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

Federal RegisterJun 30, 2025

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2003-0156; FRL-7547-02-OAR]

RIN 2060-AU60

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

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

This action finalizes the periodic review by the U.S. Environmental Protection Agency (EPA) of the emissions standards and other requirements for Other Solid Waste Incineration (OSWI) units in the OSWI New Source Performance Standards (NSPS) and Emission Guidelines (EG). The EPA is finalizing applicability-related and definitional changes; changes to OSWI subcategories and the standards for the new subcategories; changes to the startup, shutdown, and malfunction (SSM) provisions; and changes to testing, monitoring, recordkeeping, and reporting requirements. We are also making other miscellaneous technical and editorial changes to the regulatory text.

DATES:

This final rule is effective August 29, 2025. The incorporation by reference (IBR) of certain publications listed in the regulation is approved by the Director of the Federal Register as of August 29, 2025.

ADDRESSES:

The Environmental Protection Agency (EPA) has established a docket for this rulemaking under Docket ID No. EPA-HQ-OAR-2003-0156. All documents in the docket are listed on the

https://www.regulations.gov/

website. Although listed, some information is not publicly available,

e.g.,

Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available electronically through

https://www.regulations.gov/.

FOR FURTHER INFORMATION CONTACT:

For questions about this final action, contact Felica Davis, Ph.D., Sector Policies and Programs Division (E143-05), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, P.O. Box 12055, Research Triangle Park, North Carolina, 27711; telephone number: (919) 541-4857; and email address:

davis.felica@epa.gov.

SUPPLEMENTARY INFORMATION:

Preamble acronyms and abbreviations.

Throughout this preamble the use of “we,” “us,” or “our” is intended to refer to the EPA. We use multiple acronyms and terms in this preamble. While this list may not be exhaustive, to ease the reading of this preamble and for reference purposes, the EPA defines the following terms and acronyms here:

ACI air curtain incinerator

ANSI American National Standards Institute

AOGA Alaska Oil and Gas Association

ASME American Society of Mechanical Engineers

AWC alternative waste characterization

Cd cadmium

CAA Clean Air Act

CBI Confidential Business Information

CDX Central Data Exchange

CEDRI Compliance and Emissions Data Reporting Interface

CEMS continuous emissions monitoring systems

CFR Code of Federal Regulations

CISWI commercial and industrial solid waste incineration

CO carbon monoxide

carbon dioxide

CRA Congressional Review Act

D.C.Circuit United States Court of Appeals for the District of Columbia Circuit

DCOT digital camera opacity technique

EG emission guidelines

EPA Environmental Protection Agency

ERT Electronic Reporting Tool

FR Federal Register

HCl hydrochloric acid

Hg mercury

HMIWI hospital, medical, and infectious waste incineration

ICR Information Collection Request

IWI institutional waste incineration

MACT maximum achievable control technology

MSW municipal solid waste

MWC municipal waste combustor

NESHAP national emission standards for hazardous air pollutants

ng/dscm nanograms per dry standard cubic meter

NO nitric oxide

nitrogen dioxide

oxides of nitrogen

NSPS New Source Performance Standards

NTTAA National Technology Transfer and Advancement Act

oxygen

OSWI other solid waste incineration

Pb lead

PDF portable document format

PM particulate matter

ppm parts per million

ppmvd parts per million dry (volume basis)

PRA Paperwork Reduction Act

RCRA Resource Conservation and Recovery Act

RFA Regulatory Flexibility Act

SMCD substitute means of compliance demonstration

sulfur dioxide

SRI small remote incinerator

SSI sewage sludge incinerator

SSM startup, shutdown, and malfunction

TEQ toxic equivalency factor

TMB total mass basis

TPD tons per day

tpy tons per year

µg/dscm micrograms per dry standard cubic meter

UMRA Unfunded Mandates Reform Act

VCS voluntary consensus standards

VSMWC very small municipal waste combustion

XML extensible markup language

Organization of this document.

The information in this preamble is organized as follows:

I. General Information

A. Does this action apply to me?

B. How do I obtain a copy of this document and other related information?

C. Judicial Review and Administrative Reconsideration

II. Background

A. What is the statutory authority and regulatory history for this action?

B. What changes did we propose for the OSWI source category in our August 31, 2020, proposal and subsequent notices?

C. What outreach and engagement did we conduct?

III. Summary of Final Action

A. What are the final rule amendments based on the CAA section 129(a)(5) review?

B. What are the final rule changes involving the applicability of OSWI requirements?

C. What are the final rule amendments addressing OSWI subcategories and related MACT floor redeterminations?

D. What are the final rule amendments addressing other definitions for the OSWI category?

E. What are the final rule amendments addressing emissions during periods of SSM?

F. What are the final rule amendments addressing testing, monitoring, and reporting requirements?

G. What are the effective and compliance dates of the standards?

IV. Public Comments and Responses

A. What key comments did we receive on the applicability of OSWI requirements, and what are our responses?

B. What key comments did we receive on the OSWI subcategories and related MACT floor redeterminations?

C. What key comments did we receive on other amendments, and what are our responses?

D. What key comments did we receive on effective and compliance dates?

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected facilities?

B. What are the air quality impacts?

C. What are the cost and economic impacts?

D. What are the benefits?

VI. Statutory and Executive Order Reviews

A. Executive Orders 12866: Regulatory Planning and Review and Executive

Order 13563: Improving Regulation and Regulatory Review

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

C. Paperwork Reduction Act (PRA)

D. Regulatory Flexibility Act (RFA)

E. Unfunded Mandates Reform Act (UMRA)

F. Executive Order 13132: Federalism

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

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

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

J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR Part 51

K. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

Categories and entities potentially affected by this final action are those that operate OSWI units. OSWI units are not commercial and industrial solid waste incineration units (CISWI), hazardous waste combustors (HWC), hospital/medical/infectious waste incinerators (HMIWI), sewage sludge incinerators (SSI), or other incinerators regulated elsewhere under section 129 of the CAA. Although there is no specific North American Industry Classification System (NAICS) code for OSWI units, the units subject to the New Source Performance Standards (NSPS) and Emission Guidelines (EG) for OSWI, hereinafter referred to as “the OSWI standards,” may be operated by the categories of sources listed in table 1 of this preamble:

Table 1—Industrial Source Categories Affected by This Action

Source category

NAICS code

Examples of potentially regulated entities

Any state, local, or tribal government using a very small municipal waste combustion (VSMWC) unit

562213, 92411

Solid waste combustion units burning municipal solid waste (MSW).

Any correctional institutions using an institutional waste incineration (IWI) unit

922, 7213

Correctional institutions.

Any nursing or residential care facilities using an OSWI unit

623

Any nursing care, residential intellectual and developmental disability, residential mental health and substance abuse, or assisted living facilities.

Any Federal government agency using an OSWI unit

928, 7121

Department of Defense (labs, military bases, munition facilities) and National Parks.

Any educational institution using an OSWI unit

6111, 6112, 6113

Primary and secondary schools, universities, colleges, and community colleges.

Any church or convent using an OSWI unit

8131

Churches and convents.

Any civic or religious organization using an OSWI unit

8134

Civic associations and fraternal associations.

Any industrial or commercial facility using a VSMWC unit

114, 211, 212, 221, 486

Oil and gas exploration operations; mining; pipeline operators; utility providers; fishing operations.

North American Industry Classification System.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. To determine whether your entity is regulated by this action, you should carefully examine the applicability criteria found in 40 Code of Federal Regulations (CFR) 60.2885, 60.2981, and 60.2991. If you have questions regarding the applicability of this action to a particular entity, consult the person listed in the

FOR FURTHER INFORMATION CONTACT

section of this preamble, your delegated authority, or your EPA Regional representative listed in 40 CFR 60.4 (General Provisions).

B. How do I obtain a copy of this document and other related information?

The docket number for this final action regarding the OSWI EG and NSPS is Docket ID No. EPA-HQ-OAR-2003-0156. In addition to being available in the docket, an electronic copy of this final action will also be available on the internet. Following signature by the EPA Administrator, the EPA will post a copy of this final action at:

https://www.epa.gov/stationary-sources-air-pollution/other-solid-waste-incinerators-oswi-new-source-performance.

Following publication in the

Federal Register

(FR), the EPA will post the FR version and key technical documents at this same website.

C. Judicial Review and Administrative Reconsideration

Under Clean Air Act (CAA) section 307(b)(1), judicial review of this final action is available only by filing a petition for review in the United States Court of Appeals for the District of Columbia Circuit (the D.C. Circuit) by August 29, 2025. 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 the EPA to enforce the requirements.

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 (including any public hearing) may be raised during judicial review. This section also provides a mechanism for the EPA to reconsider the rule if the person raising an objection can demonstrate to the Administrator 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 should submit a Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460, with a copy to both the person(s) 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), U.S. EPA, 1200 Pennsylvania Ave. NW, Washington, DC 20460.

II. Background

A. What is the statutory authority and regulatory history for this action?

Section 129 of the CAA, entitled “Solid Waste Combustion,” requires the EPA to develop and adopt NSPS and EG for solid waste incineration units, in accordance with CAA sections 129 and 111. Section 129(a) of the CAA requires the EPA to establish NSPS for new

sources, and CAA section 129(b) requires the EPA to establish procedures for states to submit plans for implementing EG for existing sources. The EPA initially proposed NSPS and EG for OSWI units on December 9, 2004 (69 FR 71472), and finalized them on December 16, 2005 (70 FR 74870), at 40 CFR part 60, subparts EEEE and FFFF. The 2005 OSWI standards applied to an incineration unit with a capacity of less than 35 TPD burning MSW (as defined in 40 CFR 60.2977 of subpart EEEE, and 40 CFR 60.3078 of subpart FFFF) or an incineration unit located at an institutional facility burning institutional waste (as defined in 40 CFR 60.2977 of subpart EEEE and 40 CFR 60.3078 of subpart FFFF) generated at that facility. The 2005 rule has yet to be fully implemented for existing sources because most states have not developed and submitted state plans for approval and EPA has not promulgated an implementing Federal plan. Following that final action, the Administrator received a petition for reconsideration of the OSWI standards, and on June 28, 2006, the EPA announced reconsideration of the final OSWI rules (71 FR 36726). After consideration of comments and information received through the reconsideration process, we concluded that no additional changes were necessary to the final OSWI rules (72 FR 2620, January 22, 2007).

In addition to the administrative reconsideration request, some entities petitioned for judicial review of the 2005 OSWI standards. The judicial review proceedings were initially stayed and, ultimately, the EPA requested a voluntary remand of the OSWI standards. By an order dated April 21, 2016, the D.C. Circuit granted the EPA's request for a remand. Order,

Sierra Club

EPA,

No. 06-1066 (D.C. Cir. April 21, 2016). The remand was requested to allow the EPA to consider potential revisions, if any, to the OSWI standards that might be appropriate in light of certain legal developments, including 2007 and 2008 decisions from the D.C. Circuit.

Sierra Club

EPA,

479 F.3d 875 (D.C. Cir. 2007));

NRDC

EPA,

489 F.3d 1250 (D.C. Cir. 2007);

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EPA,

551 F.3d 1019 (D.C. Cir. 2008).

The OSWI NSPS establishes maximum achievable control technology (MACT) emission limits for new or modified OSWI units. For new sources, the CAA requires that MACT limits be no less stringent than the emissions control achieved in practice by the best-controlled similar unit. The OSWI EG establishes MACT emission limits for existing OSWI units. For existing sources, the CAA requires that MACT limits be no less stringent than the average emissions limitation achieved by the best-performing 12 percent of units in a source category. The 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.

Under the 2005 OSWI standards, the term “OSWI unit” means either a very small municipal waste combustion (VSMWC) unit or an institutional waste incineration (IWI) unit. A VSMWC unit is any municipal waste combustion unit that has the capacity to combust less than 35 tons per day (TPD) of municipal solid waste (MSW) or refuse-derived fuel. An IWI unit is any combustion unit that combusts institutional waste and is a distinct operating unit of the institutional facility, such as a university or prison, that generated the waste.

As required by section 129 of the CAA, the OSWI NSPS and EG rules set emission standards for nine pollutants: cadmium (Cd), carbon monoxide (CO), dioxins/furans (D/F), hydrochloric acid (HCl), lead (Pb), mercury (Hg), oxides of nitrogen (NO

), particulate matter (PM), and sulfur dioxide (SO

). They also established opacity standards.

CAA section 129(a)(5) requires the EPA to review and, if appropriate, revise the requirements for solid waste incineration units no later than five years following the initial promulgation of any performance standards and at periodic five year intervals after that. However, in 2018, the D.C. Circuit found that the EPA had failed to undertake the periodic review of the OSWI standards and placed the EPA on a schedule to issue a proposed rulemaking and a final rulemaking.

The EPA published a proposed rule on August 31, 2020, for the OSWI NSPS and EG rules that addressed the requisite CAA section 129(a)(5) periodic review (85 FR 54178, hereafter referred to as the “2020 Proposed Rule”). The EPA subsequently published three actions to address issues raised in the 2020 Proposed Rule: (1) withdrawal of certain provisions included in the 2020 Proposed Rule which proposed modifying the definition of “municipal waste combustion unit,” by removing pyrolysis/combustion units from the definition (88 FR 36524, June 5, 2023, hereafter referred to as the “2023 Withdrawal”); (2) a final rule promulgating certain provisions for OSWI air curtain incinerators (ACI) to remove the title V permitting requirements for ACIs that only burn wood waste, clean lumber, yard waste, or a mixture of those, and are not located at title V major sources or subject to title V for other reasons (89 FR 27392, April 17, 2024, hereafter referred to as the “2024 ACI Rule”); and (3) a supplemental notice of proposed rulemaking (SNPRM) to add a definition for “rudimentary combustion device” (89 FR 60342, July 25, 2024, hereafter referred to as the “2024 SNPRM”).

Order,

Sierra Club

Wheeler,

no. 16-2461 (D.D.C. filed Sept. 14, 2018) (ordering the EPA publish a notice of proposed rulemaking by August 21, 2020, and promulgate a final rulemaking by May 31, 2021); Order

Sierra Club

Wheeler,

no. 16-2461 (D.D.C. filed April 22, 2021) (extending the EPA's deadline for a final rulemaking to October 31, 2021); Order,

Sierra Club

Wheeler,

no. 16-2461 (D.D.C. filed Oct. 14, 2021) (extending the EPA's deadline for a final rulemaking to March 1, 2024); Order,

Sierra Club

Wheeler,

no. 16-2461 (D.D.C. filed Nov. 7, 2023) (extending the EPA's deadline to promulgated a final rulemaking to June 30, 2025).

B. What changes did we propose for the OSWI source category in our August 31, 2020, proposal and subsequent notices?

The EPA published the 2020 Proposed Rule in the

Federal Register

to address the requisite CAA section 129(a)(5) periodic review (85 FR 54178). We proposed that no new developments in practices, processes, or control technologies existed for any OSWI units and that it was not necessary to revise the OSWI standards for new and existing units under CAA section 129(a)(5). In addition, we proposed some changes to the OSWI standards that were occasioned by the 2016 voluntary remand of the OSWI standards (and the legal developments related to that request for a remand). In accordance with the EPA's general authority under CAA section 129(a), we proposed: (1) revised subcategories and MACT standards that better reflect actual emissions test data from OSWI units and the population of OSWI; (2) changes to applicability provisions for the EG and NSPS including definitional changes; (3) revisions to regulatory provisions related to emissions during periods of startup, shutdown, and malfunction (SSM); (4) testing and monitoring flexibilities so that VSMWC or IWI units with capacities less than or equal to 10 TPD can demonstrate compliance with the rule; (5) provisions for electronic reporting of certain notices and reports; (6) revisions to recordkeeping and reporting provisions consistent with the revised testing and monitoring; (7) changes to title V permitting requirements for air curtain incinerators that burn less than 35 TPD and burn only only wood waste, clean lumber and yard waste; and (8) other technical edits, clarifications, and

revisions intended to improve the understanding of the rules and improve consistency with other CAA section 129 rules. For a more detailed discussion of these revisions, see section II.B of the proposal preamble (85 FR 54178; August 31, 2020).

In the 2020 Proposed Rule, the EPA proposed to change the applicability of the OSWI standards to remove the reference to pyrolysis/combustion units from the definition of “municipal waste combustion unit.” At that time, we considered that the reference to a pyrolysis/combustion unit as a municipal waste combustor (MWC) should not apply to OSWI units because such units are used to combust uncontained gases and do not involve the combustion of solid waste as defined in the OSWI rule.

The EPA published an advanced notice of proposed rulemaking on September 8, 2021 (86 FR 50296), to gather more details on pyrolysis/combustion units, including how they are used, the inputs and products of the processes, and emissions from these processes. In response to significant adverse comment, the EPA subsequently withdrew the proposed revisions to the definition of “municipal waste combustion unit” (88 FR 36524, June 5, 2023). Accordingly, the EPA will not be taking additional action related to pyrolysis/combustion units in this action.

The EPA published the 2024 ACI Rule promulgating certain provisions related to the title V permitting requirements for OSWI air curtain incinerators (ACI) (89 FR 27392, April 17, 2024). Based on available data, ACIs that combust less than 35 TPD of wood waste, clean lumber, and yard waste are commonly located at facilities that would not otherwise require title V operating permits. Further, these types of ACIs are typically used temporarily at the locations for things like land clearing or storm cleanup. The EPA received overwhelming support from states and industry stakeholders to remove the title V permitting requirement for ACIs that only burn wood waste, clean lumber, yard waste, or a mixture of these wastes, and received no adverse comments on these revisions in the 2020 Proposed Rule. These changes were finalized, and a subsequent technical correction was published November 14, 2024 (89 FR 89928), to address inadvertent errors in the regulatory text in order to make the rule consistent with the description in the April 17, 2024, final rule preamble.

Following the EPA's analysis of comments received after the 2020 Proposed Rule, and discussions with the state of Alaska and Tribes, the EPA published the 2024 SNPRM on July 25, 2024, which proposed to add a definition for “rudimentary combustion device” to address the unique issues associated with these units. The EPA proposed to define a rudimentary combustion device as a combustion device with a capacity less than or equal to 10 TPD that is designed and constructed without one or more of the following elements: (1) a stack, chimney, or pipe designed for the purpose of managing air flow and discharging flue gases from combustion; (2) mechanical draft to provide air flow; (3) burners designed to manage the combustion process; (4) an ancillary power supply to operate; or (5) supplemental fuel burners or nozzles. Because rudimentary combustion devices lack one or more of these elements, the EPA proposed the emissions information, limits, and controls developed for the 2020 Proposed Rule would not be appropriate for them. Most rudimentary combustion devices are not equipped with stacks from which to sample emissions during a performance test, and a stack or extension would be needed in order to perform the testing required by the OSWI standards. Many of these devices are located within Native American villages and other remote or difficult to access areas of the country with limited road access to haul waste to a larger community for burning or landfilling. As a result, local waste disposal is the only option available, and these communities face significant challenges and constraints in addressing this issue. Given the numerous challenges regarding these units, in the 2024 SNPRM the EPA proposed postponing development of standards for units that meet the definition of rudimentary combustion devices at this time.

C. What outreach and engagement did we conduct?

In developing this rule, the EPA conducted outreach activities with states, Tribes, and communities located near OSWI facilities. In addition to public comments received, we obtained feedback from interested parties and evaluated and considered the information received as we developed this action. In June 2020, the EPA conducted four pre-proposal informational calls for federally recognized Tribes, including an overview presentation during the June 25, 2020, National Tribal Air Association call. On August 31, 2020, the EPA sent an email notification to stakeholders announcing that the action had been published with a 45-day comment period and an opportunity to request a public hearing. In September 2020, the EPA held six consultation meetings with Tribes including meetings with Northway Village, Qagan Tayagungin, Louden Tribe, and the Mescalaro Apache Tribe to give an overview of the OSWI proposal and provide instructions on how and when comments on the rule should be submitted to the docket (see Docket ID No. EPA-HQ-OAR-2003-0156). The EPA also conducted four informational calls on the OSWI rule in September 2020 including an overview at the Small Business Environmental Assistance Program (SBEAP) Annual Training, Alaska Air Workgroup call, Tribal Environmental Leaders Summit call, and an update at the National Tribal Air Association (NTAA) call. Although a public hearing was not requested, the EPA continued to seek out additional opportunities for interested parties to be informed about potential requirements of this action. This outreach has included a presentation to the Small Business Environmental Assistance Program on June 5, 2023; regular meetings with the state of Alaska to discuss the operation of incineration units; and a presentation on this action during the National Association of Clean Air Agencies (NACAA) Permitting and New Source Review Committee meeting. In March 2025, the EPA held several informational calls with AOGA and industry to discuss their comments submitted on the 2020 Proposed Rule.

III. Summary of Final Action

This action provides the EPA's final determination pursuant to the requisite CAA section 129(a)(5) periodic review for the OSWI standards and requirements in the NSPS and EG rules (see section III.A of this preamble). This action also finalizes applicability-related and definitional changes, changes to OSWI subcategories, and related MACT floor redeterminations, as well as several changes from the 2020 Proposed Rule and changes from the 2024 SNPRM (see sections III.B through D of this preamble). In addition, we are finalizing changes to the SSM provisions (see section III.E of this preamble). Lastly, we are finalizing revisions to the testing, monitoring, recordkeeping, and reporting requirements; and miscellaneous other technical and editorial changes to the regulatory text (see sections III.F.1 through III.F.4 of this preamble). The effective and compliance dates for these actions are discussed in section III.G of this preamble.

A. What are the final rule amendments based on the CAA section 129(a)(5) review?

After considering the public comments received, we are finalizing our results of the CAA section 129(a)(5) periodic review for the OSWI standards as proposed (85 FR 54178). We have determined there are no developments in practices, processes, or control technologies that warrant revisions to the OSWI standards and requirements. Consistent with the 2020 Proposed Rule, we are not revising the OSWI standards and requirements for new or existing sources based on our review under CAA section 129(a)(5).

For a detailed discussion of our review pursuant to CAA section 129(a)(5), see section II.A of the preamble to the 2020 Proposed Rule. Comments on the CAA section 129(a)(5) review and our responses can be found in section IV of this preamble and in the document, Summary of Public Comments and Responses for the Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Other Solid Waste Incineration Units Review, which is available in the docket (see Docket ID No. EPA-HQ-OAR-2003-0156) for this rulemaking.

B. What are the final rule changes involving the applicability of OSWI requirements?

Although not predicated on the CAA section 129(a)(5) review, in this rule, we are finalizing certain changes to the OSWI standards. The EPA proposed several changes involving the applicability requirements for OSWI in the 2020 Proposed Rule and the 2024 SNPRM. The EPA is finalizing proposed changes to the applicability of the OSWI standards following our consideration of comments received on the 2020 Proposed Rule, the 2024 SNPRM, and data provided by the Alaska Oil and Gas Association (AOGA) for small remote incinerators (SRIs) located in Alaska. As discussed below in this section, we are finalizing the proposed removal of the definition of the term “collected from” as used in the definition of “municipal solid waste”; the addition of a new definition for certain small units that were included in the 2024 SNPRM as “rudimentary combustion units”; and associated edits to the applicability requirements of 40 CFR 60.2885 and 40 CFR 60.2991.

In the 2020 Proposed Rule, the EPA proposed changes to the applicability of the OSWI standards. At that time, the EPA intended to resolve inconsistent definitions between OSWI and other CAA section 129 rulemakings and to update aspects of the OSWI rule based on new data used to develop revised emission limits for OSWI units with capacity less than or equal to 10 TPD.

We are finalizing the proposed removal of the definition of the term “collected from” as used in the definition of “municipal solid waste” to place the focus on the source and type or nature of the waste. The term collected from (as defined in the OSWI rule) means the transfer of material from the site at which the material is generated to a separate site where the material is burned. We noted that the 2005 OSWI rule finalized a definition of “municipal solid waste” (refuse and refuse-derived fuel “collected from” the general public and from residential, commercial, institutional, and industrial sources) that was similar to the definition of “municipal waste” provided in CAA section 129(g)(5), but was interpreted for the purposes of VSMWC applicability under OSWI, to mean that the municipal waste must be “collected from” certain types of sites or from multiple sites. Specifically, the 2005 OSWI rule stated that “small incinerators” that are located at commercial businesses (such as stores, restaurants and apartments) or industrial sites are not VSMWC units because they do not burn waste which has been “collected from” a site that generated the waste and transferred to a separate site where the waste is burned (70 FR 74882). The 2020 Proposed Rule reevaluated this interpretation, noting that other existing CAA section 129 incinerator rules (such as the municipal waste combustor (MWC) rules) do not necessarily place the same emphasis on where the waste is collected.

By removing the definition of “collected from”, such small incinerators located at commercial businesses or industrial sites would no longer be subject to this limitation and would qualify as VSMWC (provided these units burn more than 30-percent MSW) under OSWI. The CISWI NSPS and EG currently regulate small remote incinerators (SRIs) at commercial and industrial facilities that combust at least 30-percent MSW, but they would now qualify as VSMWC under OSWI in the final rule. These incinerators are primarily owned by oil and gas companies and burn municipal-type solid waste that is generated by the oil and gas workers and is not associated with oil and gas activities. The EPA's decision to regulate these SRI units located at commercial businesses under the OSWI standards is discussed further in sections III.C and IV.A of this preamble.

We are finalizing as proposed new subcategories and revised emission limits for new and existing OSWI units with capacities less than or equal to 10 TPD. In the 2020 Proposed Rule, the EPA proposed new emission standards for OSWI units with capacity less than or equal to 10 TPD, based on analysis of data collected during the development of the CISWI rules and data subsequently provided by AOGA for SRI units located in Alaska (see section III.C of this preamble for further discussion). In response to the 2020 Proposed Rule's new subcategories and emission standards for new and existing OSWI units with capacities less than or equal to 10 TPD, the EPA received numerous comments noting that it would be nearly impossible for most rural Alaskan communities to comply with the proposed requirements. Units in rural Alaskan communities are often very basic in design and function. Commenters stated that the proposed requirements are inapplicable or impractical for these types of small units (

e.g.,

burn boxes), which do not have stacks or other incinerator design elements, such as waste feed or flue gas systems, heat recovery, and bottom ash systems. Commenters stated that due to these limitations and other challenges, including the associated costs of compliance, rural communities operating these units would be unable to meet the proposed requirements and may be forced to return to less environmentally friendly waste disposal methods, such as open burning, barrel burning, or loose filling waste which could also attract wildlife that may present immediate health and safety risks. These comments are summarized in detail in the 2024 SNPRM (see section III, 89 FR 60345-60347).

Subsequent discussions with state and tribal agencies in Alaska demonstrated that most of these units have a capacity of less than or equal to 10 TPD, are rudimentary in design and function, and are generally located in remote areas. These units are not equipped with stacks with which to sample emissions during performance testing, likely cannot be physically modified to equip the unit with a stack, and may be difficult to access for testing due to their physical location.

Based on this new information, the EPA proposed a new definition for “rudimentary combustion devices” and associated edits to 40 CFR 60.2885 and 40 CFR 60.2991. Units that fall under the definition of rudimentary combustion devices are not considered VSMWC or IWI, and so are not required to comply with the emission standards for VSMWC or IWI (see section III.D of

this preamble for further discussion). As noted in the 2024 SNPRM, the EPA does not consider the emissions information, limits, and controls developed for the proposed OSWI rule to be appropriate for these devices, which lack one or more of these elements, and is therefore not setting standards for rudimentary combustion devices in this rulemaking. Further, these rules do not usurp existing local or state regulations that apply to these units, which will continue to apply as they currently do.

Comments on the proposed changes to applicability, including comments received on the 2024 SNPRM, and our responses can be found in section IV.A of this preamble and in the document,

Summary of Public Comments and Responses for the Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Other Solid Waste Incineration Units Review,

which is available in the docket (see Docket ID No. EPA-HQ-OAR-2003-0156) for this rulemaking.

C. What are the final rule amendments addressing OSWI subcategories and related MACT floor redeterminations?

The EPA is finalizing, as proposed, the revisions to the OSWI subcategories for both new and existing units and associated MACT floor recalculations included in the 2020 Proposed Rule. For the 2005 OSWI standards, the EPA lacked emissions data from OSWI units, and the emission limits were based on information for similar sources in the HMIWI unit source category, as discussed in the preamble to the proposed rule (85 FR 54183). During the development of the 2020 Proposed Rule, the EPA collected additional information on two new OSWI units (constructed after the current OSWI standards were issued) with capacities greater than 10 TPD and emissions information for certain existing small remote incineration units located in Alaska that historically have been regarded as SRIs under CISWI, but which we proposed to treat as OSWI VSMWC units.

The EPA proposed to reconsider the dividing line between the OSWI and CISWI standards and to treat these existing units as VSMWC based on data submitted by AOGA showing that most of these units burn more than 30 percent municipal type solid waste generated by staff/personnel at commercial or industrial facilities (discussed in section III.B of this preamble). Because the data indicated that SRI units combust more than 30 percent MSW, even though they are located at commercial or industrial facilities and currently subject to CISWI, we proposed that they would be subject to the OSWI rule. As discussed in the 2020 Proposed Rule, this approach is more consistent with the EPA's other CAA section 129 MWC rules and the CAA definition of “municipal waste” in CAA section 129(g)(5), which defines the term “municipal waste” to mean refuse “collected from the general public and from residential, commercial, institutional, and industrial sources consisting of paper, wood, yard wastes, food wastes, plastics, leather, rubber and other combustible materials and non-combustible materials such as metal, glass and rock.” We did not read this definition as necessitating that, to constitute MSW, that the waste must be transferred from one site and burned at another site. Additionally, the information gathered for the two new OSWI units (VSMWC with capacities greater than 10 TPD located in Arizona and Texas) indicated that these units are continuously fed rotary combustors that use add-on pollution controls to comply with the OSWI standards.

For incineration units, differences in size typically reflect differences in operation and equipment complexity. Units with capacities less than or equal to 10 TPD typically feed waste to the unit in batches and some units may not even be equipped with stacks. Units larger than 10 TPD typically feed waste to the unit continuously or semi-continuously and also typically have stacks or flues that can be routed to air pollution control devices. Based on the differences in size, design, and operation of the SRI units and the two new OSWI units, the EPA proposed to subcategorize IWI and VSMWC units under OSWI based on size. These subcategories included VSMWC units with a capacity to combust less than or equal to 10 TPD of MSW or refuse-derived fuel; IWI units with a capacity to combust less than or equal to 10 TPD of institutional waste; VSMWC units with a capacity to combust greater than 10 TPD but less than 35 TPD of MSW or refuse-derived fuel; and IWI units with a capacity to combust greater than 10 TPD of institutional waste. The proposed and final subcategories for VSMWC and IWI units are summarized in table 2 of this preamble.

Table 2—OSWI Categories and New Subcategories

2005 Final rule

Subcategory

Capacity

2020 Proposed rule

Subcategory

Capacity

2025 Final rule

Subcategory

Capacity

VSMWC

<35 TPD

Small VSMWC

≤10 TPD

VSMWC with capacity ≤10 TPD

≤10 TPD.

IWI

No capacity threshold

Large VSMWC

>10 but <35 TPD

VSMWC with capacity >10 TPD

>10 but <35 TPD.

Small IWI

≤10 TPD

IWI with capacity ≤10 TPD

≤10 TPD.

Large IWI

>10 TPD

IWI with capacity >10 TPD

>10 TPD.

The EPA subsequently proposed revised MACT floor emission limits for existing and new VSMWC and IWI units with capacities less than or equal to 10 TPD based on the updated inventory, emissions, and waste data provided by AOGA. We did not propose any revisions to the MACT floor emission limits for existing and new “large” OSWI units (greater than 10 TPD). Section II.B. of the preamble to the 2020 Proposed Rule provides additional information on the EPA's rationale for the proposed revisions to subcategorize OSWI units and the proposed emission limits.

Following review of the comments received on the 2020 Proposed Rule, we are finalizing the proposed subcategories and related MACT floor recalculations for new and existing VSMWC and IWI units with capacities less than or equal to 10 TPD based on the data gathered during the 2020 Proposed Rule, which includes data collected for SRI units previously regulated under CISWI, and which better reflects the actual emissions test data from similar units. The final subcategories for OSWI units remain

appropriate based on the differences in the size, design, and operation of the units with capacity less than or equal to 10 TPD and the two new OSWI units, that have capacities greater than 10 TPD. In addition, consistent with the proposal, we are not finalizing any changes to the 2005 OSWI emission limits for VSMWC and IWI units with capacities greater than 10 TPD (new and existing). Also, we conclude, as proposed, that revised beyond-the-floor limits are not appropriate for the OSWI subcategories (see section II.B.1 of the proposal preamble (85 FR 54178).

We have developed revised emission limits for existing OSWI units with capacities less than or equal to 10 TPD using the average emission limitation of the best performing 12 percent of such sources and also considering variability in emissions, consistent with CAA section 129(a)(2). The revised standards better reflect actual emissions test data from OSWI units and are more representative of and better reflect the emissions achievable for new and existing units in each category required under CAA sections 129(a)(2) and (4).

To calculate the MACT floor emission limits for these existing OSWI sources, we considered the available test run data provided in response to a 2010 information collection request (ICR) and test data from 2014 submitted in June 2017 by AOGA in their attempt to address concerns that they had with the 2010 ICR data pertaining to the emissions test data representativeness and waste variability. In the MACT floor analysis, we used the run data from the 2010 and 2014 emission tests to calculate the 99th percentile upper limits (UL) statistical interval for the best 12 percent of such incineration units for each pollutant to address the range of operating conditions of the incinerator. The UL is a common statistical interval used to address variability and was the same statistical interval used to calculate the CISWI SRI emission limits (76 FR 15723, March 21, 2011). We also applied a waste variability factor to account for variability in emissions expected to result from the varying waste profiles of OSWI units.

We are also finalizing revised MACT floors for new OSWI units with capacities less than or equal to 10 TPD. Section 129(a)(2) of 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. Therefore, the approach for new sources was similar to that used with the existing sources (

i.e.,

UL with a waste variability factor applied for the pollutants influenced by waste composition), except the top performing unit's data were used to calculate the MACT floor emission limit instead of the average of the best performing 12 percent of units and a 95 percentile UL was used instead of a 99 percentile UL.

We also examined whether it was appropriate to adopt more stringent “beyond-the-floor” regulatory options to determine MACT. Unlike the floor minimum stringency requirements, the EPA must consider various impacts of the more stringent regulatory options in determining whether MACT standards are to reflect “beyond-the-floor” requirements, including considering the costs, non-air quality health and environmental impacts, and energy requirements of such more stringent control. OSWI units with capacities less than or equal to 10 TPD often are of very basic, rudimentary design and function. Requiring additional controls on these units is infeasible or simply would be cost prohibitive. For OSWI units with capacities greater than 10 TPD, the 2005 final rule already incorporated beyond-the-floor requirements. We do not have sufficient information for OSWI units with capacities greater than 10 TPD that would enable us to revise the beyond the floor limits. However, based on the information we have from the 2005 rule, requiring any further controls would likely only provide minimal emissions reductions with substantial cost investments. Considering these factors, we concluded that revised beyond-the-floor limits are unreasonable for the OSWI subcategories.

The final emission limits, including the new limits for VSMWC and IWI units with capacities less than or equal to 10 TPD and the unchanged limits for units with capacities greater than 10 TPD, are summarized in table 3 of this preamble. The limits for the VSMWC and IWI with capacities less than or equal to 10 TPD are less stringent than the corresponding limits for VSMWC and IWI with capacities greater than 10 TPD. However, the VSMWC and IWI with capacities less than or equal to 10 TPD operate intermittently (average 2,620 hours or 109 days per year) with a relatively low stack gas flow rate (average 686 dry standard cubic feet per minute at 7 percent oxygen), and so the actual emissions of pollutants are relatively low for these units.

For example, the EPA estimates that a representative VSMWC with capacity greater than 10 TPD may emit between 0.006 and 0.01 tons of Cd per year while meeting its limit of 18 µg/dscm,

while the highest-emitting VSMWC with capacity less than or equal to 10 TPD emitting at the level of the standard (2,000 µg/dscm) would only emit 0.007 tons of Cd per year.

See Docket Item No. EPA-HQ-OAR-2003-0156-0143.

See Docket Item No. EPA-HQ-OAR-2003-0156-0011.

See Docket Item No. EPA-HQ-OAR-2003-0156-0143.

Table 3—Final Emission Limits for OSWI Units

Pollutant

Concentration units

Existing VSMWC and IWI units

≤10 TPD

>10 TPD

New VSMWC and IWI units

≤10 TPD

>10 TPD

µg/dscm

2,000

400

HCl

ppmvd

500

210

µg/dscm

32,000

226

26,000

226

µg/dscm

ppmvd

130

3.1

ppmvd

210

103

180

103

mg/dscm

280

210

DF (TMB)

ng/dscm

4,700

3,100

DF (TEQ)

ng/dscm

(

)

(

)

ppmvd

220

Limits are based on TPD capacity.

Limit remains unchanged from 2005 OSWI Rule. For PM, the 2005 OSWI standard was converted from grains per dscf to mg/dscm.

TMB = Total mass basis.

TEQ = Toxic equivalency basis.

DF TEQ basis was not calculated for the 2005 rule.

Comments on the proposed revisions to the MACT floor recalculations and OSWI subcategories and our responses can be found in section IV.B of this preamble. Additional information on the development of the emission limits may be found in section II.B. of the preamble to the 2020 Proposed Rule and in the memorandum,

Emission Limit Calculations for Existing and New Sources for the Final Other Solid Waste Incinerator (OSWI) Rulemaking,

which is available in the docket (see Docket EPA-HQ-OAR-2003-0156) for this action.

D. What are the final rule amendments addressing other definitions for the OSWI category?

In addition to the proposed changes to applicability-related definitions described in section III.B of this preamble, the EPA included in its 2020 Proposed Rule definitions for “waste profile” and “small OSWI unit.” As discussed in section III.C of this preamble, the EPA is finalizing the proposed subcategories and related MACT floor recalculations for new and existing VSMWC and IWI units with capacities less than or equal to 10 TPD. Accordingly, the EPA is finalizing separate flexibilities to the testing, monitoring, recordkeeping, and reporting requirements for OSWI units with capacities less than or equal to 10 TPD that require waste characterization and waste profile data (see section III.F.1 of this preamble). For these reasons, we are finalizing the proposed revision to add a definition for “waste profile” as related to compliance with the VSMWC and IWI with capacity of less than or equal to 10 TPD standards. The EPA proposed to define waste profile to mean the amount of each waste category burned as a percentage of total waste burned on a mass basis. We are not finalizing the proposed definition for “small OSWI unit,” but are retaining text for VSMWC and IWI units with capacities less than or equal to 10 TPD in keeping with the final subcategories and MACT floor redeterminations discussed in section III.C of this preamble.

Following consideration of the comments received and discussions with state and Tribal authority to gather additional data on the types of units referenced, the EPA proposed in the 2024 SNPRM to define a rudimentary combustion device separately from VSMWC or IWI because rudimentary combustion devices lack key features of commercially available incineration units and the emissions information, limits, and controls developed for the OSWI rule are not appropriate for them. The EPA proposed to define a rudimentary combustion device as a combustion device with a capacity less than or equal to 10 TPD that is designed and constructed without one or more of the following elements: (1) a stack, chimney, or pipe designed for the purpose of managing air flow and discharging flue gases from combustion; (2) mechanical draft to provide air flow; (3) burners designed to manage the combustion process; (4) an ancillary power supply to operate; or (5) supplemental fuel burners or nozzles. The EPA solicited additional comments and data to refine the definition of “rudimentary combustion device” and to better understand the number of devices and individuals using these devices in rural communities. Following review of the comments received on the 2024 SNPRM, we are finalizing revisions to the applicability requirements at 40 CFR 60.2885 and 40 CFR 60.2991 and adding a definition of “rudimentary combustion device”, with minor revisions from the 2024 SNPRM proposal. For the reasons described in section IV.A of this preamble, we are clarifying the proposed requirements and finalizing the definition of “rudimentary combustion device” as a combustion device with a capacity less than or equal to 10 TPD that is designed and constructed without one or more of the following elements: (1) a stack, chimney, or pipe designed for the purpose of discharging flue gases from combustion; (2) mechanical draft to provide air flow; (3) burners designed to initiate, and/or assist the combustion process, including burners designed to burn supplementary fuel; or (4) an ancillary power supply to operate. Additional information on this proposed revision can be found in section III of the preamble to the 2024 SNPRM.

89 FR 63045-47 (July 25, 2024).

E. What are the final rule amendments addressing emissions during periods of SSM?

Currently, the OSWI standards do not apply during SSM periods (see 40 CFR 60.2918, 60.3025). The EPA proposed to eliminate this limitation or qualification on the applicability of the OSWI standards. The EPA proposed this change in light of the 2016 remand and certain legal developments, including a decision by the D.C. Circuit that invalidated certain regulations related to SSM in the 40 CFR part 63 General Provisions (

Sierra Club

EPA,

551 F.3d 1019 (2008)). We are finalizing the proposed amendments to the OSWI standards from the 2020 Proposed Rule to remove and revise provisions related to SSM.

For the reasons explained in the 2020 Proposed Rule (see section II.B.3 of the proposal preamble at 85 FR 54178), we determined that OSWI units can meet the applicable standards at all times, including during periods of startup and shutdown. In establishing the standards in this rule, the EPA has taken into account startup and shutdown periods and, for the reasons explained below, has not established alternate standards for those periods. As explained in the 2020 Proposed Rule, we have determined that during startup most OSWI units burn natural gas or clean distillate oil, and waste is not added until the unit has reached suitable combustion temperatures; and during shutdown periods, emissions are generally significantly lower than emissions during normal operations because the materials in the incinerator will be almost fully combusted before shutdown occurs.

Periods of startup, normal operations, and shutdown are all predictable and routine aspects of a source's operations. Malfunctions, in contrast, are neither predictable nor routine. Instead, they are, by definition, sudden, infrequent, and not reasonably preventable failures of emissions control, process, or monitoring equipment. (40 CFR 63.2) (definition of malfunction). The EPA interprets CAA section 112 as not requiring emissions that occur during periods of malfunction to be factored into development of CAA section 112 standards. This reading has been upheld by the court in

U.S. Sugar Corp.

EPA,

830 F.3d 579, 606-610 (D.C. Cir. 2016). The court's reasoning in

U.S. Sugar

applies equally to CAA section 129 standards given the similarities between the CAA section 112 and 129 standard setting criteria. Therefore, we are removing 40 CFR 60.2918 and 40 CFR 60.3025, which provided exemptions for SSM.

We are also finalizing, as proposed, other changes to the SSM standards in light of the EPA's experience with the CAA section 129 solid waste incinerator rules. These changes include harmonizing revisions to other rule provisions that reference SSM, such as: revising the definition of “Deviation” to remove language for periods of SSM; clarifying that the 12-hour rolling average values must include periods of continuous emissions monitoring systems (CEMS) data during startup and shutdown by adding a definition of “CEMS data during startup and shutdown” in 40 CFR 60.2977 and 40 CFR 60.3078; revising the equations used to calculate the 12-hour rolling average for CO; and updating requirements related to SSM for recordkeeping and reporting in 40 CFR 60.2949, 60.2957, 60.2958, 60.3046, 60.3052, and 60.3053. These changes are further described in section III.F.2 of this preamble. We did not receive comments on the proposed removal and revisions of provisions related to SSM.

F. What are the final rule amendments addressing testing, monitoring and reporting requirements?

1. Initial and Continuous Compliance Demonstration

Consistent with the proposal, we are finalizing the substitute means of compliance demonstration (SMCD) for VSMWC and IWI units with capacities less than or equal to 10 TPD. We have considered the cost of testing, and we recognize that testing and monitoring requirements can impose substantial financial burdens and technical challenges on owners and operators of these sources. The SMCD provides an alternative to the general testing and monitoring requirements for VSMWC and IWI units with capacities less than or equal to 10 TPD. VSMWC and IWI units with capacities greater than 10 TPD must continue to demonstrate compliance by individual stack testing.

However, stack testing is unfeasible for some VSMWC and IWI units with capacities less than or equal to 10 TPD. As we stated in the proposal and confirmed by information we gathered between the proposal and this final action, we believe that many of these units are located in remote areas, such as SRIs located on oil and natural gas platforms on Alaska's North Slope in the Beaufort Sea and other areas that are similarly isolated which represent 29 of the 31 OSWI units that are not rudimentary combustion devices, surrounded by water or wetlands, or that have limited infrastructure or are difficult to access. Getting testing crews to those incinerators would be extremely challenging and costly. Other units could be considered readily accessible, but they are not equipped with stacks adequate to allow emissions sampling for performance tests. Such units would need to be modified to be able to conduct compliance testing. However, costs and logistics would prevent these types of incinerators from making the necessary changes. In still other cases, it simply may not be physically possible to modify an existing incinerator stack to allow compliance testing.

Therefore, we are finalizing, as proposed, an option for using a “representative” initial compliance demonstration. Owners and operators of VSMWC or IWI units with capacities less than or equal to 10 TPD who have not previously submitted testing meeting the requirements of the final standards would have to submit detailed information about their units, including: the make, model, and manufacturer of the unit; the type and capacity of the unit; the unit's air pollution control devices (if any); the type and quantity of waste incinerated; and the charge rate. They would then identify a representative performance test in the EPA's WebFIRE database.

A representative performance test must be conducted on an OSWI unit that has similar throughput, methods of processing and burning waste, operating temperatures, types of wastes or supplemental fuels burned, and waste profile as the OSWI unit using the SMCD. A representative performance test must be conducted consistent with the requirements in the OSWI rule; demonstrate compliance with the OSWI standards; and include the following information in the report: unit design (including air pollution control devices), charge rate during the test, type of operation, combustion temperature during the test, types of waste burned during the test and the relative amount of each waste to the total waste burned (waste profile), type and amount of supplemental fuels used during the test, and, if the tested unit has an air pollution control device, the operating parameter data for the control device during the test. Not all tests in the WebFIRE database may qualify. If there is no representative performance test available in the WebFIRE database, the OSWI unit with capacity less than or equal to 10 TPD cannot use the SMCD and must instead conduct its own initial performance test.

To use this substitute option for demonstrating initial compliance, the owner/operator must submit the following information: a notice of intent to use the SMCD; waste profile information; and a representative performance test.

Each of these elements is discussed below.

This information must be submitted through the EPA's Central Data Exchange (CDX) using the Compliance and Emissions Data Reporting Interface (CEDRI).

a. Notice of Intent

We are finalizing provisions that offer VSMWC and IWI units with capacities less than or equal to 10 TPD two options for initial performance tests: conducting an individual initial performance test or using the SMCD described below. New VSMWC and IWI units with capacities less than or equal to 10 TPD that were constructed after August 31, 2020, or

modified or reconstructed after December 29, 2025, must either complete initial performance tests within 60 days after reaching the charge rate at which they will operate, but no later than 180 days after initial startup,

or they must submit a notice of intent to use the SMCD by December 29, 2025, or within 60 days after initial startup, whichever of these dates is later. The notice of intent should include the manufacturer, make, model, and type of unit, and documentation showing that the capacity of the unit is less than or equal to 10 TPD. Owners and operators of existing VSMWC and IWI units with capacities less than or equal to 10 TPD (constructed on or before August 31, 2020, and not modified or reconstructed after December 29, 2025) are not required to submit a notice of intent to the EPA. However, they are required to either identify the results of an existing performance test in the EPA's WebFIRE database that is representative of their type of OSWI unit, if they intend to use the SMCD, or conduct an initial performance test; this must happen no later than 3 years after a state plan is approved or no later than July 1, 2030, whichever date is earlier.

For units that startup between August 31, 2020, and December 29, 2025, the initial performance test must be conducted within 60 days after the OSWI unit reaches the charge rate at which it will operate, but no later than 180 days after its initial startup, or by February 25, 2026, whichever date is later.

b. Waste Profile Information

As we stated in the proposal, we recognize that the SMCD relies on the availability of the results of performance tests conducted on potentially representative sources in the EPA's WebFIRE database. Because we anticipate that owners and operators using the SMCD will need time to meet its conditions, we encourage them to submit their notices of intent to use the substitute means of compliance and collect data for waste characterization as soon as possible after this rule is promulgated. For this reason, beginning on December 29, 2025, and until the owner or operator identifies a representative performance test, but before March 30, 2027 or 60 days after the OSWI unit reaches the charge rate at which it will operate or 180 days after initial startup, whichever is later, each owner or operator of a new VSMWC and IWI unit with capacity less than or equal to 10 TPD planning to use the SMCD must collect data on a weekly basis to characterize the unit's operations and waste profiles, as further discussed in section III.F.1.c of this preamble. The waste profile information will record the unit's differing waste streams and waste variability in order to develop a representative waste profile. The unit's profile can then be used to identify a representative performance test for the unit's SMCD.

c. Representative Testing

We are finalizing an SMCD alternative allowing owners and operators of VSMWC and IWI units with capacities less than or equal to 10 TPD to identify a representative performance test in the WebFIRE database and submit information about the representative performance test and documentation of how the performance test is representative for their unit (

e.g.,

based on the unit type and design, charge rate, operating temperatures, types of waste burned, and any air pollution control devices) to the Administrator through the EPA's Central Data Exchange (CDX) using the Compliance and Emissions Data Reporting Interface (CEDRI). Owners and operators must maintain a record of the representative performance test report (acquired from the EPA's WebFIRE database) and the submitted documentation of how the test is representative. The EPA encourages owners and operators to find similar sources by reviewing the notices of intent to use the SMCD and/or performance tests, available in the EPA's WebFIRE database. The EPA still anticipates that similar sources will coordinate to develop test protocols and find cost sharing opportunities by having representative sources conduct a performance test that can be used by all sources in that group.

If owners and operators of existing VSMWC and IWI units with capacities less than or equal to 10 TPD choose to use the SMCD, we are requiring them to submit SMCD information identifying the representative performance test through CDX using CEDRI beginning no later than March 30, 2027 or 60 days after the OSWI unit reaches the maximum charge rate at which it will operate, but no later than 180 days after initial startup, whichever date is later. This period will allow the owner or operator time for reviewing notices available on the EPA's WebFIRE database, finding and coordinating with similar sources, developing a testing protocol that will work for all sources within a group, conducting the performance tests, and electronically submitting the results of the test through CEDRI (see section III.E.3 of this preamble for a discussion of electronic reporting). The period will also allow time for the EPA to transfer these results to the EPA's WebFIRE database and for owners and operators to find a representative performance test and submit information on how it is representative to the Administrator.

Given the time needed to identify and coordinate similar source groups or develop test protocols, and because the compliance date for new sources is earlier than the compliance date for existing sources and it is uncertain how many tests will be conducted, owners or operators of existing sources are encouraged to start collecting information that would be useful for identifying similar sources and submit this information as soon as possible. This will greatly increase the likelihood that a representative test will be available in the WebFIRE database prior the compliance deadline.

As noted in our proposal, owners and operators who do not provide their initial waste characterization data in a timely manner could miss the opportunity to avail themselves of this option due to the amount of planning, time, and resources required for similar sources to coordinate and perform performance tests. Owners and operators who cannot find a representative test conducted for a unit that is similar to their unit must conduct their own initial performance tests.

The distinction between a new and existing unit does not in itself preclude the use of a performance test. If a new unit is similar in design and operation to an existing unit, the new unit may use a performance test conducted by an existing unit and vice versa. However, if a performance test is conducted on an existing unit, it must, among other things, demonstrate initial compliance with the emissions limits for new units for a new unit to use it as a representative performance test.

d. Continuous Compliance Demonstration

We are also finalizing, as proposed, an alternative waste characterization (AWC) option for demonstrating continuous compliance available to all VSMWC and IWI units with capacities less than or equal to 10 TPD that are subject to the OSWI rules. We are finalizing this AWC option in response to comments pointing out the difficulties of testing these units, which are generally located in areas that are remote and difficult to access.

In lieu of conducting annual performance tests, this alternative demonstration of continuous compliance will require recordkeeping. The recordkeeping requirements include recording the source-specific waste profiles and incinerator unit operating parameters, including the daily average charge rate and the 3-hour average combustion chamber temperature of the unit. As discussed in section IV.C of this preamble, in response to comments received, we have modified the final rule to require

that the facility use its records at the end of each calendar quarter to demonstrate that the waste combusted is consistent, within +/- 15 percent by weight, with the percentage established for the components of the waste stream according to the waste profiles established during the facility's initial performance test or established in the representative initial performance test for units using the SMCD.

The facility must report any deviations from the quarterly average waste profile requirements in its deviation report. Additionally, the records must demonstrate that the unit is operated within the charge rate and temperature ranges established during the initial performance test or the representative performance test.

If, for example, the paper component of the waste stream during initial testing was 20 percent, then burning waste streams with a paper component between 5 and 35 percent of the total waste stream would be acceptable quarterly operation and, assuming all other requirements are met, additional testing would not be required for the source.

As described in the proposal, we are finalizing a requirement that if the facility anticipates combusting a waste stream with a different profile, the owner/operator must conduct a performance test of the unit with a waste stream representative of the new waste profile, or alternatively, must identify a representative performance test report in the WebFIRE database and submit the information required by the SMCD, before combusting the modified waste stream.

Similarly, if the facility anticipates exceeding or operating outside of the established operating parameter ranges, the owner/operator must conduct a performance test of the unit while it is operating at the new parameter limits, or find a representative performance test with those operating parameter limits in the WebFIRE database and submit the information required by the SMCD, to confirm that the unit continues to meet the OSWI emission standards under the new operating parameter limits. Failure to comply with the retesting requirement is a deviation from the OSWI standards.

To use a representative test, the owner or operator of a unit must show that the representative test is of a unit having a similar throughput, method of processing and burning waste, charge rate, operating temperatures, waste management plan, estimated waste variability, and waste profile as its unit.

We are finalizing, as proposed in the 2020 Proposed Rule, revisions to monitoring to make the OSWI standards more consistent with the monitoring requirements in other CAA section 129 rules. For example, the only air pollution control device for which the 2005 final OSWI standards provide operating requirements is wet scrubbers. We are finalizing revisions to 40 CFR 60.2916 and table 2 to subpart EEEE and 40 CFR 60.3023 and table 3 to subpart FFFF to include operating limits and operating parameter monitoring requirements for additional controls that may be employed for OSWI units, including dry scrubbers, electrostatic precipitators, and fabric filters. Additionally, we are finalizing a clarification to 40 CFR 60.2917 and 40 CFR 60.3024 that OSWI units that use an alternate method for air pollution control beyond a wet scrubber, dry scrubber, electrostatic precipitator, or fabric filter, including other methods such as material balance, may petition the EPA for specific operating parameter limits in these cases. The final requirements add flexibility for facilities by expanding the control options available. In addition, we are finalizing as proposed revisions to the requirements in 40 CFR 60.2916, 40 CFR 60.2928, 40 CFR 60.3023, and 40 CFR 60.3023 for owners and operators of OSWI units using control options to require that the minimum operating parameters (

e.g.,

combustion operating chamber temperature, pressure drop, liquid flow rate) established for initial compliance are calculated based on the lowest 1-hour average as measured during the most recent performance test (or representative performance test) demonstrating compliance. The current OSWI standards required that these parameters be calculated using the average as measured during the most recent performance test. Similarly, we are revising the continuous compliance requirements in 40 CFR 60.2932(c) and 40 CFR 60.3023(c) to specify the averaging times for continuous compliances for operating parameters for the extended control options (generally, 3-hour rolling averages).

Moreover, as we proposed, we are removing the requirement for CO and oxygen (O

) CEMS for VSMWC and IWI units with capacities less than or equal to 10 TPD that use the AWC option in lieu of complying with the annual performance testing requirements. We are making this change for the same reasons that we are finalizing an alternative to the annual performance test. In addition to the cost of maintaining CEMS, calibrating a CEMS generally requires an annual stack test to verify the operation of the CEMS. Providing an alternative to conducting annual performance tests while continuing to require CEMS, which need annual stack tests, would not achieve the stated goals and benefits of providing an alternative to annual performance tests for showing continuous compliance.

We are finalizing, as proposed, an option included in the 2020 Proposed Rule that allows OSWI units to use CO CEMS data in lieu of initial and annual testing for CO, provided the CEMS has been previously certified and is meeting the ongoing quality assurance/quality control requirements. Currently, facilities are required under 40 CFR 60.2927 and 40 CFR 60.3030 to conduct initial and annual performance testing to determine compliance with all emission limitations, including CO, and to also continuously monitor CO emissions using CEMS under 40 CFR 60.2939 and 40 CFR 60.3038. Facilities that opt to use CO CEMS data to demonstrate continuous compliance must use a 12-hour rolling average of the 1-hour arithmetic average CEMS data to determine compliance with the CO emission limitations. However, the initial performance evaluation (CEMS certification) must be completed prior to collecting CEMS data for the initial compliance demonstration. Under the final rule, such units could also use CO CEMS data in lieu of conducting an annual performance test for CO. This change provides flexibility for sources and reduces the cost burden associated with testing, while assuring compliance based on continuously measured emissions data.

As discussed in section IV.C of this preamble, for OSWI units that choose to conduct annual testing, we are revising the compliance timeline for the annual performance test in response to comments that weather and geographic constraints may prevent facilities from meeting the timeline on a 12-month basis. The final rule requires annual performance tests to be conducted within 14 months following the initial performance test and, subsequently, within 14 months from the prior years' tests.

For a more detailed discussion of these amendments addressing testing and monitoring requirements for VSMWC and IWI units see section II.B.4 of the proposal preamble (85 FR 54178). Section IV.C of this preamble provides a summary of the significant comments on the proposal and our responses to those comments. A full compilation of comments and responses can be found in the document,

Summary of Public Comments and Responses for the Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Other Solid Waste Incineration Units Review,

which is available in the docket (see

Docket EPA-HQ-OAR-2003-0156) for this rulemaking.

2. Recordkeeping and Reporting

For units using the SMCD to demonstrate initial compliance, we are finalizing, as proposed, a requirement that owners and operators maintain the following records: the notice of intent to use the SMCD, along with documentation of the unit's design, operation, and capacity; initial waste characterization and operating data; and documentation of how the selected substitute test is representative of the unit.

We are also finalizing recordkeeping requirements to be used with the AWC option. Owners and operators must maintain records on: start and end times of the unit's operation; the amount or weight of each waste type (

e.g.,

pounds of solid waste, food waste, wood, or yard waste); the percentage of each type of waste burned; the 3-hour average temperature and charge rate; and operating records for units using air pollution controls such as a wet scrubber, dry scrubber, electrostatic precipitator, or fabric filters. Unit owners and operators must also keep records of periods when the waste profile does not meet the requirements as tested. As stated in the proposal, these recordkeeping requirements will help ensure that VSMWC and IWI units with capacities less than or equal to 10 TPD choosing the AWC option can demonstrate compliance with the emission and operating limits of the OSWI standards. The recordkeeping will also help to demonstrate that the percentage of waste components burned by VSMWC and IWI units with capacities less than or equal to 10 TPD is within +/−15 percent of the percentages established for each waste category incinerated at a unit according to the profiles established during the initial performance test or representative performance test. We are also finalizing, as proposed, a reporting requirement that owners and operators include in annual reports a statement that there were no deviations from the waste characterization requirements and that the unit has been operated within the operating parameter limits. As we stated in the proposal, these recordkeeping and reporting requirements are intended to help ensure that there is adequate information available with which to determine compliance with the standards; to ascertain the severity of any failure to meet a standard; and to further assure compliance with the standards at all times.

Consistent with the proposal, we are also clarifying the timeline for owners and operators who choose the SMCD to submit their annual compliance reports. They must submit their annual compliance reports no later than 12 months after they submit the representative initial performance test and description of how the test is representative for the OSWI unit.

We are finalizing, as proposed, revisions to the recordkeeping and reporting requirements for deviations included in the 2020 Proposed Rule to clarify that a deviation includes any “failure to meet an applicable standard” and to clarify what information must be recorded and reported. These changes include the following:

• Revising the definition of “deviation” to remove language for periods of SSM, as discussed in section III.E of this preamble.

• Revising 40 CFR 60.2932(c) and 40 CFR 60.3033(c) to clarify the alarm time that constitutes a deviation from the operating limit for OSWI units with fabric filters and bag leak detection systems.

• Revising 40 CFR 60.2942(f) and 40 CFR 60.3041(f) to clarify that, for OSWI units using CEMS, failure to collect required data is a deviation from the monitoring requirements.

• Revising 40 CFR 60.2949 and 40 CFR 60.3046 to specify that facilities must retain a record identifying the calendar dates, times, and durations of malfunctions and a description of the failure and the corrective action taken.

• Revising 40 CFR 60.2956(e) and 40 CFR 60.3051(e) to clarify that for OSWI units with CEMS, the annual report must include a statement that there were no periods during which the CEMS were inoperative, inactive, malfunctioning, or out of control.

• Removing and reserving deviation reporting requirements (previously 40 CFR 60.2956(g); 40 CFR 60.3051(g)) previously included as part of the annual report to remove redundant reporting; these requirements are included in the deviation report submitted on a semiannual basis (40 CFR 60.2958; 40 CFR 60.3053).

• Modifying the annual reporting requirements in 40 CFR 60.2956 and 40 CFR 60.3051 to require facilities to provide a statement that there was no deviation identified from the waste characterization (

i.e.,

each quarter, the waste types burned are within 15 percent variation of the profiles established during the initial performance test) and the unit has been operated within the charge rate and temperature ranges established when no deviations have occurred during the reporting period.

• For deviation reporting, revising the title of 40 CFR 60.2957 and 40 CFR 60.3052 to “What other reports must I submit if I have a deviation?” and reorganizing 40 CFR 60.2957(a) and 40 CFR 60.3052(a) to be consistent with the definition of “deviation” and to better reflect the types of deviations which must be reported.

• Modifying the requirements of 40 CFR 60.2958 and 40 CFR 60.3053 to clarify the contents of the deviation report, including identifying the calendar dates, times, and durations of any deviations and a description of any corrective actions taken, and adding new requirements to report deviations from the waste characterization and operating parameter limits established for VSMWC and IWI units with capacities less than or equal to 10 TPD.

As discussed in section IV.C.2 of this preamble, we are making one minor change to the proposed reporting requirements for qualified OSWI unit operators at 40 CFR 60.2956(j) and 40 CFR 60.3051(j) to clarify that facilities must report “the start date, start time, and duration in hours for each period of operation when all qualified OSWI unit operators were unavailable for more than 12 hours but less than 2 weeks”. The proposed language referenced “each period when qualified OSWI unit operators were unavailable . . .” and unintentionally included periods of off-season, maintenance, or periods of shutdown. The final rule clarifies the text to “each period of operation” to exclude off-season, maintenance, and shutdown periods.

Lastly, we are finalizing, as proposed, additional changes to the recordkeeping and reporting requirements in 40 CFR 60.2949(b) and 40 CFR 60.2956(d) and (f) and 40 CFR 60.3046(b) and 40 CFR 60.3051(d) and (f) from the 2020 Proposed Rule that include consistency edits based on the revisions to allow for use of CO CEMS data in lieu of annual testing for CO (for OSWI units that have capacities greater than 10 TPD) (discussed in section III.F.1 of this preamble) and the revisions to the monitoring requirements to ensure consistency with other CAA section 129 rules such as CISWI (

e.g.,

adding operating parameters for controls other than a wet scrubber that may be employed for OSWI units and clarifying the frequency of the data recording or averaging for each required operating parameter, discussed in section III.F.1 of this preamble).

For a more detailed discussion of these amendments to recordkeeping and reporting requirements, see section

II.B.5 of the proposal preamble (85 FR 54178; August 31, 2020). Section IV.B.2 of this preamble provides a summary of key comments we received on these amendments and our responses.

3. Electronic Reporting

To increase the ease and efficiency of data submittal and data accessibility, we are finalizing, as proposed, a requirement that owners or operators of OSWI units submit required performance test reports, performance evaluation reports, deviation reports, and annual compliance reports through the EPA's Central Data Exchange (CDX) using the Compliance and Emissions Data Reporting Interface (CEDRI), as included in the 2020 Proposed Rule. The final rule requires that performance test results be submitted in the format generated through the use of the EPA's Electronic Reporting Tool (ERT) or an electronic file consistent with the extensible markup language (XML) schema on the ERT website.

Similarly, performance evaluation results of CEMS that include a relative accuracy test audit must be submitted in the format generated through the use of the ERT or an electronic file consistent with the XML schema on the ERT website.

https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert

For deviation reports and annual compliance reports, the final rule requires owners and operators to use the appropriate spreadsheet template to submit information to CEDRI, beginning June 30, 2026, or once the reporting forms have been made available in CEDRI for at least 1 year, whichever date is later. The final version of the template for these reports will be located on the CEDRI website.

If the reporting template specific to this subpart is not available in CEDRI at the time that the report is due, facilities must submit the report to the Administrator at the appropriate address listed in 40 CFR 60.4. Once the form has been available in CEDRI for at least 1 year, facilities must submit all subsequent reports via CEDRI. Furthermore, we are finalizing, as proposed, provisions that allow facility operators to seek extensions for submitting electronic reports for circumstances beyond the control of the facility,

i.e.,

for a possible outage in the CDX or CEDRI (see 40 CFR 60.2961(d) and 40 CFR 60.3056(d)) or, for a force majeure event, see 40 CFR 60.2961(e) and 40 CFR 60.3056(e) in the time just prior to a report's due date, as well as provisions outlining the process to assert such a claim.

https://www.epa.gov/electronic-reporting-air-emissions/cedri

For a more detailed discussion of these final amendments, see section II.B.6 of the preamble to the 2020 Proposed Rule (85 FR 54178), as well as section III.B of this preamble on compliance with the Paperwork Reduction Act (PRA). For a more thorough discussion of electronic reporting, see the memorandum,

Electronic Reporting Requirements for New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) Rules,

which is available in the docket (see Docket EPA-HQ-OAR-2003-0156) for this rulemaking.

4. Technical Edits, Clarifications, and Additional Revisions

We are finalizing several of the revisions that we proposed for technical corrections, harmonizing changes, clarifications, and improvements to the OSWI standards in the 2020 Proposed Rule, with the exception of certain proposed changes related to testing or compliance requirements for VSMWC and IWI units with capacities less than or equal to 10 TPD that we are finalizing with revisions (see sections III.F.1 and III.G of this preamble). These revisions include:

• Including operating limits and operating parameter monitoring requirements for additional controls that may be employed for OSWI units, including dry scrubbers, electrostatic precipitators, and fabric filters, and revisions to clarify that OSWI units that use an alternate method for air pollution control may petition the EPA for specific operating parameter limits.

• Revising the requirements for owners and operators of OSWI units using control options to require that the minimum operating parameters (

e.g.,

combustion operating chamber temperature, pressure drop, liquid flow rate, etc.) established for initial compliance are calculated based on the lowest 1-hr average as measured during the most recent performance test (or representative performance test) demonstrating compliance, and revising the continuous compliance requirements to specify the averaging times for continuous compliances for operating parameters for the extended control options (which is generally based on 3-hour rolling averages).

• Clarifying that for continuous monitoring, the 12-hour rolling average values must include CEMS data during startup and shutdown.

• Adding a requirement that the incinerator operator training course under 40 CFR 60.2905(c) and 40 CFR 60.3014(c) must include coverage of good combustion practices as well as waste characterization procedures, and related actions for prevention and correction of malfunctions.

• Adding a provision to 40 CFR 60.2911 and 40 CFR 60.3020 to clarify that batch units must always have a qualified operator accessible times during the operation of the unit.

• Updating 40 CFR 60.2890 and 40 CFR 60.2998 to clarify the principal components of the subparts include definitions and table.

• For existing units, adding new section 40 CFR 60.3003 to clarify that certain substitute means of compliance demonstration requirements must be completed prior to the compliance date.

• Modifying 40 CFR 60.2910 to 40 CFR 60.3019 to clarify that site-specific documentation must include procedures for establishing initial and continuous compliance.

• Updating requirements for initial and annual performance tests such that they must be conducted according to the methods and meet the revised emissions limitations specified in tables 1 through 1b to subpart EEEE and tables 2 and 2a to subpart FFFF, as applicable.

• Updating 40 CFR 60.2922(e), 40 CFR 60.2940(c), 40 CFR 60.3027(e), and 40 CFR 60.3039(c) to add references to ASME/ANSI PTC 19.10-198 Part 10 (2010), “Flue and Exhaust Gas Analyses” (previously approved as an alternative method to EPA Method 3B in the 2005 OSWI rule).

• Adding an additional test method, ASTM D7520-16, “Standard Test Method for Determining the Opacity of a Plume in the Outdoor Ambient Atmosphere,” as an acceptable alternative to EPA Method 9 for opacity. This test method was identified as an acceptable alternative to EPA Method 9 when specific provisions are followed.

• Revising 40 CFR 60.2932(d) and 40 CFR 60.3033(d) to specify that VSMWC and IWI units with capacities less than or equal to 10 TPD using control devices must continuously monitor operating parameters and specifying the averaging values to demonstrate continuous compliance.

• Revising 40 CFR 60.2939 and 40 CFR 60.3038 (requirements for installation and calibration of CEMS) such that they apply only to OSWI units with a capacity greater than 10 TPD.

• Clarifying the installation and calibration requirements for operating parameter equipment in 40 CFR 60.2944 and 40 CFR 60.3043, including adding new requirements for bag leak detection systems.

• Revising 40 CFR 60.2949(b) and 40 CFR 60.3046(b) to incorporate

recordkeeping for data from OSWI units that use an alternate method for air pollution control beyond a wet scrubber, dry scrubber, electrostatic precipitator, fabric filter, or other method such as material balance.

• Clarifying that for CO CEMS, records of annual performance evaluations must be maintained (40 CFR 60.2949(g) and 40 CFR 60.3046(g)).

• Adding a recordkeeping requirement for notifications submitted for excluded units, such as temporary-use incinerators.

• Revising 40 CFR 60.2954 to clarify that a copy of the waste management plan must be submitted following the initial performance test, for consistency with 40 CFR 60.3049(c).

• Clarifying that for facilities with a title V permit, the permit may address the submittal timeline of the annual report (40 CFR 60.2955, 40 CFR 60.3050).

• Minor clarifications to the content of the annual reports and deviation reports, including what information must be submitted if a performance test is conducted during the annual period and what information may be excluded if the reports are submitted via CEDRI (40 CFR 60.2956, 40 CFR 60.3051).

• Other minor grammatical or technical edits (

e.g.,

corrections to typographical errors or cross-references within existing provisions, or to clarify existing provisions).

We are also including several additional minor clarifying edits in the final rule based on comments received during the public comment period, such as adjusting the testing requirements for seasonal weather issues. The comments and our responses can be found in section IV.B.1 of this preamble and in the

Summary of Public Comments and Responses for the Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Other Solid Waste Incineration Units Review,

available in the docket for this rulemaking.

G. What are the effective and compliance dates of the standards?

In the 2020 Proposed Rule, we established that OSWI units with capacities less than or equal to 10 TPD that commenced construction after August 31, 2020 are new units and those that commenced construction prior to August 31, 2020 are considered existing incineration units. We are finalizing the effective and compliance dates for OSWI units to distinguish between new and existing OSWI units and to require any incinerator already subject to a current OSWI standard to continue to comply with that standard until the effective date of the revised OSWI standards. Table 4 of this preamble provides the applicable compliance dates for new and existing OSWI units.

The effective date of this final action is August 29, 2025. We are finalizing the compliance dates for the amended rule as proposed. The compliance dates depend on whether the OSWI unit is a VSMWC or IWI unit with capacity less than or equal to 10 TPD, or a VSMWC or IWI unit with a capacity greater than 10 TPD, and whether the OSWI unit is a new or existing unit.

However, we are are revising the dates by which a source is considered a new source to be consistent with the construct of CAA sections 111 and 129. A new VSMWC or IWI unit is a unit that commenced construction after August 31, 2020, or commenced modification or reconstruction on or after December 29, 2025. Sources that commenced construction after December 9, 2004, or commenced reconstruction or modification on or after June 16, 2006, which are currently new sources under the 2005 OSWI rule, will become existing sources. However, these sources must continue to comply with the requirements of 40 CFR part 60, subpart EEEE, including the emission limits in table 1 to the subpart, until the unit is subject to 40 CFR part 60, subpart FFFF through an approved state plan or Federal plan. The 2005 OSWI rule emission limits for new and existing sources were identical, so the stringency of the limits and ability of the unit to comply with the limits is not changing for sources which were new sources under the 2005 OSWI rule and will becoming existing sources under the this final rule.

Similarly, as discussed in sections III.C and IV.A of this preamble, SRIs which are currently regulated under the CISWI rules will become subject to regulation under the OSWI rule in this final action. We believe that all or most of these units will be VSMWCs with capacities less than or equal to 10 TPD. If any SRIs meet the definition of a new unit, then these new units must demonstrate compliance with the final rule by no later than December 29, 2025, or by the date the unit first begins operation, whichever is later. If any SRIs do not meet the definition of a new unit, then these units must demonstrate compliance by July 1, 2030 or 3 years after the effective date of the state plan approval, whichever is earlier. However, SRIs that do not meet the definition of a new unit, and which are currently regulated under the CISWI rules must continue to demonstrate compliance with subpart CCCC or DDDD of this part, or subpart IIIa of part 62, until the unit becomes subject to the requirements of an approved state plan or federal plan that implements subpart FFFF of this part (Emission Guidelines and Compliance Times for Other Solid Waste Incineration Units).

Table 4—Compliance Schedule for New and Existing Units

For. . .

Complete this

action

By this date

New units as defined in 40 CFR 60.2886

Initial Performance Test

60 days after unit reaches the charge rate at which it will operate, but no later than 180 days after its initial startup.

Existing units as defined in 40 CFR 60.2992

Initial Performance Test

No later than 180 days after final compliance date.

New units as defined in 40 CFR 60.2015

Initial Performance Test

60 days after unit reaches the charge rate at which it will operate, but no later than 180 days after its initial startup.

Existing units as defined in 40 CFR 60.2550

Initial Performance Test

No later than 180 days after final compliance date.

New units subject to requirements in 40 CFR 60.2932(a)

Annual performance test

No later than 14 calendar months following the initial performance test.

Existing units subject to requirements in 40 CFR 60.3033(a)

Annual performance test

No later than 14 calendar months following the initial performance test.

This action eliminates the SSM provisions at 40 CFR 60.2918 and 40 CFR 60.3025 and adds electronic reporting. Eliminating the SSM provisions will provide more data on emission limits and operating limits. As noted at proposal, the finalized electronic reporting provisions will reduce burden on regulated facilities, delegated air agencies, and the EPA. Accordingly, we are finalizing the removal of SSM provisions and the addition of electronic reporting for all OSWI units. As stated in section III.F.3 of this preamble, for deviation reports and annual compliance reports, the final rule requires owners and operators to use the appropriate spreadsheet template to submit information to CEDRI beginning June 30, 2026, or once the reporting forms have been made available in CEDRI for at least 1 year, whichever date is later. The final rule requires owners and operators to submit performance test reports and CEMS performance evaluation reports to CEDRI beginning on December 29, 2025.

1. OSWI Units With Capacities Less Than or Equal to 10 TPD

For VSMWC and IWI units with capacities less than or equal to 10 TPD, we are finalizing revised MACT standards and revised compliance, monitoring, and testing requirements. For new sources, CAA section 129(f)(1) requires that performance standards and other requirements shall be effective 6 months after the promulgation of the final rule. For these purposes, a new VSMWC or IWI unit with capacity less than or equal to 10 TPD is a unit that commenced construction after August 31, 2020, or commenced modification or reconstruction on or after December 29, 2025. We are finalizing, as proposed, that these new units must demonstrate compliance with the final rule by no later than December 29, 2025, or by the date the unit first begins operation, whichever is later.

For existing sources, CAA section 129(f)(2) provides that the performance standards and other requirements shall be effective not later than 3 years after the state plan is approved or July 1, 2030, whichever is earlier. For these purposes, an existing VSMWC or IWI unit with capacity less than or equal to 10 TPD is one for which construction commenced on or before August 31, 2020.

For existing VSMWC and IWI units with capacities less than or equal to 10 TPD, we are finalizing a compliance date of July 1, 2030, or 3 years after the effective date of the state plan approval, whichever is earlier.

OSWI units with a capacity less than 10 TPD that commenced construction after December 9, 2004, or commenced reconstruction or modification on or after June 16, 2006, and that are subject to the 2005 OSWI standard must continue to comply with the 2005 OSWI standard until the unit is subject to 40 CFR part 60, subpart FFFF through an approved state plan or Federal plan.

2. OSWI Units With Capacities Greater Than 10 TPD

Under the final rule, OSWI units with a capacity greater than 10 TPD continue, with limited changes, to be subject to the requirements of the OSWI standards that were promulgated in 2005—either the NSPS or a plan promulgated pursuant to the EG. With certain exceptions (discussed below), these sources will continue to follow the emission and operating limits, including compliance, monitoring, and testing provisions, associated with the 2005 OSWI standards. However, because the definition of a new source is being revised, the compliance dates are changing in the final rule. Emissions and operating limits apply to new OSWI units with a capacity greater than 10 TPD when they begin to operate, although there are some pre-construction requirements (see 40 CFR 60.2881). For existing OSWI units with a capacity greater than 10 TPD (that is, OSWI units that commenced construction on or before August 31, 2020, or commenced reconstruction or modification before December 29, 2025), CAA section 129(f)(2) provides that performance standards and other requirements shall be effective as expeditiously as practicable after approval of a state plan or promulgation of a Federal plan, but no later than 5 years after they are promulgated. Therefore, compliance for existing sources must be demonstrated by July 1, 2030, or 3 years after the effective date of the state plan approval, whichever is earlier. However, incineration units with a capacity greater than 10 TPD that commenced construction after December 9, 2004, or commenced reconstruction or modification on or after June 16, 2006, and that are subject to the 2005 OSWI standard must continue to comply with the 2005 standard until the unit is subject to 40 CFR part 60, subpart FFFF through an approved state plan or Federal plan.

IV. Public Comments and Responses

Additional comments and our specific responses can be found in the comment summary and response document titled

Summary of Public Comments and Responses for the Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Other Solid Waste Incineration Units Review,

which is available in the docket (see Docket EPA-HQ-OAR-2003-0156) for this rulemaking. Key comments and responses are discussed below.

A. What key comments did we receive on the applicability of OSWI requirements, and what are our responses?

Comment:

The EPA received several comments on the proposed revisions to add a definition of “rudimentary combustion unit”. One commenter did not support the proposed addition of a definition, expressing concerns that prematurely changing the definition puts the EPA on track to develop regulations without appropriate data. The commenter requested that EPA conduct an advanced notice of proposed rulemaking to ask for additional data and work with and provide resources to Tribes to collect this data.

Other commenters supported the proposed changes, but at least one commenter recommended that the definition be simplified to provide ease of compliance. One commenter stated that the definition should include a “non-exhaustive” list of what units meet the definition of a rudimentary combustion device, such as cyclonic burn barrels, 55-gallon burn barrels, and locally obtained or manufactured burn receptables such as dumpsters.

The commenter also provided input on the individual criteria that EPA proposed as part of the definition. Specifically, commenters noted that the wording “managing air flow and discharging flue gases from combustion” is confusing. The commenters stated that in any combustion device, a stack, chimney or pipe is used to remove the post-combustion flue gases or to direct the exhaust gas to the atmosphere, and that the air flow (combustion air) is handled, controlled, and metered at the burden. Commenters therefore recommended that the text “managing air flow” be removed.

Commenters also questioned the meaning of the criterion “burners designed to manage the combustion process”. Commenters stated that EPA's intent is unclear and that if the criterion is meant to include any devices that have burners or a specific type of burner (

e.g.,

burner with modulating or staging controls) then the language should be updated to “designed to initiate and/or maintain or assist the combustion process” or to more clearly explain the type of burner. Commenters also

questioned the meaning of “supplemental fuel burners or nozzles” as included in the proposed definition. Commenters stated that if the intent is to not include devices with a specific type of burner and “supplemental fuel burners or nozzles” or to exclude devices equipped with secondary combustion, this should be more plainly stated.

One commenter added that the proposed definition's inclusion of a capacity limit of “less than or equal to 10 TPD that is designed and constructed without one or more of the following elements” may inadvertently discourage businesses or villages from acquiring small modern packaged incinerators that are cleaner burning but that are equipped with all five elements. The commenter noted that rudimentary combustion devices will almost exclusively be hand-fed in portable (hand-carried) batches, and that 10 TPD of hand-held or delivered batches would be equivalent to 500 individual batches, daily.

The commenter stated that this amount exceeds the realistic expectations of the population statistics of the average village communities using such devices. The commenter suggested that the rationale of a specific number for capacity or throughput deserves additional consideration, especially in consideration of the recordkeeping requirements that would be required for compliance with weight throughput limitations (which would be excessive for remote areas and ineffective for most batch units). The commenter questioned what recordkeeping or reporting would be required to verify compliance, especially provided that these activities generally fall below permitting thresholds. The commenter suggested that the EPA may want to consider setting a volume limit threshold for these devices (

e.g.,

“smaller than a dump truck”), or consider adding the qualifier “uncompacted, loose” to the type of trash that may be burned in such devices. Another commenter requested that EPA consider the potential unintended consequences of any future regulation of such devices. Specifically, the commenter stated that the EPA must not force communities with few resources to purchase commercially available combustion devices.

Per 40 CFR 60.2977 (Subpart EEEE) and 40 CFR 60.3078 (Subpart FFFF), a batch OSWI unit means an OSWI unit that is designed such that neither waste charging nor ash removal can occur during combustion, and a continuous OSWI unit means an OSWI unit that is designed to allow waste charging and ash removal during combustion.

Other commenters criticized the proposed definition as overly broad and lacking in protective provisions, by not adequately narrowing the circumstances, locations, or devices that would be eligible. Commenters supported including restrictions to ensure that the use of such units is limited to those areas that truly have no better options, including very clear descriptions and specifics about the types of devices that are included in the definition of “rudimentary combustion device” and the criteria that must be met for a geographic area to qualify, so that only those with the logistical challenges described in the proposal will be eligible for the exemption. Other commenters expressed that the proposed rule did not define the circumstances or restrictions under which rudimentary combustion devices may be used and recommended that the EPA add a clarification to the definition to avoid use of the devices where access to municipal solid waste disposal is readily available or where installation of such devices could result in the circumvention of the OSWI standards. Commenters also objected to the proposed definition as it would apply in their jurisdiction, which prohibits open burning; the commenters warned the definition is confusing and could lead to an increase in air pollution.

Several commenters requested that the EPA provide more clarity on what geographic areas would be qualified to be exempt from the OSWI regulations. A commenter noted that Alaska is geographically diverse, with areas of limited or no road access, and that the EPA should clarify whether units in the following circumstances are exempt: (1) devices located in rural areas not accessible by the Federal Aid Highway System, including what distance from the road area is necessary for exemption; (2) devices transported and utilized by oil spill prevention and response teams in remote areas for response cleanup; (3) devices located in municipal areas at businesses or other commercial institutions that may have refuse service provided they are only used for on-site generated waste; and (4) devices located at industrial facilities along the Federal Aid Highway system that are days away from waste disposal facilities, including what distance from an organized landfill or from an improved road system qualifies for exemption. One commenter added the rule should ensure that use of a rudimentary combustion device would not be allowed when it conflicts with more stringent state or local rules and regulations. Other commenters generally opposed the broad applicability of the definition of rudimentary combustion unit throughout the U.S., recommending that the EPA adjust the definition to pertain specifically to Alaska, and take time to develop standards for the rest of the country.

One commenter also requested that the EPA consider providing clear rules related to the use of rudimentary combustion devices during emergency remote spill responses. The commenter explained that the waste from such spills is effectively managed through incineration in small batch cyclonic burn barrels or other devices. The commenter requested that any rules on such usage be easy to interpret such that they do not require EPA agency interpretation or concurrence prior to use (including any limitations on the type of device that is a “rudimentary combustion device” or any limitations on geographic siting requirements). The commenter stated that if EPA concurrence remains necessary during an emergency spill, the authority should be granted to EPA Federal On-Scene Coordinators regardless of the disaster classification of the response.

Response:

In the final rule, we are adopting a definition of “rudimentary combustion device” to be a combustion device with a capacity less than or equal to 10 TPD that is designed and constructed without one or more of the following elements: (1) a stack, chimney, or pipe designed for the purpose of discharging flue gases from combustion; (2) mechanical draft to provide air flow; (3) burners designed to initiate and/or assist the combustion process, including burners designed to burn supplementary fuel; or (4) an ancillary power supply to operate.

For the final rule, we have revised the applicability of the final OSWI standards as proposed in the 2024 SNPRM to address issues and concerns raised for small units that are rudimentary combustion devices. The EPA is finalizing its decision to add a definition for “rudimentary combustion device” to distinguish these types of primitive devices from those addressed in today's rule. The EPA agrees with commenters regarding certain clarifications to the criteria included in the proposed definition, specifically, removal of text related to the use of a stack for “managing air flow” and the clarification of text describing the type of burners included in the criterion. The EPA is removing the phrase “managing air flow” to reduce confusion regarding the stack function. We are also clarifying the criterion regarding burners to manage the combustion process. We are adopting language similar to what commenters suggested to indicate that we mean burners that

initiate and/or assist with combustion. In light of this clarification, we have also lumped supplementary fuel burners in with other burners that mangage the combustion process, as the purpose of supplementary fuel is to initate combustion or to aid in better combustion.

We disagree with commenters who requested a specific list of unit types that are considered rudimentary combustion devices, but rather, acknowledge that a number of combustion unit types may be considered “rudimentary” if they have a capacity of less than 10 TPD and were designed or constructed without one of more of the defined criterion. As described in the 2024 SNPRM, the EPA identified rudimentary combustion devices as primarily located within the state of Alaska, and consulted with state and Tribal agencies in the state of Alaska in assessing the types of combustion devices referenced. We determined that these rudimentary devices are often primitive in nature, most often not commercially constructed or engineered, and have capacities less than 10 TPD. Although we solicited comment on the matter, we did not receive any comments on the 2024 SNPRM that provided additional information or data on the typical capacity or volume thresholds for these units, and as such, are maintaining the proposed capacity threshold of 10 TPD; this threshold remains appropriate as we anticipate that all rudimentary combustion devices that fail to include the design elements included in the definition, by their nature and construction, would have capacities less than 10 TPD. We emphasize that the final rule does not set standards for these rudimentary combustion devices because they lack key features of commercially available incineration units and the emissions information, limits, and controls developed for the OSWI rule are not appropriate for them. The EPA is therefore not setting emission standards for these units in this rule.

Although we solicited comment on the location of units, number of units in rural communities, and emissions information from these units in the 2024 SNPRM, we did not receive any additional information in response to the 2024 SNPRM. The Agency intends to consider requirements for these units in a future effort and would seek additional information regarding these units and the impacts of any regulations at that time. Because we received no information in response to our 2024 SNPRM solicition, the EPA is also not setting requirements or restrictions regarding the geographic location or circumstantial restrictions on the use of rudimentary combustion devices under the OSWI standards; the definition of rudimentary combustion device in the final OSWI rules applies to the entire United States. The final rules do not usurp existing local or state regulations that may apply to these units, which will continue to apply.

Comment:

We received one comment contending that the proposal fails to set CAA section 129 standards for previously excluded units and therefore contravenes the CAA and violates the EPA's obligations under a consent decree and pursuant to the voluntary remand. The commenter stated that the proposed regulations expressly exempt or exclude a wide variety of other waste combustion units, including: (1) solid waste-burning cement kilns; (2) various waste-burning boilers and process heaters; (3) residential incinerators; (4) agricultural waste incinerators; (5) wood waste incinerators; (6) construction and demolition waste incinerators; (7) crematories; (8) contaminated soil treatment facilities; (9) rural IWIs; (10) incinerators and ACIs in isolated areas of Alaska; (11) incinerators located on remote islands; (12) temporary use incinerators used in disaster or emergency recovery efforts; (13) units that combust contraband or prohibited goods; (14) units burning national security documents; (15) co-fired combustors; (16) institutional boilers and process heaters; and (17) pathological waste incineration units. The commenter added that all of the categories identified combust solid waste and none of them fall within the narrow exemption of CAA section 129(g).

The commenter generally contends that, under CAA section 129, the EPA must set standards for all solid waste incineration units, without exception. The commenter further contends that, under CAA section 129, the OSWI rule must set standards for all “other” incinerators, that is, all incinerators not already subject to regulation under the EPA's MWC rules, medical waste incinerator rules, or CISWI rules.

The commenter refers to a “Partial Consent Decree” entered in

Sierra Club

Jackson,

No. 01-1537 (PLF) (D.D.C.), under which the EPA was to propose, by November 30, 2004, a rule establishing standards for OSWI units and to promulgate, by November 30, 2005, a final rule establishing such standards. The commenter contends that the EPA's failure to set standards for various excluded types of combustion units violates its obligations under that Partial Consent Decree.

The commenter also asserts that the EPA sought and obtained, in 2016, a “voluntary remand” of the OSWI standards from the court (

Sierra Club

EPA,

No. 06-1066 (D.C. Cir.)). The commenter states that the EPA sought the voluntary remand to bring the OSWI standards into compliance with certain decisions issued by the D.C. Circuit. The commenter contends that the EPA's failure to set standards for the excluded types of combustion units identified by the commenter (

i.e.,

The commenter further claims that the EPA's failure to set standards for currently unregulated incinerators fails to satisfy CAA section 129(a)(5). The commenter cited

Louisiana Environmental Action Network

EPA,

955 F.3d 1088 (D.C. Cir. 2020) (

LEAN

), and maintained that the EPA is required, in the course of a CAA section 129(a)(5) rulemaking, to bring its OSWI standards into compliance with the CAA and that the EPA's failure to set standards for all OSWI units, including the excluded incinerators, in the course of its CAA section 129(a)(5) rulemaking, violates that section.

The commenter further cited

NRDC

EPA,

489 F.3d 1250 (D.C. Cir. 2007), in which, the commenter said, the D.C. Circuit made clear that institutional waste incinerators that recover energy are combusting solid waste and must be regulated as incinerators under CAA section 129. The commenter added that the

NRDC

ruling holds that any unit that combusts waste is an incinerator, whether it recovers energy or not. The commenter stated that EPA sought and obtained a voluntary remand allegedly to address the aspects of its rule that are inconsistent with

NRDC

. The commenter added that EPA's failure to change its definition of institutional waste incinerator to include units that recover energy is flatly unlawful and displays contempt for the Clean Air Act and the courts and bad faith in implementation of the unopposed remand.

Response:

As the commenter recognizes, we proposed the definition of “other solid waste incineration unit” on the 2004 proposal for the OSWI standards to cover very small municipal waste combution units and institutional waste incineration units but proposed to exclude certain types of other units (see 69 FR 71472, December 9, 2004). In response to the 2004 proposal for the

OSWI standards, the EPA received comments concerning the proposal to exclude various units from the OSWI standards, and the EPA addressed comments on both covered and excluded units at that time (70 FR 74870, 74874-74881; December 16, 2005). The EPA was challenged on the 2005 OSWI rule (

Sierra Club

EPA,

No. 06-1066, (D.C. Cir.)), which eventually led to the 2016 voluntary remand of the 2005 OSWI rule.

The EPA disagrees with the assertion that the EPA failed to satsify its obligations under the Partial Consent Decree entered in

Sierra Club

Jackson,

No. 01-1537 (PLF) (D.D.C.). Under the Partial Consent Decree, the EPA was required to issue a final rulemaking establishing standards for OSWI units under CAA section 129(a)(1)(E) on or before November 30, 2005. The Partial Consent Decree contained no requirmenets regarding the content of the regulation. The EPA satisfied this obligation by signing the final rulemaking titled, “Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Other Solid Waste Incineration Units” on November 30, 2005. 79 FR 74870.

The EPA disagrees that

NRDC

EPA,

489 F.3d 1250 (D.C. Cir. 2007), requires the EPA to set emissions standards for all OSWI units, “without exception.” Rather,

NRDC

focused on whether the EPA could determine that certain facilities that were combusting solid waste could be regulated under CAA section 112, rather than CAA section 129. The

NRDC

decision held that the statutory definition of “solid waste incineration unit” is clear and unambiguous and does not permit the EPA to exclude commercial and industrial units combusting solid waste from regulation under CAA section 129. However, the

NRDC

decision does not address whether the EPA is required to establish emissions standards for

all

“other categories” of solid waste incineration units, as opposed to commercial or industrial incinerators, which are categories Congress clearly required to be regulated. EPA is continuing to assess the the

NRDC

decision, which vacated the EPA's definition of “commercial or industrial solid waste incineration unit” because it excluded some units combusting solid waste for the purpose of energy recovery, but has not yet proposed to take action following remand on whether the language in section 129(a)(1)(E) requires requires regulation of “every [ ] possible type of incinceration unit burning any type of solid waste.”

See

70 FR at 74875.

We further disagree with the commenter's contention that the EPA is required, in the course of a periodic review of the OSWI standards under CAA section 129(a)(5), to set standards for all solid waste incinerators that are not already regulated under the rules for municipal waste incinerators; hospital, medical or infectious waste incinerators; or commercial or industrial waste incinerators. The

LEAN

(955 F.3d 1088 (D.C. Cir. 2020)) decision considered standards set under CAA section 112(d)(6). CAA section 112(d)(6) applies to “emission standards promulgated under [section 112].” CAA section 129 applies to a specific category of sources: non-hazardous solid waste incinerators. In CAA section 129, Congress itself designated the source categories to be regulated. CAA section 112, on the other hand, delegates to the Administrator the authority to identify source categories to regulate and to set emission standards for them, CAA sections 112(c) through (d). By contrast, in CAA section 129, Congress specifies sources that the EPA must regulate:

• “[S]olid waste incineration units with capacity greater than 250 [TPD] combusting

municipal waste.

” (Italics added.)

• “[S]olid waste incineration units with capacity equal to or less than 250 [TPD] combusting

municipal waste

and units combusting

hospital waste, medical waste and infectious waste.

” (Italics added.)

• “[S]olid waste incineration units combusting

commercial or industrial waste.

” (Italics added.)

However, Congress left “the promulgation of standards under section 7411 of this title and this section applicable to other categories of solid waste incineration units” (CAA section 112(a)(1)(e)) up to the Administrator's discretion.

CAA section 112(d)(6), the section of the CAA considered in

LEAN,

requires a periodic review (every 8 years) of standards promulgated under CAA section 112.

LEAN

did not discuss nor make any decisions concerning the scope or nature of the EPA's periodic review under CAA section 129(a)(5). The discussion in

LEAN

focused on the precise language in CAA section 112(d)(6), which differs from the language of CAA section 129(a)(5). Specifically, CAA section 112(d)(6) requires that the EPA periodically “review, and revise as necessary” CAA section 112 emission standards. CAA section 129(a)(5) requires that the EPA “review, and in accordance with this section and section [111] of this title, revise” the CAA section 129 standards and requirements. The language within CAA section 129(a)(5) does not otherwise cross-reference CAA section 112. Further, the “as necessary” language in CAA section 112(d)(6) (which is not found in CAA section 129(a)(5)) was key to the decision in

LEAN.

The decision notes, for example, that the “only question” was “whether the EPA lawfully may complete a section 112(d)(6) review and `revise' an existing underinclusive emission standard `as necessary' without supplying the missing controls.” 955 F.3d at 1096.

The commenter claims that the language of CAA section 129(a)(5) is “closely analogous” to CAA section 112(d)(6), and therefore imposes the same obligation the

LEAN

court found. The EPA disagrees. The two key features of the statutory language the

LEAN

court pointed to in CAA section 112(d) are not at issue here. The court first noted that the “standards” referred to in CAA section 112(d)(6) must include limits for each HAP the category emits, and an “emission standard” under that provision “includes as many limits as needed to control all the emitted air toxics of a particular source category.”

LEAN

at 1097. In contrast, CAA section 129 requires the EPA to establish emissions standards only for certain, specified pollutants. Even if “emission standard” as used in CAA section 129(a)(5) refers to all limits, the EPA has established those limits for the specified CAA section 129 pollutants.

The commenter also claims that the EPA's failure to propose, here, to eliminate the various excluded units in 40 CFR 60.2887 and 40 CFR 60.2993 and as identified by the commenter (

i.e.,

solid waste-burning cement kilns; various waste-burning boilers and process heaters; residential incinerators; agricultural waste incinerators; pathological waste incineration units, etc.) from the OSWI standards and expand the applicability or coverage of the standards fails to satisfy the terms of the voluntary remand granted by the D.C. Circuit in 2016. The EPA sought and obtained a voluntary remand of the 2005 OSWI rule “to allow the EPA to consider what potential revisions, if any to the final rule may be appropriate in light of relevant decisions including

Sierra Club

EPA,

479 F.3d 875 (D.C. Cir. 2007),

NRDC

EPA,

489 F.3d 1250 (D.C. Cir. 2007), and

Sierra Club

EPA,

551 F.3d 1019 (D.C. Cir. 2008).”

As explained in the 2020 proposal and above, this final action addresses certain issues involved in the 2016 voluntary remand of the OSWI standards

including changes to the SSM provisions and revised subcategories and MACT standards that better reflect actual emissions test data from OSWI units and the population of OSWI. The EPA is continuing to evaluate other aspects of the remand not addressed in this final action.

Motion for Voluntary Remand,

Sierra Club

EPA,

no. 06-1066 (D.C. Cir. filed Jan. 29, 2016).

For the final rule, we have revised the applicability of the final OSWI standards to address issues and concerns raised for units that are rudimentary combustion devices. As discussed in section III.B and above in this section IV.A of this preamble, the EPA is finalizing adding a definition for “rudimentary combustion device” to address certain combustion devices that lack key elements typical of incineration units. Because the EPA believes that rudimentary combustion units lack key elements of other OSWI incineration units, the emissions information, limits, and controls developed for the OSWI rule are not appropriate for them. Any limits that the EPA may set for rudimentary combustion units in the future would be based on information and data that are appropriate for those units.

Comment:

One commenter requested that the EPA clarify the applicability of the CISWI standards and the OSWI standards, asserting that as proposed, the same units that meet the definition of a “small OSWI unit” in the OSWI standards also meet the definition of a “commercial and industrial solid waste incineration unit” under the CISWI standard. The commenters stated that this potential confusion is not entirely eliminated by 40 CFR 60.2020(j) and 60.2555(j) of the CISWI rules that state that units subject to 40 CFR part 60, subparts EEEE or FFFF are exempt from the CISWI standards or by 40 CFR 60.2887(d) and 60.2993(d) in the OSWI rules that state units subject to 40 CFR part 60, subparts CCCC and DDDD are exempt from the OSWI standards. The commenter specifically urged the inclusion of a new paragraph in 40 CFR 60.2887 and 40 CFR 60.2993 of the OSWI rules that states: “Incinerators in Alaska that meet the definition of small OSWI unit under subparts EEEE and FFFF of this part are not subject to subparts CCCC or DDDD.”

Response:

We agree with commenters that clarification regarding the applicability of CISWI to certain units located in the State of Alaska that are now subject to OSWI is warranted. However, the commenter's proposed language to add an exclusion for units subject to 40 CFR part 60, subparts EEEE and FFFF from CISWI is inappropriate for OSWI. Instead, we are finalizing revisions to the CISWI NSPS and EG that clarify the applicability of the standards to small remote incinerators that may now be subject to the OSWI standards, specifically the standards for VSMWC. In 2024, the EPA finalized development of a Federal plan implementing the CISWI standards in states that do not have an approved state plan (89 FR 100092, December 11, 2024). The final rule included revisions to exclude small remote incinerators in the state of Alaska from the Federal plan, which reflected prohibitions on the implementation of CISWI standards to units in the State of Alaska that were implemented by Congress.

To address the concerns raised by commenters and to align the CISWI NSPS and EG with the CISWI Federal plan, we are finalizing a similar amendment to the CISWI NSPS and EG requirements at 40 CFR 60.2020 and 40 CFR 60.2555 to clarify that small remote incineration units located in the State of Alaska are not subject to the CISWI standards as specified in the Consolidated Appropriations Act of 2024, H.R. 4366, section 432. However, because existing units would not be subject to the control requirements in the OSWI standards until they become subject to a state plan or Federal plan that implements 40 CFR part 60, subpart FFFF, we have included language within the exclusion to clarify that such units remain subject to 40 CFR part 60, subparts CCCC or DDDD until the unit becomes subject to a state plan or Federal plan that implements 40 CFR part 60, subpart FFFF. The changes are consistent with final revisions to 40 CFR 60.2886(a)(5) and 40 CFR 60.2992(a)(3) to clarify the applicability dates for OSWI units, as discussed in section IV.D of this preamble.

As specified in the Consolidated Appropriations Act of 2024, H.R. 4366, section 432, the EPA is precluded from “expending funds to implement or enforce certain EPA regulations for commercial and industrial solid waste incineration units with respect to units in the state of Alaska that are defined as small remote incinerator until a subsequent regulation is issued.” Consolidated Appropriations Act, 2024. Public Law 118-42 (2024, March 8).

https://www.congress.gov/bill/118th-congress/house-bill/4366/text.

See also 89 FR 100097, December 11, 2024.

B. What key comments did we receive on the OSWI subcategories and related MACT floor redeterminations?

Comment:

One commenter contended that EPA has no authority to create subcategories for Section 129 standards, and therefore, cannot create subcategories in OSWI for units with capacities greater than 10 TPD and units with capacities less than 10 TPD. The commenter asserted that while Section 112 allows EPA to “distinguish among classes, types, and sizes of sources within a category or subcategory in establishing such standards,” Section 129 does not have similar language. The commenter added that Section 129 shows that Congress considered which subcategories of incinerator it wanted, and that Congress created them itself. The commenter stated that by creating additional subcategories, EPA not only exceeds its statutory authority but defies Congress's plainly expressed intent that the only subcategories of incinerator would be those Congress expressly enumerated in Section 129(a)(1). The commenter added that EPA's failure to identify any statutory authority for its subcategories or to explain why it believes it has such authority is unreasonable and arbitrary.

Response:

CAA section 129(a)(2) states that “The Administrator may distinguish among classes, types (including mass-burn, refuse-derived fuel, modular and other types of units), and sizes of units within a category in establishing such standards.” We interpret this language as allowing us to develop subcategories for source categories being regulated. Further, the EPA has cited this statutory authority for other CAA section 129 subparts. The 1999 proposed CISWI rules clearly state “Categories may be divided into subcategories when differences (such as design, fuel, or waste type, etc.) between given types of units lead to corresponding differences in the technical feasibility of applying emission control techniques” (64 FR 67097, November 30, 1999) and the 1995 HMIWI standards state, “Section 129 states that the Administrator may distinguish among classes, types, and sizes of units within a category in establishing the standards and guidelines. In other words, EPA may subcategorize the MWI source category in establishing standards and guidelines” (65 FR 10669-70, February 27, 1995). Therefore, we are establishing subcategories for OSWI (IWI and VSMWC) as proposed based on size—including units that have capacities greater than 10 TPD and units that have capacities less than or equal to 10 TPD. Our decision to finalize subcategories for IWI and VSMWC OSWI is further discussed in section III.C and this section of this preamble.

Comment:

One commenter contended that the EPA does not have sufficient data on smaller units of less than or equal to 10 TPD to establish emission limits and other requirements. Consequently, the commenters stated that it is likely that requirements for larger units will be unnecessarily placed on smaller units. Another commenter explained that comparisons of emission

limits shown in the proposed rule to the emissions from the smaller units under than 3 TPD are well below the emissions for larger incinerators for a number of pollutants. The commenter specifically compared the particulate matter and cadmium emissions limits for new small OSWI units to the emission limits for SRIs under table 8 of the CISWI rule, noting that the emissions limits for new small OSWI units for these pollutants are below the corresponding CISWI limits, and other limits for these units, including hydrogen chloride and NO

, are very close to the SRI limits in the CISWI rule. Commenters added that the proposed rule subjects incinerators with capacity less than 3 ton per day to the same requirements even if the emission profiles do not seem to justify the requirements to perform enhanced control measures (such as wet scrubbers and baghouses). These commenters included additional concerns related to the requirements to install pollution controls such as wet scrubbers for SRIs in Alaska, which they countered would only burden small operations and small businesses. The commenters requested that EPA exempt small Alaska incinerators with an operational capacity of less than or equal to 3 TPD from the final rules. One commenter suggested that EPA create a third subcategory of units that have capacities less than or equal to 3 TPD and these units should be excluded if they incinerate greater than 30 percent MSW and are not regulated under the CISWI rule. Another commenter stated that if EPA is going to regulate units with capacities less than or equal to 3 TPD, it must collect additional information from the small incinerator manufacturers and establish MACT floor emission limits that are achievable.

Other commenters supported the regulation of small remote incineration units under the OSWI standard, acknowledging that the emission limits for small OSWI units developed in the 2020 Proposed Rule were developed specifically based on test data from the Alaskan SRI units, and in many cases, these units are unable to comply with the emission limits for existing units under CISWI. These commenters generally supported the creation of a subcategory for smaller OSWI units but requested additional modifications and clarifications to the subcategory. One commenter requested that EPA reconsider defining the subcategory for small OSWI units based on the “capacity” of units less than 10 tons of solid waste per day. The commenter pointed to the prior subcategory for SRI units promulgated under CISWI, which is for incineration units “that combust 3 tons or less of solid waste per day”. The commenter stated that it is unlikely that any SRI (as included in the proposed emission limits) has the physical capacity to burn 10 TPD, or that even any facility operating an SRI has the capacity to generate 10 TPD of waste for incineration. The commenter pointed to at least one SRI unit located at the ConocoPhillips Kuparuk facility that has a manufacturer-listed capacity of over 10 TPD, however, the commenter asserted that it does not reflect the actual or practical capacity to combust solid waste because the manufacturer-listed capacity includes the weight of the incinerated material, the weight of the fuel used for combustion, the weight of air combusted, and the weight of any moisture in the unit. The commenter added that, in that case, the manufacturer-listed “capacity” is not strictly limited to the capacity to incinerate solid waste and is greater than its capacity for waste. The commenter added that it is “pragmatically impossible” for the Kuparak unit to combust 10 tons of solid waste per day, and that this capacity could not be reached even if the incinerator usage was maximized to two consecutive 12-hour shifts; the commenter provided that on average, the unit burns about 1.25 TPD and has never exceeded 3 TPD despite the manufacturer's listed capacity. The commenter requested that EPA clarify that the 10 ton per day capacity language used to differentiate the small OSWI subcategory reflects a practical or operational “capacity” to incinerate waste and not a manufacturer listed capacity that may reflect non-waste fuel, air, and moisture. The commenter asked EPA to change the size threshold to reflect the amount of solid waste the unit combusts. The commenter added that defining the subcategory on the amount of solid waste combusted, as was done in the CISWI rule, is a better approach.

Response:

Regarding the comments that EPA should set the capacity for small OSWI units considering the capacity of SRI units currently regulated under CISWI, we disagree. As we described in the proposal, the EPA has sufficient data from several small remote incinerators from testing conducted in both 2010 and 2014 to calculate emission limits using the same statistical intervals used to calculate the CISWI SRI emission limits (see 85 FR 54185).

We collected test data from 29 units of this size and proposed calculated emissions limits at the level of the MACT floor which we have determined are representative for VSMWC and IWI units with capacities less than or equal to 10 TPD in the OSWI source category.

The emission limits applicable to these units already consider their size, since they are based on test data and design information gathered from units of similar size. For these reasons, we disagree with the request that the EPA categorically exempt or create a separate subcategory for small Alaska incinerators with an operational capacity of less than or equal to 3 TPD under the OSWI rules.

See Docket Item No. EPA-HQ-OAR-2003-0156-0138 and the memorandum entitled

Small Remote Incinerator (SRI) Emissions Data From CISWI

in the docket for this action for more discussion on data collected from small remote incinerators.

For more information about emission limit calculations, see

Emission Limit Calculations for Existing and New Sources for the Final Other Solid Waste Incinerator (OSWI) Rulemkaing,

available in the docket for this action (Docket ID No. EPA-HQ-OAR-2003-0156).

Regarding the comment asking that the EPA clarify that the 10 ton per day “capacity” language reflects a practical or operational “capacity” to incinerate solid waste, not a manufacturer listed capacity, we generally disagree with the comment and believe the rules are clear as written. When determining a unit's capacity in the context of the OSWI rules, the owner or operator must use the “design capacity” of the unit calculated using the equations in the regulations. (See 40 CFR 60.2975) The “capacity” of continuous and batch

VSMWC units is defined in the rules—this contrasts with emissions-based thresholds

e.g.,

for prevention of significant deterioration (PSD) applicability which considers enforceable physical or operational constraints. While the OSWI rules sometimes refer to the “maximum design waste burning capacity” (see,

e.g.,

40 CFR 60.2953 and table 4), this phrase is also intended to describe the design “capacity” of OSWI units, with respect to the maximum design amount of municipal solid waste or refused-derived fuel that may be charged (not including air or moisture content or non-waste fuels). We believe the design capacity is the most appropriate basis for subcategorization under OSWI. Any other basis, such as operational load,

would likely be variable depending on operating conditions and could therefore result in confusion about which standards are applicable to the unit at which time. For this reason, the commenter's suggestion that the subcategories be based on practical capacity to incinerate waste is not feasible. Using design capacity,

e.g.,

is consistent with the requirements in 40 CFR, part 60, subpart AAAA, 40 CFR 60.1460(d) and (e), which cover small municipal waste combustion units. We recognize that in two situations, for exempting small municipal waste combustion units that combust less than 11 TPD and for certain co-fired combustors with a fuel limitation, 40 CFR part 60, subpart AAAA allows federally enforceable permitting limits. We created the OSWI subcategories for VSMWC and IWI units with capacities less than or equal to 10 TPD due to differences in operation (

e.g.,

batch versus continuous/semi-continuous feed), equipment complexity and whether emissions that are routed to a stack or flue could be routed to air pollution control devices for these units. Additional discussion on the final subcategories are in section III.C. of this preamble and in the preamble to the proposed rule (85 FR 54183). An OSWI unit with a capacity greater than 10 TPD may not comply with emission limits and compliance requirements for units with capacities less than or equal to 10 TPD, and consequently, the final rule does not provide for consideration of operational restrictions on the “capacity” of OSWI units to avoid compliance requirements designed for such units. As such, commenters are also incorrect that the rule subjects OSWI units with capacities less than or equal to 10 TPD to the same requirements for enhanced control measures (

i.e.,

wet scrubbers and baghouses) to meet emissions limits as those required for large units. In our analysis of the MACT floor for VSMWC and IWI units with capacities less than or equal to 10 TPD, we used data obtained from operating units with capacities less than or equal to 10 TPD and have assumed that additional units in these subcategories, should they exist, would be similar in design, uncontrolled, and burn similar MSW-type waste as those units reflected in the SRI dataset. Based on the data, we believe that any VSMWC and IWI units with capacities less than or equal to 10 TPD would not require additional controls to meet the proposed standards that are being finalized. We add that for the final rule we have also revised the applicability of the final OSWI standards to address issues and concerns raised for certain units with capacities less than or equal to 10 TPD that may be considered rudimentary combustion devices, as explained in sections III.B and IV.A of this preamble.

Comment:

A commenter stated that EPA's decision to subcategorize OSWI units greatly weakens the standards for the newly created small OSWI subcategory, contravenes CAA section 129's floor provisions, and is arbitrary. The commenter stated that some of or all these units—certainly the best performing ones, those with the lowest emissions—have already been meeting the EPA's existing standards consistently for years. The commenter added that the average emission level achieved by these units therefore cannot possibly be worse than the existing CISWI standards. The commenter concluded that the floors cannot be worse than the existing standards.

Response:

We explained in the preamble to the proposed rule that the prior floors were not based on OSWI units but on HMIWI units (85 FR 54183) and the SRI emissions test data used to calculate the emission limits for the VSMWC and IWI with capacities less than or equal to 10 TPD subcategories are more representative of and better reflect the emissions achievable for new and existing units in each category required under CAA sections 129(a)(2) and (4). The standards are based on the level of the MACT floor calculated using the SRI emission data but are not identical to the CISWI standards because updated data and procedures were used in the OSWI calculation.

While the EPA does not update MACT floors to be less stringent than existing limits for the same subcategory based on the 5-year review process, the emission limits for the VSMWC and IWI with capacities less than or equal to 10 TPD represent newly established subcategories. It is not appropriate to compare the stringency of standards between rules or subcategories. This means that neither the current CISWI standards nor the OSWI standards for units with capacities greater than 10 TPD are appropriate points of comparison for the new MACT floors.

For more information on the SRI data, see Document ID No. EPA-HQ-OAR-2003-0156-0138. For more information about the MACT floor calculation, see the memorandum

Emission Limit Calculations for Existing and New Sources for the Final Other Solid Waste Incinerator (OSWI) Rulemaking

available in the docket for this action (Docket ID No. EPA-HQ-OAR-2003-0156).

C. What key comments did we receive on other amendments, and what are our responses?

1. Testing and Compliance

Comment:

We received one comment related to the proposed 12-month deadline for annual compliance tests. The commenters stated the proposed 12-month deadline at 40 CFR 60.2933 and 40 CFR 60.3034 creates potential compliance problems over time for SRI operators in Alaska. The commenters explained that testing on SRI units is more difficult than on typical units, and the window for testing SRI units is constrained by weather and may be impracticable during the long North Slope winter season. The commenters stated the proposed 12-month window creates issues of compliance date “creep” when operators seeking to submit data reasonably in advance of the EPA deadlines (

e.g.,

one week early to ensure timely delivery), inadvertently and progressively push the testing deadline earlier and earlier into the calendar year, potentially into problematic testing periods for SRI units. The commenters requested that the EPA set the annual compliance testing deadline at 14 months, to allow operators flexibility to keep testing in optimal weather windows over time. The commenters added that this is consistent with the EPA practice for other rules and referenced 40 CFR 60.4415(a).

Response:

We agree with the commenters' assertions that, for some OSWI units, seasonal weather issues may not allow testing within exact 12-month intervals. To address this concern, the final rule requires that annual performance tests be conducted no later than 14 months following the initial performance test and subsequent annual performance tests must be conducted within 14 months following the previous performance test.

Comment:

We received two comments supporting the proposed alternative means to demonstrate compliance for VSMWC and IWI units with capacities less than or equal to 10 TPD, but the commenters contested that the proposed parameters (plus or minus 15 percent and on a weekly basis) are too narrowly constrained. The commenters explained that MSW mass generated by camp operations has the potential of being highly variable by the nature of its span of contents including paper, wood, yard wastes, food wastes, plastics, leather, rubber, and other combustible materials. The commenters stated that managing mass may be technically difficult for batch incinerators, as finite chamber volume limits mass manipulation. The

commenters further stated that managing mass also could be affected by short-duration projects that could cause food waste and other combustible materials to flux at sites using continuous, intermittent, or batch incinerators or where the incinerator is operated infrequently (

e.g.,

an incinerator operated only bi-weekly). The commenters provided two examples of occasions when the weight ratio of incinerated waste can be temporarily skewed. One example the commenters provided is during facility “turnaround” periods when all meals are eaten on disposable trays that have a very low weight-to-volume ratio, which can temporarily skew the weight ratio of incineration units. The commenters explained that some operators typically burn wooden pallets at the bottom of their incinerators to facilitate the most efficient operation of the unit, and that during turnaround where there is a high volume of disposal trays, the weight of the pallets overshadows the light-weight disposable trays, likely skewing the solid waste composition outside the plus or minus 15 percent composition by weight requirement on a weekly basis. Commenters also provided a second example: an occasion when the weight ratio can be temporarily skewed during carcass incineration, which is required on occasion by state permits to dispose of an animal carcass to prevent health and safety concerns. The commenters explained that disposal of a caribou carcass that can average 350 to 400 pounds can also skew the weight ratio in the short term. The commenters suggested setting the plus or minus 15 percent weight requirement on a calendar-quarterly, rather than weekly, basis. The commenters pointed to CISWI as an example where tracking and averaging waste streams is accounted for on a calendar-quarter basis and requested that the EPA continue this approach. Although the commenters generally preferred this suggested approach, the commenters also suggested an alternative of setting the weekly obligation at plus or minus 30 percent rather than plus or minus 15 percent. The commenters also suggested the rule should include language that prevents units that are operated only seasonally from triggering the deviation and testing upon restarting after a period of being down.

One commenter requested that the previously submitted data for SRI units in Alaska can and should be used to demonstrate initial compliance or used as representative testing results for inclusion in the WebFIRE database.

Response:

We are finalizing, as proposed, an option for using a “representative” initial compliance demonstration. We disagree with the commenters that 15 percent variability is insufficient or too narrowly constrained. The waste profile variability for a VSMWC or IWI unit with capacity less than or equal to 10 TPD will be based on the waste profile used in the unit's initial compliance test, or, for owners and operators who use the SMCD demonstrating initial compliance, the waste profile used in the chosen representative test. VSMWC and IWI units with capacities less than or equal to 10 TPD that have highly variable waste streams will account for that variability in their initial compliance tests or, if the owner or operator is using the SMCD demonstrating initial compliance, by choosing a representative test with a similarly variable waste stream. Based on information currently available, the EPA anticipates that allowing greater than 15 percent variability in a waste stream after a unit's initial compliance demonstration would not provide a sufficient means of demonstrating compliance on a continuous basis because it would not be representative of the conditions established during the compliance test. As such, it would not be possible to provide assurance that the unit continuously complies with the emission standards. Provided the facility has conducted or selected a representative performance test, the facility should be able to demonstrate compliance by assuring that the wastes combusted do not exceed 15 percent variability.

However, we also acknowledge that some OSWI units may be needed to dispose of unexpected and unplanned animal carcasses in remote areas. In such cases, the carcasses would skew the waste profile. To address this concern, we have revised the final rule to allow the percentage of waste burned for each waste category to be calculated on a quarterly average instead of weekly average.

We encourage owners and operators who elect to use the SMCD to identify their waste variability and waste characterization data as soon as possible so that representative waste profiles are tested in a timely manner. Owners and operators of VSMWC or IWI units with capacities less than or equal to 10 TPD who have not previously submitted testing data meeting the requirements of the rule in the development of the final standards will have to submit detailed information about their units and identify a representative performance test in the EPA's WebFIRE database. As noted in the preamble to the proposed rule (85 FR 54190), the representative performance tests must have been conducted according to the requirements in the OSWI rule, demonstrate compliance with the OSWI standards, and include the following information in the report: unit design (including air pollution control devices), charge rate during the test, type of operation, combustion temperature during the test, types of waste burned during the test and the relative amount of each waste to the total waste burned, type and amount of supplemental fuels used during the test, and, if the tested unit has an air pollution control device, the operating parameter data for the control device during the test. We understand that the units the commenters are referring to have conducted prior tests. However, if a test in question does not include all of the information needed to meet the requirements for the representative performance test in the rule, that test cannot be used as a representative performance tests for other OSWI units and will not be made available in WebFIRE. However, the owners or operators of these units can contact the Administrator under the General Provisions (see 40 CFR 60.8), to determine whether the prior tests conducted on the unit are acceptable to demonstrate compliance with requirements of the OSWI rule.

2. Recordkeeping and Reporting

Comment:

Commenters stated that the requirements at 40 CFR 60.2956(j) and 40 CFR 60.3051(j) to report the start date, start time, and duration in hours for each period when all qualified OSWI unit operators were unavailable for more than 12 hours, but less than 2 weeks, appear to contemplate that an OSWI unit is under continuous operation. The commenters further stated that is not the case for many SRI units and stated that some SRI units are operated only seasonally, while other units may be shut down for days or weeks at a time for maintenance or other reasons. The commenters added that during those non-operational times, there may not be a qualified OSWI unit operator available onsite. To avoid unnecessary reporting, the commenters request that the reporting requirement be modified to require reporting for each period “of operation” when all qualified OSWI unit operators were unavailable.

Response:

We agree with commenters that the reporting requirements for qualified OSWI unit operators were intended to apply for periods of active operation, and it was not our intent to require additional reporting for non-

operational periods. We are revising the proposed requirements at 40 CFR 60.2956(j) and 40 CFR 60.3051(j) to clarify that facilities must report the start date, start time, and duration in hours for each period of operation when all qualified OSWI unit operators were unavailable for more than 12 hours but less than 2 weeks.

D. What key comments did we receive on effective and compliance dates?

Comment:

Commenters requested EPA clarify the applicability timeline for existing SRI units at 40 CFR 60.2886(a)(5). The commenters stated that the language as written appears to treat all existing SRI units (those constructed prior to August 31, 2020) as new units, subject to the OSWI NSPS, until a state or Federal plan is implemented for existing units, in which case these SRI units become existing units again. Specifically, commenters stated that the effective and compliance dates of the proposed NSPS and EG are unclear and present a conflict related to the definition of new units. The commenters stated that the proposed OSWI rule at 40 CFR 60.2886(a)(3) establishes that small OSWI units that commenced construction after August 31, 2020 are new units, but at section 60.2886(a)(5), says that small OSWI units that “commenced construction . . . prior to August 31, 2020 . . . are considered new incineration units.” The commenters stated that this conflicting language could be interpreted as treating certain VSMWC and IWI units with capacities less than or equal to 10 TPD that are currently in operation as new units because they were constructed prior to August 31, 2020. The commenters noted that the proposed language is inconsistent with the proposed transition provision in 40 CFR part 60, subpart EEEE, which recognizes that under the existing rules, OSWIs that commenced construction on or before December 9, 2004 are considered existing OSWIs (see proposed 40 CFR 60.2992(b)). The commenters indicated that the intent, based on the preamble for the proposed rule, is that a unit that is currently subject to the new source OSWI standard or other incinerator standard, continue to comply with that standard until it becomes subject to an approved state or Federal plan under 40 CFR part 60, subpart FFFF. However, the commenter stated that as drafted, this provision would force a unit that is currently classified as an existing OSWI to comply with the new source standard during th

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