHAP from the Portland Cement Manufacturing Industry (75 FR 21136, September 9, 2010). Cement kilns combusting solid waste are waste-burning kilns subject to this final rule, not the otherwise applicable NESHAP.

E. What is EPA's approach for conducting a 5-year review under CAA section 129(a)(5)?

Section 129(a)(5) of the CAA requires EPA to conduct a review of the section 129 standards at 5-year intervals and, in accordance with CAA sections 129 and 111, revise the standards. We do not interpret CAA section 129(a)(5), together with CAA section 111, as requiring EPA to recalculate MACT floors in connection with this periodic review. (71 FR 27324, 27327-28, May 10, 2006;

NRDC and LEAN

EPA,

529 F.3d 1077, 1083-84 (DC Cir. 2008) (upholding EPA's interpretation that the periodic review requirement in CAA section 112(d)(6) does not impose an obligation to recalculate MACT floors). Rather, in conducting such periodic reviews, EPA attempts to assess the performance of and variability associated with control measures affecting emissions performance at sources in the subject source category (including the installed emissions control equipment), along with recent developments in practices, processes, and control technologies, and determines whether it is appropriate to revise the standards. This is the same general approach taken by EPA in periodically reviewing CAA section 111 standards, because CAA section 111 contains a similar review and revise provision.

Our obligation to conduct a 5-year review based on implementation of the 2000 CISWI rule is fulfilled with the finalization of these CISWI standards. This action responds to the vacatur and remand of the CISWI Definition Rule and the voluntary remand of the 2000 CISWI NSPS and EG, and, in this response, EPA is requiring new standards based on a MACT methodology that is consistent with the CAA and District of Columbia Circuit Court precedent. The MACT levels required herein reflect MACT floor levels determined by current emissions data from CISWI units, and, therefore, reflect the current performance of the best-performing unit or units subject to the CISWI standards. Consequently, we believe that our obligation to conduct a 5-year review based on implementation of the 2000 CISWI rule is fulfilled.

Our conclusion is supported by the fact that the revised MACT standards included in this final remand response are based on the available performance data for the currently operating CISWI units, including those units that are subject to the 2000 CISWI rule and those units that will be subject to the CISWI standards for the first time based on the final Non-hazardous Solid Waste Definition Rulemaking under RCRA. In establishing MACT floors based on currently available emissions information, we address the technology review's goals of assessing the performance efficiency of the installed equipment and ensuring that the emission limits reflect the performance of the technologies required by the MACT standards. In addition, in establishing these final standards, we considered whether new technologies, processes, and improvements in practices have been demonstrated at sources subject to the 2000 CISWI rule and at sources that will be subject to these proposed standards for the first time based on the proposed definition of solid waste. Accordingly, the remand response in this final action fulfills EPA's obligations regarding the 5-year review of the CISWI standards. Further discussion of the EPA's response to the CAA section 129(a)(5) 5-year review is found in section III.B of the proposal preamble (75 FR 31946).

F. What is the relationship of this final action to section 112(c)(6) of the CAA?

Section 112(c)(6) of the CAA requires EPA to identify categories of sources of seven specified pollutants to assure that sources accounting for not less than 90 percent of the aggregate emissions of each such pollutant are subject to standards under CAA section 112(d)(2) or 112(d)(4). EPA has identified certain CISWI units as sources necessary to meet the 90 percent requirement under section 112(c)(6). In the

Federal Register

notice “Source Category Listing for Section 112(d)(2) Rulemaking Pursuant to Section 112(c)(6) Requirements”, 63 FR 17838, 17849, Table 2 (1998), EPA identified source categories that must be “subject to regulation” for purposes of CAA section 112(c)(6). Included in that list are cement kilns and combustion units (e.g., major source boilers and process heaters). Cement kilns, boilers, and process heaters that combust solid waste are subject to the CAA section 129 standards for CISWI as either waste-burning kilns or ERUs. These CISWI units emit five of the seven CAA section 112(c)(6) pollutants: POM, dioxins, furans, Hg and PCBs. The POM emitted by CISWI is composed of 7-PAH and 16-PAH.

this issue, the CAA section 129 standards effectively control emissions of the five identified CAA section 112(c)(6) pollutants. Further, since CAA section 129(h)(2) precludes EPA from regulating CISWI units under CAA section 112(d), EPA cannot further regulate the emissions of 112(c)(6) pollutants from CISWI units under CAA section 112(d). As a result, EPA considers emissions of these five pollutants from waste-burning kilns and ERUs “subject to standards” for purposes of CAA section 112(c)(6). The remaining CISWI subcategories will be subject to MACT standards either in this action or in a future action, but regulation of the remaining subcategories is not required for EPA to complete its 112(c)(6) obligations.

III. Summary of the Final Rule

A. Which units are affected by this final rule?

This final rule defines a CISWI unit as any combustion unit at a commercial or industrial facility that is used to combust solid waste (as defined under RCRA). (40 CFR 60.2265 (NSPS) and 60.2875 (EG)). Therefore, in this final rule, CISWI units subject to standards in this final rule include incinerators designed to burn discarded waste materials; units designed for heat recovery that combust solid waste materials (

i.e.,

ERUs that would be boilers or process heaters if they did not burn solid waste); and waste burning kilns (

i.e.,

units that would be cement kilns if they did not burn solid waste); we also define other CISWI units that are not subject to standards in this final action. The final rule contains definitions of the four subcategories of CISWI units that are subject to standards under these amendments: incinerators, small remote incinerators, ERUs, and waste burning kilns. At proposal, we also defined and proposed standards for burn-off ovens. Based on information obtained during proposal, and because we do not need such units to comply with our section 112(c)(6) obligations, we are not finalizing standards for burn-off ovens as explained further below in response to comments on this issue.

We are revising the definition of CISWI unit to reflect the Court's decision that all units burning solid waste as defined under RCRA are to be covered by regulation under CAA section 129. To ensure consistency with the definition of CISWI unit, we are also adding a definition of “solid waste incineration unit” and removing the definition of “commercial and industrial waste.”

The 2000 CISWI rule, through the definition of “commercial and industrial waste,” excluded from regulation combustion units at commercial or industrial facilities that recovered energy for a useful purpose. We are eliminating those exemptions that were vacated by the Court.

Qualifying small power producers, qualifying cogeneration units, and materials recovery units continue to be expressly exempt from coverage pursuant to CAA exclusions from the definition of “solid waste incineration unit” set forth in CAA section 129(g)(1). Units that are required to have a permit under section 3005 of the SWDA (

i.e.,

hazardous waste combustion units) are also exempt from section 129 rules per CAA section 129(g)(1). Air curtain incinerators at commercial or industrial facilities combusting “clean wood” waste are also excluded from the definition of solid waste incineration unit set forth in CAA section 129(g)(1), but that section provides that such units must comply with opacity limits to maintain that exemption.

Solid waste incineration units that are included within the scope of other CAA section 129 categories include MWC units; institutional, pathological waste incineration units (EPA intends to regulate these units under OSWI standards); SSI units (EPA is issuing final standards for these units in a concurrent action), and HMIWI units. These solid waste incineration units will remain exempt from the CISWI standards. As stated above, we created subcategories for waste-burning kilns and ERUs, and they are subject to this final rule in light of the CISWI Definitions Rule vacatur. We note that other CAA section 129 standards may contain an exemption for cement kilns. Those exemptions do not excuse waste burning kilns from compliance with these final standards. As those other CAA section 129 rules are amended, we will clarify that cement kilns that meet the definition of waste-burning kiln and other CISWI units, that may be expressly exempt from those standards, are subject to CISWI standards if they are located at a commercial or industrial facility and they combust solid waste.

B. What are the emission limits in the final rule?

The final MACT floor emission limits for new and existing sources are presented in Tables 1 and 2 of this preamble. These emission limits are based on subcategories established considering sources that we believe are CISWI units under the final definition of non-hazardous secondary materials, as discussed in the concurrent Non-hazardous Solid Waste Definition Rulemaking. The final MACT floor emission limits for existing sources in each subcategory are shown in Table 1 of this preamble.

Table 1—Comparison of Existing Source MACT Floor Limits for 2000 CISWI Rule and the Final MACT Floor Limits (Based on the Definition of Solid Waste in the Final Non-hazardous Solid Waste Definition Rulemaking)

Pollutant (units)

Incinerators

(2000 CISWI

limit)

Final CISWI subcategories

Incinerators

ERUs—solids

ERUs—

liquid/gas

Waste-burning

kilns

Small, remote

incinerators

HCl (ppmv)

0.45

220

CO (ppmv)

157

490 (biomass units)/59 (coal units)

110

Pb (mg/dscm)

0.04

0.0036

0.096

0.0026

2.7

Cd (mg/dscm)

0.004

0.0026

0.00051

0.023

0.00048

0.61

Hg (mg/dscm)

0.47

0.0054

0.00033

0.0013

0.0079

0.0057

PM, filterable (mg/dscm)

250

110

6.2

230

Dioxin, furans, total (ng/dscm)

(no limit)

4.6

0.35

2.9

0.20

1,200

Dioxin, furans, TEQ (ng/dscm)

0.41

0.13

0.059

0.32

0.0070

(ppmv)

388

290 (biomass units)/340 (coal units)

540

240

(ppmv)

6.2 (biomass units)/650 (coal units)

720

420

All emission limits are expressed as concentrations corrected to 7 percent oxygen.

See the memorandum “CISWI Emission Limit Calculations for Existing and New Sources” for details on this calculation.

The new source MACT floor emission limits for each CISWI subcategory are shown in Table 2 of this preamble.

Table 2—Comparison of New Source MACT Floor Limits for 2000 CISWI Rule and the Final MACT Floor Limits (Based on the Primary Definition of Solid Waste in the Solid Waste Definition Rule)

Pollutant (units)

Incinerators

(2000 limit)

Final CISWI subcategories

Incinerators

ERUs—solids

ERUs—

liquid/gas

Waste-burning

kilns

Small, remote

incinerators

HCl (ppmv)

0.091

0.45

14b

3.0

200

CO (ppmv)

157

160 (biomass units)/ 46 (coal units)

Pb (mg/dscm)

0.04

0.0019

0.0031

0.096

0.0026

0.26

Cd (mg/dscm)

0.004

0.0023

0.00051

0.023

0.00048

0.61

Hg (mg/dscm)

0.47

0.00016

0.00033

0.00025

0.0062

0.0035

PM, filterable (mg/dscm)

250

110

2.5

230

Dioxin, furans, total (ng/dscm)

(no limit)

0.052

0.068

(no limit)

0.090

1,200

Dioxin, furans, TEQ (ng/dscm)

0.41

0.13

0.011

0.002

0.0030

(ppmv)

388

290

(biomass units)/340 (coal units)

200

(ppmv)

6.2

(biomass units)/650 (coal units)

720

1.2

All emission limits are measured at 7 percent oxygen.

See

the memorandum “CISWI Emission Limit Calculations for Existing and New Sources” for details on this calculation.

The NSPS limit equals the EG limit. The EG limit was selected as the NSPS limit.

Dioxin/furan TEQ and Hg limits for ERUs—liquid/gas were replaced with D/F TEQ limits for liquid fuel major source boilers.

See

“CISWI Emission Limit Calculations for Existing and New Sources” for details.

Hg limit was developed using material input data from CISWI kilns identified within the Portland Cement NESHAP database.

See

the memorandum “CISWI Emission Limit Calculations for Existing and New Sources” for details on this calculation.

C. What are the testing and monitoring requirements?

This final rule requires all CISWI units to demonstrate initial compliance with the revised emission limits. For existing CISWI units, these amendments require annual inspections of scrubbers, FF, and other air pollution control devices that are used to meet the emission limits. In addition, a Method 22 (40 CFR part 60, appendix A-7) visible emissions test of the ash handling operations is required during the annual compliance test for all subcategories except waste-burning kilns, which do not have ash handling systems. Furthermore, for any existing CISWI unit that operates a FF air pollution control device, we are requiring that a bag leak detection system be installed to monitor the device. These amendments continue to require parametric monitoring of all other add-on air pollution control devices, such as wet scrubbers and ACI. Commercial and industrial solid waste incineration units that install SNCR technology to reduce NO

emissions are required to monitor the reagent (

e.g.,

ammonia or urea) injection rate and secondary chamber temperature (if applicable to the CISWI unit).

This final rule also requires subcategory-specific monitoring requirements in addition to the aforementioned inspection, bag leak detection, and parametric monitoring requirements that are applicable to all CISWI units. Existing incinerators, small, remote incinerators, and ERUs would have annual emissions testing for all nine pollutants: PM, SO

, HCl, NO

, CO, lead, Cd, Hg, and dioxins and furans. Existing kilns are required to monitor Hg, PM, and HCl (if no wet scrubber) emissions using a CEMS and perform annual testing for the remaining pollutants. These amendments provide reduced annual testing requirements for all nine pollutants when testing results are shown to be well below the limits. If the ERU has a design capacity less than or equal to 250 mmBtu/hr and is not equipped with a wet scrubber control device, then a continuous opacity monitor is required or, as an alternative, a PM CEMS could be employed (see below). If the ERU has a design capacity greater than 250 mmBtu/hr, then PM emissions must be monitored using a PM CEMS.

For new CISWI units, the final rule requires the same monitoring

requirements as for existing units, but also requires CO CEMS for all subcategories. Additionally, SO

and NO

CEMS are required for all new kilns.

For all subcategories of existing CISWI units, use of CO CEMS is an approved alternative and specific language with requirements for CO CEMS is included in these amendments. For new and existing CISWI units, use of PM, NO

, SO

, HCl, multi-metals and Hg CEMS and integrated sorbent trap Hg monitoring and dioxin monitoring (continuous sampling with periodic sample analysis) also are approved alternatives, and specific language for those alternatives is included in these amendments.

D. What are the requirements during periods of SSM?

The 2000 CISWI standards did not apply during periods of SSM. This final rule revises the 2000 CISWI rule such that the standards apply at all times, including during SSM periods. As further explained in section V.H of this preamble, the revision is being made in light of the Court decision that vacated portions of regulations related to SSM in the General Provisions of 40 CFR part 63. EPA is including in this final rule an affirmative defense to civil penalties for exceedances of emission limits that are caused by malfunctions. The full rationale for these decisions is presented in section V.H of this preamble.

E. How do the rule amendments affect the applicability of the 2000 NSPS and EG?

Incinerators subject to the 2000 CISWI standards are treated differently under the amended standards than they were under the 2000 CISWI rule in terms of whether they are “existing” or “new” sources.

Consistent with the CAA section 129 definition of “new” sources, there are new dates defining what units are “new” sources. Incinerators that are currently subject to the NSPS will become “existing” sources under the final amended standards and are required to meet the revised EG by the applicable compliance date for the revised guidelines. Those units will continue to be NSPS units subject to the 2000 CISWI rule until they become “existing” sources under the amended standards. Incinerators and small remote incinerators that are existing sources under the 2000 EG must continue to comply with those standards until the applicable compliance date for the revised EG, at which time those sources must be in compliance with the applicable EG.

We believe that all the units in the small remote incinerator subcategory as defined in this final rule qualified for the exemption for MWC in the 2000 CISWI standards.

See

40 CFR 60.2020(c)(2) and 60.2555(c)(2).

Commercial and industrial solid waste incineration units in the four subcategories for which we are issuing final standards in this rule that commenced construction after June 4, 2010, or for which a modification is commenced on or after 6 months after promulgation of these final standards, are “new” units subject to more stringent NSPS emission limits. Units for which construction or modification is commenced prior to those dates would be existing units subject to the EG, except that units in the incinerators and small remote incinerators subcategories remain subject to the 2000 CISWI rule until the compliance date of the CISWI EG as discussed below. Commercial and industrial solid waste incineration units in the subcategories other than the incinerator subcategory and small remote incinerator subcategory (if a unit was not exempt) will not in any case be subject to the standards in the 2000 CISWI rule.

Under this final rule, incinerators that commenced construction after November 30, 1999, and on or before June 4, 2010, or that were reconstructed or modified prior to the date 6 months after promulgation of any revised final standards, are subject to the 2000 CISWI NSPS until the applicable compliance date for the revised EG, at which time those units would become “existing” sources. Similarly, units in the incinerator or small remote incinerator subcategories that are subject to the EG under the 2000 CISWI rule must meet the revised EG by the applicable compliance date for the revised guidelines. Commercial and industrial solid waste incineration units that commence construction after June 4, 2010, or that are reconstructed or modified 6 months or more after the date of promulgation of the revised standards, must meet the revised NSPS emission limits in the NSPS within 6 months after the promulgation date of the amendments or upon startup, whichever is later.

F. What is the compliance schedule?

New CISWI units must demonstrate compliance with the applicable emission limit within 60 days after the CISWI unit reaches the charge rate at which it will operate, but no later than 180 days after its initial startup.

Existing CISWI units must demonstrate compliance with the applicable emission limits as expeditiously as practicable after approval of a state plan, but no later than 3 years from the date of approval of a state plan or 5 years after promulgation of these revised standards, whichever is earlier.

G. What is the state plan implementation schedule?

Under the final amendments to the EG, and consistent with CAA section 129, revised state plans containing the revised existing source emission limits and other requirements in the final amendments are due within 1 year after promulgation of the amendments. States must submit revised state plans to EPA March 21, 2012.

These amendments to the EG allow existing CISWI to demonstrate compliance with the amended standards as expeditiously as practicable after approval of a state plan, but no later than 3 years from the date of approval of a state plan or 5 years after promulgation of the revised standards, whichever is earlier. Because we believe that many CISWI units will find it necessary to retrofit existing emission control equipment and/or install additional emission control equipment in order to meet the final revised limits, EPA anticipates that states may choose to provide the 3-year compliance period allowed by CAA section 129(f)(2).

In revising the standards in a state plan, a state has two options. First, it may include both the 2000 CISWI standards and the new standards in its revised state plan, which allows a phased approach in applying the new limits. The state plan must make clear that the standards in the 2000 CISWI rule remain in force for subject units and apply until the date the revised existing source standards are effective (as defined in the state plan).

States where existing CISWI incinerators do not need to improve their performance to meet the revised standards, may want to consider a second approach as follows. The state may replace the 2000 CISWI rule standards with the standards in this final rule; follow the procedures in 40 CFR part 60, subpart B; and submit a revised state plan to EPA for approval. If the revised state plan contains only the revised standards (

i.e.,

the 2000 CISWI rule standards are not retained), then the revised standards must become effective immediately for those units that are subject to the 2000 CISWI rule, since the 2000 CISWI rule

standards would be removed from the state plan.

All sources currently subject to the 2000 CISWI EG or NSPS will become existing sources in the incinerator or small remote incinerator subcategories once the final revised CISWI standards are in place.

See

section III.F of this preamble.

EPA will revise the existing federal plan to incorporate any changes to existing source emission limits and other requirements that EPA has promulgated. The federal plan applies to CISWI units in any state without an approved state plan. The proposed amendments to the EG would allow existing CISWI units subject to the federal plan up to 5 years after promulgation of the revised standards to demonstrate compliance with the amended standards, as required by CAA section 129(b)(3).

H. What are the requirements for submission of emissions test results to EPA?

EPA must have performance test data and other compliance data to conduct effective reviews of CAA section 112 and 129 standards, as well as for many other purposes including compliance determinations, emissions factor development, and annual emissions rate determinations. In conducting these required reviews, EPA has found it ineffective and time consuming not only for us but also for regulatory agencies and source owners and operators to locate, collect, and submit emissions test data because of varied locations for data storage and varied data storage methods. One improvement that has occurred in recent years is the availability of stack test reports in electronic format as a replacement for cumbersome paper copies.

In this final rule, EPA is taking steps to improve data accessibility. Owners and operators of CISWI units are required to submit to EPA an electronic copy of reports of certain performance tests required under the CISWI EG and NSPS. Sources must submit data through the ERT. The ERT was developed with input from stack testing companies who generally collect and compile performance test data electronically and offices within state and local agencies which perform field test assessments. The ERT is currently available, and access to direct data submittal to EPA's electronic emissions database (WebFIRE) is scheduled to become available by December 31, 2011.

The requirement to submit source test data electronically to EPA will not require any additional performance testing and will apply to those performance tests conducted using test methods that are supported by ERT. The ERT contains a specific electronic data entry form for most of the commonly used EPA reference methods. The Web site listed below contains a listing of the pollutants and test methods supported by ERT. In addition, when a facility submits performance test data to WebFIRE, there would be no additional requirements for emissions test data compilation. Moreover, EPA believes industry will benefit from development of improved emissions factors, fewer follow-up information requests, and better regulation development as discussed below. The information to be reported is already required for the existing test methods and is necessary to evaluate the conformance to the test method.

One major advantage of collecting source test data through the ERT is that it provides a standardized method to compile and store much of the documentation required to be reported by this final rule while clearly stating what testing information EPA requires. Another important benefit of submitting these data to EPA at the time the source test is conducted is that it substantially reduces the effort involved in data collection activities in the future. Specifically, because EPA would already have adequate source category data to conduct residual risk assessments or technology reviews, there would likely be fewer or less substantial data collection requests (

e.g.,

CAA section 114 letters). This results in a reduced burden on both affected facilities (in terms of reduced labor to respond to data collection requests) and EPA (in terms of preparing and distributing data collection requests).

State/local/tribal agencies may also benefit in that their review may be more streamlined and accurate because the states would not have to re-enter the data to assess the calculations and verify the data entry. Finally, another benefit of submitting these data to WebFIRE electronically is that these data would improve greatly the overall quality of the existing and new emissions factors by supplementing the pool of emissions test data upon which the emissions factor is based and by ensuring that data are more representative of current industry operational procedures. A common complaint EPA receives from industry and regulators is that emissions factors are outdated or not representative of a particular source category. Receiving and incorporating data for most performance tests would ensure that emissions factors, when updated, represent accurately the most current operational practices. In summary, receiving test data already collected for other purposes and using them in the emissions factors development program would save industry, state/local/tribal agencies, and EPA, time and money and work to improve the quality of emissions inventories and related regulatory decisions.

As mentioned earlier, the electronic database that would be used is EPA's WebFIRE, which is a database accessible through EPA's TTN (see

http://cfpub.epa.gov/webfire/

). The WebFIRE database was constructed to store emissions test and other data for use in developing emissions factors. A description of the WebFIRE database can be found at

http://cfpub.epa.gov/oarweb/index.cfm?action=fire.main

Source owners and operators will be able to transmit data collected via the ERT through EPA's CDX network for storage in the WebFIRE database. Although ERT is not the only electronic interface that can be used to submit source test data to the CDX for entry into WebFIRE, it makes submittal of data very straightforward and easy. A description of the ERT can be found at

http://www.epa.gov/ttn/chief/ert/ert_tool.html

Source owners and operators must register with the CDX system to obtain a user name and password before being able to submit data to the CDX. The CDX registration page can be found at

https://cdx.epa.gov/SSL/CDX/regwarning.asp?Referer=registration

. If they have a current CDX account (

e.g.,

they submit reports for the EPA's TRI Program to the CDX), then the existing user name and password can be used to log in to the CDX.

I. What are the costs and benefits of this final rule?

EPA estimated the costs and benefits associated with the final rule, and the results are shown in the following table. For more information on the costs and benefits for this rule, see the Regulatory Impact Analysis (RIA) in the EPA-HQ-OAR-2003-0119.

Table 3—Summary of the Monetized Benefits, Social Costs, and Net Benefits for the CISWI NSPS and Emissions Guidelines in 2015

[Millions of 2008$]

a d

3% Discount rate

7% Discount rate

Option 1: MACT Floor:

Total Monetized Benefits

$340 to $830

$310 to $750.

Total Social Costs

;

$280

$280.

Net Benefits

$60 to $550

$30 to $470.

Non-monetized Benefits

25,000 tons of CO.

470 tons of HCl.

260 pounds of Hg.

0.95 tons of Cd.

4.1 tons of lead.

92 grams of dioxins/furans.

Health effects from NO

and SO

exposure.

Ecosystem effects.

Visibility impairment.

Option 2: Beyond-the-Floor:

Total Monetized Benefits

$430 to $1,100

$390 to $960.

Total Social Costs

$300

$300.

Net Benefits

$130 to $770

$90 to $660.

Non-monetized Benefits

25,000 tons of CO.

470 tons of HCl.

260 pounds of Hg.

0.95 tons of Cd.

4.1 tons of lead.

92 grams of dioxins/furans.

Health effects from NO

and SO

exposure.

Ecosystem effects.

Visibility impairment.

All estimates are for the implementation year (2015), and are rounded to two significant figures. These results include units anticipated to come online and the lowest cost disposal assumption.

The total monetized benefits reflect the human health benefits associated with reducing exposure to PM

2.5

through reductions of directly emitted PM

2.5

and PM

2.5

precursors such as NO

and SO

. It is important to note that the monetized benefits include many but not all health effects associated with PM

2.5

exposure. Benefits are shown as a range from Pope, et al. (2002) to Laden, et al. (2006). These models assume that all fine particles, regardless of their chemical composition, are equally potent in causing premature mortality because there is no clear scientific evidence that would support the development of differential effects estimates by particle type. These estimates include energy disbenefits valued at $3.8 million.

The methodology used to estimate social costs for 1 year in the multimarket model using surplus changes results in the same social costs for both discount rates.

The estimates in this table reflect the estimates in the RIA. Due to last minute changes, we were unable to incorporate the final engineering costs and emission reductions into the RIA, which would decrease the costs by approximately 22% and increase the monetized benefits by approximately 4% from those shown here.

IV. Summary of Significant Changes Since Proposal

EPA received over 3,500 public comments on the proposed rulemaking. Furthermore, we conducted three public hearings to allow the public to comment on the proposed rulemaking and the inter-related Boiler and RCRA rules. Following are the major changes to the rule since the proposal. The rationale for these and any other significant changes can be found in section V of this preamble or in the document titled “Commercial and Industrial Solid Waste Incineration (CISWI) Rule: EPA's Response to Public Comments” available in the docket for this rulemaking.

• Clarified and revised the applicability and compliance requirements for CISWI units that cease or begin combusting solid waste.

• Determined that this final action will not subject burn-off ovens, soil treatment units, cyclonic burn barrels, laboratory analysis units, and space heaters to this standard.

• Further subcategorized ERUs with separate limits for NO

, CO, and SO

for coal and biomass units.

• Revised the definition of small, remote incinerators.

• Incorporated new data submitted by facilities since December 15, 2010.

• Revised the emission limit methodology to use the UPL for ERUs and waste-burning kilns.

• Revised the statistical analysis to use the log normal distribution of data in cases where a normal data distribution is not indicated conclusively by normality tests for the data.

• Revised the nondetect methodology to calculate emission limits using three times the reported nondetect values where the value equal to three times the representative MDL was greater than the calculated MACT floor emission limit.

• Revised the requirements for opacity.

• Revised the monitoring requirements for continuous compliance via testing and parametric monitoring and to allow CEMS use to demonstrate compliance over a 30-day rolling average as an alternative.

• Revised the CO CEMS monitoring requirement from mandatory to voluntary for existing ERUs.

• Incorporated hourly CEMS data into emissions limit calculations and 24-hour CEMS data into costing and impacts analyses.

• Revised the calculation methodology of D/F TEQ and clarified that sources must comply with either the TMB or TEQ basis limit.

• Added tire certification procedures for all CISWI units to allow them to certify that the tires are from a program that enables them to be considered non-waste materials.

• Added recordkeeping and reporting requirements for units that burn materials other than traditional fuels.

• Revised the annual performance testing requirements to clarify the schedule for completion of subsequent performance tests.

• Revised the reduced testing provision to state testing for a given pollutant may be performed every 3 years, instead of annually, if measured emissions during two consecutive annual performance tests are less than 75 percent of the applicable emission limit.

• Revised the test methods for cement kilns to require EPA Method 321 for HCl testing of these units.

• Removed the allowance for sources to use the results of previously conducted tests to demonstrate compliance.

• Revised monitoring requirements for the waste-burning kilns subcategory.

• Provided an affirmative defense to civil penalties for exceedances of emission limits that are caused by malfunctions.

V. Public Comments

A. Legal and Applicability Issues, Compliance Schedule, and Certification Procedures

1. Section 129 vs. Section 112—Applicability for Waste Firing Boilers and Kilns That Opt To Stop Burning Waste

Comment:

Many commenters stated that ERUs and waste-burning kilns should be able to move between CAA sections 129 and 112 standards based on the materials being burned. Commenters argued that EPA should provide flexibility for operators of units burning co-fired waste to consider the stringency of all applicable standards and opt into the appropriate rule. Many commenters contended that requiring operators who stop burning solid waste to remain regulated under CISWI would penalize them with no benefit gained. One commenter stated that no law or regulation prevents EPA from allowing a unit to opt out of CISWI and that the concern that facilities would “backslide” from MACT control levels is not applicable. Further, commenters argued that the once-in-always-in policy should not apply to CISWI and requested clarification on how the policy applies to sources subject to CAA section 129 standards that either continue or begin combusting solid waste. One commenter requested that EPA clarify whether the CISWI rule would apply to any kiln that is actually using solid waste or to any kiln authorized to do so.

Response:

This rule addresses the combustion of solid waste materials (as defined by the Administrator under RCRA) in combustion units at commercial and industrial facilities. If an owner or operator of a CISWI unit permanently ceases combusting solid waste, the affected unit is no longer subject to this regulation under CAA section 129, and the unit would become subject to any applicable regulations under CAA section 112. Likewise, if an owner or operator of any commercial or industrial unit starts combusting solid waste in that unit, it becomes subject to CISWI, and is no longer subject to any previously applicable regulations under section 112. Consistent with CAA section 129(h)(2), no solid waste incineration unit subject to performance standards under section 129 and section 111 shall be subject to standards under section 112(d) of the Act.

CISWI units that cease burning solid waste in the ERU and waste-burning kiln subcategories may be subject to one of three rulemaking actions under CAA section 112. EPA is finalizing in a parallel action two NESHAP applicable to boilers, one for area source boilers and one for major source boilers that also regulates process heaters at major sources. EPA also recently finalized revised NESHAP for cement kilns (74 FR 54970, September 9, 2010). Energy recovery units and waste-burning kilns subject to CISWI that cease burning solid waste, and thus cease being subject to this final rule, will be subject to the NESHAP for area source boilers, major source boilers and process heaters, or cement kilns, as appropriate.

Today's final rule includes provisions to address the situation where CISWI units cease burning solid waste, and where existing commercial and industrial facilities start burning solid waste. Units that cease burning solid waste remain subject to CISWI for at least 6 months after solid waste is no longer present in the combustion chamber. After 6 months, sources must either comply with any applicable section 112 standards or, if they intend to combust solid waste in the unit in the future, opt to remain subject to CISWI. Sources switching out of CISWI due to cessation of solid waste combustion must submit advance notification of the effective date of the waste-to-fuel switch consistent with new procedures in this rule. Units that begin combusting solid waste are considered existing sources under CISWI and must comply with the emissions guidelines set forth in the CISWI final rule at the time they begin burning solid waste.

EPA acknowledges that sources may stop and start burning solid waste in their combustion units, and that regulatory procedures are necessary to guide sources through the changes in applicability that may result due to a switch in combustion materials. New provisions in the final rule account for the fact that facilities may start and stop burning solid waste and ensure that any resulting changes in applicability between section 129 and section 112 rules do not occur with so much frequency that sources are unable to demonstrate continuing compliance with the applicable standards.

To ensure that frequent switching does not impede our ability to determine continuous compliance and create undue permitting and testing burdens, sources remain subject to CISWI for a minimum of 6 months. The definition of CISWI unit has been revised to clarify that a CISWI unit includes a distinct operating unit of any commercial or industrial facility that combusts any solid waste in a 12-month period. This change accounts for sources that periodically burn solid waste throughout a given 12-month period, but that also has long periods in which no solid waste is combusted at all. We believe this change will reduce administrative and compliance costs to both the source and the regulatory agencies. For example, sources will not have to re-establish initial compliance with CISWI or revise their operating permit to reflect a switch out of and back into the CISWI regulations. Instead, facilities that combust solid waste would continue to be subject to the CISWI regulations at least 6 months after waste is no longer combusted. The regulations also allow facilities to remain subject to CISWI beyond 6 months after cessation of solid waste combustion, at their own discretion, if the source determined that continued compliance with CISWI is appropriate because the source intends to combust solid waste in the future. Source owners or operators may, alternatively, choose a date at least 6 months after ceasing solid waste combustion on which they would no longer be subject to CISWI, and would instead be subject to any applicable section 112 standards. This date is called the effective date of the waste-to-fuel switch.

Specifically, the new provisions direct a source owner or operator to select an effective date for the waste-to-fuel, or fuel-to-waste switch, and that date becomes the date on which all of the newly applicable requirements apply. When a source begins combusting solid waste, the effective date of the fuel-to-waste switch must be the same as the actual date the unit begins combusting solid waste because by statute any source that combusts any solid waste is a solid waste incineration unit subject to standards under CAA section 129.

See

section 129(g)(1)

(defining “solid waste incineration unit”). For sources that cease burning solid waste, they may pick an effective date for the waste-to-fuel switch that is at least 6 months after the last date on which solid waste is combusted. This allows sources that cease combusting solid waste to comply with an applicable NESHAP or opt to remain subject to CISWI at the discretion of the owner or operator. We allow the owner or operator of a CISWI unit the option of remaining subject to CISWI to account for sources that may want to retain the ability to burn waste intermittently without having to periodically switch between the section 112 and section 129 regulatory programs. If a source wishes to end applicability of CISWI to its unit, the source must submit an advance notification of the effective date of the waste-to-fuel switch. The source must be in compliance with any NESHAP that applies as a result of ceasing the combustion of solid waste on the effective date of the waste-to-fuel switch. The source must remain in continuous compliance with the CISWI regulations until that date.

As stated above, boiler and process heaters that commence combustion of any solid waste and become solid waste incineration units as defined in section 129(g)(1) are subject to CISWI standards applicable to ERUs as of the date they commence combusting solid waste. Likewise, cement kilns that begin combusting solid waste and become solid waste incineration units must comply with the CISWI standards applicable to waste-burning kilns at the time they begin combusting solid waste.

The new waste-to-fuel switch provisions in the final rule include requirements to conduct performance testing that will assure compliance with all applicable standards. Specifically, performance tests must be conducted within 60 days of the date on which the unit begins combusting solid waste. In addition, the owner or operator must collect and report any PM CEMS and/or PM parametric monitoring data for those monitors that are operated at the same time as the performance test to determine whether the existing calibrations and/or correlations are still applicable. After the testing is completed, and it is demonstrated that the source is operating in compliance with the applicable standards, the owner or operator should adjust any PM CEMS calibration and any correlation for PM to correspond to the performance test results and data.

The new provisions also require advance notification of the effective date of the waste-to-fuel switch. The notification includes basic information that will enable the reviewing authority to determine the date on which CISWI will no longer apply to the facility and the date on which any newly applicable section 112 regulations may apply. Notification must be submitted to both the EPA Regional Office and the delegated state or local agency.

To ensure that frequent switching does not impede our ability to determine continuous compliance, sources may not switch between applicable section 129 and section 112 standards without completing the initial performance test. Therefore, sources that wish to start burning solid waste before they have demonstrated compliance with their existing section 112 standard must complete the performance test for the 112 rule before switching to solid waste combustion.

If a source switches back to a fuel or non-waste material for which a performance test was conducted within the 6 months preceding the effective date of the fuel-to-waste or waste-to-fuel switch, and if there are no changed conditions that would affect emissions, the source need not retest that source until 6 months from the effective date of the switch.

If a source is subject to any emissions limits for which compliance is determined on an annual average or other averaging period that is for a period of time less than the period in which the source will be combusting the fuel or non-waste material, the source must comply with the emission limit in the shorter time period in which the fuel or material is combusted. For example, if a source chooses to demonstrate compliance with the Hg limits of the major source Boiler NESHAP through fuel analysis, which has a 12-month rolling average limit, and opts to start burning solid waste and become subject to CISWI after combusting the fuel under the Boiler NESHAP for only 9 months, the source must demonstrate compliance with the Hg limit based on a 9-month average instead of the annual average. The EPA believes this is necessary to assure that switching to solid waste combustion does not compromise our ability to determine compliance with standards under section 112.

The rules do not allow for compliance extensions associated with changes to the fuels or materials that are combusted. After the first substantive compliance date (

e.g.,

the effective date of the state program or 5 years after publication of the final CISWI rule for incineration units), sources must be in compliance with the standard that is applicable to the source based on the type of unit and the fuels or materials that are combusted. Sources that change fuels or materials are considered existing sources and, as such, they must be in compliance on the date they begin combusting the new fuel or material. For example, a waste-burning cement kiln that ceases burning solid waste becomes subject to and must comply with the Portland Cement NESHAP as of the date that it is no longer subject to CISWI. For all sources that commence combustion of solid waste, the CISWI requirements become applicable on the date that the fuel switch occurs.

2. Homogeneous Waste

Comment:

Many commenters requested that EPA reaffirm the exemption of qualifying small power production and cogeneration facilities as promulgated in the 2000 CISWI regulations. Several commenters requested that EPA clarify the term “homogeneous waste.” Some commenters requested that certain mixtures or blends of fuels fall under the definition of homogeneous waste.

Response:

Homogeneous wastes are stable, consistent in formulation, have known fuel properties, have a defined origin, have predictable chemical and physical attributes, and result in consistent combustion characteristics and have a consistent emissions profile. Qualifying small power production and cogeneration facilities requesting an exemption from CISWI on the basis that they burn homogeneous waste may be asked to demonstrate, using defined test methods acceptable to EPA, that the physical and chemical characteristics of the waste are consistent throughout such that the emission profile of any sample of waste combusted is similar or identical to any other sample. Mixtures of different types of wastes are generally not homogeneous, unless the mixtures are from materials that are each individually determined to be homogeneous, are from known origin, are mixed in constant proportion, and are conditioned or processed, such as would occur in the gasification of the wastes. Gasification processes that incorporate clean up technologies in the production of synthesis gas would generally result in a homogeneous product, however a consistent waste input would still be necessary to ensure a consistent emissions profile of the synthesis gas. Whether a waste is homogeneous is a case-by-case determination. As such, EPA has added provisions to the CISWI rule that require source owners or operators seeking the exemption to submit a request for a homogeneous fuel determination to EPA, and that they support their request

with information describing the materials to be combusted and why they believe the waste is homogeneous. The determination of what constitutes a homogeneous waste is not delegable to the state or local agencies.

3. Lab Analysis Units

Comment:

Commenters stated that they do not believe CAA section 129 is intended to regulate laboratory analysis units that involve combustion to generate analytical results. Commenters contend that samples are not solid waste and have definite purpose separate from disposal of sample material. They stated that it is physically impossible for many, if not all, of these uses to comply with CISWI requirements and therefore operations would likely cease. Several commenters indicated that it is unclear as to whether the material referenced in the existing definition of laboratory units in 40 CFR 60.2020(o) (subpart CCCC) and 40 CFR 60.2555(o) (subpart DDDD) is a solid waste. Several commenters stated that other CISWI requirements including operator certification, performance tests, and SSM requirements are not appropriate for laboratory units. If regulated, commenters requested that EPA clarify whether the rule is applicable to all laboratory units or limited to those at commercial and industrial facilities. Many argued that EPA underestimated the number of laboratory units affected by this regulation because the Phase I ICR was not clear that these units were included in the scope of the survey. Commenters also stated that EPA did not provide cost or impact analysis for these units.

Response:

EPA agrees that samples used in laboratory analysis units have a purpose separate from the disposal of material, and we believe based on the information available at this time, that the material that is combusted is likely not a solid waste as that term is defined in the Solid Waste Definition Rule. We have no information that refutes our conclusions, and we have no data from laboratory analysis units on which to establish section 129 standards in any case. We have determined that this final action will not subject laboratory analysis units to this standard.

4. Asphalt Recycling

Comment:

One commenter requested that EPA provide a clarification as to whether asphalt plants utilizing recycled asphalt would be subject to the CISWI rule.

Response:

EPA did not receive any information to indicate that recycled asphalt is a solid waste, or that the recycled asphalt or solid waste is being combusted in asphalt plants. Absent that information, we are not establishing separate standards regulating asphalt plants at this time. However, any combustion unit that combusts solid waste and meets the definition of a CISWI unit may be subject to the CISWI rule, including combustion units at asphalt plants. If the combustion unit is recovering useful heat (

e.g.,

process heaters and boilers), the unit may be subject to standards applicable to ERUs and sources should contact EPA or their state for a specific determination.

5. Chemical Recovery (SARUs)

Comment:

Several commenters suggested that EPA provide a clear definition of a chemical recovery unit in the final rule. They requested that EPA specifically define chemical recovery units burning pulping liquors and kilns burning lime as not CISWI units.

Commenters suggested that EPA include language that explicitly states SARUs are not subject to CISWI citing the CAA exemption for analogous processes. Some commenters argued that materials burned in SARUs are not “solid wastes” because they are not burned for the purpose of being disposed of or discarded. Instead, commenters asserted that the primary purpose of SARUs is to combust materials to recover sulfur in order to produce virgin sulfuric acid. A few commenters also stated that SARUs are already regulated under 40 CFR part 60, subpart H, Standards of Performance for Sulfuric Acid Plants.

Response:

The Solid Waste Definition Rule exempts materials pursuant to subtitle C of RCRA. Any SARU, chemical recovery unit, recovery furnace, or lime kiln that is exempt pursuant to subtitle C of RCRA is not a CISWI unit subject to this final rule unless the unit combusts material that is solid waste and is not specifically exempt from the definition pursuant to subtitle C of RCRA. We are currently not aware of any subtitle C exempt facilities burning such materials. We are also not aware of any lime kilns that are combusting solid waste as that term is defined in the Solid Waste Definition Rule. To the extent there are lime kilns or chemical recovery units combusting solid waste, those units may be subject to the final CISWI standards as incinerators, ERUs, or waste-burning kilns, as appropriate. Units discussed in this comment that are combusting solid waste should consult EPA or their state concerning applicability of this final rule to their combustion unit.

6. Exemptions—Hazardous Waste Combustion Units

Comment:

Several commenters urged EPA to retain the exemption for hazardous waste combustion units or clarify that these units are not subject to the proposed rule and do not need an exemption. Commenters suggested that the removal of this exemption could shift certain RCRA provisions from a RCRA permit to a Title V permit.

Response:

Hazardous waste combustion units that are required to have a permit under section 3005 of the SWDA are exempt from CAA section 129 rules per CAA section 129(g)(1). Thus, these hazardous waste combustion units would not be subject to the CISWI requirements.

7. CISWI Promulgation Schedule and 112(c)(6) Obligations

Comment:

Many commenters requested that EPA delay issuing the CISWI standard until the Solid Waste Definition Rule is finalized. They argued that the court-ordered deadline does not apply to CISWI and that the lack of certainty in the outcome of the Non-Hazardous Solid Waste Definition Rule affects all aspects of the CISWI proposal including the number of facilities affected, the MACT floors, and the total anticipated compliance costs. Some commenters believe that this violates EPA's duty to provide a full and fair opportunity to develop and submit comments on the proposal. They contend that this problem can only be addressed by promulgating the waste rule and then re-proposing CISWI standards based on the known population of units.

One commenter suggests that EPA's proposal to treat the proposed CAA section 129 standards as satisfying CAA section 112(c)(6) requirements is unlawful. They argue that EPA's statement that its proposed CAA section 129 standards “effectively control” emissions of POM and PCBs, identified in CAA section 112(c)(6) as pollutants for which EPA must regulate 90 percent of aggregate emissions under CAA sections 112(d)(2) or 112(d)(4), is illegal. The commenter asserts that the CAA requires EPA to subject 90 percent of the emissions of the pollutants identified in CAA section 112(c)(6), including POM and PCBs, to CAA section 112(d)(2) or (d)(4) standards. The commenter argues that assuming EPA could meet CAA section 112(c)(6) requirements by taking credit for standards established under CAA section 129, EPA would have to set specific CAA section 129 standards for POM and PCBs. They suggest that although CAA section 129(a)(4) gives

EPA authority to do just that, EPA has not proposed CAA section 129 standards for POM or PCBs. The commenter believes that the proposed CISWI standards would not satisfy CAA section 112(c)(6) even if CAA section 129 standards could do so. The commenter states that EPA cannot meet its obligations to regulate PCBs and POM under CAA section 112(c)(6) with the proposed CAA section 129 standards for other pollutants. Another commenter claims that they cannot find documentation in the proposed rulemaking package to explain how and why coverage of CISWI sources is necessary to meet the 90 percent requirement.

Response:

EPA disagrees with the commenters who suggest the Court-ordered deadline does not apply to certain CISWI units. The EPA maintains that we are under a Court-ordered deadline to complete our CAA section 112(c)(6) obligations by January 16, 2011. Because we need certain CISWI units to comply with our 112(c)(6) obligations, the Court-ordered deadline requires EPA to promulgate the CISWI standards for certain subcategories by January 16, 2010. The EPA may therefore not postpone issuance of the final CISWI rules until after the Solid Waste Definition Rule is promulgated.

Section 112(c)(6) of the CAA requires EPA to regulate sources accounting for not less than 90 percent of the aggregate emissions of each pollutant listed in CAA section 112(c)(6). EPA has historically interpreted CAA section 112(c)(6) as allowing EPA to count CAA section 129 emission standards, such as CISWI, for the purpose of meeting its 90 percent obligation under CAA section 112(c)(6) (62 FR 33625, 33632, June 20, 1997). For example, both municipal waste combustion units and medical waste incinerators are listed CAA section 112(c)(6) source categories, and they are regulated under CAA section 129.

As EPA stated in 1998, we need to issue emissions standards for all Portland Cement kilns that combust non-hazardous waste (both major and area sources) to meet our obligation under CAA section 112(c)(6) (63 FR 17838, 17849, April 10, 1998). In addition, EPA must issue standards for commercial and institutional combustion units (

e.g.,

boilers and process heaters) to comply with the section 112(c)(6) obligation (63 FR 32006, June 4, 2010). We must set standards for all CAA section 112(c)(6) categories by the Court-ordered deadline, and that includes setting emission standards pursuant to CAA section 129 for those Portland Cement kilns and commercial and institutional boilers and process heaters that combust non-hazardous solid waste and are thus subject to CISWI as waste-burning kilns and ERUs, respectively.

As we stated in section VI of the proposed rule, section 112(c)(6) of the CAA requires EPA to identify categories of sources of seven specified pollutants to assure that sources accounting for not less than 90 percent of the aggregate emissions of each such pollutant are subject to standards under CAA section 112(d)(2) or 112(d)(4). EPA has identified certain CISWI units as sources necessary to meet the 90 percent requirement under section 112(c)(6). In the

Federal Register

notice “Source Category Listing for Section 112(d)(2) Rulemaking Pursuant to Section 112(c)(6) Requirements,” 63 FR 17838, 17849, Table 2 (1998), EPA identified source categories that must be “subject to regulation” for purposes of CAA section 112(c)(6). Included in that list are cement kilns and combustion units (

e.g.,

major source boilers and process heaters). Cement kilns, boilers, and process heaters that combust solid waste are subject to the CAA section 129 standards for CISWI as either waste-burning kilns or ERUs. These CISWI units emit five of the seven CAA section 112(c)(6) pollutants: POM, dioxins, furans, Hg and PCBs. The POM emitted by CISWI is composed of 7-PAH, 16-PAH, and EOM.

For purposes of CAA section 112(c)(6), EPA has determined that standards promulgated under CAA section 129 are substantively equivalent to those promulgated under CAA section 112(d). (63 FR 17845; 62 FR 33625, 33632 (1997)). As discussed in more detail in response to comments on this issue, the CAA section 129 standards effectively control emissions of the five identified CAA section 112(c)(6) pollutants. Further, since CAA section 129(h)(2) precludes EPA from regulating CISWI units under CAA section 112(d), EPA cannot further regulate the emissions of 112(c)(6) pollutants from CISWI units under CAA section 112(d). As a result, EPA considers emissions of these five pollutants from waste-burning kilns and ERUs “subject to standards” for purposes of CAA section 112(c)(6). The remaining CISWI subcategories will be subject to MACT standards either in this action or in a future action, but regulation of the remaining subcategories is not required for EPA to complete its 112(c)(6) obligations.

As required by the statute, the CAA section 129 CISWI standards include numeric emission limitations for the nine pollutants specified in CAA section 129(a)(4). The combination of waste segregation, good combustion practices, and add-on air pollution control equipment (sorbent injection, FF, wet scrubbers, or combinations thereof) effectively reduces emissions of the pollutants for which emission limits are required under CAA section 129: Hg, dioxins, furans, Cd, Pb, PM, SO

, HCl, CO, and NO

. Thus, the standards specifically require reduction in emissions of three of the CAA section 112(c)(6) pollutants: dioxins, furans, and Hg. As explained below, the air pollution controls necessary to comply with the requirements of the CISWI standards also effectively reduce emissions of the following CAA section 112(c)(6) pollutants that are emitted from waste-burning kilns and ERUs: POM and PCBs. Although the CAA section 129 CISWI standards do not have separate, specific emissions standards for POM and PCBs, emissions of these two CAA section 112(c)(6) pollutants are effectively controlled by the same control measures used to comply with the numerical emissions limits for the pollutants enumerated in CAA section 129(a)(4). Specifically, as by-products of combustion, the formation of POM and PCBs is effectively reduced by the combustion and post-combustion practices required to comply with the CAA section 129 standards, primarily the standards for CO and D/F. In fact, EPA has used CO as a surrogate for organic HAP such as POM, and the controls for PCBs are the same controls that reduce emissions of dioxin and furans. Polycyclic Organic Matter and PCBs that do form during combustion are further controlled by the various post-combustion CISWI controls. The add-on PM control systems (either FF or wet scrubber) and ACI further reduce emissions of these organic pollutants and also reduce Hg emissions, as is evidenced by performance data for MWCs and another similar source category, HMIWI. Specifically, the post-MACT compliance tests at currently operating HMIWI that were also operational at the time of promulgation of the 1997 HMIWI MACT standards show that, for those units, the regulations reduced Hg emissions by about 60 percent and reduced dioxin and furans emissions by about 80 percent from pre-MACT levels. Dioxin and furans have similar chemical composition and structure as PCBs and POM; moreover, similar controls have been demonstrated to reduce emissions of D/F, POM, and PCBs from MWCs. It is reasonable to conclude that POM and PCB emissions would be effectively controlled to a MACT level at all CISWI

units meeting the emission limits for the section 129 pollutants. Thus, while the rule does not identify specific numerical limits for POM and PCB, emissions of those pollutants are, for the reasons noted above, nonetheless “subject to regulation” for purposes of CAA section 112(c)(6).

Finally, we disagree with comments that EPA should not finalize the CISWI standards until after the Solid Waste Definition Rule is final because EPA does not know the population of sources that will be subject to the CISWI standards. As stated above, we must finalize the CISWI standards for certain subcategories to comply with the Court-ordered deadline; but, in any case, we would not postpone the standards absent the deadline based on the commenters' issue. EPA must establish standards for all rules based on the best information available at the time of issuance. In this case, we have included those units that we believe combust solid waste as that term is defined in the final Solid Waste Definition Rule. We have no information at this time that allows us to determine that the units we have included are not combusting solid waste. Furthermore, sources in the waste-burning kilns and ERUs subcategories and their CAA section 112 counterparts may start or stop combusting solid waste at any time and thus move between CAA sections 112 and 129. Sources in any of the subcategories could also cease operation all together. For these reasons, we conclude it is not appropriate to postpone regulation in this case because we could never be certain that the list of units we identify is perfect. We maintain that the approach we have taken is reasonable because it is based on the best information available to EPA at the time of promulgation.

8. CISWI Implementation Schedule

Comment:

Several commenters suggested that the date for compliance should be set at 5 or 6 years, not 3 years. Several commenters raised concern that many facilities may not have sufficient time to engineer and design the emissions control systems, raise the amount of capital to purchase the equipment, and install the required equipment. In addition, there could be hardware backlogs, insufficient skilled labor, and gridlock in state permitting processes which could delay compliance. Further commenters stated that they need time to plan a shutdown of a unit when everything is properly staged to ensure minimal disruption of the facility's operation.

Response:

The terms of CAA section 129(b)(2), where state plan implementation schedules are specified, outline the maximum time available for implementation and enforcement of EG for solid waste incineration units. As CAA section 129(b)(2) states, the state plan “* * * shall provide that each unit subject to the guidelines shall be in compliance with all requirements of this section not later than 3 years after the state plan is approved by the Administrator but not later than 5 years after the guidelines were promulgated.” This allows 2 years for state plans to be updated, modified, and approved by the Administrator, followed by a period of compliance not to exceed 3 years after the state plan has been approved.

B. MACT Floor Analysis

1. Pollutant-by-Pollutant Approach and Alternative Approaches

Comment:

Many commenters objected to setting MACT floors on a pollutant-by-pollutant basis. They argue that setting MACT floors on a pollutant-by-pollutant basis is unlawful and results in MACT floors that bear no relation to emission limits that are being achieved at the best-performing existing sources pursuant to CAA section 129(a)(2). The commenters suggested that EPA has misinterpreted many court cases involving CAA section 112(d) over the years and that the proposed MACT standards are inconsistent with the legal principles established under previous court decisions because emission standards must be “achieved in practice” before finalizing the regulation. Commenters continued by explaining that EPA applies the “achieved in practice” standard on a pollutant-by-pollutant basis, which results in a final standard that they assert has never been achieved by any subject facility or best performer. Some commenters contended that this method violates the plain language and intent of the MACT process, and the result is a MACT floor that reflects a standard that no one plant in existence currently achieves. The commenters declared that the plain language of MACT process requires EPA to set a MACT floor for existing sources that is not less stringent than “the average emission limitation achieved by the best-performing 12 percent of units in the category.” The commenters asserted that CAA sections 129(a)(2) and 112(d) use of the terms “best-performing” and “existing” clearly means that sources in a category or subcategory that are used to set the MACT floor are to be real, not theoretical or hypothetical sources. Some commenters maintained that CAA section 129(a)(2) instructs that the MACT floor “shall not be less stringent than the emission control that is achieved in practice by the best controlled similar source” and the phrase “achieved in practice” can only mean that Congress intended actual sources, performing under real-life conditions, to be the benchmark for determining the MACT floors. The commenters stated that in the CISWI rulemaking, EPA has chosen to establish the MACT floor by assessing the best-performing sources on a pollutant-by-pollutant basis, rather than by identifying the overall best-performing sources taking into account all pollutants.

Some commenters insisted that if Congress wanted EPA to establish separate MACT floor levels for different pollutants, it would have worded CAA section 129(a)(2) to allow this result by referring to the best-performing sources “for each pollutant” or “for each group of pollutants.” Further, they argued that EPA's pollutant-by-pollutant methodology is at odds with the legislative history underlying the MACT setting process. The commenters cited the Senate report on the 1990 Amendments where Congress required “the selection of emissions limitations which have been achieved in practice (rather than those which are merely theoretical) by sources of a similar type or character. An emissions limitation achieved in practice is one based on control technology that works reasonably well (doesn't require frequent and extensive modification or repair) under realistic operating conditions.”

See

S. Rep. No. 228, 101st Cong., 1st Sess. 169 (1989). The commenters suggested that the focus on overall performance is not surprising because in the 1990 CAA Amendments, Congress abandoned the previous focus on individual pollutant standards, and adopted the technology-based multi-pollutant approach to regulating emissions in use under the CWA. A few commenters suggested that if one source can achieve a firm degree of control for one pollutant but not for another, there may be no justification for including it in the set of sources from which the floor is calculated.

Several commenters recommended that EPA develop overall rankings for each unit in each subcategory based on their emissions of all nine pollutants and develop floors based on a common set of top performers. The commenters asserted that this approach would identify the overall best-performing sources taking into account all pollutants. The commenters argued that the statute unambiguously directs EPA to set standards based on the overall performance of “units.” They

maintained that CAA section 129(a)(2) specifies that emissions standards must be established based on the performance of “units” in the category or subcategory, and that EPA's discretion in setting standards for such units is limited to distinguishing among classes, types, and sizes of units. By setting floors based on the average of the top performing 12 percent of units in a subcategory and also using a confidence limit to attempt to account for variability, one would assume that at least 6 percent of all units in each subcategory would be able to comply with the emission limits with no further controls.

Several commenters argued that while an individual MACT floor for one pollutant might not appear cost-prohibitive, the total cost implications when combined with all of the other MACT floors for other pollutants, could become especially onerous, potentially forcing some regulated parties out of business, and barring the market entry for other potential entities. The commenters contended that this result is compounded when the proposed emission limits cannot be met even after the installation and proper operation of MACT hardware such as scrubbers and baghouses. The commenters stated that some facilities cannot operate certain types of control devices due to local operational constraints and feed material composition. The commenters declared that such a result violates the court's declaration in

National Lime Association

627 F.2d 416, 443 (DC Cir. 1980), that under the CAA “EPA has a statutory duty to promulgate achievable standards.” A few commenters insisted that while the CAA was authored with the intent of reducing air pollution, Congress did not intend to disrupt the “productive capacity” of the United States through the promulgation of economically unachievable standards. 42 U.S.C. 7401(b)(1). The commenters maintained that by setting MACT floors individually and ignoring the collective cost implications of the entire rule, EPA would effectively disregard the CAA requirement that air pollution control be advanced while promoting the nation's “productive capacity.” The commenters stated that emissions standards are to be established by taking costs into consideration. 42 U.S.C. 7429(a)(2).

One commenter discussed that EPA previously used a pollutant-by-pollutant methodology to set MACT floors in the context of the Proposed National Emissions Standards for Hazardous Waste Combustors (69 FR 21198, April 20, 2004), hereinafter referred to as the HWC NESHAP. The commenter stated that several parties submitted public comments questioning EPA's approach and pointed to the fact that EPA had failed to cite a single existing source which met the various MACT floor standards. They stated that EPA attempted to defend its practice of establishing pollutant-by-pollutant MACT standards by citing the

Chemical Manufacturer Association

EPA,

870 F.2d 177, 239 1989), clarified 885 F.2d 253, 264 (5th Cir. 1989), cert. denied, 495 U.S. 910, (1990), a Fifth Circuit case where the court held that, under the CWA, “best available technology” referred to the single best-performing plant on a pollutant-by-pollutant basis. The commenter asserts that EPA's reliance on

Chemical Manufacturer Association

EPA

is misplaced as the CAA's procedure regarding the selection of MACT technologies differs on a textual basis from the CWA's procedure for identifying BAT. The commenter argued that under the CWA, BAT standards are to be set based on “the best practicable control technology currently available.” The commenter suggested that the Court in

Chemical Manufacturer Association

EPA

read this provision to allow for pollutant-by-pollutant determinations finding no statutory requirement that all of the BATs actually be achieved by an existing plant, just that each technology be demonstrated available. 885 F.2d at 264. The commenter continued that the CAA, on the other hand, more narrowly limits the basis for MACT designation to what has been achieved at existing sources, not what could be hypothetically achievable on a per-pollutant basis.

A few commenters also cited the HWC NESHAP as an example where EPA attempted to support its use of the pollutant-by-pollutant methodology by stating that “EPA believes that because all our standards are not technically interdependent (

i.e.,

implementation of one emission control technology does not prevent the source from implementing another control technology), the fact that sources are not achieving all the standards simultaneously does not indicate a flaw in the methodology.” The commenters argued that EPA's conclusion in the HWC NESHAP is inapplicable to the proposed CISWI rule. They provided an example problem that they claimed has been observed in the MSW industry using ACI (an EPA-identified technology to reduce Hg emissions) and could also occur in the cement industry could be the formation of additional solid-phase dioxins/furans, thus increasing the emissions of D/F (which are regulated under the MACT standards). The commenters suggested that these findings call into question EPA's legal justification that control requirements for one pollutant do not impact another. Several commenters suggested that there is an inverse relationship between CO and NO

where improving combustion to control CO may affect NO

. Finally, many commenters requested that EPA require work practice standards in lieu of emission limits for certain ERUs.

Response:

We disagree with the commenters who object to setting MACT floors on a pollutant-by-pollutant basis. Contrary to the commenters' suggestion, CAA section 129(a)(2) does not mandate a total facility approach. EPA previously has explained that although CAA section 129 does not unambiguously declare that MACT floors must be established on a pollutant-by-pollutant basis, applying the requirement to set MACT floors based on what has been achieved by the best-performing sources for

each

of the pollutants covered by CAA section 129 is a reasonable interpretation of EPA's obligation under that provision (62 FR 48363-64).

Commenters' primary argument is premised on a reading of two clauses in CAA section 129(a)(2). Specifically, commenters cite the provision of CAA section 129 that, for new sources, states that MACT floors “shall not be less stringent than the emission control that is achieved in practice by the best controlled similar unit” and, for existing sources, states that MACT floors must be based on “the average emissions limitation achieved by the best-performing 12 percent of units in the category.” Commenters make the assumption that “achieved in practice” as applied to the best controlled “similar unit” and “best-performing 12 percent of units in the category” must be interpreted to mean the best-performing unit or units with respect to the entire suite of pollutants.

EPA makes no such assumption, primarily because to do so would lead to the illogical result of basing emissions limitations on units that may not be the best-performing source for any single covered pollutant. Instead, EPA interprets the provision to support establishing emissions standards based on the actual emissions of “the best controlled similar unit” or “best-performing 12 percent of units in the category” for each covered pollutant. Even if we were to conclude that the commenters' interpretation is equally reasonable under the statute, which we do not, the commenters' interpretation is certainly not compelled by the statute. We maintain that our interpretation is reasonable under the

statute and appropriate given the problems associated with implementing the commenters' approach.

Commenters' interpretation also ignores the rest of the CAA section 129. That provision requires EPA to “establish performance standards and other requirements pursuant to section [111] of this title and this section [129] for each category of solid waste incineration units.” Pursuant to CAA section 129(a)(2), those standards “shall reflect the

maximum degree of reduction

in emissions of air pollutants listed under section (a)(4) that the Administrator, taking into consideration the cost of achieving such emission reduction, and any nonair quality health and environmental impacts and energy requirements, determines is achievable for new or existing units in each category” (emphasis added). Subsection (a)(4) then states: “The performance standards promulgated under section [111] of this title and this section [129] and applicable to solid waste incineration units shall specify numerical emissions limitations for the following substances or mixtures: particulate matter (total and fine), opacity (as appropriate), sulfur dioxide, hydrogen chloride, oxides of nitrogen, carbon monoxide, lead, cadmium, mercury, and dioxins and furans.” Thus, the statute requires EPA to set individual numeric (a) Performance standards; (b) based on the maximum degree of reduction in emissions actually achieved; (c) for each of nine listed pollutants. Based on this, EPA believes—and has long believed—the statute supports, if not requires, that MACT floors be derived for each pollutant based on the emissions levels achieved for each pollutant.

Looking at the statute as a whole, EPA declared in 1997 rulemaking for medical waste incinerators: “The EPA does not agree that the MACT floors are to be based upon one overall unit” (62 FR 48364). Pointing for instance to CAA section 129(a)(4), EPA explained:

This provision certainly appears to direct maximum reduction of each specified pollutant. Moreover, although the provisions do not state whether there is to be a separate floor for each pollutant, the fact that Congress singled out these pollutants suggests that the floor level of control need not be limited by the performance of devices that only control some of these pollutants well.

Id.

Since 1997, the courts have consistently acknowledged that EPA set emission standards based on the best-performing source for

each

pollutant.

See, e.g., Cement Kiln,

255 F.3d 855, 858 (DC Cir.) (“[T]he Agency first sets emission floors for each pollutant and source category * * *”). Accordingly, EPA's pollutant-by-pollutant approach has, as outlined above, been in place since 1997 for medical waste incinerators, and even earlier for other types of incinerators regulated under section 129.

See, e.g.,

59 FR 48198 (Sept. 20, 1994) (MWC). Commenters fail to cite to a single case even questioning EPA's pollutant-by-pollutant approach. In addition, such an approach has been upheld in other contexts.

See, e.g., Chemical Manufacturers Association

EPA,

870 F.2d 177, 239 (5th Cir. 1989) (concluding that basing CWA BAT standards on a pollutant-by-pollutant basis was a rational interpretation of EPA's obligations under that similar statute). Commenters maintain that the CWA BAT analogy is not apt due to differences in the statute. We disagree and note that the CAA MACT provisions were fashioned on that CWA program. S. Rep. No. 228, 101st Cong. 2d sess. 133-34.

Further, utilizing the single-unit theory proffered by commenters would likely result in EPA setting the standards at levels that could, for some pollutants, actually be based on emissions limitations achieved by the worst-performing unit, rather than the best-performing unit, as required by the statute (61 FR 173687, April 19, 1996; 62 FR 48363-64, September 15, 1997). For example, if the best-performing 12 percent of facilities for metals did not control PCDD/PCDF as well as a different 12 percent of facilities, the floor for PCDD/PCDF and metals would end up not reflecting best performance. Moreover, a single-unit approach would require EPA to make value judgments as to which pollutant reductions are most critical in working to identify the single unit that reduces emissions of the nine pollutants on an overall best-performing basis. Such value judgments are antithetical to the command of the statute at the MACT floor stage. It would essentially require EPA to prioritize the nine pollutants based on the relative risk to human health of each pollutant, a criterion that has no place in the establishment of MACT floors. The idea is to set limits that, as an initial matter, require all sources in a category to at least clean up their emissions to the level that their best performing peers have shown can be achieved.

Sierra Club

EPA (Copper Smelters),

353 F.3d 976, 979-80 (DC Cir. 2004).

Commenters' argument that Congress could have mandated a pollutant-by-pollutant result by using the phrase “for each pollutant” at appropriate points in CAA section 129(a)(2) misses the point. While doing so would have removed ambiguity from CAA section 129(a)(2), the fact that the statute does not contain the phrase does not compel any inference that Congress was

sub silentio

mandating a different result when it left the provision ambiguous on this issue. The argument that MACT floors set pollutant-by-pollutant are based on the performance of a hypothetical facility, so that the limitations are not based on those achieved in practice, just re-begs the question of whether CAA section 129(a)(2) refers to whole facilities or individual pollutants. All of the limitations in the floors in this rule of course reflect sources' actual performance and were achieved in practice.

An interpretation that the floor level of control must be limited by the performance of devices that only control some of these pollutants effectively “guts the standards” by including worse performers in the averaging process, whereas EPA's interpretation promotes the evident Congressional objective of having the floor reflect the average performance of best-performing sources. Since Congress has not spoken to the precise question at issue, and EPA's interpretation effectuates statutory goals and policies in a reasonable manner, its interpretation must be upheld.

See Chevron

NRDC,

467 U.S. 837 (1984).

The legislative history can sometimes be so clear as to give clear meaning to what is otherwise ambiguous statutory text, but that is not the case with the legislative history cited by the commenters: “The selection of emissions limitations which have been achieved in practice (rather than those which are merely theoretical) by sources of a similar type or character. An emissions limitation achieved in practice is one based on control technology that works reasonably well (doesn't require frequent and extensive modification or repair) under realistic operating conditions.”

See

S. Rep. No. 228, 101st Cong., 1st Sess. 169 (1989). In fact, that language quoted equally supports EPA's approach of establishing the standards based on actual emission data from existing sources, which we consider realistic operating conditions. We further consider whether all the MACT standards can be achieved simultaneously under realistic operating conditions by evaluating the compatibility of different control technologies for the various 129 pollutants, as discussed below.

Commenters also make much of the fact that no single facility is presently achieving all of the nine pollutant limits proposed. But this fact is irrelevant, and only shows that plants will need to reduce their emissions of certain

pollutants to meet standards reflecting the average of best industry performers for that pollutant. We recognize that the pollutant-by-pollutant approach for determining the MACT floor can, as it does in this case, increase the overall cost of the regulation compared to the cost under a unit-based methodology. For example, the pollutant-by-pollutant approach for the CISWI regulation results in a stringent MACT floor for HCl based on control using a wet scrubber, and stringent MACT floors for PM and metals based on control using a FF. We interpret CAA section 129 to support determining the MACT floor in this manner, and we believe that Congress did in fact, intend that sources subject to regulations developed under CAA section 129 meet emissions limits that are achieved by the best controlled unit for each pollutant, as long as the control systems are compatible with each other. To our knowledge, there is no technical reason why these air pollution control systems cannot be combined. Regarding the inverse relationship between CO and NO

with regard to combustion control, it is incumbent upon the CISWI facility to determine whether combustion conditions can be adjusted to meet both standards and, if not, install add-on NO

controls as necessary,

e.g.,

SNCR systems.

All available data for cement kilns indicate that there is no technical problem achieving the floor levels for each pollutant simultaneously, using the MACT floor technology. For most kilns, compliance with the Hg limits will be accomplished using ACI followed by a second PM control consisting of a FF. There is no technical impediment to using this same system for control of PCDD/PCDF. We note that the ACI system would have to be installed downstream of the existing PM control, therefore, there would be no effect on the cement kiln dust collected in the existing PM control. One industry commenter claimed ACI increases dioxin emissions. Considering the fact that ACI can actually be used to remove dioxins from kiln exhaust gas, we see no basis for that statement. Regarding the commenter's claim that ACI increases D/F in MWC, our experience with the MWC source category has shown that this technology has been demonstrated to be effective at reducing D/F emissions from these sources and is being used extensively by MWC units. Furthermore, we have not been provided information from either the commenter or the MWC industry that substantiates the commenter's claim that ACI increases D/F emissions from these sources.

After the ACI system, a wet scrubber can be used for HCl and SO

control. We would expect the wet scrubber to be the downstream control because it creates a moisture laden exhaust that would require reheating to then apply ACI. Again, there is no technical impediment to adding a wet scrubber after the ACI system, and the two control devices should not interfere with each other's performance. If the facility required an RTO to meet the CO limit, the RTO would be installed downstream of the wet scrubber in order to protect the RTO from any acid gases in the kiln exhaust. The wet scrubber/RTO combination has been demonstrated in cement kiln applications.

In order to meet the PM and metals standards a facility could choose to modify their existing PM control to meet the revised limits, or design a new baghouse downstream of the ACI injection point to meet the PM and metals limits.

Though we have described some fairly complicated control scenarios, there are simpler applications of control technology that would likely be used successfully. One example would be simultaneous injection of alkaline materials (lime or sodium compounds) and activated carbon downstream of the existing PM control device followed by collection with a FF. This type of injection scheme would potentially control acid gases (HCl and SO

), PCDD/PCDF, Hg, and PM.

Regarding the comment that EPA should consider work practice standards in lieu of emission limits for certain types of ERUs, we again point out that CAA section 129(a)(4) says that the standards promulgated under CAA section 129 shall specify numerical emissions limitations for each pollutant enumerated in that provision. Section 129(a)(4) requires MACT standards for, at a minimum, PM, SO

, HCl, NO

, CO, Pb, Cd, Hg, and PCDD/PCDF. Section 129 does not contain a work practice standard provision similar to that contained in CAA section 112(h) and applicable to NESHAP.

Finally, several commenters suggested that EPA must consider costs when establishing MACT standards. EPA is prohibited from considering costs when determining the minimum standards for each pollutant—the “MACT floor;” however, EPA is required to consider costs, among other things, when evaluating whether the MACT standards should be more stringent than the MACT floor, so called “beyond-the-floor” standards. See section 129(a)(2). EPA did consider costs in its beyond-the-floor analysis consistent with the statute.

2. MACT-on-MACT

Comment:

Several commenters argued that EPA's recalculation of the 2000 MACT floors using post-MACT compliance data results in so-called “MACT-on-MACT” standards. They suggest that the limits are being set using a very small amount of data from a very small number of sources. The commenters argue that for the incinerator subcategory, the presumed reason a small number of units are being used to set the limits is that the existing standard caused many units to shut down. The commenters suggest that the remaining units likely installed or improved controls in order to comply with the original CISWI standards, effectively resulting in the new limits being set based on the top performers among the already top performers. One commenter asserted that these floors cannot be achieved and are contrary to the CAA and the intent of Congress. The commenter urged EPA to use the population of pre-2000 CISWI incinerators and their emissions data to establish the revised MACT floors. The commenter declares that the CAA never intended to impose technology every 5 years with no consideration of costs and risk, and that it is not reasonable to assume that Congress intended for existing sources subject to CAA section 129 to have their standards tightened up to levels comparable to those for new sources over time where their circumstances have not changed.

Response:

We disagree with the commenters' assertions that we are employing a MACT-on-MACT approach to set limits that are not achievable by CISWI. The purpose of this action is not to force units who have complied with a lawfully adopted MACT standard to have to subsequently comply with another round of updated MACT standards, but to respond to the voluntary remand granted by the Court. As stated at proposal, we requested a voluntary remand of the 2000 CISWI standards after Sierra Club filed a petition for review of the final CISWI standards, and the Court issued its

Cement Kilns

decision which called into question EPA's procedures for establishing MACT floors for CISWI units.

Cement Kiln Recycling Coalition

EPA

, 255 F.3d 855 (DC Cir. 2001). Specifically, EPA established the 2000 CISWI MACT floors by identifying the MACT floor control technology and calculating the MACT floor using emissions information from all units, not only best-performing units, that used the MACT floor technology. EPA

recognized that the Court rejected this methodology in the

Cement Kilns

case in which the Court rejected EPA's MACT floor approach under CAA section 112 and concluded that EPA may account for variability by setting the floor at a level that reasonably estimates the performance of the best controlled sources under the worst foreseeable conditions but not the worst foreseeable conditions faced by any unit in the source category.

Id.

at 865. The MACT processes under CAA sections 112 and 129 are essentially the same, thus the decision identified a flaw in EPA's 2000 CISWI standards.

CAA section 129 requires EPA to set the MACT floor based on emissions limitations

actually achieved

by the best-performing solid waste incineration units. In addition, the Court has made it abundantly clear that in issuing revised MACT standards pursuant to remand, EPA may not ignore this Court's intervening holdings:

If the Environmental Protection Agency disagrees with the Clean Air Act's requirements for setting emissions standards, it should take its concerns to Congress. If EPA disagrees with this court's interpretation of the Clean Air Act, it should seek rehearing en banc or file a petition for a writ of certiorari. In the meantime, it must obey the Clean Air Act as written by Congress and interpreted by this court.

Sierra Club

EPA (Brick)

, 479 F.3d 875, 884 (DC Cir. 2007).

The best way to ascertain the actual emissions limitations achieved by the best-performing units, and thus comply with the Court's dictates, is to use data reflecting the actual emissions of operating units. For that reason, EPA collected data from solid waste incineration units, including the existing units in the incinerator subcategory, pursuant to a CAA section 114 ICR. In establishing the revised CISWI standards, we used the emissions information from the existing sources in each subcategory to set the MACT limits. For the incinerator subcategory, we determined that the information available from the 2000 rulemaking was insufficient and limited, and that it did not represent the current emissions limitations achieved by the sources in that subcategory since many of the units in that data set have since shut down.

Notwithstanding that clear statutory mandate to establish the MACT floors based on the emission limitations actually achieved by the best-performing sources, commenters assert that EPA's promulgation of the CISWI standards for the incinerators subcategory conflicts with the intent of the statute. Commenters use the term “MACT-on-MACT” to give the false impression that EPA's resetting of the MACT floors pursuant to CAA section 129(a)(2) somehow requires sources to constantly upgrade their control technologies. Commenters' MACT-on-MACT label is based on the faulty premise that the original MACT floors accurately reflected what the statute required. Although the units in the incinerators' subcategory had to comply with the 2000 MACT floors, the standards were not established based on the performance of the best-performing units as the statute requires and, therefore, the limitations are likely considerably higher than the limits being achieved by the then existing best controlled incinerator units. Accordingly, a more accurate label for the MACT standards as EPA re-proposed them in 2009 might be: “MACT-on-Unsupportable-Standards-Erroneously-Labeled-as-MACT.”

We also disagree with commenters' assertion that we should not use the new emissions information from units in the incinerator subcategory, and instead base the MACT standards for the incinerator subcategory on the population of pre-2000 CISWI incinerators and their emissions data to establish the revised MACT floors. The first problem with this approach is that, as commenters note, many of the then existing incinerator units are no longer in operation. Section 129(a)(2) of the CAA requires EPA to establish standards for new units based on the “best controlled similar unit” and, for existing units, based on “the average emissions limitation achieved by the best-performing 12 percent of units in the category.” We fail to see how the statute would allow us to consider emissions limitations from sources no longer in existence or ignore the emissions information on which we based the revised standards, and instead rely on information that does not reflect what sources are actually achieving today. Furthermore, even if we believed we had the authority to ignore the new data and establish the standards based on the inventory of units in existence before the 2000 CISWI standards, we do not have sufficient data from those units on which to base MACT standards based on that pre-2000 universe of sources. Specifically, EPA has data on only 17 units out of an estimated 112 units then in existence, and we have a complete data set for only 12 units. Because we do not have a complete data set, EPA cannot determine whether the then existing units for which we have data from that time period were best-performing units at that time, such that we could develop MACT standards consistent with the statute, and there is no mechanism by which EPA could reconstruct the category at this time.

Finally, we disagree with commenters' assertion that the units in the incinerator subcategory are unable to meet the revised CISWI standards. As stated above, the emissions data upon which the revised standards rely comes directly from CISWI units that have achieved the resulting levels, and we accounted for variability in establishing the standards to account for the performance of sources over a period time and different operating conditions. We believe that together this demonstrates that the incinerator units can achieve the individual standards, though admittedly units may have to take additional steps to comply with the validly established MACT standards.

3. Methodology (UL or UPL)

Comment:

At proposal, EPA requested comment on whether an alternate statistical interval should be used, the 99 percent UPL. Some commenters supported the use of the 99 percent UPL, citing cases where this statistical interval had been used in other rulemakings for boilers and cement kilns. Several commenters stated that the statistical method used by EPA in setting the CISWI MACT floors is flawed due to the use of data sets that are not statistically significant. Commenters asserted that the 99 percent UL floor is calculated from data which 99 percent of units in MACT floor data population would fall below, which they argue sets up an automatic 1 percent failure rate for the top 12 percent sources. Commenters request that this be addressed by using a statistical approach which increases the allowance for variability of the data set.

One commenter stated that since EPA is using a limited data set that in some cases contains predominantly nondetect values to set floors that units must meet at all times, consideration of variability, and use of the appropriate statistical approach is crucial to ensuring units can achieve the emission limits. The commenter argues that in cases of severely limited or censored data sets, EPA should use either the 99.9 percent UL or use the UTL, which is meant for use in situations where the amount of data available does not represent the entire population. The commenter maintains that EPA is inappropriately using the 99 percent UL statistic to calculate the proposed CISWI emission limits because this does not capture enough variability in emissions to ensure the limits will be met by the top performers 100 percent of the time. They argue that the approach is flawed,

given that the number of units the limits are based on is very small, and the limits are being developed on a pollutant-by-pollutant basis in a way that does not account for variability of the fuels and wastes being burned. The commenter asserts that EPA does not justify the appropriateness of the use of the 99 percent UL over the use of other statistical procedures typically used for censored or limited data. Further, the commenter argues that although this calculation methodology was used in the HMIWI standard, it is not consistent with statistical procedures used to develop other emission standards. For example, the commenters explain that EPA used a complicated statistical approach in the development of the HWC NESHAP standard to account for intra-unit variability as well as inter-unit variability among the units in the MACT floor.

Response:

In assessing sources' performance, EPA may consider variability both in identifying which performers are “best” and in assessing their level of performance.

Sierra Club

EPA (Brick MACT),

479 F.3d 875, 881-82 (D.C. Cir. 2007); see also

Mossville Environmental Action Now

EPA,

370 F.3d 1232, 1241-42 (DC Cir 2004) (EPA must exercise its judgment, based on an evaluation of the relevant factors and available data, to determine the level of emissions control that has been achieved by the best-performing sources considering these sources' operating variability). The

Brick MACT

decision reiterated that EPA may account for variability in setting floors; however, the Court found that EPA erred in assessing variability because it relied on data from the worst performers to estimate best performers' variability. The Court held that “EPA may not use emission levels of the worst performers to estimate variability of the best performers without a demonstrated relationship between the two.” 479 F.3d at 882.

In determining the MACT limits, we first determine the floor, which, for existing sources, is the emissions limitation achieved in practice by the average of the top 12 percent of existing sources, or the level achieved in practice by the best controlled similar source for new sources. In this rule, EPA is using lowest emissions limitation as the measure of best performance. We are then assessing variability of the best performers by using a statistical formula designed to estimate a MACT floor level that can be met by the average of the best-performing sources based on the expected distribution of future compliance tests (or calculated inputs in the case of Hg for waste-burning kilns). Specifically, for ERUs and waste-burning kilns, the MACT floor limit is an UPL, and for incinerators and small remote incinerators, the UL calculated with the student's t-test using the TINV function in Microsoft Excel®. The student's t-test has also been used in other EPA rulemakings (

e.g.,

NSPS for HMIWI, NESHAP for Industrial, Commercial, and Institutional Boilers and Process Heaters) in accounting for variability.

As we discussed at proposal, the UL computation assumes that the data available represents the entire population of data from the best-performing CISWI units used to establish the standards. We have concluded that this statement applies to the incinerator and small remote incinerator subcategories, since we believe our inventory of these units is more certain than is our inventory of ERUs and waste-burning kilns for several reasons. In the 2000 CISWI rule, EPA only regulated solid waste incineration units that operated for the sole purpose of disposing of waste. Many incinerators subject to the 2000 CISWI rule ceased operation before the compliance date for those standards. Once the revised CISWI standards are finalized, these types of solid waste incineration units (i.e., incinerators and small remote incinerators) will either comply with the revised CISWI standards or cease operation, much as they did in response to the 2000 standards. The same is not necessarily correct for units in the ERUs and waste-burning kilns subcategories. For those sources, once the CISWI standards are promulgated, they will likely either comply with the CISWI standards or cease burning solid waste and comply with the applicable NESHAP. We think units in those subcategories will generally not cease operation. Furthermore, because incinerator and small remote incinerator unit's sole purpose is waste disposal, the only practical manner in which additional sources will be added to the inventory is through new construction. Again, this is different than for ERUs and waste-burning kilns because, for those subcategories, additional units may be added if existing boilers (and process heaters) and cement kilns begin combusting solid waste and thereby become ERUs and waste-burning kilns, respectively. For these reasons, we believe we have a complete inventory of units in the incinerators and small remote incinerators subcategories.

We sent Phase II testing requests to all incinerator and small remote incinerator units that are in our inventory. We required testing for all incinerator and small remote incinerator units, making allowances for identical units from a facility to only test one unit, and not each identical unit. Therefore, our data represent the entire population of data for these two subcategories. For this reason, we believe the UL is the appropriate statistical approach for the incinerators and small remote incinerators subcategories. The 99 percent UL represents a value that 99 percent of the data in the MACT floor population would fall below, and therefore accounts for the run-to-run and test-to-test variability observed in the MACT floor data set.

For ERUs and waste-burning kilns, however, we recognize that our data may not represent the entire population of units. As stated above, there is greater uncertainty involved in determining the universe of sources in these two source categories because we cannot be certain that we have identified all the units that would be considered to be burning solid waste, had the newly-adopted definition for solid waste been promulgated and effective at the time of testing. We also do not know whether the units we have identified will continue to burn waste after the final CISWI standards are issued. Unlike incinerators and small remote incinerators, the primary purpose of waste-burning kilns and ERUs is the production of a product or generation of energy, not the disposal of waste. Therefore, operators will decide whether it is economically feasible to continue or start combusting solid waste to support their industrial process and, if they decide that it is not, they will use traditional fuels or non-waste inputs instead of solid waste. For example, an ERU that is combusting solid waste that has little or no cost may decide that compliance with CISWI is an economically viable option compared to purchasing traditional fuels at market rates; but, if the costs of compliance with CISWI exceed the costs of traditional fuel, the source will likely cease burning solid waste. Conversely, a boiler that currently combusts only traditional fuels may be presented with a solid waste fuel option that makes it to their economic advantage to begin combusting solid waste. For these reasons, the population of units in the ERU and waste-burning kiln subcategories is inherently uncertain. We have for these reasons concluded that a prediction interval (e.g., UPL) is more appropriate for these two subcategories, and this approach is also consistent with the NESHAP statistical approach being used for the non-waste-burning counterparts of these units (i.e.,

boilers/process heaters and cement kilns).

A prediction interval for a future observation is an interval that will, with a specified degree of confidence, contain the next (or some other pre-specified) randomly selected observation from a population. In other words, the prediction interval estimates what the upper bound of future values will be, based upon present or past background samples taken. The UPL consequently represents the value which we can expect the mean of future observations (3-run average) to fall below within a specified level of confidence, based upon the results of an independent sample from the same population. In other words, if we were to select at random a future test condition from any of the top 12 percent (MACT floor pool) of sources (average of 3 runs), we can be 99 percent confident that the reported level will fall at or below the UPL value. Use of the UPL is appropriate in this rulemaking for these two subcategories because it sets a limit any single or future source can meet based on the performance of members of the MACT floor pool.

The UPL is calculated as shown in Equation 1:

ER21MR11.013

Where:

= Mean of the sample data set

n = Number of test runs

m = Number of test runs in the compliance average

= Observed variance

t = Student t distribution statistic

This calculation was performed using the following spreadsheet functions:

Normal distribution: 99 percent UPL = AVERAGE (Test Runs in Top 12 percent) + [STDEV (Test Runs in Top 12 percent) × TINV (2 × probability, n-1 degrees of freedom) * SQRT ((1/n) + (1/m))], for a one-tailed t-value, probability of 0.01, and sample size of n. The value of “m” denotes the number of future observations, and it is used to calculate an estimate of the variance of the average of m-future observations.

This formula uses a pooled variance (in the s

term) that encompasses all the data-point to data-point variability of the best-performing sources comprising the MACT floor pool for each pollutant. Where variability was calculated using the UPL statistical approach, we used the average (or sample mean) and sample standard deviation, which are two statistical measures calculated from the data distributions for each pollutant. The average is a central value of a data set, and the standard deviation is the common measure of the dispersion of the data set around the average. We note here that the methodology accounts for both short-term and long-term variability and encompasses run-to-run and test-to-test variability. The formula also applies differently depending on how the underlying data set is distributed. To this end, EPA carefully evaluated the data sets for each HAP to ascertain whether the data were normally distributed, or distributed in some other manner (

i.e.,

lognormal). After applying standard and rigorous statistical tests (involving the degree of “skewness” of the data), we determined the distributions for each pollutant, which in turn determined the final form of the UPL equation.

See

“CISWI Emission Limit Calculations for Existing and New Sources” in the docket.

The results are floors that reasonably estimate the performance over time of the best-performing sources, as do the standards based on those floors. It is true that many sources will need to install controls to meet these standards, and that these controls have significant costs (although EPA estimates that the rule's costs are substantially outweighed by its benefits). See section VI of this preamble. This is part of the expected MACT process where, by definition, the averaged performance of the very best performers sets the minimum level of the standard. The EPA believes that it has followed the statute and applicable case law in developing its MACT floors. The summary of results of UL and UPL calculations and the MACT floor emission limits for each subcategory for existing and new sources are presented in Tables 4 through 9 of this preamble.

Table 4—Summary of MACT Floor Results for Existing Units—PM, Hg, Cd and Pb

Subcategory

Parameter

(mg/dscm)

Incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

4.571

0.0006

0.0004

0.0013

99% UL of top% (test runs) =

33.6004

0.00533

0.00256

0.00352

Limit =

0.0054

0.0026

0.0036

ERUs—Solids

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

2.85061

0.0000520

0.0001713

0.0012704

99% UPL of top% (test runs) =

246.9158

0.0003

0.0003(a)

0.0035(a)

Limit =

250

0.00033

0.00051(a)

0.0036(a)

ERUs—Liquid/Gas

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

18.588

0.001

0.005

99% UPL of top% (test runs) =

101.7548

1.313

0.023

0.096

Limit =

110

0.0013

0.023

0.096

Waste-burning kilns

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

2.8378

N/A

0.0002

0.0012

99% UPL of top% (test runs) =

6.1115

0.0079(b)

0.0005

0.0026

Limit =

6.2

0.0079(b)

0.00048

0.0026

Small, remote incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

84.052

0.0012

0.027

0.238

99% UL of top% (test runs) =

220.826

0.006

0.603

2.657

Limit =

230

0.0057

0.61

2.7

A calculated limit equal to three times the MDL was used in place of the calculated MACT floor emission limit. For further explanation,

see

section V. of the preamble.

For details on this calculation,

see

the memorandum “CISWI Emission Limit Calculations for Existing and New Sources” in the Docket for this rulemaking.

Table 5—Summary of MACT Floor Results for Existing Units—CO, NO

and SO

Subcategory

Parameter

(ppmvd)

Incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

16.800

14.7

0.733

99% UL of top% (test runs) =

32.378

52.419

10.418

Limit =

ERUs—Liquid/Gas

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

36.00

58.733

641.352

99% UPL of top% (test runs) =

36.00

75.6305

712.3156

Limit =

720

ERUs—Biomass

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

247.3333

86.7595

1.4039

99% UPL of top% (test runs) =

485.3681

287.9536

6.1751

Limit =

490

290

6.2

ERUs—Coal

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

40.3031

307.2352

624.0054

99% UPL of top% (test runs) =

58.0304

330.7464

641.9307

Limit =

340

650

Waste-burning kilns

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

70.4280

437.7682

15.6660

99% UPL of top% (test runs) =

105.0945

536.4268

37.9704

Limit =

110

540

Small, remote incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

12.756

67.212

1.403

99% UL of top% (test runs) =

19.104

237.326

410.006

Limit =

240

420

A calculated limit equal to three times the MDL was used in place of the calculated MACT floor emission limit.

Table 6—Summary of MACT Floor Results for Existing Units—HCl and D/F

Subcategory

Parameter

HCl

(ppmvd)

D/F (TMB)

(ng/dscm)

D/F (total TEQ basis)

(ng/dscm)

Incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

0.181

0.238

0.004302537

99% UL of top% (test runs) =

28.045

4.504

0.1286

Limit =

4.6

0.13

ERUs—Solids

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

0.16719

0.093487

.0088932

99% UPL of top% (test runs) =

0.4456

0.3443

0.0586

Limit =

0.45

0.35

0.059

ERUs—Liquid/Gas

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

4.440

1.110

0.0463

99% UPL of top% (test runs) =

4.927

13869.523

30.0133

Limit =

(a)

14,000

Waste-burning kilns

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

3.5665

0.0752

0.0005

99% UPL of top% (test runs) =

24.8634

0.1909

0.0070

Limit =

0.2

0.007

Small, remote incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

35.289

333.080

7.288

99% UL of top% (test runs) =

214.233

1183.196

56.933

Limit =

220

1,200

A calculated limit equal to three times the MDL was used in place of the calculated MACT floor emission limit.

Table 7—Summary of MACT Floor Results for PM and Metals for New Sources

Subcategory

Parameter

(mg/dscm)

Incinerators

Avg of top performer

3.0608

0.0001

0.0002

0.0007

99% UL of top (test runs) =

17.7867

0.000151

0.0023

(a)

0.0015

Limit =

0.00016

0.0023

(a)

0.0019

ERUs—Solids

Avg of top performer

2.640916

0.00003192

0.00013696

0.00045367

99% UPL of top (test runs) =

1094.5327

0.0028

2.8369

0.0030

Limit =

(b)

250

(b)

0.00033

(b)

0.00051

0.0031

ERUs—Liquid/Gas

Avg of top performer

18.588

0.001

0.005

99% UPL of top (test runs) =

101.7548

1.313

0.023

0.096

Limit =

110

(d)

0.00025

0.023

0.096

Waste-burning kilns

Avg of top performer

1.2173

N/A

0.0001

0.0011

99% UPL of top (test runs) =

2.3591

(c)

0.0062

0.0006

0.045852

Limit =

(a)

2.5

(c)

0.0062

(b)

0.00048

(b)

0.0026

Small, remote incinerators

Avg of top performer

83.534

0.001

0.011

0.086

99% UL of top (test runs) =

733.5002

0.0013

0.6692

0.2589

Limit =

(b)

230

(a)

0.0035

(b)

0.61

0.26

A calculated limit equal to three times the MDL was used in place of the calculated MACT floor emission limit.

The NSPS limit exceeds the EG limit. The EG limit was selected as the NSPS limit.

Hg limit was developed using material input data from CISWI kilns identified within the Portland Cement NESHAP database. See the memorandum “CISWI Emission Limit Calculations for Existing and New Sources” for details on this calculation.

Dioxin/furan TEQ and Hg limits for ERUs—liquid/gas were replaced with D/F TEQ limits for liquid fuel major source boilers.

See

“CISWI Emission Limit Calculations for Existing and New Sources” for details.

Table 8—Summary of MACT Floor Results for New Units—CO, NO

, SO

Subcategory

Parameter

(ppmvd)

Incinerators

Avg of top performer

12.000

9.0333

0.2233

99% UL of top (test runs) =

12.000

22.3685

39.5108

Limit =

(a)

ERUs—Liquid/Gas

Avg of top performer

36.000

58.733

641.352

99% UPL of top (test runs) =

36.000

75.6305

712.3156

Limit =

720

ERUs—Biomass

Avg of top performer

153.0000

62.3233

1.0492

99% UPL of top (test runs) =

153.0000

344.7699

20.8889

Limit =

160

(a)

290

(a)

6.2

ERUs—Coal

Avg of top performer

35.4778

307.2352

624.0054

99% UPL of top (test runs) =

45.0280

330.7464

641.9307

Limit =

340

650

Waste-burning kilns

Avg of top performer

58.57

1.4742

7.2187

99% UPL of top (test runs) =

89.7816

195.2522

124.3390

Limit =

200

(a)

Small, remote incinerators

Avg of top performer

12.000

60.769

0.131

99% UL of top (test runs) =

12.000

77.283

1.164

Limit =

1.2

The NSPS limit exceeds the EG limit. The EG limit was selected as the NSPS limit.

Table 9—Summary of MACT Floor Results for New Units—HCl and Dioxins/Furans

Subcategory

Parameter

HCl

(ppmvd)

D/F (TMB)

(ng/dscm)

D/F (Total TEQ basis)

(ng/dscm)

Incinerators

Avg of top performer

0.0413

0.0176

0.001266667

99% UL of top (test runs) =

0.0901

0.0228

2.1464

Limit =

0.091

(a)

0.052

(b)

0.13

ERUs—Solids

Avg of top performer

0.068133

0.0161

0.000501333

99% UPL of top (test runs) =

0.5435

0.0674

0.0103

Limit =

(b)

0.45

0.068

0.011

ERUs—Liquid/Gas

Avg of top performer

4.440

1.110

0.046335368

99% UPL of top (test runs) =

(a)

13.2107

13869.5228

30.0133

Limit =

(a)

(no limit)

(c)

0.002

Waste-burning kilns

Avg of top performer

0.3994

0.0562

0.000105

99% UPL of top (test runs) =

0.3994

0.0895

0.0029

Limit =

(a)

0.09

0.003

Small, remote incinerators

Avg of top performer

27.678

299.827

4.868700057

99% UL of top (test runs) =

196.6311

1700.6082

30.0810

Limit =

200

(d)

1,200

A calculated limit equal to three times the MDL was used in place of the calculated MACT floor emission limit.

The NSPS limit exceeds the EG limit. The EG limit was selected as the NSPS limit.

Dioxin/furan TEQ and Hg limits for ERUs—liquid/gas were replaced with D/F TEQ limits for liquid fuel major source boilers.

See

“CISWI Emission Limit Calculations for Existing and New Sources” for details.

The measurements for HCl from waste-burning kilns are very close to the detection limit for analytic Method 321 actually calculated in the field for HCl. As discussed elsewhere, we have implemented a procedure for adjusting limits to account for measurement variability using data at the detection limit. This results in a floor of 3 ppmvd for the new waste-burning kilns for HCl, adjusted to a dry basis at 7 percent oxygen. This represents the lowest level that can be reliably measured using this test method, and we therefore believe that it is the lowest level we can set as the MACT limit taking the appropriate measurement variability into account.

The Hg standard for waste-burning kilns reflects 30 days of data for all Hg inputs, reasonable estimates of control device performance (for the few controlled sources), plus a reasonable statistical methodology to account for variability (including variability of Hg content of kiln inputs). EPA also used a pooled variability factor (pooling variability for all kilns in the MACT floor pool), which increased variability estimates. This analysis is based upon data collected for development of the final Portland Cement NESHAP, but screened such that the CISWI analysis used only the data from kilns that would have been identified as CISWI units had the newly-adopted solid waste definition been promulgated and effective at the time of performance testing, and converted to a concentration basis for consistency with the CISWI standards.

See

“CISWI Emission Limits Calculations for Existing and New Sources.”

4. Statistical Analysis (Lognormal vs. Normal Distribution)

Comment:

Several commenters suggested that EPA's data distribution designations are flawed and that EPA must default to non-normal distributions unless sufficient data are available to conduct robust analyses which unambiguously show the distribution can only be described by normal statistics. One commenter suggests that the non-normal distribution is consistent with both conventional wisdom and EPA's own guidance in “Guidance for Data Quality Assessment: Practical Methods for Data Analysis”, EPA/600/R-96/084, July 2000, which holds that it is more likely that environmental data are distributed log-normally. Commenters state that where there is any uncertainty according to EPA's criteria using Excel skewness and kurtosis, EPA biases its findings on distributions in favor of normality, the opposite of EPA's own guidance. The commenter states that EPA's Guidance for Data Assessment provides that the lognormal distribution is “a commonly met distribution in environmental work,” also stating “Environmental data commonly exhibit frequency distributions that are non-negative and skewed with heavy or long right tails,” and “The lognormal distribution is a commonly used distribution for modeling environmental contaminant data.”

Response:

EPA has revised the methodology to use the lognormal distribution when the normal distribution is not clearly indicated based on the skewness and kurtosis tests to be more consistent with EPA's guidance in “Guidance for Data Quality Assessment: Practical Methods for Data Analysis” EPA/600/R-96/084, July 2000.

5. Treatment of Detection Levels

Comment:

Many commenters argued that EPA should not use data below detection limits to set standards. They contend that EPA's use of data below MDLs to set standards invalidates EPA`s analysis, creates emissions limits that are biased low, and sets emission standards that would not allow facilities to demonstrate compliance without taking undue risk of facing non-compliance. They suggested that no numerical emission standard for a pollutant should be set below the measurement ability of the reference test method. Some commenters stated that EPA does not appear to have systematically screened the emissions data for cases where a detection limit should be applied, and has erroneously recorded zero values for emissions where those are reported in the original test reports. The commenters further assert that in addition to failing to promul

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