The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2026-2289; Project Identifier MCAI-2025-01592-T” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments.

Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Joseph Catanzaro, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7300; email: 9-avs-nyaco-cos@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Transport Canada, which is the aviation authority for Canada, has issued Transport Canada AD CF-2025-49, dated October 1, 2025 (Transport Canada AD CF-2025-49) (also referred to as the MCAI), to correct an unsafe condition for certain Bombardier, Inc., Model BD-700-2A12 airplanes. The MCAI states there have been reports of low clearance in the right wing between the fuel line flexible coupling and the harness support bracket clip-nut located in bay 3, between the fuel line flexible coupling and hydraulic system 3 line located in bay 18, and between the hydraulic system 3 lines and fuel vent tube located in bay 20. These low clearance conditions, if not addressed, may result in an ignition source developing in the fuel tank in the event of a lightning strike.

The FAA is proposing this AD to address the unsafe condition on these products.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-2289.

Transport Canada AD CF-2025-49 specifies procedures for rectifying the low clearance condition between the fuel line flexible coupling and the harness support bracket clip-nut located in bay 3 of the right wing by replacing the clip-nut on the harness bracket in the right-hand wing between rib 3 and rib 4, rectifying the low clearance condition between the fuel line flexible coupling and the hydraulic system 3 line located in bay 18 of the right wing by replacing fuel tube assemblies in the right-hand wing between rib 17 and rib 20, doing an inspection for adequate clearance between the hydraulic system 3 lines and the fuel vent tube located in bay 20 of the right wing, and applicable on-conditions actions. On-condition actions include rectifying any low clearance condition found ( i.e., replace the hydraulic system support brackets in the right-hand wing between rib 19 and rib 21). This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop in other products of the same type design.

This proposed AD would require accomplishing the actions specified in Transport Canada AD CF-2025-49 described previously, except for any differences identified as exceptions in the regulatory text of this proposed AD.

In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate Transport Canada AD CF-2025-49 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with Transport Canada AD CF-2025-49 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Material required by Transport Canada AD CF-2025-49 for compliance will be available at regulations.gov under Docket No. FAA-2026-2289 after the FAA final rule is published.

The FAA estimates that this AD, if adopted as proposed, would affect 60 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

The FAA estimates the following costs to do any necessary on-condition action that would be required based on the results of any required actions. The FAA has no way of determining the number of aircraft that might need this on-condition action:

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some or all of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify this proposed regulation:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Under section 721(d)(1) of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 379e(d)(1)), we are giving notice that we have filed a color additive petition (CAP 6C0341), submitted by Ecoflora Cares, c/o Exponent, Inc., 1150 Connecticut Avenue NW, Suite 1100, Washington, DC 20036. The petition proposes that we amend our color additive regulations in § 73.225 (21 CFR 73.225) ( Listing of Color Additives Exempt from Certification ) to provide for the safe use of jagua (genipin-glycine) blue as a color additive in pet foods at levels consistent with good manufacturing practice.

The petitioner claims that this action is categorically excluded under 21 CFR 25.32(k) because the substance is intended to remain in food through ingestion by pet consumers and is not intended to replace macronutrients in food. In addition, the petitioner states that, to their knowledge, no extraordinary circumstances exist. If FDA determines a categorical exclusion applies, neither an environmental assessment nor an environmental impact statement is required. If FDA determines a categorical exclusion does not apply, we will request an environmental assessment and make it available for public inspection.

Under section 409(b)(5) of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 348(b)(5)), we are giving notice that we have filed a food additive petition (FAP 2325), submitted by Kemin Industries, Inc, 1900 Scott Avenue, Des Moines, IA 50317. The petition proposes to amend in 21 CFR part 573—Food Additives Permitted in Feed and Drinking Water of Animals, to provide for the safe use of chromium propionate to be used as a source of chromium in food for layer and breeding chickens.

We are reviewing the potential environmental impact of this petition. To encourage public participation consistent with regulations issued under the National Environmental Policy Act (40 CFR 1501.4(b)), we are placing the environmental assessment submitted with the petition that is the subject of this notice on public display at the Dockets Management Staff (see DATES and ADDRESSES ) for public review and comment.

We will also place on public display, at the Dockets Management Staff and at https://www.regulations.gov, any amendments to, or comments on, the petitioner's environmental assessment without further announcement in the Federal Register . If, based on our review, we find that an environmental impact statement is not required, and this petition results in a regulation, we will publish the notice of availability of our finding of no significant impact and the evidence supporting that finding with the regulation in the Federal Register in accordance with 21 CFR 25.51(b).

In accordance with 5 U.S.C. 552, 1 Commission regulations describe, among other things, the agency's central organization, as well as “the general course and method by which its functions are channeled and determined, including the nature and requirements of all formal and informal procedures available.” See 39 CFR part 3000; see also 5 U.S.C. 552(a)(1)(A) and (B). Thus, revisions to agency regulations are necessary when an agency's structure or its organizational functions are modified internally or when other statutory changes are enacted that require revisions to agency regulations.

In addition, the Commission seeks to end its codification of both the Market Dominant and Competitive product lists. These product lists currently appear at 39 CFR part 3040, Appendix A and B to subpart A. However, Postal Accountability and Enhancement Act (PAEA), 2 does not require the codification of the product lists in the CFR, it only requires publication of the product lists in the Federal Register when the Commission revises those lists. The Commission also proposes revisions to the product list regulations that better reflect the Commission's process related to these updates.

The proposed rules reflect the creation of the new Office of Budget and Finance (OBF), which was created to better align with federal agency best practices in organizing finance budget operations, including having a more appropriate separation of agency functions. In addition, to better reflect that certain filings are directed by and performed on behalf of the Commission or the Chairman, the Commission proposes to replace “the Secretary” with “the Commission” or “the Chairman” in discrete proposed rule amendments.

Moreover, consistent with statutory updates, the proposal revises Commission regulations regarding the Office of Inspector General (OIG). The PSRA eliminated the requirement of a separate Commission OIG and effectively merged the legacy Commission OIG with the Postal Service OIG. 3 Accordingly, these proposed regulatory changes conform Commission rules to the updated statutory framework.

The PRA required the establishment of an MCS. 4 In Docket No. RM85-1, the Commission codified the MCS in 39 CFR part 3001, Appendix A to Subpart C to make the MCS more readily available to interested persons. 5 However, no provision of the PRA required codification of the MCS as part of the CFR. It was an effort by the Commission to make the MCS accessible at a time when information was not readily available on a Commission website or the internet in general. Later, the PAEA bifurcated all Postal Service products into separate categories labeled Market Dominant and Competitive, originally listed at 39 U.S.C. 3621 and 3631, respectively. The PAEA required the development of the product lists and Federal Register publication whenever the Commission changes either product list. See 39 U.S.C. 3642. The PAEA also does not require the codification of the product lists in the CFR. The only restrictions imposed are that the Notice of Product List Update must be published in the Federal Register , which must include: (1) the revised product list(s), and (2) how and when the previous list is superseded. See 39 U.S.C. 3642(d)(2).

However, currently, each notice includes three items: (1) the revised product list(s), which include amendatory language necessary to update the CFR, (2) an indication of how and when the previous list is superseded, and (3) lists of every product addition and/or removal. 6 Thus, each Commission notice is an unnecessary action that contains information not required by statute and costly to the Commission. First, the codification of each product list as an appendix to 39 CFR part 3040, subpart A is not required by statute. This agency-imposed regulation, stemming from the PRA-era, when access to information related to Postal Service offerings was sparse and unclear. Now, the Commission maintains an MCS on its website, which includes each product list and is easily accessible. Thus, codification of the product lists is unnecessary. Second, including a separate list of product additions and removals in each publication is duplicative, making publications longer, and thus more costly to the Commission. In recent years, Postal Service product changes have increased significantly, and burdensome publication costs and challenging resource burdens have only continued to impede product list updates. 7 To reduce these burdens that the excessive information generates, the Commission proposes to modify its Notice of Product List Update publication to include information that strictly adheres to the requirements of 39 U.S.C. 3642(d)(2).

Additionally, the Administrative Procedure Act, Public Law 79-404, 60 Stat. 237 (1946) (APA), requires certain agency documents be published in the Federal Register . 5 U.S.C. 553 and 554. Generally, documents submitted to the Federal Register must include information used to develop the action, detail agency choices and reasoning, cite to important data, identify the applicable legal authority and, in the case of rulemakings, include affected regulatory text. 8

For many years, a Commission's Federal Register submission and the Commission document prompting the Federal Register submission would match verbatim. However, Commission rulemaking proceedings can involve dense records and analysis, oftentimes containing in-depth discussion of all issues presented, even issues that may be outside the scope of that particular proceeding. Thus, Commission Orders often have information above and beyond the information required by the Federal Register .

Therefore, the Commission is updating applicable regulations that clarify documents sent to the Federal Register may be summarized at the Commission's discretion, in compliance with all Federal Register requirements.

For the reasons stated in the preamble, the Commission proposes to amend 39 CFR chapter III as set forth below:

(a) The rules in this part require the Commission to establish and maintain a Mail Classification Schedule.

(b) The Mail Classification Schedule shall provide lists of Postal Service products, as well as current price and classification information applicable to the products appearing on the market dominant and competitive product lists.

(c) Once established the Mail Classification Schedule and the product lists may be modified subject to the procedures specified in this part.

(d) Modification of the competitive product list to add a competitive negotiated service agreement is not governed by this part but is governed by part 3041 of this chapter. The rules in part 3041 of this chapter regarding removal of a negotiated service agreement from the competitive product list supersede any conflicting rules in this part.

The addition and revisions read as follows:

Throughout this document, “we,” “us,” and “our” refer to the EPA.

Under section 109 of the CAA, the EPA has established primary and secondary NAAQS for certain pervasive air pollutants (referred to as “criteria pollutants”) and conducts periodic reviews of the NAAQS to determine whether they should be revised or whether new NAAQS should be established. The primary NAAQS represent ambient air quality standards the attainment and maintenance of which the EPA has determined are requisite to protect public health with an adequate margin of safety. The secondary NAAQS represent ambient air quality standards the attainment and maintenance of which the EPA has determined are requisite to protect public welfare from any known or anticipated adverse effects associated with the presence of such an air pollutant in the ambient air.

Under the CAA, the EPA must establish NAAQS for criteria pollutants, including SO 2 . SO 2 is released to the atmosphere primarily through the burning of fossil fuels by power generation and certain industrial processes. Short-term exposure to SO 2 can damage the human respiratory system and increase breathing difficulties. Small children and people with respiratory conditions, such as asthma, are more sensitive to the effects of SO 2 . Sulfur oxides at high concentrations in ambient air can also react with compounds to form small particulates (fine particulate matter) that can penetrate deeply into the lungs and cause health problems.

The EPA first established primary SO 2 standards in 1971. 1 The short-term (24-hour) standard of 0.140 parts per million (ppm) was not to be exceeded more than once per calendar year. The long-term standard specifies an annual arithmetic mean not to exceed 0.030 ppm. The level of the secondary SO 2 NAAQS is 0.5 ppm over a 3-hour averaging period (not to be exceeded more than once per year). 2

On March 3, 1978, for lack of a state recommendation, the EPA designated Pinal County as a primary SO 2 nonattainment area based on monitored violations of the primary SO 2 NAAQS in the county between 1975 and 1977. 3 At the request of the Arizona Department of Environmental Quality (ADEQ), the nonattainment area was subsequently reduced to nine townships in and around Hayden, Arizona. 4

On the date of enactment of the 1990 CAA Amendments, SO 2 areas meeting the conditions of section 107(d) of the Act were designated nonattainment for the SO 2 NAAQS by operation of law. Section 107(d) of the CAA describes the processes by which nonattainment areas are designated, including the pre-existing SO 2 nonattainment areas. Thus, the Hayden area remained nonattainment for the primary SO 2 NAAQS following enactment of the 1990 CAA Amendments on November 15, 1990.

On June 22, 2010, the EPA promulgated a new 1-hour primary SO 2 NAAQS of 75 parts per billion (ppb). 5 This standard is met at an ambient air quality monitoring site when the 3-year average of the annual 99th percentile of daily maximum 1-hour average concentrations does not exceed 75 ppb, as determined in accordance with Appendix T of 40 CFR part 50. 6 The EPA provided that the 24-hour and annual standards established in 1971 were to remain in place for those areas designated nonattainment for the 2010 SO 2 NAAQS until such time that the state submits, and the EPA approves, an implementation plan providing for attainment of the 2010 SO 2 NAAQS. 7

Under CAA section 107(d)(1), the EPA is required to designate areas as “nonattainment,” “attainment,” or “unclassifiable” within two years of establishing a new standard or revising an existing standard. The Hayden nonattainment area for the 2010 SO 2 NAAQS was established effective October 4, 2013. 8 The dominant source of SO 2 emissions in the Hayden SO 2 nonattainment area is the Hayden copper smelter (“Hayden Smelter” or “Smelter”), owned and operated by ASARCO LLC (“Asarco”). 9 This final area designation triggered a requirement for Arizona to submit by April 4, 2015 (within 18 months per CAA section 191(a)), a SIP revision with an attainment plan for how the Hayden SO 2 nonattainment area would attain the 2010 SO 2 NAAQS as expeditiously as practicable, but no later than October 4, 2018, per CAA section 192(a) in accordance with CAA sections 110(a), 172(c), 191, and 192.

As required by CAA section 110(k)(1)(B), the EPA published a final rule on March 18, 2016, finding that Arizona had failed to submit the required SO 2 nonattainment area plan by the submittal deadline. 10 This finding initiated a deadline under CAA section 179(a) for the potential imposition of new source and highway funding sanctions. Additionally, under CAA section 110(c), the finding triggered a requirement that the EPA promulgate a Federal implementation plan (FIP) within two years of the effective date of the finding unless by that time the State had made the necessary complete submittal and the EPA had approved the submittal as meeting applicable requirements.

In response to the requirement for SO 2 nonattainment area plan submittals, ADEQ submitted a SIP revision on March 9, 2017, titled “Arizona State Implementation Plan Revision: Hayden Sulfur Dioxide Nonattainment Area for the 2010 SO 2 NAAQS” (“2017 Hayden SO 2 Plan”). The emission limits that were intended to provide for attainment of the 2010 SO 2 NAAQS for the Hayden area were codified in the Arizona Administrative Code (AAC), Title 18, Chapter 2, Article 13, section R18-2-B1302 (“Limits on SO 2 Emissions from the Hayden Smelter”) (“Rule B1302”). ADEQ submitted Rule B1302 to the EPA on April 6, 2017. 11 The EPA issued letters dated July 17, 2017, and September 26, 2017, finding the submittals complete and stopping the sanctions clocks under CAA section 179(a). 12

On November 5, 2020, the EPA finalized a limited approval and limited disapproval of Arizona Rule B1302, 13 and on November 10, 2020, the EPA finalized a partial approval and partial disapproval of the 2017 Hayden SO 2 Plan. 14 The EPA finalized a limited disapproval of Rule B1302 because we found that some of the rule provisions conflicted with the requirements of CAA sections 110 and 172(c)(6), including that the rule did not contain any numeric emissions limit(s) or ongoing monitoring requirements corresponding to the levels of fugitive emissions that were modeled in the 2017 Hayden SO 2 Plan. 15 The EPA finalized a partial disapproval of the 2017 Hayden SO 2 Plan because we found that the plan did not meet the attainment demonstration, RACM/RACT, enforceable emission limitations, RFP, and contingency measure requirements of the CAA for the 2010 SO 2 NAAQS. 16 The final limited disapproval of Rule B1302 and partial disapproval of the 2017 Hayden SO 2 Plan became effective on December 7, 2020, and December 10, 2020, respectively, and initiated deadlines under CAA section 179(a) for the imposition of new source review offset and highway funding sanctions unless the State had made the necessary complete submittal and the EPA approved the submittal as meeting applicable requirements prior to those deadlines. 17

On January 31, 2022, the EPA determined that the Hayden SO 2 nonattainment area failed to attain the 2010 1-hour primary SO 2 NAAQS by the October 4, 2018 applicable attainment date, which triggered a requirement under CAA section 179(d) for Arizona to submit a revised SIP by January 31, 2023, that provides for expeditious attainment of the 2010 SO 2 NAAQS in the Hayden SO 2 nonattainment area by January 31, 2027. 18

The remainder of this document describes the requirements that nonattainment area plans must meet to obtain EPA approval, provides a review of the Hayden SO 2 Plan with respect to these requirements, and describes the EPA's proposed action on the Plan.

Nonattainment area SO 2 SIPs must meet the applicable requirements of the CAA, specifically CAA sections 110, 172, 191, and 192. The EPA's regulations governing nonattainment area SIP submissions are set forth at 40 CFR part 51, with specific procedural requirements and control strategy requirements residing at subparts F and G, respectively. Soon after Congress enacted the 1990 amendments to the CAA, the EPA issued comprehensive guidance on SIP revisions in the “General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990” (“General Preamble”). 19 Among other things, the General Preamble addressed SO 2 SIP submissions and fundamental principles for SIP control strategies. 20 On April 23, 2014, the EPA issued guidance and recommendations for meeting the statutory requirements in SO 2 SIP submissions, in a document titled, “Guidance for 1-Hour SO 2 Nonattainment Area SIP Submissions” (“2014 SO 2 Guidance”). 21 In the 2014 SO 2 Guidance, the EPA described the statutory requirements for the elements of a nonattainment area plan as listed at CAA section 172(c), which include an accurate emissions inventory of current emissions for all sources of SO 2 within the nonattainment area; an attainment demonstration; a demonstration of RFP; implementation of RACM (including RACT); emission limitations and control measures necessary to provide for attainment; nonattainment NSR; and adequate contingency measures. This guidance supplements the EPA's 1994 “SO 2 Guideline Document,” which remains applicable unless specifically altered by the 2014 SO 2 Guidance. 22

In general, the EPA's duties in reviewing state attainment plans are described in CAA sections 110(k) and 110(l). The EPA is first required to determine whether a SIP submission meets certain minimum criteria for completeness. Once a SIP submission has been determined to be complete, the EPA is required to approve the submission, as a whole, if it meets all applicable requirements of the CAA. State attainment plans are approved by the EPA as meeting the minimum requirements of the CAA if they fully address the requirements of CAA sections 110, 172, 191, and 192, and the EPA's regulations at 40 CFR part 51.

Also, under CAA section 110(l), the EPA may not approve a SIP revision that would interfere with any applicable requirement concerning NAAQS attainment and RFP, or any other applicable requirement. Further, under CAA section 193, no control requirement in effect before November 15, 1990 (or required to be adopted by an order, settlement, agreement, or plan in effect before November 15, 1990), in any area that is a nonattainment area for any air pollutant, may be modified in any manner unless the modification insures equivalent or greater emission reductions of such air pollutant.

CAA sections 172(c)(1) and 172(c)(6) direct states with areas designated as nonattainment to demonstrate that the submitted plan and its emissions limitations and control measures provide for attainment of the NAAQS. The EPA's regulations at 40 CFR part 51, subpart G further delineate the control strategy requirements that plans must meet, and that all SIPs and control strategies reflect the four fundamental principles of quantification, enforceability, replicability, and accountability. 23 SO 2 nonattainment area plans must consist of two components: (1) enforceable emission limits and other control measures that assure implementation of permanent, enforceable, and necessary emission controls, and (2) a modeling analysis that meets the requirements of 40 CFR part 51, appendix W and demonstrates that these emission limits and control measures provide for timely attainment of the primary SO 2 NAAQS as expeditiously as practicable, but by no later than the attainment date for the affected area. In all cases, the emission limits and control measures must be accompanied by appropriate methods and conditions to determine compliance with the respective emission limits and control measures and must be quantifiable ( i.e., a specific amount of emission reduction can be ascribed to the measures), fully enforceable ( i.e., specifying clear, unambiguous, and measurable requirements for which compliance can be practicably determined), replicable ( i.e., the procedures for determining compliance are sufficiently specific and non-subjective so that two independent entities applying the procedures would obtain the same result), and accountable ( i.e., source specific limits must be permanent and must reflect the assumptions used in the plan demonstrations).

The EPA's 2014 SO 2 Guidance recommends that the emission limits established for an attainment demonstration be expressed as short-term average limits ( e.g., addressing emissions averaged over one hour consistent with the averaging time of the 1-hour SO 2 NAAQS), but also describes the option to utilize emission limits with longer averaging times of up to 30 days so long as the limit is demonstrated by the state to assure comparable stringency to a 1-hour average limit that demonstrates attainment of the 1-hour SO 2 NAAQS. The 2014 SO 2 Guidance includes suggested criteria and procedures for making this demonstration. 24 The 2014 SO 2 Guidance recommends that, should states and sources utilize longer averaging times, the longer-term average limit should be set at an adjusted level that reflects a stringency comparable to the 1-hour average limit at the critical emission value shown to provide for attainment.

The 2014 SO 2 Guidance provides an extensive discussion of the EPA's rationale for concluding that appropriately set, comparable stringent limitations based on averaging times as long as 30 days can be found to provide for attainment of the 2010 SO 2 NAAQS. In evaluating this option, the EPA considered the nature of the standard, conducted detailed analyses of the effect of 30-day average limits on the prospects for attaining the standard, and carefully reviewed how best to achieve an appropriate balance among the various factors that warrant consideration in judging whether a state's plan provides for attainment. 25

As specified in 40 CFR 50.17(b), the 1-hour primary SO 2 NAAQS is met at an ambient air quality monitoring site when the 3-year average of the annual 99th percentile of daily maximum 1-hour average concentrations is less than or equal to 75 ppb. In a year with 365 days of valid monitoring data, the 99th percentile would be the fourth highest daily maximum 1-hour value. Because the standard has this form, a single hourly exceedance of the 75 ppb NAAQS level does not by itself result in a violation of the standard. Instead, at issue is whether a source operating in compliance with a properly set longer-term average could cause multiple hourly exceedances over multiple days in a year, and if so, the resulting frequency and magnitude of such exceedances, and in particular, whether the EPA can have reasonable confidence that a properly set longer-term average limit will provide that the 3-year average of annual fourth highest daily maximum hourly values will be at or below 75 ppb. A synopsis of how the EPA evaluates whether such plans “provide for attainment,” based on modeling of projected allowable emissions and in light of the form of the SO 2 NAAQS for determining attainment at monitoring sites, follows.

For SO 2 attainment plans based on 1-hour emission limits, the standard approach is to conduct modeling using fixed 1-hour emission rates. The maximum modeled emission rate that results in attainment is labeled the “critical emission value” (CEV). The modeling process for identifying this CEV inherently considers the numerous variables that affect ambient concentrations of SO 2 , such as meteorological data, background concentrations, and topography. In the standard approach, the state would then provide for attainment by setting a continuously applicable 1-hour emission limit for each stationary SO 2 source at this CEV.

The EPA recognizes that some SO 2 sources have highly variable emissions, for example due to variations in fuel sulfur content and operating rate, that can make it extremely difficult, even with a well-designed control strategy, to ensure in practice that emissions for any given hour do not exceed the CEV. The EPA also acknowledges the concern that longer-term emission limits can allow short periods with emissions above the CEV, which, if coincident with meteorological conditions conducive to high SO 2 concentrations, could in turn create the possibility of an hourly NAAQS exceedance occurring on a day when an exceedance would not have occurred if emissions were continuously controlled at the level corresponding to the CEV. However, for several reasons, the EPA believes that the approach recommended in its guidance document suitably addresses this concern.

First, from a practical perspective, the EPA expects the actual emission profile of a source subject to an appropriately set longer-term average limit to be similar to the emission profile of a source subject to an analogous 1-hour average limit. The EPA expects this similarity because it has recommended that the longer-term average limit be set at a level that is comparably stringent to the otherwise applicable 1-hour limit (reflecting a downward adjustment from the CEV) and that takes the source's emissions profile (and inherent level of emissions variability) into account. As a result, the EPA expects either form of emission limit to yield comparable air quality.

Second, from a more theoretical perspective, the EPA has compared the likely air quality with a source having maximum allowable emissions under an appropriately set longer-term limit, to the likely air quality with the source having maximum allowable emissions under the comparable 1-hour limit. In this comparison, in the 1-hour average limit scenario, the source is presumed at all times to emit at the CEV, and in the longer-term average limit scenario, the source is presumed occasionally to emit more than the CEV, but on average, and presumably at most times, to emit well below the CEV. In an “average year,”  26 compliance with the 1-hour limit is expected to result in three exceedance days ( i.e., three days with maximum hourly values above 75 ppb) and a fourth day with a maximum hourly value at 75 ppb. By comparison, with the source complying with a longer-term limit, it is possible that additional hourly exceedances would occur that would not occur in the 1-hour limit scenario (if emissions exceed the CEV at times when meteorology is conducive to poor air quality). However, this comparison must also factor in the likelihood that exceedances that would be expected in the 1-hour limit scenario would not occur in the longer-term limit scenario. This result arises because the longer-term limit requires lower emissions most of the time (because the limit is set below the CEV), so a source complying with an appropriately set longer-term limit is likely to have lower emissions at critical times than would be the case if the source were emitting as allowed with a 1-hour limit.

To illustrate this point, the EPA conducted a statistical analysis using a range of scenarios using actual plant data. This analysis is described in Appendix B of the EPA's 2014 SO 2 Guidance. Based on the analysis described in the 2014 SO 2 Guidance, the EPA expects that an emission profile with maximum allowable emissions under an appropriately set, comparably stringent 30-day average limit is likely to have the net effect of having a lower number of hourly exceedances and better air quality than an emission profile with maximum allowable emissions under a 1-hour emission limit at the CEV. This result provides a compelling policy rationale for allowing the use of a longer averaging period, in appropriate circumstances where the facts indicate this result can be expected to occur.

The 2014 SO 2 Guidance offers specific recommendations for determining an appropriate longer-term average limit. The recommended method starts with determination of the 1-hour emission limit that would provide for attainment ( i.e., the CEV), and applies an adjustment factor to determine the (lower) level of the longer-term average emission limit that would be estimated to have a stringency comparable to the otherwise necessary 1-hour emission limit. This method uses a database of continuous emission data reflecting the type of control that the source will be using to comply with the plan's emission limits, which (if compliance requires new controls) may require use of an emission database from another source. The recommended method involves using these data to compute a complete set of emission averages, computed according to the averaging time and averaging procedures of the prospective emission limitation ( i.e., using 1-hour historical emission values from the emissions database to calculate 30-day average emission values). In this recommended method, the ratio of the 99th percentile among these longer-term averages to the 99th percentile of the 1-hour values represents an adjustment factor that may be multiplied by the candidate 1-hour emission limit CEV to determine a longer-term average emission limit that may be considered comparably stringent. 27

The 2014 SO 2 Guidance also addresses a variety of related topics, including the potential utility of setting supplemental emission limits, such as mass-based limits or work practice requirements for the operation of SO 2 control equipment, to reduce the likelihood and/or magnitude of elevated emission levels that might occur under the longer-term emission rate limit.

Preferred air quality models for use in regulatory applications are described in Addendum A of the EPA's “Guideline on Air Quality Models” (“Appendix W”). 28 In 2005, the EPA promulgated the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) as the Agency's preferred near-field dispersion model for a wide range of regulatory applications addressing stationary sources ( e.g., in estimating SO 2 concentrations) in all types of terrain based on an extensive developmental and performance evaluation. Supplemental guidance on modeling for purposes of demonstrating attainment of the SO 2 standard is provided in Appendix A of the 2014 SO 2 Guidance. Appendix A provides extensive guidance on the modeling domain, the source inputs, assorted types of meteorological data, and background concentrations. Consistency with the recommendations in the 2014 SO 2 Guidance would generally ensure that the attainment demonstration offers adequately reliable assurance that the plan provides for attainment.

Attainment demonstrations for the 2010 1-hour primary SO 2 NAAQS must demonstrate future attainment and maintenance of the NAAQS in the entire area designated as nonattainment ( i.e., not just at the violating monitor) by using air quality dispersion modeling (see Appendix W) to show that the mix of sources and enforceable control measures and emission rates in an identified area will not lead to a violation of the SO 2 NAAQS. For a short-term ( i.e., 1-hour) standard, the EPA believes that dispersion modeling, using allowable emissions and addressing stationary sources in the affected area (and in some cases those sources located outside the nonattainment area that may affect attainment in the area) is technically appropriate, efficient, and effective in demonstrating attainment in nonattainment areas because it takes into consideration combinations of meteorological and emission source operating conditions that may contribute to peak ground-level concentrations of SO 2 .

The meteorological data used in the analysis should generally be processed with the most recent version of AERMET. AERMET is a meteorological data preprocessor that incorporates air dispersion based on planetary boundary layer turbulence structure and scaling concepts. Estimated concentrations should include ambient background concentrations, should follow the form of the standard, and should be calculated as described in section 2.6.1.2 of the August 23, 2010, clarification memo on “Applicability of Appendix W Modeling Guidance for the 1-hour SO 2 National Ambient Air Quality Standard.”  29

Finally, CAA section 123(a) provides that the degree of emission limitation required for control of any air pollutant under an applicable implementation plan shall not be affected in any manner by so much of the stack height of any source as exceeds good engineering practice (GEP) (as determined under regulations promulgated by the Administrator). The EPA's regulations implementing section 123 reside at 40 CFR 51.118 to 51.119, and in a series of definitions at 40 CFR 51.100(ff) to (nn). GEP stack height is defined as the greatest among three values, based on three defined approaches for determining GEP stack height. As relevant here, under the third approach the creditable stack height is defined in 40 CFR 51.100(ii)(3) as “[t]he height demonstrated by a fluid model . . . which ensures that the emissions from a stack do not result in excessive concentrations of any air pollutant as a result of atmospheric downwash, wakes, or eddy effects created by the source itself, nearby structures or nearby terrain features.” “Nearby” is defined in 40 CFR 51.100(jj)(2) as not greater than 0.8 kilometers (km) ( 1/2 mile) with a set of exceptions applying to terrain features. “Excessive concentrations” is defined in 40 CFR 51.100(kk)(1), which also specifies that, “[t]he allowable emission rate to be used in making demonstrations under this part shall be prescribed by the new source performance standard that is applicable to the source category unless the owner or operator demonstrates that this emission rate is infeasible.” Since this demonstration must rely on allowable emissions, the SIP must include the appropriate limit, either the new source performance standard (NSPS) limit or an alternative limit if the NSPS limit is infeasible, as an adopted part of the plan. 30

Arizona submitted the “Final SIP Revision: 2023 Hayden Sulfur Dioxide Nonattainment Area for the 1971 and 2010 SO 2 NAAQS” (“2023 Hayden SO 2 Plan”) to the EPA as a revision to the Arizona SIP on October 3, 2023. 31 The 2023 Hayden SO 2 Plan includes a copy of Significant Permit Revision No. 96410, Attachment “I” Hayden Smelter Site-Specific SIP Requirements (“Hayden SO 2 Permit Revision”), which includes numerical fugitive emissions limits, work practice standards, and recordkeeping/reporting requirements to ensure attainment of the SO 2 NAAQS in the Hayden SO 2 nonattainment area. ADEQ's letter adopting and submitting the 2023 Hayden SO 2 Plan for inclusion in the Arizona SIP clarifies that the SIP revision is intended to satisfy the CAA requirements for the Hayden SO 2 planning area for both the 1971 and 2010 SO 2 NAAQS. 32 The October 3, 2023 submittal became complete by operation of law on April 3, 2024. On May 2, 2024, the EPA issued a completeness letter, determining that Arizona's October 3, 2023 submittal includes all SIP elements required as a result of the January 31, 2022 finding of failure to attain and that the submittal meets the minimum completeness criteria in 40 CFR part 51, appendix V. 33

On December 8, 2025, ADEQ submitted for parallel processing the proposed “SIP Revision: Rules Incorporating Hayden Smelter Permit Conditions to Supplement Arizona's 2023 SO 2 SIP” as a supplement to the 2023 Hayden SO 2 Plan (“Hayden SO 2 Supplement”). 34 In addition to addressing attainment planning requirements, the Hayden SO 2 Supplement includes revisions to Rule B1302 and AAC Title 18, Chapter 2, Appendix 14 (“Procedures for Sulfur Dioxide and Lead Fugitive Emissions Studies for the Hayden Smelter”) (“Appendix 14”) that establish certain enforceable control requirements that are relied upon in the attainment demonstration. ADEQ's December 5, 2025 letter accompanying the Hayden SO 2 Supplement explains that the rule revisions “replace the existing references to the Hayden Smelter permitting conditions in Permit No. 39945 (as amended by Significant Permit Revision No. 92168 and Significant Permit Revision No. 96410) with direct incorporation by reference of the equivalent requirements now codified in the A.A.C.,” and that where the 2023 Hayden SO 2 Plan referred to the conditions in the permit, ADEQ now requests that EPA instead refer to the applicable rules. 35 These rule revisions have been adopted under State law. 36 However, ADEQ notes that the State is requesting parallel processing of these submissions to help facilitate timely EPA action on the 2023 Hayden SO 2 Plan, given the additional administrative steps required before codification of the rule revisions in the AAC.

Parallel processing refers to a process where the state submits a SIP revision prior to actual adoption by the state. 37 The EPA reviews the proposed SIP revision and prepares a notice of proposed rulemaking under Federal law. Any final rule action by the EPA will occur only after the state formally adopts and submits its final submission to the EPA.

Section 110(k)(1)(B) of the CAA requires the EPA to determine whether a SIP submission is complete within 60 days of receipt. This section also provides that if the EPA has not affirmatively determined a SIP submission to be complete or incomplete, it will become complete by operation of law six months after the date of submission. The EPA's SIP completeness criteria are found in 40 CFR part 51, appendix V. The EPA has reviewed the Hayden SO 2 Supplement and finds that it fulfills the completeness criteria of appendix V, with the exception of the requirements of paragraphs 2.1(e)-2.1(h), which do not apply to plans submitted for parallel processing.

CAA sections 110(a)(1) and (2) and 110(l) require each state to provide reasonable public notice and opportunity for public hearing prior to the adoption and submission of a SIP submission to the EPA. To meet this requirement, a state's SIP submission must include evidence that the state provided adequate public notice and an opportunity for a public hearing, consistent with the EPA's implementing regulations in 40 CFR 51.102. However, because ADEQ submitted the Hayden SO 2 Supplement for parallel processing, this initial submission is exempt from this requirement pursuant to 40 CFR part 51, appendix V, section 2.3.1. ADEQ is required to meet these procedural criteria during the parallel processing period and prior to adopting and submitting the final SIP submission to the EPA. The EPA will evaluate whether the final submission meets these requirements at the time of any final action on the Hayden SO 2 Supplement.

In addition to the 2023 Hayden SO 2 Plan and Hayden SO 2 Supplement, ADEQ previously submitted amendments to AAC Title 18, Chapter 2, Article 13, section R18-2-715 (“Standards of Performance for Existing Primary Copper Smelters: Site-Specific Requirements”) (“Rule 715”) and section R18-2-715.01 (“Standards of Performance for Existing Primary Copper Smelters; Compliance and Monitoring”) (“Rule 715.01”) on April 6, 2017. 38 We have not yet acted on these amendments to Rules 715 and 715.01, which are related to the revisions to Rule B1302. These amendments sunset Rule 715 and 715.01 requirements upon the approval and effective date of Rule B1302. Further details can be found in the technical support document (TSD) titled “Technical Support Document for Rule Revisions in the Hayden SO 2 Supplement to the 2023 Hayden SO 2 Plan” included in the docket for this proposed action. 39 On July 17, 2017, the EPA issued a completeness letter for Rules 715 and 715.01, finding that they fulfill the completeness criteria in 40 CFR part 51, appendix V. 40 In the December 5, 2025 letter submitting the revised rules for parallel processing, ADEQ requests that EPA act on the previously submitted Rules 715 and 715.01.

Table 1 lists the rules addressed by this proposal with the dates that they were adopted and submitted by ADEQ.

Throughout this document whenever “we,” or “our” is used, it refers to EPA.

EPA sets the NAAQS for certain ambient air pollutants at levels required to protect human health and the environment. Particulate matter with an aerodynamic diameter less than or equal to 2.5 micrometers, or PM 2.5 , is one of the air pollutants for which EPA has established health-based standards. On October 17, 2006 (71 FR 61144), EPA set the level of the primary 24-hour PM 2.5 NAAQS to 35 µg/m 3 . On November 13, 2009 (74 FR 58688), EPA designated a portion of Klamath County, Oregon, as nonattainment for the 2006 24-hour PM 2.5 NAAQS, triggering Clean Air Act attainment planning requirements for the area. On June 2, 2014 (79 FR 31566), EPA classified the Klamath Falls area as a Moderate nonattainment area.

On December 12, 2012, Oregon submitted an attainment plan (Klamath Falls Attainment Plan) to EPA that focused primarily on reducing emissions from residential wood combustion during the winter heating season, which is when violations of the 2006 24-hour PM 2.5 typically NAAQS occurred. The Klamath Falls Attainment Plan demonstrated how the Klamath Falls 2006 24-hour PM 2.5 nonattainment area (Klamath Falls area) would attain the 2006 24-hour PM 2.5 NAAQS by the December 2014 attainment date. EPA approved the Klamath Falls Attainment Plan in two actions, on August 25, 2015, and June 6, 2016. 1 The June 6, 2016, action included EPA's finding that the Klamath Falls area had attained the 2006 24-hour PM 2.5 NAAQS by December 31, 2014, and finalized a Clean Data Determination (CDD) pursuant to 40 CFR 51.1015. The CDD suspended the requirements for the state to submit an attainment demonstration, associated Reasonably Available Control Measures, Reasonable Further Progress, contingency measures, and any other SIP planning requirements related to the attainment of the 2006 PM 2.5 NAAQS, so long as the area continues to meet the standard. 2

On August 20, 2024, Oregon submitted revisions to the Klamath Falls Attainment Plan as well as a request to EPA to redesignate the Klamath Falls area to attainment for the 2006 24-hour PM 2.5 NAAQS and to approve into the Oregon SIP a maintenance plan for the area that demonstrates continued attainment through 2037. Oregon clarified its submissions in two letters dated April 4, 2025, and December 9, 2025.

Oregon's submission includes revisions to the Klamath Falls Attainment Plan to incorporate updates to the Klamath County Clean Air Ordinance (Ordinance No. 63-06).

EPA approved Ordinance No. 63-06 (adopted on December 31, 2012) into Oregon's SIP August 25, 2015. 3 The ordinance includes several control measures that EPA determined meet CAA moderate area control strategy requirements, particularly for the solid fuel burning area source category. On June 25, 2024, Klamath County adopted updates to the SIP-approved Klamath County Clean Air ordinance in the form of Ordinance No. 63-07. Oregon submitted Klamath County Ordinance No. 63-07 to EPA for approval into Oregon's SIP. The following is EPA's discussion and analysis of revisions to the Klamath County Clean Air Ordinance.

Klamath County made minor changes to the policy and purpose provision, 406.001, and the severability provision, 406.450. These include wording changes such as replacing “problems” with “issues,” “address” with “assess,” “clean” with “cleaner,” “jurisdiction” with “jurisdictions.”

EPA is proposing to approve these minor revisions.

Klamath County made several non-substantive changes to the definitions in the Clean Air Ordinance. For example, the County capitalized certain words that were originally lower case. In other instances, the County made minor word choice changes ( e.g., replacing “die down” with “completely extinguish,” and “violator” with “individual or entity in violation”). Klamath County removed unused definitions, e.g., “urban growth boundary.” The County consolidated the definition of “pellet stove” into the definition of “wood burning device.”

Likewise, Klamath County consolidated certain definitions associated with outdoor burning into a central definition of “open/outdoor burning.” This central definition includes agricultural waste, commercial waste, construction waste, demolition waste, domestic waste, forest slash waste, and industrial waste, and waste from agricultural operations. This new term applies to all open or outdoor fires intended for the combustion of yard debris and cites the definition of “open burning” in OAR 340-264-0030(25)(c), a SIP-approved rule. In line with the removal of waste categories, Klamath County revised the definition of yard debris by removing criteria that distinguish between domestic and commercial waste and changing “waste” in the definition of “open/outdoor burning” to “yard debris.” The County also revised the definition of “open/outdoor burning” to remove “open or outdoor fires intended for heating.”

The County removed the definition of “person” and changed the definition of “responsible person” to “responsible party,” which is consistent with the updated outdoor burning requirements in section 406.100(3)(K). The County also replaced the term “Air Quality Inspector” with “Air Quality Specialist” and added language clarifying the Air Quality Specialist's role to develop forecasts and respond to violations, and to educate the public about the ordinance and violations.

The County also revised the definition of the Klamath County Advisory Committee from being appointed by the Klamath County Board of Commissioners to being selected by the Klamath County Public Health department. The revised ordinance clarifies that a role of the committee is to provide community input on program implementation and removes the duty of the committee to identify significant emissions sources. Klamath County also removed the legal description of air quality zone (AQZ); however, the ordinance already contains a map of the AQZ.

The County added new definitions for “Air quality outlook” and “Air Quality Index (AQI)” which are used to provide air quality information to the public based on the Oregon AQI. The purpose of the air quality outlooks is to inform the public of air quality when conditions are at or above levels that are unhealthy for sensitive groups (AQI of 101).

In addition, Klamath County replaced outdated specifications in the definition of “woodstove/woodheater” and “American Society for Testing and Materials (ASTM) Standards” with references to “current EPA emissions standards,” which are incorporated into the definition of “certified woodburning device.”

The County replaced the definitions of “solid fuel fired appliance” and “woodstove/woodheater” with “wood burning device.” Accordingly, the County replaced the definition of “exempt solid-fuel fired appliance” with “exempt wood burning device” and removed the definition of “woodstove/woodheater.” In the definition of “certificate of exemption,” the County removed language that provided for exempting open or outdoor burning from burning curtailments. The County also removed the definition of “particulate matter ten microns and less (PM 10 )” and removed PM 10 wood burning curtailment advisories.

Klamath County also made several changes to certain definitions associated with the issuance of burn bans. The County issues burn notifications under section 406.150 of the Ordinance. Klamath formerly used a color-code to issue burn notifications (red, yellow, green). In section 406.005, the County defined each color based on the projected PM 2.5 level. Klamath County replaced the former definition of each color with burn notifications phrases (“burning allowed,” “exempt wood burning devices only,” and “no burning allowed”).

The County defined the “burning allowed” notice as when the air quality forecast projects that PM 2.5 levels will be below 22 micrograms per cubic meter (µg/m 3 ) for a 24-hour average. Under this notice there is no burn ban. “Exempt wood burning devices only” is defined as when the forecast projects that PM 2.5 levels have the potential to exceed 22 µg/m 3 for a 24-hour average. Under this notice, the County will allow burning in only devices for which the County has issued a certificate of exemption under section 406.200. “No burning allowed” is defined as when the forecast indicates that PM 2.5 levels have the potential to exceed 35 µg/m 3 for a 24-hour average. Under this notice, no burning is allowed in any devices.

Klamath County revised the definition of “low income” from the Housing and Urban Development definition of “very low income” to using 250 percent of the Federal poverty level. Under 406.200, the County issues certificates of exemption to only “low income” individuals for the purposes of the “exempt wood burning devices only” notification.

Section 406.005 includes a definition of “certificate of variance,” which is a term used throughout the ordinance. However, Oregon did not include 406.250 Certificate of Variance in its submittal. Therefore, the variance authority referenced in the definitions and other portions of the ordinance is not proposed for approval into the Klamath Falls Attainment Plan.

EPA has evaluated the changes to section 406.005 and proposes to approve them for the following reasons. Many of the revisions are minor editorial corrections that do not change the substance of the associated definitions or regulatory provisions. The revisions including the replacement of person with responsible party, revision to the definition of air quality zone, and the change to “open/outdoor burning”, clarify the rules and make the rules easier to implement.

The revisions to air advisory committee and air quality outlook do not change the substance or stringency of the control measures in the Ordinance. The replacement of outdated woodstove/woodheater specifications improves the stringency of the Ordinance. Similarly, the consolidation of multiple definitions into “wood burning device” simplifies the Ordinance and will improve implementation. The County's removal of the exemption for open and outdoor burning from burning curtailments in the definition of “certificate of exemption” improves the stringency of the Ordinance.

In addition, the County's removal of definitions of PM 10 is appropriate for the Klamath Falls area because EPA previously approved removing the PM 10 monitor from the area and approved an approach using the Klamath Falls PM 2.5 monitoring data as a surrogate for measuring PM 10 . Moreover, the revised PM 2.5 curtailment trigger (when the 24-hour average PM 2.5 concentrations have the potential to exceed or are exceeding an estimate of 35 µg/m 3 ) is more protective than the former PM 10 curtailment trigger (when PM 10 concentrations have the potential to exceed or are exceeding an estimate of 150 ug/m 3 ).

With respect to the revisions to the burn curtailment advisory definitions, the replacement of the color code with natural language advisories will provide for equivalent emissions reductions. Notably, the new natural language advisories do not exactly parallel the former color code but will simplify implementation. We note that the new “Exempt Wood Burning Device” category significantly limits the categories of exempt devices than the former red and yellow advisories. This will lead to significant emissions reductions well before the area is forecasted to experience PM 2.5 levels at the NAAQS. Likewise, the “No Burn Period” advisory limits burning to only individuals with a wood stove as a sole source of heat. Although the “No Burn Period” is called when levels are projected to exceed 35 µg/m 3 as opposed to 30 µg/m 3 in the former regulation, the broader applicability will compensate in terms of greater emission reductions.

Likewise, the revision to the definition of “low income” is appropriate. We acknowledge that this revision may allow more people to qualify for exemptions during a burning curtailment. As of 2025, the very low-income limit for a four-person household in Klamath County was $40,700. 4 According to the U.S. Department of Health and Human Services, 250 percent of the Federal poverty level for a four-person household is $80,375. 5 Thus, this revision broadens the scope of individuals eligible to obtain a certificate of exemption. However, other changes to the definitions strengthen the Ordinance. Notably, pellet stoves, fireplaces, cook stoves, masonry heaters, and open burning are no longer exempt from burn bans. We also acknowledge that adjusting the income limits is necessary to ensure the measure is feasible to implement. 6 Individuals making 250 percent of the Federal poverty level likely cannot afford alternative sources of heat. Between 40 and 49 percent of Klamath County residents earning 200 percent or below the Federal poverty level experience high or severe energy burden. 7 The U.S. Department of Energy classifies a household spending 6 percent or more of its income on home energy costs as experiencing high energy burden. 8 The per capita energy expenditures in Oregon in 2022 was $4,594, which is a 61percent increase since 2020. 9 At this expenditure level, households making 250 percent of the Federal poverty level would experience high energy burden.

Klamath County revised section 406.100 to incorporate the updated definitions discussed previously. The County clarified the open burning hours in two primary ways. First, the county replaced “sunrise” and “sunset” with times of day, “8 a.m.” and “5 p.m.,” respectively. Second, under the current rule, burning conducted for “forest slash fires” or “ecosystem management” are not required to be extinguished by sunset. The County revised the rule to exempt Federal, State, and local agency managed open burning ( e.g., forest fuel reduction, fire training, and ecosystem management) from the requirement to extinguish the fire by sunset. In addition, the revised Ordinance expands and clarifies the burn notification period from “during the winter heating season” to “from October 15 through March 15.” The County added a requirement that newly retrofitted fireplaces must comply with fireplace ASTM standards. The County also added a provision allowing certain types of fires: “outdoor fires used for cooking, personal warmth, lighting, ceremonial, or aesthetic purposes, and are not associated with waste disposal” but provided that such fires must be contained within a fireproof container designed for outdoor burning, be capable of containing the fire and coals above the ground surface, and may not exceed two feet in diameter and two feet in height.

EPA reviewed the revisions to section 406.100 and proposes to approve them for the following reasons. Several revisions improve the clarity and enforceability of the section. Notably, the changes to the burn ban season and time periods make the section easier to follow and enforce. The addition of the requirement that newly installed fireplaces meet ASTM standards strengthens the Ordinance. Also, the former open burn hours exemption for slash fires and ecosystem management was ambiguous. Klamath County's revisions clarify and narrow the exemption's scope. Finally, we acknowledge that the addition of the exemption for certain small fires makes the rule less stringent. However, we do not anticipate that this narrow exemption will interfere with attainment of the NAAQS because the exemption is limited to very small fires for certain limited purposes.

Klamath County revised section 406.150 to incorporate the updated definitions discussed previously and to remove the 3-minute per hour exemption from the 20 percent opacity limit and the exemption for pellet stoves, antique stoves, masonry fireplaces, and cookstoves, during wood burning curtailments. Other revisions to the Ordinance include removing the requirement that three weekends be included in the open/outdoor burning window and removing the option to extend the open burn window by the number of days that burning was prohibited. The requirement to consult with the City of Klamath Falls Code Compliance Officer before an open burn window is declared was also removed. The County added a provision to prohibit structures that can impede the view of material being burned outdoors. 10

We discussed the reasons for proposing to approve the updated burn ban requirements under section 406.005. In addition, we are proposing to approve revisions to section 406.150 because these revisions strengthen the Ordinance. The County removed exemptions on certain devices and removed the opacity limit exemption for 3 minutes each hour. These changes increase the stringency of the Ordinance.

Klamath County revised section 406.200 to incorporate the updated definitions discussed previously. Klamath County also revised the section to clarify that the certificate of exemption is for low-income households or those with wood heating as a sole source of heat.

For the reasons discussed under section 406.005, EPA is proposing to approve these revisions.

Klamath County's revisions to section 406.500 changed the board composition from persons “representing industry” and the “general public” to “community members.” Outdated contingency measures that might have been triggered in 2014 and 2015 and are no longer relevant.

EPA is proposing to approve these revisions.

The CAA provides the requirements for redesignating a nonattainment area to attainment. Specifically, CAA section 107(d)(3)(E), allows for redesignation provided that: (1) EPA determines that the area has attained the applicable NAAQS; (2) EPA has fully approved the applicable implementation plan for the area under CAA section 110(k); (3) EPA determines that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable SIP and applicable Federal air pollutant control regulations and other permanent and enforceable reductions; (4) EPA has fully approved a maintenance plan for the area as meeting the requirements of CAA section 175A; and (5) the State has met all requirements applicable to the area under CAA section 110 and part D. In this proposed rulemaking, EPA will review CAA section 107(d)(3)(E) requirements (2) and (5) together as part of our evaluation of Oregon's redesignation request.

EPA has provided guidance on redesignations in the “General Preamble,”  11 and has provided further guidance on processing redesignation requests in the following documents: (1) “Procedures for Processing Requests to Redesignate Areas to Attainment,” Memorandum from John Calcagni, Director, Air Quality Management Division, September 4, 1992 (Calcagni Memo); (2) “State Implementation Plan (SIP) Actions Submitted in Response to Clean Air Act (CAA) Deadlines,” Memorandum from John Calcagni, Director, Air Quality Management Division, October 28, 1992; and (3) “Part D New Source Review (part D NSR) Requirements for Areas Requesting Redesignation to Attainment,” Memorandum from Mary D. Nichols, Assistant Administrator for Air and Radiation, October 14, 1994. These documents are included in the docket for this proposed rulemaking.

EPA is proposing to redesignate the Klamath Falls area to attainment for the 2006 24-hour PM 2.5 NAAQS and to approve a maintenance plan for the area (the Klamath Falls Maintenance Plan) that demonstrates the area will remain in attainment of the 2006 24-hour PM 2.5 NAAQS for 10 years after redesignation. EPA's proposed approval of the redesignation request and maintenance plan is based upon EPA's determination that the area continues to attain the 2006 24-hour PM 2.5 NAAQS and that all other redesignation criteria have been met for the area. The following is a description of how Oregon's August 20, 2024, submission and the April 4, 2025, and December 9, 2025, clarification letters, available in the docket for this rulemaking, satisfy the requirements of CAA section 107(d)(3)(E) for the 2006 24-hour PM 2.5 standard.

To redesignate an area from nonattainment to attainment, the CAA requires EPA to determine that the area has attained the applicable NAAQS (CAA section 107(d)(3)(E)(i)). An area is attaining the 2006 24-hour PM 2.5 NAAQS, when the 3-year average 98th percentile mass concentrations produce a valid design value that is less than or equal to 35 µg/m 3 , based on 3 complete, consecutive calendar years of quality-assured air quality monitoring data, as determined in accordance with 40 CFR 50.13 and 40 CFR part 50, appendix N. 12

As previously noted, on June 6, 2016 (81 FR 36176), EPA determined that the Klamath Falls area had attained the 2006 24-hour PM 2.5 NAAQS of 34 µg/m 3 based on the 2012-2014 design value period. For this proposed rulemaking, EPA reviewed the recent PM 2.5 ambient air monitoring data in the Klamath Falls area for the 2022 through 2024 design value period. The Klamath Falls area continues to attain the 2006 24-hour PM 2.5 NAAQS with a 2022 through 2024 design value of 34 µg/m 3 .

EPA's review of the monitoring data supports the previous determination and therefore EPA finds it is appropriate to conclude the area has continued to attain the 2006 24-hour PM 2.5 NAAQS, based on attaining design values at the Peterson School regulatory monitor (AQS ID 41-035-0004).

CAA section 107(d)(3)(E)(ii) and (v) states that for an area to be redesignated to attainment, it must be determined that the Administrator has fully approved the applicable implementation plan for the area under CAA section 110(k) and all the requirements applicable to the area under CAA section 110 (general SIP requirements) and part D of title I (SIP requirements for nonattainment areas) must be met. We interpret this to mean that, for a redesignation request to be approved, the state must have met all requirements that applied to the subject area prior to, or at the time of, submitting a complete redesignation request. EPA may rely on prior SIP approvals in approving a redesignation request as well as any additional measure it may approve in conjunction with a redesignation action. 13

CAA section 110(a)(2) of title I delineates the general requirements for a SIP, which include enforceable emissions limitations and other control measures, means or techniques, provisions for the establishment and operation of appropriate devices necessary to collect data on ambient air quality, and programs to enforce the limitations. The general SIP elements and requirements set forth in CAA section 110(a)(2) include, but are not limited to the following:

• Submittal of a SIP that has been adopted by the state after reasonable public notice and hearing;

• Provisions for establishment and operation of appropriate procedures needed to monitor ambient air quality;

• Implementation of a minor source permit program;

• Provisions for the implementation of part C requirements (referred to as prevention of significant deterioration or PSD);

• Provisions for the implementation of CAA part D requirements for nonattainment new source review (referred to as part D NNSR, NNSR, nonattainment NSR, or NSR) permit programs;

• Provisions for air pollution modeling; and

• Provisions for public and local agency participation in planning and emission control rule development. 14

We note that SIPs must be fully approved only with respect to applicable requirements for purposes of redesignation in accordance with CAA section 107(d)(3)(E)(ii). Similarly, EPA believes that the other CAA section 110(a)(2) (and part D) requirements that are not connected with nonattainment plan submittals and not linked with an area's attainment status are not applicable requirements for purposes of redesignation. EPA considers the CAA section 110(a)(2) (and part D) requirements that relate to a particular nonattainment area's designation and classification as the relevant measures to evaluate in reviewing a redesignation request. This approach is consistent with EPA's existing policy on applicability of the conformity SIP requirement for redesignations. 15

EPA has reviewed the relevant measures in the Oregon SIP and concludes that they meet the general SIP requirements under CAA section 110(a)(2). EPA has previously approved provisions of Oregon's SIP as demonstrating compliance with the CAA section 110(a)(2) requirements for the 2006 PM 2.5 NAAQS. 16 These requirements are, however, statewide requirements that are not linked to the PM 2.5 nonattainment status of the Klamath Falls area. In addition, there are no outstanding or disapproved applicable SIP submittals with respect to the Klamath Falls area that would prevent redesignation of the Klamath Falls area for the 2006 PM 2.5 NAAQS. Therefore, EPA concludes that Oregon has met all general SIP requirements for the Klamath Falls area for purposes of redesignating the area to attainment for the 2006 PM 2.5 NAAQS.

As set forth in CAA part D of title I, the basic nonattainment plan requirements applicable to all nonattainment areas at subpart 1 (CAA sections 172 through 176) and requirements specific to PM 10 and PM 2.5 areas at subpart 4 (CAA section 189). On August 24, 2016 (81 FR 58010), EPA promulgated the Fine Particulate Matter National Ambient Air Quality Standards; State Implementation Plan Requirements rule which implements the CAA part D requirements for areas designated nonattainment for any PM 2.5 NAAQS. 17

States containing Moderate PM 2.5 nonattainment areas were required to submit SIPs, by December 31, 2014, that demonstrated how the areas would attain the PM 2.5 NAAQS by December 31, 2015. 18 As discussed in section I of this document, EPA approved the Klamath Falls Attainment Plan, determined that the Klamath Falls area had attained the 2006 24-hour PM 2.5 NAAQS by the attainment date, and finalized a CDD pursuant to 40 CFR 51.1015. 19 In accordance with 40 CFR 51.1015, upon a CDD, the requirements for the state to meet certain nonattainment plan requirements under CAA section 172(c) shall be suspended until such time as: (1) the area is redesignated to attainment, after which such requirements are permanently discharged; or, (2) EPA determines that the area has re-violated the PM 2.5 NAAQS. This includes the requirements to submit an attainment demonstration, provisions demonstrating that reasonably available control measures (RACM), including reasonably available control technologies (RACT) for stationary sources, shall be implemented no later than 4 years following the date of designation of the area, reasonable further progress (RFP) plan, quantitative milestones (QM) and reports, and contingency measures for the area. However, determinations of attainment do not relieve states from submitting and EPA from approving certain other CAA part D planning requirements for the 2006 PM 2.5 NAAQS. CAA section 172(c)(3) requires submittal and approval of a comprehensive, accurate and current inventory of actual emissions. For purposes of the PM 2.5 NAAQS, this emissions inventory should address not only direct emissions of PM 2.5 , but also emissions of all precursors to PM 2.5 formation, i.e., SO 2 , NO X , VOC, and ammonia. EPA determined that Oregon met the CAA section 172(c)(3) comprehensive emissions inventory requirement for the Klamath Falls area on June 6, 2016. 20

CAA section 172(c)(4) requires the identification and quantification of allowable emissions for major new or modified stationary sources in an area, and CAA section 172(c)(5) requires source permits for the construction and operation of new or modified major stationary sources anywhere in the nonattainment area. EPA most recently approved Oregon's NSR permit program as meeting these requirements on July 23, 2024 (89 FR 59610).

Once the Klamath Falls area is redesignated to attainment, sources located in the Klamath Falls area will be subject to Oregon's NSR regulations applicable to maintenance areas. Oregon's NSR and PSD regulations are codified in the Oregon Administrative Rules (OAR), chapter 340, divisions 200, 202, 209, 212, 216, 222, 224 (except 0510(3) inter-pollutant offset ratios), 225, and 268. EPA finds that Oregon's NSR and PSD provisions meet all applicable Federal requirements for any area designated unclassifiable or attainment, and these provisions will become fully effective in the Klamath Falls area upon redesignation to attainment. EPA most recently approved revisions to division 224, Oregon's NSR program, on July 23, 2024 (89 FR 59610).

CAA section 172(c)(7) requires the SIP to meet the applicable provisions of CAA section 110(a)(2). As explained previously in section IV.B.1 of this document, we have proposed to find that the Oregon SIP meets the CAA section 110(a)(2) applicable requirements. For purposes of redesignation to attainment for the 2006 24-hour PM 2.5 NAAQS, EPA also proposes to find that Oregon has met all the applicable SIP requirements under CAA part D of title I in accordance with CAA section 107(d)(3)(E)(v).

CAA section 110(k) sets out provisions governing EPA's review of SIP submittals. For an area to qualify for redesignation, the SIP for the area must be fully approved under CAA section 110(k). As discussed in sections IV.B.1 and IV.B.2 of this document, for purposes of redesignation to attainment for the 2006 24-hour PM 2.5 NAAQS, EPA has fully approved all applicable requirements in the Klamath Falls Attainment Plan into the Oregon SIP in accordance with CAA section 110(k). Therefore, the criterion for redesignation, set forth at CAA section 107(d)(3)(E)(ii), is satisfied.

CAA section 107(d)(3)(E)(iii) provides that for an area to be redesignated to attainment, the Administrator must determine that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable implementation plan, implementation of applicable Federal air pollutant control regulations, and other permanent and enforceable reductions. In making this demonstration for the Klamath Falls area, Oregon explained that residential wood heating was the major source of emissions contributing to violations of the 24-hour PM 2.5 NAAQS, which occur primarily during the winter season. The permanent and enforceable control measures included in the Klamath Falls Attainment Plan focused on reducing emissions from residential wood combustion, as well as other contributing sources including open burning, permitted industrial facilities, and mobile sources. The following paragraphs describe the permanent and enforceable local and state control measures that were adopted in the Klamath Falls Attainment Plan.

Oregon identified emissions from residential wood heating in the winter months as the major contributor to nonattainment in the Klamath Falls area. The Klamath Falls Attainment Plan implemented enforceable state and local strategies to reduce emissions from residential wood heating and EPA approved them into the Oregon SIP on June 6, 2016 (81 FR 36176), making them federally enforceable. In this rulemaking, EPA is proposing to approve revisions to the Klamath Falls Attainment Plan, as discussed in section II of this document. The strategies in the Klamath Falls Attainment Plan include curtailing wood heating on days when exceedances of the 2006 24-hour PM 2.5 NAAQS are most likely to occur, a woodstove change out program, prohibitions on resale and installation of non-certified  21 solid fuel heating devices, requirements to remove non-certified solid fuel heating devices at the time of home sale, and certain operational requirements for solid-fuel heating.

The mandatory curtailment program, under the Klamath Clean Air Ordinance, restricts combustion in residential wood burning devices when elevated PM 2.5 concentrations are forecast in the air quality zone. 22 Key elements of the curtailment program include daily burn notifications during the heating season, from October 15 through March 15. A “no burning allowed” notification is issued when 24-hour average PM 2.5 concentrations have the potential to exceed or are exceeding 35μg/m 3 . During this time, operating any wood burning device is prohibited. An “exempt wood burning devices only” notification is issued when PM 2.5 24-hour average concentrations have the potential to exceed 22μg/m 3 but are not projected to exceed 35μg/m 3 . During this time, only devices with an approved certificate of exemption may burn. A certificate of exemption may be issued by the Klamath County Public Health Administrator or designee to applicants who qualify as low income or whose sole source of heat is a wood burning device. A “burning allowed” notification is issued when 24-hour average PM 2.5 concentrations are forecast to not exceed 22μg/m 3 . All wood burning devices may be used during this time.

To reduce the number of high-emitting wood burning devices that operate in the Klamath Falls area, Oregon implemented a woodstove changeout program, prohibited the sale and installation of non-certified devices, required the removal and destruction of all non-certified wood burning devices at the time of home sale (including residences, shops, garages, and outbuildings), and established new fireplace standards. The woodstove changeout program provided financial incentives for homeowners to replace non-certified woodstoves with newer, cleaner heating devices. Oregon stated that 180 woodstoves had been replaced in the changeout program, and 7 uncertified woodstoves had been removed upon home sale as of the date of its redesignation request and maintenance plan submission. Oregon projects that by 2028, 411 woodstoves will have been replaced. The removal of non-certified woodstoves and the prohibition on their sale and installation ensures the emissions reductions from changeouts and removal at time of home sale are permanent and enforceable.

The Klamath Falls Attainment Plan includes operational requirements for residential wood heating, specifically limits on opacity and restrictions on materials that can be burned. The Klamath Clean Air Ordinance prohibits operating a wood burning device in a manner that produces smoke with opacity greater than 20 percent, except during the first 10 minutes of operation. 23 The Ordinance also lists the types of fuel that can be used in a wood burning device as: only dry, seasoned cordwood, pressed sawdust logs, organic charcoal or pellets specifically manufactured for the appliance. Both the Klamath Clean Air Ordinance and the Oregon Heat Smart Program (OAR Division 262) list materials that are prohibited from being burned in a solid-fuel heating device. The combined list of prohibited materials include: garbage, treated wood, plastic or plastic products, rubber or rubber products, animal carcasses, products that contain asphalt, petroleum products, paint, chemicals, products containing lead, mercury or other heavy or toxic metals, materials containing asbestos, wire insulation, automobile parts, particleboard, and animal or vegetable matter resulting from the handling, preparation, cooking or service of food that normally results in dense or noxious smoke when burned.

While emissions from residential wood heating in the winter months was identified as the major contributor to nonattainment in the Klamath Falls area, and therefore the Attainment Plan largely relies on implemented enforceable state and local strategies to reduce emissions from residential wood heating, other permanent and enforceable measures contained in the Klamath Falls Attainment plan include those for open burning, permitted industrial facilities, and industrial sources. The Klamath Clean Air Ordinance allows for open and outdoor burning during specific time periods, and within the Klamath Falls air quality zone during open burn periods declared by Klamath County Public Health. To address emissions from industrial facilities, the Klamath Falls Attainment Plan implemented rules requiring all permitted facilities emitting 10 or more tons per year of PM 2.5 to implement RACT. Specifically, the rules (OAR 340-240-0510 through OAR 340-240-0530) include opacity limits, fugitive emissions plans, and operations and maintenance best practices. Emissions reductions are expected to increase in future years as the motor vehicle fleet in Klamath Falls turns over. Further, the Klamath Falls Attainment Plan stated that efforts to reduce road dust emissions generated by motor vehicle traffic had been achieved through road paving, minimizing the use of sanding material, and controlling mud and dirt track out from industrial, construction and agricultural operations. The Interagency Agreement to Reduce Particulate Emissions from Winter Road Sanding between the Oregon Department of Transportation, the Klamath County Public Works Department, and the City of Klamath Falls Public Works Department was approved into the Oregon SIP.

Based on EPA's evaluation of the control measures, we propose to determine that the improvement in air quality is reasonably attributable to permanent and enforceable reductions in emissions resulting from implementation of the applicable state, local, and Federal air pollutant control regulations, and other permanent and enforceable emissions reductions.

In conjunction with Oregon's request to redesignate the Klamath Falls area to attainment, Oregon submitted a plan to provide for maintenance of the 2006 24-hour PM 2.5 NAAQS through 2037 (Klamath Falls Maintenance Plan). EPA is proposing to approve the Klamath Falls Maintenance Plan, and if this proposed rulemaking is finalized, the Klamath Falls area will have an approved PM 2.5 maintenance plan.

CAA section 107(d)(3)(E)(iv) requires that, for a nonattainment area to be redesignated to attainment, EPA must fully approve a maintenance plan for the area as meeting the requirements of CAA section 175A. The maintenance plan must demonstrate continued attainment of the relevant NAAQS in the area for at least 10 years after redesignation. Eight years after redesignation, the state must submit a revised maintenance plan demonstrating attainment for an additional 10-year period. The maintenance plan must also contain a contingency plan to ensure prompt correction of any violation of the NAAQS that occurs after redesignation of the area. See CAA sections 175A(a), (b) and (d). The Calcagni Memo provides additional guidance on the content of a maintenance plan, stating that a maintenance plan should include the following elements: (1) an attainment emissions inventory; (2) a maintenance demonstration showing attainment for 10 years following redesignation; (3) a commitment to maintain and operate an appropriate air quality monitoring network; (4) verification of continued attainment; and (5) a contingency plan to prevent or correct future violations of the NAAQS. The following describes how each of the maintenance plan elements are addressed in the maintenance plan.

As discussed in the CAA General Preamble ( See 57 FR 13498, April 16, 1992) and the Calcagni Memo, PM 2.5 maintenance plans should include an attainment emission inventory to identify the level of emissions in the area which are sufficient to maintain the NAAQS. The attainment inventory should be consistent with EPA's emissions inventory requirements and most recent guidance on emission inventories for nonattainment areas available at the time and should represent emissions during the time period associated with the monitoring data showing attainment. 24 The inventory must be comprehensive, including emissions from stationary point sources, area sources, and mobile sources, and must be based on actual emissions during the appropriate season, if applicable.

The Klamath Falls Maintenance Plan includes an attainment inventory for the year 2017, which is associated with monitoring data showing attainment of the 2006 24-hour PM 2.5 NAAQS with a 2015-2017 design value of 32 µg/m 3 . 25 Therefore, the 2017 emissions inventory identifies the level of emissions in the Klamath Falls area that is sufficient to attain the 2006 24-hour PM 2.5 NAAQS. The 2017 emissions inventory includes annual emissions and typical season day emissions. Typical season day emissions represent emissions from November 1 through the end of February, which is when the 2006 24-hour PM 2.5 NAAQS has historically been exceeded in the Klamath Falls area. The attainment inventories shown in table 1 of this document, include emissions of PM 2.5 , nitrogen oxides (NO X ), sulfur dioxide (SO 2 ), ammonia (NH 3 ) and volatile organic compounds (VOC) for the four major source categories: events and natural sources, mobile sources, 26 nonpoint sources, and point sources.

EPA has reviewed the results, procedures, and methodologies for the Klamath Falls 2017 attainment inventories and proposes to find that they are based on the most current and accurate information available to Oregon at the time they were developed. Based on our review of the emissions inventories that Oregon provided in its submission, we propose to find that Oregon prepared an adequate attainment inventory for the Klamath Falls area. 27

CAA section 175A requires a state seeking redesignation to attainment to submit a SIP revision to provide for maintenance of the NAAQS in the area “for at least 10 years after the redesignation.” A state can make this demonstration by either showing that future emissions of a pollutant or its precursors will not exceed the level of the attainment inventory or by modeling to show that the future mix of sources and emissions rates will not cause a violation of the NAAQS. 28

In the Klamath Falls Maintenance Plan, Oregon elected the attainment inventory method to show that the Klamath Falls area will remain in attainment. Oregon developed projected emissions inventories for the year 2037, shown in table 2 of this document, which satisfies the 10-year interval required in CAA section 175A. Like the attainment inventories, the 2037 inventories include the four major source categories: events and natural sources, mobile sources, nonpoint sources, and point sources. Oregon projected future year emission inventories using the latest socioeconomic growth indictors and applying emissions reduction benefits from adopted control strategies when appropriate. 29 Oregon estimated “no growth” in emissions from 2017 to 2037 for point sources, events (wildfires/prescribed and structural fires) and some agriculture sources.

Table 3 of this document shows the change in projected annual and typical season day emissions between the 2017 attainment year and 2037 future year inventories. Future emissions of direct PM 2.5 , NO X , and VOC are expected to be lower than in the 2017 attainment year, while future NH 3 and SO 2 emissions are expected to increase slightly, by approximately one percent by 2037. Oregon attributes the reductions in directly emitted PM 2.5 primarily to the removal of residential wood heating devices and their replacement with heat pumps or gas furnaces and to wood burning curtailment during stagnant conditions. 30

EPA has reviewed the documentation provided by Oregon for developing the projected 2037 emissions inventories for the Klamath Falls area. Based on our review, EPA finds that the projected inventories were developed using appropriate assumptions and procedures, comprehensively address all source categories in the Klamath Falls area, and sufficiently account for PM 2.5 and NH 3 , NO X , and VOC precursor emissions. These inventories indicate a decrease in directly emitted PM 2.5 . The inventories indicate that NO X and VOC emissions will decrease throughout the maintenance period and that NH 3 and SO 2 will remain relatively stable or increase slightly throughout the maintenance period. Therefore, EPA proposes to determine that the projected emissions inventories in the Klamath Falls Maintenance Plan sufficiently demonstrate that the Klamath Falls area will continue to attain the 2006 24-hour PM 2.5 standard for the 10-year maintenance period.

Once a nonattainment area has been redesignated to attainment, the state must continue to operate an appropriate air quality monitoring network, in accordance with 40 CFR part 58, to verify the attainment status of the area. The maintenance plan should contain provisions for continued operation of air quality monitors that will provide such verification.

Oregon committed to continue to operate the air monitoring network in accordance with 40 CFR part 58. Oregon will use air monitoring results to verify continued attainment of the 2006 24-hour PM 2.5 NAAQS and to track progress of the Klamath Falls Maintenance Plan. Oregon stated that it will work with EPA through the air monitoring network review process to determine the adequacy of the monitoring network and consult with EPA on any modifications to the network. 31 EPA proposes to determine that the Klamath Falls Maintenance Plan contains adequate provisions for continued operation of an air quality monitoring network to verify maintenance of the 2006 24-hour PM 2.5 NAAQS. Additionally, Oregon is required to periodically update the emissions inventory for Klamath County in accordance with the Annual Air Emissions Reporting Requirements Rule. 32 This includes developing annual inventories for major point sources and a comprehensive periodic inventory covering all source categories every 3 years.

CAA section 175A(d) requires that a maintenance plan also include contingency provisions, as necessary, to promptly correct any violation of the NAAQS that occurs after redesignation of the area to attainment. For the purposes of CAA section 175A, a state is not required to have fully adopted contingency provisions that will take effect without further action by the state in order for the maintenance plan to be approved. However, the contingency plan is an enforceable part of the SIP and should ensure that contingency provisions are adopted expeditiously once they are triggered. The contingency plan should discuss the measures to be adopted and a schedule and procedure for adoption and implementation. The contingency plan must require that the state will implement all measures contained in the CAA part D nonattainment plan for the area ( i.e., Klamath Falls Attainment Plan) prior to redesignation. The state should also identify the specific indicators, or triggers, that will be used to determine when the contingency plan will be implemented. 33

The Klamath Falls Maintenance Plan outlines the procedures for the adoption and implementation of contingency provisions to further reduce emissions should a violation of the 2006 24-hour PM 2.5 NAAQS occur. If monitored PM 2.5 levels exceed 35 μg/m 3 (24-hr average), Oregon will work to determine the cause of the exceedance within 6 months of annual data certification. 34 Oregon will assess probable emissions sources and meteorological events contributing to elevated PM 2.5 levels, including information on wildfires or winter power outages.

Oregon has identified additional potential contingency measures for the Klamath Falls Maintenance Plan that may be implemented as appropriate. These include:

• Developing Red Day Plans for industrial sources of PM 2.5 with title V permits to be implemented on non-wildfire related predicted red days;

• Developing updated RACT measures for industrial sources with the capacity to emit more than 50 pounds per day of PM 2.5 ;

• Using the application process for debris burning or agricultural burning to spread out incidents of burning and limit exceedances;

• Developing a street sweeping plan with local highway districts and the Oregon Department of Transportation to prioritize the reduction of fugitive road dust; and

• Additional street paving projects.

Oregon commits to adopting and implementing the necessary contingency measures as expeditiously as possible, but not later than one year after a violation, based on confirmed quality-assured data. Any contingency measures adopted and implemented will become part of the control measures in the next revised maintenance plan submitted to EPA for approval.

Based on EPA's review of Oregon's submittal, we propose to find that the contingency measure provisions provided in the Klamath Falls Maintenance Plan are sufficient and meet the requirements of CAA section 175A(d).

Transportation conformity is required by CAA section 176(c). EPA's transportation conformity rule at 40 CFR part 93, subpart A, requires that transportation plans, programs, and projects conform to SIPs and establishes the criteria and procedures for determining whether they conform to the SIP. Conforming to a SIP means that onroad transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the NAAQS. Thus, EPA's transportation conformity rule requires a demonstration that emissions from a metropolitan planning organization's regional transportation plan and transportation improvement program, involving Federal Highway Administration (FHWA) or Federal Transit Administration (FTA) funding or approval, are consistent with the motor vehicle emissions budgets contained in a control strategy SIP revision or maintenance plan (40 CFR 93.101, 93.118, and 93.124). Generally, the budgets are the level of mobile source emissions of a pollutant relied upon in the attainment or maintenance demonstration to attain or maintain compliance with the NAAQS in the nonattainment or maintenance area. A PM 2.5 maintenance plan should identify budgets for direct PM 2.5 , NO X and all other PM 2.5 precursors from onroad mobile source emissions that are determined to significantly contribute to PM 2.5 levels in the area. 35

Oregon indicated that the Klamath Falls nonattainment area meets the definition of an “isolated rural nonattainment area” at 40 CFR 93.109(g) because the area does not contain, and is not part of, a metropolitan planning organization. Neither a transportation improvement plan nor a regional transportation plan was developed for the Klamath Falls area. Instead, transportation projects for Klamath Falls are included in a statewide transportation improvement plan. The Oregon Department of Transportation is responsible for transportation conformity determinations in this isolated rural nonattainment area.

The Klamath Falls Maintenance Plan identifies budgets for PM 2.5 and NO X , which are displayed in table 4 of this document. Oregon used EPA's Motor Vehicle Emission Simulator model (MOVES3.1) in emissions inventory mode to estimate 2037 future year emissions from onroad mobile sources for a typical season day. The budgets for the 2037 future year will be 77 and 1,448 lbs/day for PM 2.5 and NO X respectively. The Klamath Falls Maintenance Plan also established a safety margin for the 2037 future year budgets along with additional margin allocated from emissions reductions from woodstoves. The safety margin was applied to the 2037 future year motor vehicle emissions budgets to account for emissions from future transportation projects. Oregon projects that 411 woodstoves will be removed from the Klamath Falls nonattainment area by 2028, which Oregon projects will lead to decreases in PM 2.5 and NO X emissions. To provide an extra safety margin for mobile vehicle emissions, a portion of the projected emissions reductions from the 411 woodstove removals was allocated to the 2037 future year motor vehicle emissions budgets. Oregon did not include emissions from paved road dust because those emissions were found to be insignificant. Oregon also found that motor vehicle emissions of VOC, SO 2 and NH 3 contributed minimally to PM 2.5 in the area and did not include budgets for these precursors in accordance with 40 CFR 93.102(b)(2)(v).

EPA is proposing to find that Oregon has evaluated the appropriate pollutants and precursors and established appropriate budgets for PM 2.5 and NO X . Oregon used the most up-to-date model (MOVES3.1) available at the time of submission to appropriately calculate these budgets. 36 The budgets are based on the control measures in the Klamath Falls Maintenance Plan and consistent with maintaining the 2006 24-hour PM 2.5 NAAQS.

EPA completed the adequacy review for the motor vehicle emissions budgets in a separate, tangential process which is detailed in 40 CFR 93.118(f). The adequacy review process consists of three basic steps: (1) public notification of a SIP submission; (2) a public comment period; and (3) EPA's adequacy determination. EPA completed steps (1) and (2) by posting a notice on the Office of Transportation and Air Quality website inviting the public to comment on the adequacy of the NO X and PM 2.5 motor vehicle emissions budgets in the Klamath Falls Maintenance Plan. 37 The comment period was open from September 5, 2024, through October 7, 2024. EPA did not receive adverse comments and found the budgets adequate on April 23, 2025. EPA published a notice of adequacy on August 21, 2025 (90 FR 40737). Because EPA found the motor vehicle emissions budgets adequate, we are not soliciting comments on budget adequacy as part of this notice of proposed rulemaking. The motor vehicle emissions budgets adequacy review process is separate from any action on the submitted SIP and allows for motor vehicle emissions budgets to be used for transportation conformity purposes, provided they meet the criteria in 40 CFR 93.118(e).

Based on the information presented in the Klamath Falls Maintenance Plan for the 2006 24-hour PM 2.5 NAAQS, and the adequacy review of the motor vehicle emissions budgets that we have completed, we propose to approve the motor vehicle emissions budgets in the Klamath Falls Maintenance Plan as meeting the requirements of the CAA and EPA regulations.

Oregon also submitted rule revisions to reflect the anticipated redesignation of the Klamath Falls PM 2.5 nonattainment area to attainment (OAR 340-204-0010, -0030, -0040, and OAR 340-240-0010, -0500, -0550, -0560). Additionally, Oregon submitted rule revisions that reflect the attainment status of the Oakridge PM 2.5 and PM 10 former nonattainment areas which EPA redesignated to attainment in 2022 (OAR 340-204-0030, -0040). 38 These revisions remove Klamath Falls and Oakridge from Oregon's list of PM 2.5 nonattainment areas, and they remove Oakridge from Oregon's list of PM 10 nonattainment areas. Accordingly, the revisions also add these areas to Oregon's list of PM 2.5 and PM 10 maintenance areas.

EPA proposes to redesignate the Klamath Falls, Oregon PM 2.5 nonattainment area to attainment and approve the Klamath Falls Maintenance Plan. If this proposal is finalized, the designation status of the Klamath Falls, Oregon PM 2.5 nonattainment area under 40 CFR part 81 will be revised to attainment upon the effective date of that final action.

EPA proposes to approve and incorporate by reference into the Oregon SIP, the submitted revisions to OAR 340-204-0010, -0030, -0040, and OAR 340-240-0010, -0500, -0550, -0560, state effective May 25, 2024; and Klamath County Code Chapter 406, Ordinance No. 63.07, state effective June 25, 2024, except the following provisions that were not submitted for approval into the Oregon SIP: 406.150(1)(D)(e) regarding emergency conditions, section 406.250 regarding certificate of variance, section 406.300 regarding enforcement, and section 406.400 regarding penalties.

Finally, we propose that the motor vehicle emissions budgets in the Klamath Falls Maintenance Plan meet applicable CAA requirements for maintenance plans and transportation conformity requirements.

In this document, EPA proposes to include, in a final rule, regulatory text that includes incorporation by reference. In accordance with the requirements of 1 CFR 51.5, EPA proposes to incorporate by reference the provisions described in section IV of this document.

EPA has made, and will continue to make, these documents generally available through https://www.regulations.gov and at the EPA Region 10 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

Under the Clean Air Act, the Administrator is required to approve a SIP submission that complies with the provisions of the Clean Air Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve State choices, provided that they meet the criteria of the Clean Air Act. Accordingly, this action merely approves State law as meeting Federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);

• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866;

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);

• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a State program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rule does not have Tribal implications and will not impose substantial direct costs on Tribal governments or preempt Tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

Throughout this document wherever “we,” “us,” or “our” is used, we mean the EPA.

Section 111 of the CAA, “Standards of Performance for New Stationary Sources,” directs the EPA to establish emission standards for stationary sources of air pollution that could potentially endanger public health or welfare. These standards are referred to as New Source Performance Standards (NSPS). Section 111(d) addresses the process by which the EPA and states regulate standards of performance for existing sources. When NSPS are promulgated for new sources, section 111(d) and EPA regulations require that the EPA publish an Emission Guideline (EG) to regulate the same pollutants from existing facilities. While NSPS are directly applicable to new sources, EG for existing sources (designated facilities) are intended for states to use to develop a state plan to submit to the EPA.

State plan submittal and revisions under CAA section 111(d) must be consistent with the applicable EG and the requirements of 40 CFR part 60, subpart B, and part 62, subpart A. The regulations at 40 CFR part 60, subpart B, contain general provisions applicable to the adoption and submittal of state plans under CAA section 111(d). Additionally, 40 CFR part 62, subpart A, provides the procedural framework by which the EPA will approve or disapprove such plans submitted by a state. Once approved by the EPA, the state plan becomes federally enforceable. If a state does not submit an approvable state plan to the EPA, the EPA is responsible for developing, implementing, and enforcing a federal plan.

The MSW landfills NSPS for new landfills and EG for existing landfills were first promulgated by EPA on March 12, 1996, in 40 CFR part 60, subparts WWW and Cc, respectively (61 FR 9905). On August 29, 2016, the EPA finalized revisions to the MSW landfills NSPS and EG in 40 CFR part 60, subparts XXX and Cf, respectively (81 FR 59332; 81 FR 59313). The 2016 EG revision updates the control requirements and monitoring, reporting, and recordkeeping provisions for existing MSW landfill sources.

The current MSW landfills EG, found at 40 CFR part 60, subpart Cf, concerns the regulation of landfill gas and its components, including methane, from MSW landfills for which construction, reconstruction, or modification was commenced on or before July 17, 2014. The deadline to submit a state plan to the EPA was May 30, 2017. On May 21, 2021, EPA finalized the MSW landfills federal plan in 40 CFR part 62, subpart OOO (86 FR 27756). The MSW landfills federal plan at 40 CFR part 62, subpart OOO, applies to states that do not have an EPA-approved state plan. The MSW landfills federal plan is currently in effect in Texas.

In order to fulfill obligations under CAA section 111(d), the Texas Commission on Environmental Quality (TCEQ) submitted a revised state plan for the control of emissions from existing MSW landfills for the State of Texas on September 15, 2023. The Texas MSW landfills plan implements and enforces the applicable provisions under the MSW landfills EG at 40 CFR part 60, subpart Cf, and additionally meets the relevant requirements of the CAA section 111(d) implementing regulations at 40 CFR part 60, subpart B. The Texas submittal and the supplements are included in the public docket for this rulemaking (Docket No. EPA-R06-OAR-2023-0478).

The EPA has evaluated the Texas MSW landfills plan to determine whether the plan meets applicable requirements from the MSW landfills EG at 40 CFR part 60, subpart Cf, and the CAA section 111(d) implementing regulations at 40 CFR part 60, subpart B. The EPA's detailed rationale and discussion on the Texas MSW landfills plan can be found in the EPA Technical Support Document (TSD), located in the docket for this rulemaking.

The state plan submittal package includes all materials necessary to be deemed administratively and technically complete according to the criteria of 40 CFR part 60, subpart B. The state plan document (the “Texas State Plan for the Control of Designated Facilities and Pollutants”) includes all the necessary authority for the implementation and enforcement of the MSW landfill Emission Guidelines in the State. Specifically, the State met applicable Federal requirements while incorporating the EG at 40 CFR part 60, subpart Cf, into the Texas Administrative Code (TAC) Title 30, Part 1, Chapter 113, Subchapter D, Division 6, 2016 Emission Guidelines for Existing Municipal Solid Waste Landfills (30 TAC § 113.2400-30 TAC § 113.2412). Both the adopted state plan document and the relevant TAC regulations, as well as all other relevant plan submittal materials may be found in the docket for this action. Necessary State legal and enforcement authorities required for plan approval are located elsewhere in Texas's statute, rules and regulations and have been reviewed and approved of by the EPA in the course of prior state implementation plan as well as section 111(d) and/or 129 state plan approvals. See 40 CFR part 52, subpart SS, and 40 CFR part 62, subpart SS.

The Texas MSW landfills plan has been evaluated in detail in the TSD. Our evaluation demonstrates that the Texas MSW landfills plan meets the requirements in 40 CFR part 60, subpart Cf and subpart B, and is consistent with the requirements for an approvable section 111(d) state plans for MSW landfills.

Under 40 CFR part 60, subpart B, section 60.24(f) allows for less stringent regulations in a state's CAA section 111(d) plan if a technical or economic justification supports it. The Texas MSW landfills plan includes two provisions which differ from the EG. First, Texas used an alternative date range for determining applicability of EG requirements in its previous 1998 MSW landfills plan and its current 2023 MSW landfills plan. The MSW landfills EG contains gas collection and control system requirements for designated facilities (as defined in the EG) that have accepted waste after November 8, 1987, that meet specific design capacity and NMOC (nonmethane organic compound) emission rate thresholds (50 megagrams per year (Mg/yr) for closed landfills). In the previous Texas MSW landfills plan submitted in 1998 and approved by EPA in 1999, 1 TCEQ  2 provided a detailed technical analysis indicating that no designated landfills that closed between November 8, 1987, and October 9, 1993, would have estimated NMOC emission rates above the 50 Mg/yr control threshold by 2004. In the 1999 approval, 3 the EPA concurred with TCEQ that controlling these closed landfills would not result in a significant reduction in NMOC emissions compared to the cost of installing gas collection systems at these sites. In the previous state plan, TCEQ adjusted its definition to reflect actual conditions in Texas based on section 60.24(f). As part of this state plan, 30 TAC § 113.2406(a) explicitly exempts MSW landfills that have not accepted waste since October 9, 1993, and do not have additional design capacity available for future waste deposition. In its current submittal, Texas states that none of the landfills which stopped accepting waste during the relevant 1987-1993 time period would have current NMOC emissions above the 50 Mg/year threshold. Therefore, these closed landfills in Texas (which stopped accepting waste during the applicable 1987-1993 time period) would not be subject to gas collection and control system requirements nor likely result in a reduction in NMOC or landfill emissions even if Texas did not exempt these landfills as part of its current MSW landfills plan. EPA proposes to find that the state's use of section 60.24(f), to exempt certain MSW landfills from the requirements of 40 CFR part 60, subpart Cf, is reasonable and proposes to approve the Texas MSW landfill plan's alternative date range for determining applicability of requirements.

Under the adopted 30 TAC 113.2404(b), landfill gas collection and control systems that have been approved by the TCEQ and installed in accordance with 30 TAC § 115.152 are considered to meet certain technical requirements of the emission guidelines, specifically 40 CFR 60.33f(b) and (c). TCEQ has identified that the purpose of this state regulation is to minimize redundant and duplicative requirements for landfill gas collection and control systems that fall under both 30 TAC Chapter 115 and 40 CFR part 60, subpart Cf. Table C.5.1 in the Texas submission compares 30 TAC § 115.152 with 40 CFR part 60, subpart Cf, and outlines which state rules correspond to each federal requirement for the regulatory changes TCEQ intends to implement. The EPA is proposing to approve this aspect of Texas's state plan, proposing to find that MSW landfills in compliance with 30 TAC § 115.152 satisfy the requirements of the EG. The EPA's detailed rationale and discussion on the Texas MSW landfills plan can be found in the EPA Technical Support Document (TSD), located in the docket for this rulemaking.

The EPA is proposing to approve the Texas MSW landfill plan submitted by TCEQ in accordance with the requirements of section 111(d) of the CAA and to amend 40 CFR part 62, subpart SS, to codify EPA's approval. The EPA is proposing to find that the Texas MSW landfill plan meets the Federal requirements provided under CAA section 111(d), the MSW landfills EG codified at 40 CFR part 60, subpart Cf, and the CAA section 111(d) implementing regulations at 40 CFR part 60, subpart B. Once approved by the EPA, the Texas MSW landfills plan will become federally enforceable.

In accordance with the requirements of 1 CFR 51.5, we are finalizing regulatory text that includes the incorporation by reference of Texas Administrative Code (TAC) Title 30, Part 1, Chapter 113, Subchapter D, Division 6, adopted July 14, 2023, and effective July 19, 2023, which is part of the CAA section 111(d) Plan applicable to existing MSW landfills subject to the MSW Landfills Emission Guidelines, at 40 CFR part 60, subpart Cf, within TCEQ's jurisdiction in the State of Texas. The regulatory provisions of TAC Title 30, Part 1, Chapter 113, Subchapter D, Division 6, incorporate the MSW Landfills Emissions Guidelines promulgated by the EPA at 40 CFR part 60, subpart Cf, and establish emission standards and compliance times for the control of municipal solid waste landfills, as defined in subpart Cf, that commenced construction, modification, or reconstruction on or before July 17, 2014. The EPA has made and will continue to make TAC Title 30, Part 1, Chapter 113, Subchapter D, Division 6, generally available at the EPA Region 6 office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information). They are also available at: https://www.regulations.gov. This incorporation by reference has been approved by the Office of the Federal Register and the state plan is federally enforceable under the CAA as of the effective date of this final rulemaking.

Under the CAA, the Administrator is required to approve a CAA section 111(d)/129 submission that complies with the provisions of the Act and applicable Federal regulations. 42 U.S.C. 7411(d); 42 U.S.C. 7429; 40 CFR part 60, subparts B and Cf; and 40 CFR part 62, subpart A. Thus, in reviewing CAA section 111(d)/129 state plan submissions, EPA's role is to approve state choices, provided that they meet the criteria of the Act and implementing regulations. Accordingly, this action merely proposes to approve state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason:

This action is not a significant regulatory action as defined in Executive Order 12866 (58 FR 51735, October 4, 1993) and was therefore not subject to a requirement for Executive Order 12866 review.

This action is not an Executive Order 14192 regulatory action because this action is not significant under Executive Order 12866.

This action does not impose an information collection burden under the PRA (44 U.S.C. 3501 et seq. ) because it does not contain any information collection activities.

This action is certified to not have a significant economic impact on a substantial number of small entities under the RFA (5 U.S.C. 601 et seq. ). This action will approve a state plan pursuant to CAA section 111(d) and will therefore have no net regulatory burden for all directly regulated small entities.

This action does not contain any unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. This action imposes no enforceable duty on any State, local, or tribal governments or the private sector.

This action does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999). It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government.

This action will not apply to areas of Indian country within Texas and therefore does not have tribal implications as specified in E.O. 13175 (65 FR 67249, November 9, 2000). This action will neither impose substantial direct compliance costs on federally recognized tribal governments, nor preempt tribal law. This action will not impose substantial direct compliance costs on federally recognized tribal governments because no actions will be required of tribal governments. This action will also not preempt tribal law as no Texas tribe implements a regulatory program under the CAA and thus does not have applicable or related tribal laws.

EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997) as applying only to those regulatory actions that concern environmental health or safety risks that EPA has reason to believe may disproportionately affect children, per the definitions of “covered regulatory action” in section 2-202 of the Executive Order. Therefore, this action is not subject to Executive Order 13045 because it approves a state program.

This action is not subject to Executive Order 13211 (66 FR 28355, May 22, 2001), because it is not a significant regulatory action under Executive Order 12866.

This rulemaking does not involve technical standards. This action is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act.

Participation in virtual public hearing. To request a virtual public hearing, contact the public hearing team at (888) 372-8699 or by email at IPPDpublichearing@epa.gov. If the EPA receives a request for a public hearing, the Agency will hold a hearing via virtual platform on March 18, 2026. The EPA may close a session 15 minutes after the last pre-registered speaker has testified if there are no additional speakers. The EPA will announce further details at https://www.epa.gov/stationary-sources-air-pollution/marine-vessel-loading-operations-national-emission-standards.

If the EPA receives a request for a public hearing, the Agency will begin pre-registering speakers for the hearing no later than one business day after receiving the request. To register to speak at the virtual hearing, please use the online registration form available at https://www.epa.gov/stationary-sources-air-pollution/marine-vessel-loading-operations-national-emission-standards or contact the public hearing team at (888) 372-8699 or by email at IPPDpublichearing@epa.gov. The last day to pre-register to speak at the hearing will be March 15, 2026. Prior to the hearing, the EPA will post a general agenda that will list pre-registered speakers at: https://www.epa.gov/stationary-sources-air-pollution/marine-vessel-loading-operations-national-emission-standards.

The EPA will make every effort to follow the schedule as closely as possible on the day of the hearing; however, please plan for the hearings to run either ahead of schedule or behind schedule.

Each commenter will have four minutes to provide oral testimony. The EPA encourages commenters to submit the text of your oral testimony as written comments to the rulemaking docket.

The EPA may ask clarifying questions during the oral presentations but will not respond to the presentations at that time. The EPA will consider written statements and supporting information submitted during the comment period with the same weight as oral testimony and supporting information presented at the public hearing.

Please note that the EPA will post updates to any aspect of the hearing online at https://www.epa.gov/stationary-sources-air-pollution/marine-vessel-loading-operations-national-emission-standards. While the EPA expects the hearing to go forward as set forth above, please monitor our website or contact the public hearing team at (888) 372-8699 or by email at IPPDpublichearing@epa.gov to determine if there are any updates. The EPA does not intend to publish a document in the Federal Register announcing updates.

If you require special accommodations such as audio description, please pre-register for the hearing with the public hearing team and describe your needs by March 10, 2026. The EPA may not be able to arrange accommodations without advance notice.

Docket. The EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2025-0207. All documents in the docket are listed at https://www.regulations.gov. Although listed, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. The EPA does not place certain other material, such as copyrighted material, on the internet; this material is publicly available only as portable document format (PDF) versions accessible only on EPA computers in the docket office reading room. The public cannot download certain databases and physical items from the docket but may request these items by contacting the docket office at (202) 566-1744. The docket office has 10 business days to respond to such requests. With the exception of such material, publicly available docket materials are available electronically at https://www.regulations.gov or on EPA computers in the docket office reading room at the EPA Docket Center, WJC West Building, Room Number 3334, 1301 Constitution Ave. NW, Washington, DC. The Public Reading Room hours of operation are 8:30 a.m. to 4:30 p.m. ET, Monday through Friday. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the EPA Docket Center is (202) 566-1742.

Written Comments. Direct your comments to Docket ID No. EPA-HQ-OAR-2025-0207. The EPA's policy is that the public docket will contain all comments received without change and made available online at https://www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be CBI or other information for which a statute restricts disclosure. Do not submit electronically to https://www.regulations.gov any information that you consider to be CBI or other information for which a statute restricts disclosure. You should submit this type of information as described in the Submitting CBI section of this preamble.

The EPA may publish any comment received to its public docket. A written comment must accompany multimedia submissions (audio, video, etc. ). The EPA considers the written comment to be the official comment, and it should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( i.e., on the Web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

The https://www.regulations.gov website allows you to submit your comment anonymously, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through https://www.regulations.gov, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any digital storage media you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should not include special characters or any form of encryption and be free of any defects or viruses. For additional information about the EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.

The EPA is soliciting comment on numerous aspects of this proposed rule. The EPA has indexed each comment solicitation with an identifier ( e.g., “C-1, C-2, . . .”) to provide a consistent framework for effective and efficient provision of comments. Accordingly, we ask that commenters include the corresponding identifier when providing comments relevant to that comment solicitation. We ask that commenters include the identifier in either a heading or in the text of each comment ( e.g., “In response to C-1, . . .”) to make clear which comment solicitation you are addressing. We emphasize that we are not limiting comment to these identified areas and encourage you to provide any other comments relevant to this proposal.

Submitting CBI. Do not submit information containing CBI to the EPA through https://www.regulations.gov. Clearly mark the part or all the information that you claim to be CBI. For CBI information on any digital storage media that you mail to the EPA, note the docket ID, mark the outside of the digital storage media as CBI, and identify electronically within the digital storage media the specific information that you claim as CBI. In addition to one complete version of the comments that includes information claimed as CBI, you must submit a copy of the comments that does not contain the information claimed as CBI directly to the public docket through the procedures outlined in the Written Comments section of this preamble. If you submit any digital storage media that does not contain CBI, mark the outside of the digital storage media clearly that it does not contain CBI and note the docket ID. The public docket and the EPA's electronic public docket will include information not marked as CBI without prior notice. The EPA will not disclose information marked as CBI except in accordance with procedures set forth in 40 Code of Federal Regulations (CFR) part 2.

Our preferred method to receive CBI is by electronic transmittal, via email attachments, File Transfer Protocol (FTP), or other online file sharing services ( e.g., Dropbox, OneDrive, Google Drive). You must send electronic submissions directly to the Office of Clean Air Programs (OCAP) CBI Office at the email address oaqps_cbi@epa.gov, and as described earlier in this preamble, you should include clear CBI markings and note the docket ID. If you need assistance with submitting large electronic files that exceed the file size limit for email attachments, and if you do not have your own file sharing service, please email oaqps_cbi@epa.gov to request a file transfer link. If sending CBI information through the postal service, please send it to the following address: OCAP Document Control Officer (C404-02), OCAP, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2025-0207. You should double-wrap and clearly mark the mailed CBI material. Any CBI markings should not show through the outer envelope.

Preamble acronyms and abbreviations. Throughout this preamble the use of “we,” “us,” or “our” refers 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:

The source category that is the subject of this proposal is composed of facilities that conduct MTVLO regulated under 40 CFR part 63 subpart Y (also referred to as the MTVLO NESHAP). The MTVLO source category covers any facility engaged in the direct loading of bulk liquids onto marine vessels at marine terminals. The 2022 North American Industry Classification System (NAICS) code for MTVLO is 4883. The EPA has identified this NAICS code to indicate types of entities that this proposed action likely would affect but notes that this proposed action also may affect facilities classified under other NAICS codes. The proposed standards, if finalized, would directly apply to the affected sources. This proposed action would not have a substantial impact on Federal, State, local, and Tribal entities that own and/or operate MTVLO. The EPA did not include the MTVLO source category in the Initial List of Categories of Sources Under Section 112(c)(1) of the Clean Air Act Amendments of 1990 and Documentation for Developing the Initial Source Category List, Final Report, 1 because the Agency originally intended to regulate the emissions of hazardous air pollutants (HAP) as well as volatile organic compounds (VOC) under CAA section 183(f). 2 After publication of the initial list of source categories, the Agency decided to regulate HAP emissions from major sources of MTVLO facilities under CAA section 112. 3

CAA sections 112 and 301(a), as amended (42 U.S.C. 7401 et seq. ) provide the statutory authority for this action. CAA section 112 establishes a two-stage regulatory process to develop standards for emissions of HAP from stationary sources. Generally, the first stage involves establishing technology-based standards that reflect the maximum achievable control technology (MACT) or an appropriate alternative. 4 The second stage involves evaluating those standards within eight years to determine whether additional standards are needed to address any remaining risk associated with HAP emissions. 5 The EPA commonly refers to this second stage as the “residual risk review.” In addition to the residual risk review, CAA section 112 also requires the EPA to review the standards every eight years and “revise as necessary” taking into account “developments in practices, processes, or control technologies.”  6 This review, commonly referred to as the “technology review,” is the subject of this proposal. The discussion that follows identifies the most relevant statutory sections and briefly explains the contours of the methodology used to implement these statutory requirements.

In the first stage of the CAA section 112 standard setting process, the EPA promulgates technology-based standards under CAA section 112(d) for categories of sources identified as emitting one or more of the HAP listed in CAA section 112(b). Sources of HAP emissions are either major sources or area sources, and CAA section 112 establishes different requirements for major source standards and area source standards. “Major sources” are sources that emit or have the potential to emit 10 tons per year (tpy) or more of a single HAP or 25 tpy or more of any combination of HAP. All other sources are “area sources.” For major sources, CAA section 112(d)(2) provides that the technology-based NESHAP must reflect the maximum degree of emission reductions of HAP that the Administrator determines to be achievable, taking into consideration cost, energy requirements, and non-air quality health and environmental impacts. The EPA commonly refers to these standards as MACT standards. CAA section 112(d)(3) also establishes a minimum control level for MACT standards, known as the MACT “floor,” based on emission limitations achieved in practice by the best performing sources.

In certain instances, as provided in CAA section 112(h), the EPA may set work practice standards in lieu of numerical emission standards. Under CAA section 112(h), the EPA may adopt a work practice standard in lieu of a numerical emission standard if it is “not feasible in the judgment of the Administrator to prescribe or enforce an emission standard for control of a hazardous air pollutant or pollutants.”  7 CAA section 112(h)(2) defines the phrase “not feasible to prescribe or enforce an emission standard” to mean any situation where the Administrator either determines that a HAP or HAPs “cannot be emitted through a conveyance designed and constructed to emit or capture such pollutant, or that any requirement for, or use of such a conveyance would be inconsistent with any Federal, State or local law”  8 or determines that “the application of measurement methodology to a particular class of sources is not practicable due to technological and economic limitations.”  9 The EPA considers a measurement to be not “technologically practicable” within the meaning of CAA section 112(h)(2)(B) if the majority of the measurements are below the detection limit. Such measurements raise issues of questionable reliability, feasibility, and enforceability. Additionally, the application of measurement methodology in such situations could be “not practicable due to . . . economic limitation” within the meaning of CAA section 112(h)(2)(B), because it would result in expenditures that produce analytically suspect measurements.

The EPA must also consider control options that are more stringent than the floor, commonly referred to as beyond-the-floor standards. 10 For area sources, CAA section 112(d)(5) allows the EPA to set standards based on generally available control technologies or management practices (GACT standards) in lieu of MACT standards.

For categories of major sources and any area source categories subject to MACT standards, the second stage focuses on identifying and addressing any remaining ( i.e., “residual”) risk within eight years pursuant to CAA section 112(f). The EPA conducts this review concurrently with the initial technology review pursuant to CAA section 112(d)(6); the EPA commonly refers to the combined review as the “risk and technology review” (RTR). For categories of area sources subject to GACT standards, there is no requirement to address residual risk, but, similar to the major source categories, the technology review is required every eight years. 11

CAA section 112(d)(6) requires the EPA to review standards promulgated under CAA section 112 and revise them “as necessary (taking into account developments in practices, processes, and control technologies)” no less often than every eight years. For this review (the “technology review”), the CAA does not require the EPA to recalculate the MACT floors established in earlier rulemakings. The EPA may consider cost in deciding whether to revise the standards pursuant to CAA section 112(d)(6).

The EPA also must specify relevant test methods, best practices, procedures, or protocols and recordkeeping requirements for standards promulgated under CAA section 112. 12 Further, CAA section 301(a) provides that “[t]he Administrator is authorized to prescribe such regulations as are necessary to carry out his functions.”

The EPA first promulgated MACT standards for the MTVLO source category in 1995. 13 The EPA completed the RTR of the MTVLO NESHAP in 2011. 14 In October 2020, several environmental advocacy organizations filed a citizen suit under CAA section 304, alleging, inter alia, that the EPA failed to conduct mandatory CAA section 112(d)(6) technology reviews for multiple source categories and seeking the court to compel the EPA to complete those reviews. 15 To resolve the litigation, the EPA and the plaintiffs entered into a consent decree. 16 This action satisfies the Agency's obligation to issue a proposed rule pursuant to CAA section 112(d)(6) as a step towards finalizing the results of the technology review.

CAA section 183(f) requires the Administrator, within two years of November 15, 1990, and in consultation with the Secretary of the Department in which the United States Coast Guard (USCG) is operating, to “promulgate standards applicable to the emission of VOCs and any other air pollutant from loading and unloading of tank vessels” as defined in 46 U.S.C. 2101 “which the Administrator finds causes, or contributes to, air pollution that may be reasonably anticipated to endanger public health or welfare.”  17 CAA section 183(f) further requires that these standards apply “reasonably available control technology [(RACT)], considering costs, any non-air quality benefits, environmental impacts, energy requirements, and safety factors associated with alternative control techniques” and that “[t]o the extent practicable such standards shall apply to loading and unloading facilities and not to tank vessels.” As part of the 1995 rulemaking, the EPA promulgated RACT standards under CAA section 183(f) to limit emissions of VOC from new and existing MTVLO sources. 18 The MTVLO NESHAP includes monitoring, inspection, recordkeeping, and reporting requirements that are applicable both to sources subject to MACT emission standards for organic HAP and sources subject to RACT emission standards for VOC.

While the EPA's primary rulemaking objective is to complete the technology review required by CAA section 112(d)(6) the Agency recognizes the efficiencies in codifying the MACT and RACT standards from the 1995 final rule in a single regulation ( i.e., 40 CFR part 63 subpart Y). Thus, some of the revisions proposed in this action would also apply to RACT sources regulated by CAA section 183(f). For example, as part of the CAA section 112(d)(6) technology review, the EPA is proposing revisions to MTVLO monitoring, inspection, recordkeeping, and reporting requirements in the MTVLO NESHAP to ensure sources are meeting the required standards at all times. Considering the overlap of regulatory language between the RACT and MACT standards for control device monitoring in the MTVLO NESHAP, and considering that all existing sources subject to RACT standards are major sources of HAP subject to the MACT standards in the MTVLO NESHAP, the EPA is proposing that these revisions apply to sources subject to RACT standards under CAA section 183(f). In developing this proposed rule, the EPA consulted with the USCG, as CAA section 183(f) requires. Meetings between the EPA and the USCG involved discussions on pertinent issues for the MTVLO NESHAP technology review. The EPA met with the USCG on June 4 and September 2, 2025. A memorandum from each consultation meeting is in the docket for this action. 19

In addition to the docket, an electronic copy of this action is available on the internet. In accordance with 5 U.S.C. 553(b)(4), a summary of this rule may be found at https://www.regulations.gov, Docket ID No. EPA-HQ-OAR-2025-0207. Following signature by the Administrator, the EPA will post a copy of this proposed action at https://www.epa.gov/stationary-sources-air-pollution/marine-vessel-loading-operations-national-emission-standards. Following publication in the Federal Register , the EPA will post the Federal Register version of the proposal and key technical documents at this same website.

A memorandum showing the rule edits that would be necessary to incorporate the changes to 40 CFR part 63 subpart Y proposed in this action is in the docket. 20 Following signature by the EPA Administrator, the EPA also will post a copy of this document to https://www.epa.gov/stationary-sources-air-pollution/marine-vessel-loading-operations-national-emission-standards.

The subject of this proposal is the MTVLO source category, regulated under 40 CFR part 63 subpart Y. As promulgated in 1995 and further amended, the MTVLO NESHAP regulates HAP emissions from the direct loading of bulk liquids from marine vessels at marine terminals. 21

The source category includes sources that directly emit HAP generated or displaced from the marine vessel's cargo tank when loading bulk liquids containing HAP onto marine tank vessels, including vapor collection and control systems, but does not include storage tanks and leaking equipment associated with liquid terminal unloading or ballasting operations. 22 Nor does this source category regulate emissions from offshore vessel-to-vessel bulk liquid transfer operations ( i.e., lightering operations). 23 In the 1995 MTVLO NESHAP final rule, the EPA removed unloading operations and ballasting from the source category in response to public comments. 24 The 1995 MTVLO NESHAP rulemaking established specific MACT and RACT standards designed to reduce VOC and HAP emissions (see section III.A.2). Under the MTVLO NESHAP, facilities were required to monitor performance of the control technology installed to achieve the required emission reductions for the appropriate standard. The 1995 final rule also included reporting and recordkeeping requirements to assure compliance with the promulgated standards. 25

As part of the April 2011 RTR, the EPA re-adopted the existing MACT standards for MTVLO based on its determination that the 1995 MACT standards reduced risk to an acceptable level, provided an ample margin of safety to protect public health, and prevented adverse environmental effects. 26 The EPA also added submerged loading standards for two subcategories of MTVLO as detailed in Table 1: (1) existing MTVLO facilities that are major sources of HAP emissions and that have emissions less than 10 tpy of any individual HAP or 25 tpy of aggregate HAP considering only MTVLO emissions; and (2) existing offshore loading terminals. 27 As part of the 2011 RTR, the EPA identified 152 MTVLO facilities in operation and subject to the MVTLO NESHAP, based on the 2005 National Emissions Inventory (NEI). 28

As part of the current technology review, the EPA identified approximately 190 facilities in operation and subject to the MTVLO NESHAP. The list of facilities is in the document titled List of Facilities Subject to the MTVLO NESHAP, which is in the docket for this action. 29

The EPA used several data sources to identify facilities that are subject to the MTVLO NESHAP. The EPA reviewed the facility list underlying the 2011 RTR and evaluated whether the listed facilities were still operational. Additionally, the EPA evaluated sources from the 2020 Organic Liquids Distribution (Non-Gasoline) RTR rulemaking to identify sources co-located with MTVLO facilities. 30 The EPA also reviewed air emissions permits issued by State regulatory agencies and electronic reports submitted through the Compliance and Emissions Data Reporting Interface (CEDRI) to develop the final facility list. The EPA excluded facilities subject to the marine vessel loading requirements under the National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries, as these sources are part of the petroleum refinery source category. 31 In developing this action, the EPA reviewed the RACT/Best Available Control Technology (BACT)/Lowest Achievable Emission Rate (LAER) Clearinghouse and regulatory documents addressing similar sources published since the 1995 MVTLO NESHAP. Additionally, the EPA reviewed the Army Corps of Engineers' Waterborne Commerce of the United States Statistics Report and used data from that report in developing this proposal action. 32

This action includes proposed amendments to the current flare requirements in the MTVLO NESHAP. In proposing these amendments, the EPA relied on certain technical reports and memoranda developed for flares used as air pollution control devices in the Petroleum Refinery Sector Risk and Technology Review and New Source Performance Standards rulemaking (“2015 Refineries Rule”). 33 For the sake of completeness and for the public's convenience, the EPA has included the most relevant, flare-related technical support documents from the 2015 Refineries Rule in the docket for this rulemaking. 34 Notably, the document titled Technology Review for National Emission Standards for Marine Tank Vessel Loading Operations lists all documents the EPA used to inform the flare provisions in the 2015 Refineries Rule, and is in the current action's docket. Additional information related to the promulgation and subsequent amendments of the NESHAP is available in the docket for this rulemaking.

When conducting a technology review, the EPA primarily focuses on identifying and evaluating developments in practices, processes, and control technologies that have occurred since the Agency last promulgated MACT standards or amendments. Where the EPA identifies such developments, the Agency analyzes technical feasibility, estimated costs, energy implications, and non-air environmental impacts. The EPA also considers the emission reductions associated with the potential application of each development. This analysis informs the Agency's decision whether it is “necessary” to revise the emissions standards. In addition, the EPA considers the appropriateness of applying controls to new sources versus retrofitting existing sources. For this exercise, the EPA considers any of the following to be a “development”:  35

• Any add-on control technology or other equipment that was not identified and considered during development of the original MACT standards;

• Any improvements in add-on control technology or other equipment (that were identified and considered during development of the original MACT standards) that could result in additional emissions reduction;

• Any work practice or operational procedure that was not identified or considered during development of the original MACT standards;

• Any process change or pollution prevention alternative that could be broadly applied to the industry and that was not identified or considered during development of the original MACT standards; and

• Any significant changes in the cost (including cost effectiveness) of applying controls (including controls the EPA considered during the development of the original MACT standards).

In addition to reviewing the practices, processes, and control technologies that the EPA considered during the original promulgation or in previous updates to the NESHAP, the Agency reviews a variety of data sources in our investigation of potential practices, processes, or controls. Pursuant to the decision of the U.S. Court of Appeals for the D.C. Circuit in LEAN, the EPA also reviews the available data to determine if there are any unregulated emissions of HAP within the source category and evaluates this data for use in developing new emission standards. The LEAN decision requires the EPA to address regulatory gaps, such as missing MACT standards for listed air toxics with known emissions from the source category. 36 See sections II.B and II.C of this preamble for information on the specific data sources that the EPA reviewed as part of the technology review.

The EPA evaluated developments in practices, processes, and control technologies since promulgation of the original MACT standards and the subsequent RTR consistent with CAA section 112(d)(6) and as noted in section II.D of this preamble. As noted in section I.B of this preamble, the MTVLO NESHAP also contains RACT standards for the control of VOC from gasoline and crude oil MTVLO. Based on available information, all facilities subject to the RACT standards are also subject to the MACT standards. The memorandum titled Technology Review for National Emission Standards for Marine Tank Vessel Loading Operations summarizes the Agency's technology review and is available in the docket for this rulemaking. 37

The MACT standards apply to major sources of HAP emissions. For “onshore” existing sources, the MTVLO NESHAP requires loading emission controls for facilities that are major sources of HAP emissions and that have emissions above 10 tpy of any individual HAP or 25 tpy of aggregate HAP considering only the MTVLO emissions ( i.e., the “10 or 25 ton” emissions threshold). 38 As part of the 2011 RTR, the EPA established a submerged fill loading standard for sources below the “10 or 25 ton” emissions threshold, in accordance with the MACT floor level of control, 39 and consistent with standards set in place by the USCG. 40

First, the EPA conducted an analysis of MTVLO sources that would have emissions below the “10 or 25 ton” emissions threshold to determine if applying controls to smaller MTVLO would be cost-effective. Based on our analysis, given the low emissions reductions that could be achieved from these sources and the costs associated with additional controls, we are proposing that it is not necessary to amend the requirements under the technology review. We note that the cost effectiveness of implementing additional controls for smaller facilities exceeds $15,000 per ton of organic HAP reduced, which is above the range the EPA generally considers cost effective for organic HAP. 41 Based on this analysis, the EPA determined that the current “10 or 25 ton” HAP emissions applicability threshold is reasonable, and the Agency proposes that no revision to this applicability provision is necessary under the technology review. The EPA solicits comment on its technical evaluation of the MACT applicability thresholds and proposal to maintain the current “10 or 25 ton” standards for onshore existing sources (C-1).

Second, the current MACT standards do not apply to commodities with a vapor pressure less than 1.5 pounds per square inch absolute (psia) at standard conditions. 42 As the USCG already requires marine cargo tanks to meet submerged loading control requirements at 46 CFR 153.282, the EPA assessed whether it would be reasonable to lower this vapor pressure threshold for all materials loaded and whether the Agency should require additional controls beyond submerged loading. Although the EPA found that sources generally would not need more control device capacity, sources would incur additional operational costs ( e.g., increased fuel for thermal oxidizers) to control these low vapor pressure streams and the result would be limited emission reductions. The incremental cost effectiveness for eliminating the 1.5 psia vapor pressure exemption generally exceeded $100,000 per ton of additional HAP removed. The EPA concluded that these costs were not reasonable and thus is proposing no revisions to the vapor pressure exemption. The EPA solicits comment on its proposal to maintain the 40 CFR 63.560(d)(1) exemption provision for commodities with vapor pressure less than 1.5 psia (C-2).

While the EPA is not proposing to revise the applicability thresholds, the Agency is proposing to clarify the emission estimation procedures in 40 CFR 63.565(l) to ensure that all controls for reducing HAP emissions from MTVLO facilities have federally enforceable operating limits. The MACT provisions in the MTVLO NESHAP only apply to major sources of HAP emissions. MTVLO facilities that use controls to get below the major source emission limits can apply for a synthetic minor permit, provided the control provisions are federally enforceable. The current provisions in 40 CFR 63.565( l ) are unclear, and a source could interpret the provisions to allow controls to achieve emissions under 10 and 25 tons without any federally enforceable limits on the continuous operation of the controls. The EPA finds that facilities with pre-controlled emissions of 10- or 25-tons HAP should comply with the control provisions in the MTVLO NESHAP or have enforceable, permitted control requirements to ensure emissions remain below 10- and 25-tons HAP at all times. Specifically, the EPA is proposing to add the word “permitted” to the last sentence in 40 CFR 63.565( l ) so that the sentence applies to test data or techniques “. . . for permitted operating conditions at the source” (emphasis added). The EPA is proposing this revision to ensure that permitted, enforceable control requirements are the sole method for reducing potential emissions when “considering controls.”

The EPA is also proposing to remove the word “actual” in the first sentence of the definitions of “Source(s) with emissions less than 10 and 25 tons” and “Source(s) with emissions of 10 or 25 tons.”  43 These definitions reference the calculation methodology in 40 CFR 63.565(l), which the EPA is proposing to limit to permitted operating conditions. Because the word “actual” could be construed to include emission reductions from controls that are not federally enforceable, the Agency is proposing to remove the word “actual” from these definitions, consistent with the proposed revision to 40 CFR 63.565( l ).

Finally, the EPA is proposing to revise paragraph 40 CFR 63.567(j)(3), regarding the submission of annual HAP control efficiency reports, to require identification of the monitoring parameter(s) used and ensure the source continuously maintains HAP control efficiency while loading a regulated commodity. This revision provides a means to ensure the source is continuously operating the control device in a manner consistent with the performance test or other emission estimation methods used under 40 CFR 63.565( l ). The EPA solicits comments on the number of sources that use controls to achieve emissions less than 10- and 25-tons HAP and whether the rule should require these control requirements to be permitted or otherwise federally enforceable (C-3).

The EPA also requests comment on the proposals to clarify the emission estimation procedures in 40 CFR 63.565(l), the reporting requirement in 40 CFR 63.567(j)(3) to consider only “permitted” controls, and the definitions of “source(s) with emissions less than 10 and 25 tons” and “source(s) with emissions of 10 or 25 tons,” (C-4).

The MTVLO NESHAP includes three subcategories: “onshore” terminals, offshore terminals, and the Alyeska Pipeline Service Corporation's Valdez Marine Terminal (VMT). The MTVLO NESHAP includes “new” and “existing” MACT standards for both onshore and offshore terminals, depending on the quantity of loading emissions. The MACT control requirements in the MTVLO NESHAP for displaced vapors include submerged fill operations and control efficiencies that range from 95 percent for new offshore facilities to 98 percent for new onshore facilities. Table 1 details the MTVLO standards for both MACT and RACT applicable facilities. The table presents RACT applicability thresholds in units of million barrels (MMbbl) and vapor concentrations in units of parts per million by volume (ppmv).

As part of conducting the technology review in accordance with CAA section 112(d)(6), the EPA reviewed Federal and State rules, conducted a review of the RACT/BACT/LAER Clearinghouse, and assessed international best practices applicable to MTVLO and MTVLO sources.

The EPA identified no new technologies for emissions control relevant to the MTVLO source category. However, we evaluated whether improved control device performance and/or cost effectiveness would support the conclusion that amendments are “necessary” pursuant to the technology review. Based on the cost estimates for improving control device performance, the EPA has determined that a marginal control efficiency improvement would likely result in the replacement of existing controls is unreasonable for these sources. As such, the EPA proposes it is not necessary to revise the control standards for vapors displaced during MTVLO. The EPA also evaluated more frequent performance testing related to non-flare controls, as discussed in section III.B.5 of this preamble, and improvements to flare monitoring requirements, as discussed in section III.B.6 of this preamble. The EPA solicits comment on whether there are control technology developments that the EPA should consider in the EPA's technology review of the MTVLO NESHAP (C-5).

The MTVLO NESHAP has standards for monitoring vapor collection systems and control devices to detect leaks and ensure effective routing of vapors to the control device. Owners or operators must conduct annual monitoring using EPA Method 21 and must repair leaks with emissions above a concentration of 10,000 ppmv. Additionally, if at other times an owner or operator identifies a potential leak by audible, visual, or olfactory (AVO) or other detection method, the owners or operator must monitor the potential leak using EPA Method 21 and repair the leak if the monitored concentration exceeds 10,000 ppmv. The rule has no direct equipment leak “standard” ( i.e., no provisions in 40 CFR 63.562) and does not require monitoring for leaks from liquid components ( e.g., pumps, valves, or connections associated with liquid loading lines). The USCG regulations require leak observations at the connection to the ship's cargo fill line, essentially a form of AVO requirements for a portion of the liquid components.

The EPA evaluated a variety of leak detection and repair (LDAR) program requirements, which included adding liquid components to the LDAR program, lowering the leak definition from 10,000 ppmv to 500 ppmv, and conducting more frequent monitoring surveys (semiannual or quarterly monitoring). The EPA used a Monte Carlo model to randomly initiate modeled leaks from individual equipment components present at MTVLO facilities and to estimate the emissions that occur under the various monitoring alternatives that the Agency evaluated. The EPA found that the most cost-effective option assessed was the addition of monitoring requirements for liquid components; however, the incremental cost effectiveness of this option compared to the current provisions exceeds $18,000 per ton of HAP reduced. Additionally, for the approximately 190 facilities subject to the rule, the EPA expects that revisions to the standards would result in minimal reductions in HAP emissions nationwide (between 4 and 7.4 tpy). Therefore, the EPA concludes that including liquid components or revising the leak definition or frequency of EPA Method 21 monitoring is not necessary pursuant to the technology review. For more information on the Monte Carlo model, modeling assumptions, and cost analysis used to assess alternative equipment LDAR programs, see the memorandum titled Technology Review for National Emission Standards for Marine Tank Vessel Loading Operations available in the docket for this rulemaking. 44 The EPA solicits comment on whether the Agency should revise equipment leak provisions to include liquid components, revise the leak definition, or revise the monitoring frequency (C-6).

While the EPA is not proposing standards for equipment leaks within 40 CFR 63.562, the Agency identified several gaps in the compliance provisions at 40 CFR 63.563(c) that warrant clarification.

First, the annual EPA Method 21 monitoring requirement of the vapor collection systems and control devices does not specify that owners or operators at an MVTLO facility must conduct monitoring when actively loading regulated materials (commodities with vapor pressure above 1.5 psia) into marine vessel cargo tanks. However, for EPA Method 21 to effectively detect leaks from the vapor collection system or from a control device, monitoring must occur when the systems and devices are actively loading. Therefore, the EPA is proposing to clarify that owners or operators must conduct the annual EPA Method 21 monitoring during active loading of materials subject to control requirements in 40 CFR 63.562(b), (c), or (d).

Second, the repair requirements in the MTVLO NESHAP only indicate the timing for a “first effort of repair” and do not specify a timeline for completing the repair if the “first effort of repair” is unsuccessful. Therefore, the EPA is proposing to revise this wording to require leak repair within 15 days of identification or prior to the next loading operation, whichever is later. The EPA is also proposing that the owner or operator must verify the repair by re-monitoring the component using the method by which the leak was identified, consistent with LDAR programs in other NESHAP. 45 The EPA solicits comment on the proposed clarifications that EPA Method 21 owners or operators must conduct monitoring when actively loading regulated material and must conduct repair and verify the repair by re-monitoring rather than solely attempt repair (C-7).

Finally, at some new offshore loading terminals, ships are moored by anchoring buoys in open water rather than mooring at the facility's dock. Vapor lines at these offshore loading terminals may be underwater or may float on the water surface. Offshore loading terminals that load ships moored by anchoring buoys have indicated that EPA Method 21 is infeasible on these underwater or floating vapor lines. EPA Method 21 is commonly applied to valves, connectors, flanges, or open-ended lines and not to flexible tubing commonly used for offshore loading. Also, some of the tubing may be underwater. Thus, the use of EPA Method 21 to find leaks in the piping and connectors that are underwater or in the water (with portions of the tubing and connectors in the water) is not technically feasible. Owners or operators can use AVO methods to identify leaks for fully or partially submerged piping or connectors. However, the current rule requires EPA Method 21 monitoring of leaks, identified via AVO methods, to confirm the leak exceeds a 10,000 ppmv concentration. This requirement is technically infeasible for vapor lines in the water. It also adds burden to MTVLO owners and operators since most AVO-detected leaks will need to be fixed and the additional EPA Method 21 monitoring is not needed to find the leak.

Based on our review of the monitoring requirements for vapor collection systems and control devices, the EPA is proposing to exempt certain piping and connections from the annual EPA Method 21 monitoring requirement. Specifically, the EPA is proposing to exempt piping and equipment components that are underwater or floating in the water from EPA Method 21 monitoring and to allow the use of AVO methods for this equipment. Additionally, consistent with other equipment leak provisions, such as those in 40 CFR part 60 subpart VVb, the EPA is proposing to exempt piping and equipment components that require elevating inspecting personnel more than two meters above a support surface ( i.e., difficult-to-monitor components) from EPA Method 21 monitoring requirements. Instead, the EPA is proposing that owners or operators must monitor these equipment components, to the extent practicable, using AVO methods. To implement this revision, the EPA is also proposing to revise the definition of “leak” to include liquid or gaseous releases from vapor collection systems and control devices identified by AVO, or any other method, as a leak. Additionally, the EPA is proposing that owners and operators must repair any leaks identified using AVO, thereby eliminating the EPA Method 21 monitoring requirement for AVO-detected leaks. The EPA solicits comment on the proposed revisions to allow AVO monitoring for vapor lines that may be underwater or may float on the water surface, to allow AVO monitoring for difficult-to-monitor equipment components, and to eliminate the EPA Method 21 monitoring requirement for AVO-detected leaks (C-8).

In addition to the proposed amendments described earlier in this preamble, the EPA is proposing additional revisions to the NESHAP. As part of the 2011 RTR, the EPA revised the SSM provisions of the MTVLO NESHAP to ensure they were consistent with the D.C. Circuit's interpretation of emission standards provisions in Sierra Club v. EPA, 46 and to include an affirmative defense provision related to the availability of penalties. 47 The EPA intended the 2011 final rule to remove all exemptions for periods of SSM in the MTVLO NESHAP but has since identified additional provisions addressing SSM periods that provide exemptions from CAA section 112 standards. Consistent with the 2008 Sierra Club decision, the EPA is proposing to remove both the maintenance allowance provisions and the penalty-related affirmative defense provisions in the MTVLO NESHAP. The EPA is also proposing to require electronic reporting, improve performance testing and monitoring requirements, improve flare monitoring requirements, update cross-references, and clarify certain applicability provisions. We discuss our proposed changes and related analyses later in this preamble.

First, the EPA is proposing to clarify the general duty clause at 40 CFR 63.562(e) by revising this paragraph title from “Operation and maintenance requirements for air pollution control equipment and monitoring equipment for affected sources” to “General duty requirements” to confirm that the general duty requirements apply more broadly to the source (MTVLO terminal) and not only to the control device and monitoring equipment. Second, the EPA is proposing that the general duty requirement applies at all times, including when a marine tank vessel is at the terminal and when no active loading operations are occurring. Some facilities vent or purge MTVLO cargo tanks prior to connecting to control for loading. The EPA considers these displaced vapors, which could otherwise be routed to controls, to be inconsistent with the general duty requirement to minimize emissions. The EPA is also proposing revisions to 40 CFR 63.562(e)(1), (2), (3)(ii) and (iii), and (4) to clarify when owners and operators follow the procedures in the operation and maintenance plan, “variances” to the operating limits are deviations rather than variances from the emission limitations. The operation and maintenance plan should minimize these deviations and include the implementation of corrective actions to prevent reoccurrence. The current operation and maintenance plan requirements include provisions similar to the SSM exemption language that the D.C. Circuit found inconsistent with the statute in Sierra Club. The EPA solicits comment on the proposed revisions to clarify the general duty requirements for MTVLO terminals (C-9).

As part of the 2011 MTVLO NESHAP RTR, the EPA included provisions allowing sources to assert an affirmative defense to civil penalties for violations caused by malfunctions. 48 Under these provisions, if a source could demonstrate in a judicial or administrative proceeding that the source met the regulatory criteria for raising an affirmative defense, the court or the EPA would not assess civil penalties. However, in 2014, the D.C. Circuit in NRDC v. EPA vacated such a penalty-focused affirmative defense provision in another CAA section 112 regulation. 49 The Court found that the EPA lacked authority to establish such an affirmative defense provision for private civil suits because CAA section 304(a) vests authority over private suits in the Federal courts, not the EPA. Specifically, the Court found that “[a]s the language of the statute makes clear, the courts determine, on a case-by-case basis, whether civil penalties are `appropriate,' ” and that this determination “is a job for the courts, not EPA.”  50

Since NRDC, the EPA has been removing such penalty-related affirmative defense provisions from CAA section 112 rules. 51 Here, the EPA is proposing to remove the affirmative defense at 40 CFR 63.562(e)(7), the definition of “affirmative defense” in 40 CFR 63.561 and any references to these provisions from the MTVLO NESHAP as of the effective date of the final amendments. If a source is unable to comply with emissions standards because of a malfunction, the EPA may use its case-by-case enforcement discretion to provide flexibility, as appropriate. Further, as the D.C. Circuit recognized, courts have the discretion to consider any defense raised in an EPA or citizen enforcement action and to determine whether penalties are appropriate. 52 The same is true for the presiding officer in the EPA's administrative enforcement actions. 53

The EPA has long interpreted CAA section 112 as not requiring the Agency to factor emissions that occur during periods of malfunction into the development of CAA section 112 standards. In 2016, the D.C. Circuit upheld this reading in U.S. Sugar Corp. v. EPA. 54 The EPA's reasoning related to the difficulties in determining an appropriate numerical standard that would reflect the MACT standard required by CAA section 112 and the immense variation that would result if the EPA included conditions during a malfunction in the standard-setting process. The court agreed, finding that any such standard would be too broad and meaningless with respect to the intent of CAA section 112 MACT standards. Thus, during periods of malfunction, the EPA generally requires compliance with the otherwise applicable standard for normal operation.

Although no statutory language compels the EPA to set different standards for malfunctions, we have the discretion to do so where certain criteria are met. Under CAA section 112(h), the Administrator may promulgate a “design, equipment, work practice, or operational standard, or combination thereof” to apply in lieu of an emission standard if the Administrator determines (1) that “it is not feasible . . . to prescribe or enforce an emission standard” for the relevant pollutant and (2) that the design, equipment, work practice, or operational standard (or combination thereof) is consistent with the provisions of CAA section 112(d) or (f). 55 If the Administrator promulgates a design or equipment standard under CAA section 112(h)(1), the standard must include “such requirements as will assure the proper operation and maintenance of any such element of design or equipment.”  56 Thus, the EPA may consider whether circumstances warrant setting work practice standards for a particular type of malfunction to minimize emissions. The EPA solicits comment on whether circumstances warrant setting work practice standards for periods of malfunction at MTVLO consistent with the requirements of CAA section 112(h) (C-10).

Additionally, on September 5, 2025, the D.C. Circuit held in SSM Litigation Group v. EPA that although the EPA has no authority under the CAA to “create a regulatory `defense' that limits the remedial authority granted by Congress to the Federal courts,” a “complete affirmative defense, like the one at issue [in that case], is permissible because it relates to the antecedent question of liability and therefore does not impinge on the judiciary's authority to award ‘appropriate civil penalties.' ”  57 Although the affirmative defense provision that the EPA is now proposing to remove is not a “complete” affirmative defense ( i.e., the affirmative defense provision only pertains to civil penalties), the EPA requests comment on whether and how we should address affirmative defense provisions within this and other new source performance standard (NSPS) or NESHAP in response to the SSM Litigation Group decision (C-11). Due to the timing of the D.C. Circuit's decision in SSM Litigation Group and the Agency's consent decree deadline to issue this proposed action, the EPA may address the impacts of the SSM Litigation Group decision on this NESHAP in an appropriate future action but will consider all comments received on this issue in reaching a final decision.

The EPA previously proposed to remove the affirmative defense provisions from the MTVLO NESHAP as part of a proposed rule titled Removal of Affirmative Defense Provisions from Specified New Source Performance Standards and National Emissions Standards for Hazardous Air Pollutants. 58 The EPA now proposes to remove these provisions as part of this action. The EPA will only consider comments submitted to the docket for this action and will not consider comments previously submitted on the prior proposal. 59 The EPA solicits comment on this proposal to remove the affirmative defense provisions from the MTVLO NESHAP (C-12).

Finally, the EPA is proposing to remove the maintenance allowance provisions provided in 40 CFR 63.562(b)(6), (c)(6), and (d)(2)(ii)(B). As explained in the original 1995 rulemaking, the EPA included maintenance allowances as a variance to the emission standard during repairs, and to allow facilities to have additional time beyond the compliance deadline to meet the applicable standards. 60 These provisions are inconsistent with the CAA as interpreted by the D.C. Circuit in Sierra Club. The EPA is proposing to remove these provisions to ensure the consistent use of controls and application of a CAA section 112 standard at all times. Consistent with the removal of the maintenance allowance provisions, the EPA is proposing to remove the definition of “maintenance allowance” in 40 CFR 63.561. The EPA considered the possibility of prescribing specific work practice standards as a potential replacement for the maintenance allowance provisions under 40 CFR 63.562(b)(6), (c)(6), and (d)(2)(ii)(B). CAA section 112(h)(1) states that the Administrator may prescribe a work practice standard or other requirements, consistent with the provisions of CAA section 112(d) or (f), in those cases where, in the judgment of the Administrator, it is not feasible to enforce an emission standard. However, the EPA was unable to identify specific work practice standards that would allow operation to continue consistently with Sierra Club. The EPA is soliciting comment on the removal of maintenance allowance provisions for MTVLO (C-13). The EPA also is soliciting comment on potential work practice standards that could be implemented in lieu of the applicable emission standards during periods of maintenance (C-14).

The EPA is proposing that owners and operators of facilities subject to the MTVLO NESHAP submit electronic copies of required notifications and reports through the EPA's Central Data Exchange (CDX) using CEDRI. The memorandum Electronic Reporting Requirements for New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, describes the electronic data submission process and is available in the docket for this rulemaking.

The 2011 MTVLO NESHAP RTR included requirements that affected sources electronically submit performance test results collected using test methods that are compatible with the EPA's Electronic Reporting Tool (ERT) to the EPA's CDX by using the ERT or other compatible electronic spreadsheet. 61 In this proposal, the EPA is making minor updates to the electronic reporting language for performance tests to reflect the current electronic reporting process ( e.g., all methods are now compatible with the ERT). Similar to performance test results, the EPA proposes to add language that would require submitting continuous emissions monitoring systems (CEMS) performance evaluation results in the format generated through the use of the ERT or an electronic file consistent with the xml schema on the ERT website. 62 Electronic files consistent with the xml schema on the ERT website must accompany all the information required by 40 CFR 63.7(g)(2) in PDF format.

For periodic reports, the proposed rule would require that owners and operators use the appropriate spreadsheet template to submit information to CEDRI. A draft version of the proposed template for this report is in the docket for this action. 63 The EPA specifically requests comment on the content, layout, and overall design of the template (C-15). The proposed rule would require that owners and operators submit all other notifications and reports as a PDF upload in CEDRI.

The electronic submittal of the reports addressed in this proposed rulemaking will increase the usefulness of the data contained in those reports, keep with current trends in data availability and transparency, further assist in the protection of public health and the environment, and improve compliance by facilitating the ability of regulated entities to demonstrate compliance with requirements. Further, the electronic submittal of reports facilitates the ability of the EPA and delegated State, local, Tribal, and territorial air agencies to assess and determine compliance and will ultimately reduce burden on regulated facilities, delegated air agencies, and the EPA. Electronic reporting also eliminates paper-based, manual processes, thereby saving time and resources, simplifying data entry, eliminating redundancies, minimizing data reporting errors, and providing data quickly and accurately to the affected facilities, air agencies, the EPA, and the public. For more information on the benefits 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, referenced earlier in this section.

To facilitate electronic reporting, the EPA proposes to specify several reporting elements commonly included in periodic reports that are not always directly required in the regulatory text (like facility name, address, contact person information, period covered by the report). Specifying these reporting elements provides a clear and distinct reference for all reporting elements included in the reporting form, which improves transparency and clarity for the requirements in each report. Affected sources can easily copy most of these data elements into subsequent reporting forms or save the form as a template with these data elements populated, thus minimizing burden to reporters.

Additionally, the EPA proposes that periodic reporting occur semiannually. Currently, the MTVLO NESHAP includes provisions to allow facilities to request annual reporting after meeting certain conditions. This is inconsistent with the general provisions codified at 40 CFR part 63 subpart A, which establish a default semiannual reporting frequency and only allow requests for reduced reporting frequency in cases that require quarterly periodic reports. Further, the NESHAP currently exempts owners and operators from reporting exceedances if the exceedances occur for less than five percent of the operating time, which is also inconsistent with the general provisions. Table 1 in 40 CFR 63.650 indicates that 40 CFR 63.10(e)(3)(vi) applies. There is no allowance in the general provisions to forego submittal of the summary report based on the duration of exceedances. In fact, the summary report is always required, and the duration of excess emissions and downtime determines when a facility must submit a full excess emissions report. Therefore, the EPA proposes to remove this allowance and to require that each periodic report includes a clear indication of whether there were deviations during the reporting period. If deviations occur, the EPA would require facilities provide information to identify the exceeded operating limit, the time and duration of the deviation, the cause of the deviation, and the taken corrective action or adopted preventative measures.

To better transition from the current “excess emission reports” to semiannual electronic reporting, the EPA proposes to sunset the provisions addressing summary reports and excess emissions and monitoring system performance reports in 40 CFR 63.567(e) and the malfunction reporting in 40 CFR 63.567(m) within 180 days of the publication of the final rule in the Federal Register . On or after 180 days of the publication of the final rule in the Federal Register , the EPA proposes that owners and operators must meet the new reporting requirements in 40 CFR 63.567(o). The reporting requirements in 40 CFR 63.567(o) include information similar to that previously required, as well as reporting elements to improve transparency and clarity for electronic reporting and additional reporting elements based on other proposed revisions, such as reporting elements associated with the enhanced flare monitoring requirements discussed in section III.B.6 of this preamble.

The EPA solicits comment on its proposal to require electronic reporting and the revisions made to the reporting requirements to facilitate electronic reporting and directly report deviations (C-16).

General Provisions Table. Table 1 to 40 CFR 60.560 provides an applicability crosswalk of the part 63 general provisions (40 CFR part 63 subpart A) to the MTVLO NESHAP. Since the EPA last reviewed table 1 to 40 CFR 60.560, the EPA has reserved or eliminated some sections of the general provisions (if they were at the end of a series of paragraphs). Therefore, the EPA is proposing to revise numerous table entries that currently indicate “yes” as the applicability to “no” for sections that are now reserved. The EPA is also proposing to remove table entry lines for sections that no longer exist in the general provisions. For numerous entries, the EPA indicates the general provisions section does not apply because the MTVLO NESHAP does not include opacity monitoring standards. The EPA is proposing to add a comment for several similar entries in table 1 to 40 CFR 60.560 to explain in a consistent manner that these sections do not apply because “[n]o opacity monitoring is required under subpart Y.”

In addition to these straightforward updates, the EPA notes that the current table 1 entry for 40 CFR 63.7(g)(2) indicated “no” for the applicability with a comment marking the section as reserved. The provisions in 40 CFR 63.7(g)(2) now include reporting elements necessary for performance test reports. After reviewing these reporting elements, the EPA proposes to revise the “no” for applicability for 40 CFR 63.7(g)(2) to “yes” because the Agency deems these reporting elements to be reasonable and necessary for inclusion in the performance test report to understand the source being tested, the test methods used, and the operating conditions during the performance test.

Other Cross-Reference Revisions. In our review of the MTVLO NESHAP, the EPA also noted that 40 CFR 63.563(a)(3) referenced 33 CFR 154.814 for operating pressure requirements for the marine tank vessel's vapor collection system. The cross-referenced requirements no longer exist. The EPA reviewed the former requirements and found that these requirements now reside in 33 CFR 154.2103. Therefore, the EPA proposes to replace the outdated cross-reference to 33 CFR 154.814 with reference to 33 CFR 154.2103.

The EPA solicits comment on its proposal to update cross-references in table 1 to 40 CFR 63.560 to account for part 63 general provisions revisions and to update the cross-reference for operating pressure requirements in 40 CFR 63.653(a)(3) (C-17).

In reviewing the exemptions in 40 CFR 63.560(d), the EPA notes that the exclusion in paragraph (d)(6), which involves the applicability of existing offshore loading terminals, is broader than other provisions. Most of the other exclusions include the phrase “pertaining to . . .” that helps focus the exemption, whereas the exclusion in paragraph (d)(6) does not contain that phrase. The EPA notes that the RACT standards do not differentiate between new and existing sources, so the Agency considers this requirement under 40 CFR 63.560(d)(6) to apply specifically to MACT standards. Therefore, the EPA proposes to clarify that the exclusion in 40 CFR 63.560(d)(6) pertains to the MACT standards in 40 CFR 63.562(b). Also, because the VMT source is a standalone affected source with site-specific MACT and RACT standards, the EPA proposes to correct the language in paragraphs 40 CFR 63.560(a) and (b).

The EPA also seeks to clarify the applicability of the RACT provisions to offshore terminals. In the preamble to the 1995 final rule, the EPA explained: “Since most of the other comments noted that the significantly higher costs and poor cost effectiveness shown by these sources . . . would make control requirements unreasonable for these offshore terminals, the Agency determined that the requirements for controls at offshore RACT terminals would not be consistent with the requirements for the technology to be `reasonable.' ”  64 Therefore, the EPA proposes to clarify in the regulatory text, consistent with the 1995 final rule preamble, that the RACT provisions do not apply to offshore loading terminals. The EPA solicits comment on this proposed clarification for the applicability of the MACT and RACT standards to offshore loading terminals (C-18).

The EPA has received inquiries about the applicability of the MTVLO NESHAP to liquified natural gas (LNG) loading terminals. The EPA expects that LNG terminals are exempt under the provision in 40 CFR 63.560(d)(5). The EPA notes that the provision under 40 CFR 63.560(d)(5) is specific to “loading berths that only transfer liquids containing organic HAP as impurities, as that term is defined in 40 CFR 63.561.” The EPA expects that a loading berth used for LNG is specialized for loading LNG and would meet this exemption without revisions to the rule. The EPA requests comment on the need to further clarify the rule applicability related to LNG and whether the exemption in 40 CFR 63.560(d)(5) should refer to the commodity rather than the loading berth (C-19).

As part of the EPA's review of the requirements of the MTVLO NESHAP, the Agency noted that the rule only requires an initial performance test. It is common for the control efficiency of control devices to degrade over time, and periodic performance testing provides a means to update operating parameters and ensure compliance as the control devices age. Therefore, the EPA evaluated requiring periodic performance tests at a minimum frequency of once every 60 calendar months. The EPA estimates that the average control efficiency of regularly tested control devices is 98 percent and that the average control efficiency of devices not periodically tested is 95 percent. Costs per test are estimated at approximately $25,200, with annualized costs of $6,230 considering one performance test over a 5-year period, in 2023 dollars. The EPA assumes the periodic testing would generally lead to higher temperature operating limits. The EPA estimates the annual cost of maintaining the higher temperature operating limits at $1,640 per combustion device. The Agency expects that complying with revised operating limits would entail minimal additional costs for vapor recovery devices. For control devices that use a VOC CEMS, the EPA proposes to require annual relative accuracy test audits (RATAs) to maintain the accuracy of CEMS. The EPA estimates the annual costs of RATA at approximately $19,000. The EPA estimates the average cost effectiveness of the periodic performance test and annual RATA requirements at $7,520 per ton HAP reduced. Based on the analysis of the costs of conducting the performance test and the expected improvement in control device performance over time, the EPA determined that a periodic testing requirement and annual RATA requirement is reasonable. Therefore, the EPA proposes to require periodic performance tests at least once every 60 calendar months and annual RATAs for VOC CEMS. For more detail regarding this assessment, see the memorandum Technology Review for National Emission Standards for Marine Tank Vessel Loading Operations in docket for this rulemaking. 65 The EPA solicits comment on the proposed requirement to conduct periodic performance tests at least once every 60 calendar months and the proposed requirement to conduct annual RATAs (C-20).

The EPA evaluated monitoring requirements to ensure that flares meet the desired minimum control efficiency at all times. Since the previous technology review of the MTVLO NESHAP, the EPA has promulgated numerous standards that include new operating limits and monitoring requirements to ensure flares achieve the MACT level of control at all times, starting with the amendments in the 2015 Refineries Rule. 66 The current MTVLO NESHAP requires that an owner or operator using flares demonstrate initial compliance of those devices with the requirements in 40 CFR 63.11(b), but the MTVLO NESHAP does not require ongoing monitoring. The general provisions at 40 CFR 63.11(b)(1) require “[o]wners or operators using flares to comply with the provisions of this part shall monitor these control devices to assure that they are operated and maintained in conformance with their designs” and state that “[a]pplicable subparts will provide provisions stating how owners or operators using flares shall monitor these control devices.” The EPA believes that the lack of ongoing monitoring requirements in the MTVLO NESHAP conflicts with this general provision requirement. Further, the EPA believes that the general provision requirements are insufficient for ensuring high destruction efficiencies for assisted flares and understands that most flares at MTVLO use assist air or steam.

The 2015 Refineries Rule requires operating limits and monitoring requirements for the following: continuous pilot or flame, visible emissions, maximum flare tip velocity, flare gas flow rate, combustion zone net heating value (NHV cz ), and, for perimeter air-assisted flares, net heating value dilution (NHV dil ) parameter. Additionally, MTVLO facilities co-located with petroleum refineries already must comply with the improved monitoring requirements.

Consistent with the impact analysis conducted for the 2015 Refineries Rule, the EPA assumed that the average control efficiency of MTVLO flares, which are subject only to pilot flame monitoring, would achieve a baseline control device efficiency of approximately 94 percent. The EPA also assumed that those MTVLO flares meeting the operating limits for flares in the 2015 Refineries Rule would achieve at least 98 percent control. Costs to comply with the 2015 Refineries Rule monitoring provisions can vary widely, depending on whether an owner or operator needs continuous net heating value (NHV) monitoring or can use a sampling demonstration for waste gas streams with consistent composition or a fixed minimum NHV. Because MTVLO facilities often load a consistent slate of products and because the control requirements only apply when loading liquids with a vapor pressure of 1.5 psia or greater, the EPA expects most MTVLO facilities are able to conduct a sampling demonstration and use the fixed, minimum NHV from the demonstration rather than install continuous NHV monitors. Also, the EPA expects liquid loading volumes to provide a reasonable measure of the waste gas flow rate from the MTVLO facilities, so waste gas flow monitors would not generally be required. Across all flares used at MTVLO facilities, the EPA estimates the average cost effectiveness of applying the 2015 Refineries Rule's enhanced flare monitoring provisions to the MTVLO source category to be $8,150 per ton of HAP reduced. For more detail regarding this assessment, see the memorandum Technology Review for National Emission Standards for Marine Tank Vessel Loading Operations in the docket for this action. 67 Based on the EPA's analysis of the monitoring costs and the expected improvement in control device performance, the Agency finds the enhanced flare monitoring provisions to be reasonable.

The EPA understands that some flares MTVLO facilities use to control emissions may be subject to a 95 percent (offshore) or 97 percent (existing onshore) control standard. The EPA developed enhanced flare monitoring provisions from the 2015 Refineries Rule to meet a 98 percent control efficiency. Enhanced flare monitoring requirements appear to be necessary because the current provisions in the MTVLO NESHAP do not ensure that these flares consistently meet the required control efficiencies. The EPA notes that flare performance often drops dramatically below the target operating limits, so there is not a significant difference in operating limits to ensure 97 percent control efficiency versus 98 percent control efficiency. The 2015 Refineries Rule applied these enhanced monitoring provisions to all flares at the refinery, including those MTVLO flares at petroleum refineries that cross-reference into the MTVLO NESHAP and are subject to a 95, 97, and 98 percent control efficiency requirements under 40 CFR 63.651(e). Therefore, the EPA proposes to require that flares used to comply with the MTVLO control requirements meet the operating limits in 40 CFR 63.670 and the monitoring requirements in 40 CFR 63.671, with some minor revisions as discussed in the following paragraphs. The EPA also proposes to sunset the flare performance test requirement at 40 CFR 63.565(e) and to add specific flare recordkeeping and reporting requirements in 40 CFR 63.567(o) and (p), consistent with those in the 2015 Refineries Rule and with the proposed flare monitoring requirements. The EPA solicits comment on the proposed revisions to the flare monitoring and recordkeeping requirements, consistent with those included in the 2015 Refineries Rule (C-21).

The EPA proposes revisions to the 14-day grab sampling provisions in 40 CFR 63.670(j)(6)(i)(D) to allow fewer days for collecting samples but to maintain the 14-grab sample requirement. The intent of the 14 samples is to assess the variability of NHV during the low NHV commodity loading scenario to account for these factors. Although the EPA expects the loaded commodity to drive the lowest NHV, the Agency also expects that the NHV will vary somewhat with temperature and with the fill level of the cargo tank. The time that a MVTLO facility needs to load a marine vessel depends on the size of the vessel and can vary from several hours to a week or more. Considering the typical time needed to load a marine tank vessel, the EPA proposes that MVTLO facility owners and operators collect samples at intervals of no less than 60 minutes apart. This will allow the collection of 14 grab samples over a few days but will cover a range of temperatures during the sampling day(s) and different loading liquid levels in the marine vessel's cargo tank. Thus, the EPA expects this sampling schedule would maintain the same level of variability in the samples as expected over a 14-day period. Therefore, the EPA proposes to include in the MTVLO flare requirements at 40 CFR 63.563(b)(5) a provision to allow the collection of 14 grab samples over fewer days, provided at least 60 minutes run between the collection of each grab sample. This provision will reduce the burden of the sampling demonstration while still accounting for changes in NHV due to temperature and other loading conditions. The EPA solicits comment on its proposal for allowing hourly grab samples rather than daily grab samples to determine the consistent or minimum NHV of the flare gas (C-22).

The EPA also proposes to include in the MTVLO flare requirements at 40 CFR 63.563(b)(5) a provision to allow use of the cumulative liquid loading rate as an alternative to monitoring the waste gas flow rate. The EPA expects the MTVLO vapor collection system to operate at low pressures and the flow rate of displaced vapors by the MTVLO facility to be equal to the liquid filling rate. The EPA finalized a similar provision for gasoline loading racks in the gasoline distribution NSPS. 68 The Agency considers this a reasonable alternative for MTVLO sources because of similarities in the processes and operating pressures. The EPA solicits comment on its proposal for allowing the MTVLO source to use volumetric liquid loading rate as a proxy for the flare gas flow rate (C-23).

As part of this review, the EPA noted several inconsistencies in the compliance provisions that the Agency is proposing to address. First, the EPA believes that the temperature operating limits required for condensers and refrigeration units in 40 CFR 63.653(b)(7)(ii) and (iii) are ineffectual and technically unsound. For carbon adsorption units, the temperature operating limit must be “no more than 10 percent or 5.6 [degrees Celsius] °C (10 [degrees Fahrenheit] °F) above the baseline carbon bed temperature, whichever is less stringent.” For condensers, refrigeration units, and combustion devices (except for flares), the temperature operating limit must be “no more than 28 °C (50 °F) below the baseline temperature.” The EPA suspects that the temperature operating limit provisions for condensers and refrigeration units incorrectly uses the combustion device temperature requirement in the provision rather than the carbon adsorber temperature requirement, which would better represent condensers and refrigeration units and provide stronger compliance assurance with the emissions standard. For example, a condenser/refrigeration unit that operated at 35 °F during the performance test would not have comparable emissions reductions to a unit operated at 80 °F, as the amount of VOC that remain uncondensed in the gas stream at 80 °F is much greater than at 35 °F. However, the current provisions in 40 CFR 63.653(b)(7)(ii) and (iii) that allow a 28 °C (50 °F) variance in the condenser/refrigeration unit's operating temperature would allow a condenser/refrigeration unit that operated at 35 °F during the performance test to continuously operate at 80 °F after the performance test. To correct this suspected error, the EPA proposes to revise the temperature requirement for condensers/refrigeration units in 40 CFR 63.653(b)(7)(ii) to be no more than 10 percent or 5.6 °C (10 °F) above the baseline temperature, consistent with the requirement for carbon adsorption units. The EPA solicits comment on the proposed revisions to the temperature operating limit provisions for condensers and refrigeration units (C-24).

Second, the EPA proposes to sunset the provisions that allow owners and operators to use manufacturer's recommendations to set baseline operating temperatures. First, the EPA finds that the MTVLO NESHAP provisions that allow operation at 50 °F below the manufacturer's recommended minimum operating temperature do not ensure that the control device operates at least as high as the manufacturer's recommended minimum temperature. As such, there is no guarantee, even from the manufacturer, that operation at the allowed baseline temperature will meet the required MACT/RACT control efficiencies. Second, as noted in section III.B.5 of this preamble, the EPA proposes periodic performance tests as a means to update operating limits and ensure compliance as the control device ages. Using the manufacturer's recommended minimum operating temperature limit undermines the purpose of using the periodic performance tests to adjust the control device operating limits, as necessary, based on actual performance of the control device as it ages and begins to degrade. Therefore, the EPA proposes that owners and operators can no longer use the provision in 40 CFR 63.565(f)(2), which allows the use of manufacturer's recommended minimum (or maximum) temperature to set baseline temperature for any performance tests conducted after the effective date of the final rule. The EPA proposes to add “, if applicable” in the definition of “baseline operating parameter” and in paragraphs 40 CFR 63.563(b)(4)(ii), 63.564(e)(3), and (h)(1) when referencing the manufacturer's recommended minimum temperature, consistent with the proposed sunsetting of these provisions. The EPA requests comment on the proposal to sunset the use of manufacturer's minimum (or maximum) temperatures and to require that the baseline temperature rely on the control device temperature during the performance test (C-25).

Third, the EPA notes that the RACT compliance option of 1,000 ppmv outlet concentration for gasoline loading is a direct standard, not a parameter operating limit, and suspects that its application is inconsistent between control devices. The RACT standards at 40 CFR 60.562(c)(4) state that an “owner or operator of a source with throughput of 10 M barrels or 200 M barrels, except the VMT source, may meet the requirements of paragraph (c)(3) by reducing gasoline loading emissions to, at most, 1,000 ppmv outlet VOC concentration.” The existing MVTLO NESHAP provides this 1,000 ppmv outlet VOC concentration RACT alternative for gasoline loading carbon adsorption systems in 40 CFR 63.563(b)(6)(iii) and, with some additions, for condensers/refrigeration units in 40 CFR 63.563(b)(7)(iii), but the option is not in the provision for combustion devices (other than flares) or for absorbers. The EPA understands that this compliance option is not appropriate for combustion devices because a combustion device will have significant dilution with combustion air. As such, a 1,000 ppmv outlet VOC concentration for a combustion device would be significantly less stringent than for a 1,000 ppmv outlet VOC concentration recovery device. This may be contrary to the RACT provisions, which require MTVLO using a combustion device to achieve a 98 percent reduction, while a recovery device is only required to achieve a 95 percent reduction. Thus, the EPA agrees that the 1,000 ppmv outlet VOC concentration alternative should not apply to MTVLO using a combustion device. However, as currently worded, the alternative in 40 CFR 60.562(c)(4) appears to apply to both provisions in 40 CFR 60.562(c)(3). Therefore, the EPA proposes to clarify in 40 CFR 60.562(c)(4) that this 1,000 ppmv outlet VOC concentration limit is only available as an alternative to the requirements in 40 CFR 60.562(c)(3) when using a recovery device.

With that proposed clarification, the EPA finds no reason not to provide this 1,000 ppmv outlet VOC concentration compliance option equally for all recovery devices. Therefore, the EPA proposes to add compliance options at 40 CFR 63.563(b)(8)(iii) to allow owners and operators of absorbers to use this outlet concentration standard, when it applies. The EPA also proposes to revise the compliance provisions in 40 CFR 63.563(b)(7)(iii) for condenser/refrigeration units to parallel the compliance provisions for this alternative provided for other recovery devices. As previously noted, the temperature operating limit provided in 40 CFR 63.563(b)(7)(iii) is inappropriate, and the EPA is proposing to remove this temperature operating limit option for the 1,000 ppmv VOC compliance alternative.

While the MTVLO NESHAP provides some operational flexibility for operating parameters used to ensure the source is operating similarly to when the source conducted the performance test and demonstrated compliance with the applicable standard, the EPA finds no rationale for allowing similar flexibility when complying with a direct emissions limit. The EPA finds the current provisions that allow up to 1,200 ppmv VOC outlet concentrations for this alternative effectively allows exceedances of this direct emissions limitation. Therefore, the EPA proposes to revise the compliance requirements for this optional standard to require compliance with the 1,000 ppmv limit at all times, rather than allowing deviations up to 1,200 ppmv. The EPA solicits comment on the proposed revisions to the 1,000 ppmv VOC outlet concentration RACT alternative, specific for gasoline loading operations, to clarify this provision is an alternative only for RACT facilities using recovery devices and to treat this limit as a direct emissions limit. The EPA also requests information on the number of sources currently complying with this 1,000 ppmv VOC outlet concentration limit (C-26).

In assessing the 1,000 ppmv VOC outlet concentration RACT alternative in relationship with the MACT requirements, the EPA investigated whether any facilities could use that alternative. The EPA expects that terminals meeting the throughput thresholds for RACT facilities would also be major sources of HAP emissions subject to MACT requirements. Since the MACT standard for existing onshore sources require a minimum of 97 percent reduction independent of the control device, the EPA expects these RACT facilities using a recovery device would have to comply with the MACT requirements and that the RACT provisions allowing 95 percent reduction or 1,000 ppmv VOC outlet concentration would not apply.

The EPA proposes to clarify in 40 CFR 63.560(a)(2) that the MACT emission standards do not apply below the emissions threshold. Similarly, the EPA proposes to clarify in 40 CFR 63.560(b)(2) that the RACT emission standards do not apply below the throughput threshold. Finally, the EPA proposes to add overlap provisions at 40 CFR 63.560(f) that directly address cases where MACT and/or RACT provisions apply. For sources other than the VMT source, the EPA proposes to clarify that sources subject to both the MACT standards in 40 CFR 63.562(b) and the RACT standards in 40 CFR 63.562(c), respectively, must comply only with the most stringent of the applicable requirements. Thus, MTVLO terminals meeting the applicability requirements for both MACT and RACT standards would have to comply with the 98 percent control efficiency requirement when using a combustion device and comply with the 97 percent control efficiency requirement when using a recovery device. The EPA requests comment on the proposed overlap provisions and associated clarifications to limit the exclusion of the standards as provided in 40 CFR 63.560(a)(2) and (b)(2) (C-27).

The EPA proposes several revisions to clarify and provide consistency in the MTVLO NESHAP requirements:

• The EPA proposes revisions to 40 CFR 63.560(e) to clarify the compliance dates for offshore terminals and remove erroneous references to the VMT source.

• The EPA proposes revisions to the definition of “affected sources” in 40 CFR 63.561 to more clearly delineate that sources subject to the submerged loading standards are affected sources under the MTVLO NESHAP.

• The EPA proposes to revise the definition of “marine tank vessel loading operation” in 40 CFR 63.561 to clarify that loading commodities at an offshore loading terminal qualifies as a MTVLO source.

• The EPA proposes to add a definition of “regulated commodity” to mean any commodity other than those exempted under 40 CFR 63.560(d)(1) or (5) as a term of convenience for some of the proposed recordkeeping and reporting requirements.

• The EPA proposes an editorial revision the definition of “terminal” in 40 CFR 63.561 to replace “land or sea based structure(s)” with “land- or sea-based structure(s).”

• The EPA proposes to add “captured” prior to “HAP emissions” in 40 CFR 63.652(b)(3) and (4), consistent with the phrasing used in 40 CFR 63.652(b)(2).

• The EPA proposes to replace “HAP” with “VOC” in 40 CFR 63.562(c)(5) because these are RACT provisions that regulate VOC rather than HAP.

• The EPA proposes to add “and VOC” following “HAP” because these are both MACT and RACT provisions that regulate both HAP and VOC vapors from MTVLO sources.

• The EPA proposes to correct subparagraph cross-references in 40 CFR 63.562(d)(2)(ii)(B) by replacing references to paragraphs (d)(2)(ii)(B)( a ), ( b ), or ( c ) with (d)(2)(ii)(B)( 1 ), ( 2 ), or ( 3 ), respectively.

• The EPA proposes to clarify that the “cycle” is the average duration of the individual performance test runs for the operating limits based on performance test data.

The EPA requests comment on the proposed editorial revisions and requests information on other revisions that would improve the clarity of the rule requirements (C-28).

This proposed action contains several discrete components, which the EPA views as severable as a practical matter— i.e., they are functionally independent and if finalized as proposed would operate in practice independently of the other components. These discrete components are generally delineated by the section headings within section III.B of this document. For example, the proposed electronic reporting provisions, performance testing provisions, and flare monitoring provisions discussed in sections III.B.2, III.B.5, and III.B.6 generally function independently of one another. The EPA invites comment on the severability of this proposed rule, and in particular whether any components are not functionally independent (C-29).

Most of the proposed revisions are clarifications and editorial revisions. The EPA proposes that the compliance date for these clarifications ( i.e., those not specifically addressed below) would be the effective date of the final rule. The EPA is proposing additional compliance time for a limited number of proposed revisions. The following sections provide the proposed compliance dates for revisions that have a compliance date other than the effective date of the final rule and our rationale for the proposed compliance dates. The EPA requests comment on the proposed compliance dates for the proposed revisions to the MTVLO NESHAP (C-30).

The EPA proposes to provide 180 days after the effective date of the final rule to comply with the proposed electronic reporting requirements. This will generally allow facilities to complete their reporting period under the current provisions and provide sufficient time to transition to the new electronic reporting requirements.

The EPA proposes that owners and operators conduct the first periodic performance test within 180 days of the effective date of the final rule. The Agency considers 180 days to be as expedient as realistically practicable for MTVLO terminals. This allows owners and operators time to identify an appropriate testing contractor and to schedule and conduct the performance tests. Additionally, the EPA proposes to allow owners and operators to use tests conducted up to two years prior to the effective date of the final rule as the first periodic performance test. This will reduce the burden on owners and operators who have recently conducted testing by allowing them to use data that is still representative of facility operations and control device performance instead of immediately requiring a new performance test.

The EPA proposes to provide three years to comply with the additional monitoring requirements proposed for flares. This is consistent with the timeframe we provided for petroleum refineries when first proposing those requirements. The new requirements may require owners or operators to upgrade monitoring systems, and three years is as expedient as realistically practicable considering the number of monitoring systems that owners or operators may need to upgrade.

The EPA proposes that other proposed revisions would become effective on the effective date of the final rule.

The EPA estimates that approximately 190 facilities are subject to the MTVLO NESHAP MACT standards. The list of facilities is in the document titled List of Facilities Subject to the MTVLO NESHAP in the docket for this rulemaking. 69

The EPA estimates that the proposed amendments to the NESHAP would reduce overall VOC and HAP emissions from the MTVLO source category by 3,500 tpy and 280 tpy, respectively. These reductions include approximately 118 tons per year of hexane emissions, 62 tons of benzene emissions, and 56 tons of methanol emissions.

Considering secondary impacts ( e.g., emission increases associated with supplemental fuel or additional electricity), the EPA estimates that the proposed action would result in additional criteria pollutant emissions of 14.7 tpy of carbon monoxide and 3.2 tpy of nitrogen oxides. For more information about the estimated emission reductions and secondary impacts of this proposed action, see the memorandum Technology Review for National Emission Standards for Marine Tank Vessel Loading Operations in the docket. 70

The proposed action would cost (in 2023 dollars) approximately $3,560,000 in first year costs (testing and initial demonstrations); $3,000,000 in capital costs for monitoring systems; and an estimated $2,135,000 in total annualized costs (TACs) based on our analysis of the proposed changes to testing and flare monitoring described in section III.B.5 and III.B.6 of this preamble. For more detail regarding this assessment, see the memorandum Technology Review for National Emission Standards for Marine Tank Vessel Loading Operations included in the docket for this rulemaking. 71

The EPA conducted an economic impact analysis for this proposal, Economic Impact Analysis for the Proposed National Emission Standards for Hazardous Air Pollutants (NESHAP) for Marine Tank Vessel Loading Operations, which is available in the docket for this rulemaking. 72

The EPA often prepares a partial equilibrium analysis for economic impact analyses of rules that directly affect industries. In this type of economic analysis, the EPA estimates any impacts on a single affected industry or several affected industries. The EPA assumes that all impacts of this rule on industries outside of those affected are zero or so inconsequential that those impacts do not require consideration in the analysis. If the compliance costs, which are key inputs to an economic impact analysis, are quite insignificant, then the impact analysis could consist of a calculation of annual (or annualized) costs as a percentage of sales for affected companies. The EPA applies this latter type of analysis (termed a screening analysis) when the Agency deems a partial equilibrium or more complex economic impact analysis unnecessary given the expected size of the impacts.

The EPA calculates the economic impacts of the proposal on small entities as the percentage of TACs incurred by affected ultimate parent owners to their revenues. This ratio provides a measure of the direct economic impact to ultimate parent owners of MTVLO terminals while presuming no impact on consumers. The EPA estimates the average small entity impacted by the proposal will incur TACs of 0.50 percent of their revenue, with none exceeding 4.11 percent. The EPA estimates fewer than 20 percent of impacted small entities will incur TACs greater than one percent of their revenue. This is based on a conservative estimate of costs imposed on ultimate parent companies, where TACs are an average across all facilities due to lack of facility specific cost information.

In addition to the screening analysis, the EPA also prepared a present value analysis to capture the stream of costs over time. The EPA selected a 15-year period from 2027 to 2041 as the best measure of the economic impacts of this action. This allows for a reasonable and consistent timeframe over which to examine impacts of this proposed action from a present value (PV) perspective and aligns with several cycles of performance testing and emission monitor procurement. The PV of costs in 2024 dollars is approximately $19 million using a three percent discount rate and $15 million using a seven percent discount rate. The equivalent annualized value (EAV) in 2024 dollars is approximately $1.6 million using a discount rate of three percent and $1.7 million using a discount rate of seven percent.

Given the results of the analysis, these economic impacts are relatively low for affected industries and entities impacted by this proposed rule, and the EPA does not anticipate substantial impacts on the markets for affected products. The EPA does not expect costs of the proposed rule to result in a significant market impact, regardless of whether the firms pass costs to the purchaser or absorb costs. The EPA expects minimal to no impacts on employment.

If finalized, this proposed rule would reduce HAP and VOC emissions from MTVLO sources. VOCs form ground-level ozone in conjunction with nitrogen oxides and in the presence of sunlight. Due to methodology and data limitations, the EPA did not attempt to monetize the health benefits of HAP reductions in this analysis. The Economic Impact Analysis for this proposed action includes a qualitative discussion of the health effects associated with HAP emitted from sources subject to control under the proposed action.

The EPA is obligated to present the agency's best scientific understanding and the implications of that science when developing policies and regulations. However, the EPA's analytical practices may not have presented the full range of uncertainties and associated confidence level regarding the potential benefit estimates from reduction in exposure from fine particulate matter (PM 2.5 ) and ozone. In addition, the science regarding the exposure, health effects from exposure and valuation of reduction in health effect are evolving with better data and methods, especially at low concentrations of PM and ozone. The EPA's use of benefit per ton (BPT) monetized values introduces additional uncertainty. Although developed as a screening tool when full-form photochemical modeling was not feasible, the BPT approach reduces complex spatial and atmospheric relationships and may be more suited to model emissions that are geographically more uniform and species better mixing, thereby adding uncertainty associated with those estimates. Some of the sources of uncertainties include the set of assumptions used in projecting the health impact of reducing particulate matter. These projections are based on a series of models that take into account emissions changes, resulting distributions of changes in ambient air quality, the estimated reductions in health effects from changes in exposure, and the composition of the population that will benefit from the reduced exposure. Each component includes assumptions, each with varying degrees of uncertainty.

In addition, the EPA historically provided point estimates rather than just ranges of emission-related effects or only quantifying emissions when monetizing proved to be too uncertain. Therefore, to address these concerns, the EPA is refraining in providing primary estimates resulting from changes in PM 2.5 and ozone exposure resulting from changes in VOC emissions but will continue to quantify the emissions until the Agency if confident enough in the modeling to robustly monetize those impacts.

The EPA solicits comments on this proposed action. In addition to general comments on this proposed action, the EPA is also interested in additional data that may improve the analyses (C-31). The EPA is specifically interested in receiving any information regarding developments in practices, processes, and control technologies that reduce HAP emissions.

C-1: Should the EPA maintain the current applicability standards for onshore existing sources?

C-2: Should the EPA maintain the vapor exemption provision established under 40 CFR 63.560(d)(1)?

C-3: Do facilities currently use controls to achieve emissions less than 10- or 25-tons HAP and are these controls federally enforceable?

C-4: Should the emission estimation procedures in 40 CFR 63.565(l) be limited to federally enforceable (“permitted”) controls?

C-5: Are there any control technology developments that the EPA should consider as part of the EPA's technology review?

C-6: Should the EPA maintain current monitoring requirements for vapor collection system, or should the EPA revise the equipment leak provisions to include liquid components, revise the leak definition, or revise the monitoring frequency?

C-7: Should the EPA require sources to conduct EPA Method 21 monitoring when actively loading regulated material, and should the EPA require repair of leaks within 15 days or prior to the next loading operation?

C-8: Should the EPA allow AVO monitoring for vapor lines that are under water or float on the water surface and for difficult-to-monitor equipment components, and should the EPA eliminate the subsequent EPA Method 21 monitoring requirement for AVO detected leaks?

C-9: Should the EPA broaden and strengthen the general duty provision for MTVLO terminals?

C-10: Do circumstances warrant setting work practice standards for periods of malfunction at MTVLO consistent with the requirements of CAA section 112(h)?

C-11: How should the Agency address affirmative defense provisions in other NSPS or NESHAP rules in response to the D.C. Circuit's SSM Litigation Group decision?

C-12: Should the EPA remove the affirmative defense provisions from the MTVLO NESHAP?

C-13: Should the EPA remove maintenance allowance provisions from the MTVLO NESHAP?

C-14: What potential appropriate work practice standards could the EPA require, in light of the proposed removal of the maintenance allowance provision?

C-15: What additional aspects should the EPA consider regarding the content, layout, and overall design of the CEDRI electronic reporting template?

C-16: Should the EPA require electronic reporting?

C-17: Should the EPA update the general provisions cross-references in table 1 and the outdated cross-reference to operating pressure requirements in 40 CFR 63.653(a)(3)?

C-18: How should MACT and RACT standards apply to offshore marine terminals?

C-19: Should the EPA clarify the exemption at 40 CFR 63.560(d)(5) or otherwise amend the rule to clarify the applicability of the rule to loading LNG in marine tank vessels?

C-20: Should the EPA require periodic performance tests at least every five years (60 calendar months), and the proposed requirement to conduct and annual RATA?

C-21: Should the EPA enhance the flare monitoring and recordkeeping provisions in accordance with those provisions in the 2015 Refineries Rule?

C-22: Should the EPA allow hourly grab samples rather than daily grab samples to determine the consistent or minimum NHV of the flare gas?

C-23: Should the EPA allow sources to use the MTVLO liquid loading rate as a proxy for the flare gas flow rate?

C-24: What are appropriate temperature operating limits for condensers and refrigeration units?

C-25: Should the EPA require the baseline temperature operating limit to be based on the control device temperature during the performance test?

C-26: Should the EPA treat the 1,000 ppmv VOC outlet concentration alternative as a direct emission limit only allowed specifically for all recovery devices, and how many facilities would revisions to the 1,000 ppmv VOC outlet concentration standard impact?

C-27: Should the EPA include an overlap provision to clarify applicability of requirements for facilities subject to MACT and RACT standards?

C-28: Should the EPA implement the proposed editorial revisions listed in Section III.B.8 and are there additional editorial revisions needed to improve the clarity of the rule?

C-29: Should the EPA consider any components of this proposed rule not functionally independent or severable?

C-30: Are the compliance dates for the proposed revisions to the MTVLO NESHAP appropriate?

C-31: The EPA solicits comment on whether there is any additional data that may improve the analyses for this technology review, including the number of affected sources.

Additional information about these statutes and Executive Orders is available at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

This action is a significant regulatory action that was submitted to OMB for review. Any changes made in response to E.O. 12866 interagency review recommendations have been documented in the docket for this rulemaking. The EPA prepared an economic analysis of the potential costs and benefits associated with this action. This analysis, Economic Impact Analysis for the Proposed National Emission Standards for Hazardous Air Pollutants (NESHAP) for Marine Tank Vessel Loading Operations, is available in the docket for this rulemaking and is briefly summarized in section IV of this preamble. 73

This action is expected to be an Executive Order 14192 regulatory action. Details on the estimated costs of this proposed rule can be found in the EPA's analysis of the potential costs and benefits associated with this action.

The information collection activities in this proposed rule have been submitted for approval to OMB under the PRA. The Information Collection Request (ICR) document that the EPA prepared is assigned OMB Control Number 2060-0289 (EPA ICR number 1679.13). You can find a copy of the ICR in the docket for this rule, and it is briefly summarized here.

In this action, the EPA is proposing enhanced flare monitoring requirements, requirements to perform periodic performance testing, and electronic reporting provisions. The rulemaking also addresses emissions during SSM and includes other minor clarifications and corrections. This information will be collected to ensure compliance with the MTVLO NESHAP.

Respondents/affected entities: Owners or operators of marine tank vessel loading operation terminals.

Respondent's obligation to respond: Mandatory (40 CFR part 63 subpart Y).

Estimated number of respondents: 190 (assumes no new respondents over the next three years).

Frequency of response: Initially, semiannually, and annually.

Total estimated burden: 1,950 hours (per year). Burden is defined at 5 CFR 1320.3(b).

Total estimated cost: $2,135,128, includes $1,945,841 annualized capital or operation & maintenance costs.

An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB control number. The OMB control numbers for the EPA's regulations in 40 CFR are listed in 40 CFR part 9. Submit your comments on the Agency's need for this information, the accuracy of the provided burden estimates and any suggested methods for minimizing respondent burden to the EPA using the docket identified at the beginning of this rule. The EPA will respond to any ICR-related comments in the final rule. You may also send your ICR-related comments to OMB's Office of Information and Regulatory Affairs using the interface at https://www.reginfo.gov/public/do/PRAMain. Find this information collection by selecting “Currently under Review—Open for Public Comments” or by using the search function. OMB must receive comments no later than April 3, 2026.

I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA. The small entities subject to the requirements of this action are small businesses and government jurisdictions within the MTVLO source category. The Agency has identified 26 small entities that may be impacted by this proposed rule. The EPA calculated the cost-to-sales ratios for all the affected facilities to determine (i) the magnitude of the costs of the rule, and (ii) whether there would be a significant impact on small entities compared to large entities. On average the small entities are estimated to experience an impact of 0.50 percent cost-to-sales. The results of this small entity screening analysis do not indicate that a substantial share of the small entities affected by this rule would incur potentially high costs relative to their revenues. Details of this analysis are presented in Economic Impact Analysis for the Proposed National Emission Standards for Hazardous Air Pollutants (NESHAP) for Marine Tank Vessel Loading Operations, which is available in the docket for this action.

This action does not contain an unfunded mandate of $100 million or more as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. The action imposes no enforceable duty on any State, local or Tribal governments or the private sector.

This action does not have federalism implications. It will not have substantial direct effects on the States, on the relationship between the National Government and the States, or on the distribution of power and responsibilities among the various levels of government.

This action does not have Tribal implications as specified in Executive Order 13175. None of the facilities that have been identified as being affected by this action are owned or operated by Tribal governments or located within Tribal lands. Thus, Executive Order 13175 does not apply to this action. However, consistent with the EPA Policy on Consultation and Coordination with Indian Tribes, the EPA will offer government-to-government consultation with Tribes upon request.

Executive Order 13045 directs Federal agencies to include an evaluation of the health and safety effects of the planned regulation on children in Federal health and safety standards and explain why the regulation is preferable to potentially effective and reasonably feasible alternatives. This action is not subject to Executive Order 13045 because it is not a significant regulatory action under section 3(f)(1) of Executive Order 12866, and because the EPA does not believe the environmental health or safety risks addressed by this action present a disproportionate risk to children. The proposed revisions reduce HAP and VOC emissions generated from MTVLO and are projected to improve overall health, including that of children.

This action is not a “significant energy action” because it is not likely to have a significant adverse effect on the supply, distribution or use of energy. The amendments proposed in this action involve minor improvements to the monitoring, inspection, recordkeeping, and reporting requirements for MTVLO and would have a minimal impact on the amount of imports or exports of crude oils, condensates, or other organic liquids used in the energy supply industries. Additionally, the EPA expects this proposed action would not reduce crude oil supply, fuel production, coal production, natural gas production, or electricity production. Thus, given the minimal impacts on energy supply, distribution, and use nationally, no significant adverse energy effects are expected to occur. For more information on these estimates of energy effects, please refer to the supporting document, Economic Impact Analysis for the Proposed National Emission Standards for Hazardous Air Pollutants (NESHAP) for Marine Tank Vessel Loading Operations, which is available in the docket for this rulemaking.

The NTTAA requires the EPA to use voluntary consensus standards (VCS) in addition to the EPA methods in regulatory activities unless doing so would be inconsistent with applicable law or otherwise impracticable. VCS are technical documents, such as test methods, that are developed or adopted by VCS bodies using procedures that ensure that the standards development process is open to all interested parties. VCS bodies are generally private sector, not-for-profit entities such as the American Society for Testing and Materials. The EPA searched the Enhanced NSSN Database managed by the American National Standards Institute for VCS that could be used in the MTVLO NESHAP. The EPA also contacted VCS organizations and accessed and searched their databases. While the EPA made a reasonable effort to identify and evaluate potentially practical VCS, our findings do not necessarily represent all potential alternative standards which may exist.

The EPA searched for acceptable alternatives for EPA Methods 1, 1A, 2, 2A, 2C, and 2D of 40 CFR part 60, Appendix A-1; EPA Methods 21, 22, 25, 25A, and 25B of 40 CFR part 60, Appendix A-7; EPA Performance Specification 8 of 40 CFR part 60, Appendix B; and, EPA Method 301 of 40 CFR part 63, Appendix A. The Agency found no VCS are acceptable alternatives for these EPA methods and performance specification.

According to 40 CFR 63.7(f) and 40 CFR 63.8(f) of subpart A of the general provisions, a source may apply to the EPA to use alternative test methods or alternative monitoring requirements in place of any required testing methods, performance specifications or procedures in the final rule or subsequent amendments.

The EPA welcomes comments on this aspect of the proposed rulemaking and specifically invites the public to identify potentially applicable VCS and to explain why such standards should be used in this regulation.

EPA is issuing a proposed rule to delete six sites and partially delete two sites from the NPL and requests public comments on these proposed actions. The NPL constitutes appendix B of 40 CFR part 300 which is the NCP, which EPA created under section 105 of the CERCLA statute of 1980, as amended. EPA maintains the NPL as those sites that appear to present a significant risk to public health, welfare, or the environment. Sites on the NPL may be the subject of remedial actions financed by the Hazardous Substance Superfund (Fund). These partial deletions are proposed in accordance with 40 CFR 300.425(e) and are consistent with the Notice of Policy Change: Partial Deletion of Sites Listed on the National Priorities List. 60 FR 55466 (November 1, 1995). As described in 40 CFR 300.425(e)(3) of the NCP, a site or portion of a site deleted from the NPL remains eligible for Fund-financed remedial action if future conditions warrant such actions.

EPA will accept comments on the proposal to delete or partially delete these sites for thirty (30) days after publication of this document in the Federal Register .

Section II. of this document explains the criteria for deleting sites from the NPL. Section III. of this document discusses procedures that EPA is using for this action. Section IV. of this document discusses the site or portion of the site proposed for deletion and demonstrates how it meets the deletion criteria, including reference documents with the rationale and data principally relied upon by the EPA to determine that the Superfund response is complete.

The NCP establishes the criteria that EPA uses to delete sites from the NPL. In accordance with 40 CFR 300.425(e), sites may be deleted from the NPL where no further response is appropriate. In making such a determination pursuant to 40 CFR 300.425(e), EPA will consider, in consultation with the State, whether any of the following criteria have been met:

i. Responsible parties or other persons have implemented all appropriate response actions required;

ii. All appropriate Fund-financed response under CERCLA has been implemented, and no further response action by responsible parties is appropriate; or

iii. The remedial investigation has shown that the release poses no significant threat to public health or the environment and, therefore, the taking of remedial measures is not appropriate.

Pursuant to CERCLA section 121(c) and the NCP, EPA conducts five-year reviews to ensure the continued protectiveness of remedial actions where hazardous substances, pollutants, or contaminants remain at a site above levels that allow for unlimited use and unrestricted exposure. EPA conducts such five-year reviews even if a site is deleted from the NPL. EPA may initiate further action to ensure continued protectiveness at a deleted site if new information becomes available that indicates it is appropriate. Whenever there is a significant release from a site deleted from the NPL, the deleted site may be restored to the NPL without application of the hazard ranking system.

In accordance with 40 CFR 300.425(e), the following procedures apply to the deletion or partial deletion of the sites in this proposed rule:

(1) EPA consulted with the respective State before developing this Notice of Intent for deletion.

(2) EPA has provided the State 30 working days for review of site deletion documents prior to publication of it today.

(3) In accordance with the criteria discussed above, EPA has determined that no further response is appropriate.

(4) The State, through their designated State agency, has concurred with the proposed deletion action.

(5) Concurrently, with the publication of this Notice of Intent for deletion in the Federal Register , a notice is being distributed to the surrounding community via one or more of the following methods: publication in a major local newspaper of general circulation near the site, a news release, listservs, social media, or the site's web page. The notice announces the 30-day public comment period concerning the proposed action for deletion.

(6) EPA placed copies of documents supporting the proposed deletion in the deletion docket and made these items available for public inspection and copying at the Regional Records Center identified above.

If comments are received within the 30-day comment period on this document, EPA will consider the comments and respond accordingly before making a final decision to delete or partially delete the site. If necessary, EPA will prepare a Responsiveness Summary to address any significant public comments received. After the public comment period, if EPA determines it is still appropriate to delete or partially delete the site, the EPA will publish a final Notice of Deletion or Partial Deletion in the Federal Register . Public notices, public submissions and copies of the Responsiveness Summary, if prepared, will be made available to interested parties and included in the site information repositories listed above.

Deletion of a site or a portion of a site from the NPL does not itself create, alter, or revoke any individual's rights or obligations. Deletion of a site or a portion of a site from the NPL does not in any way alter EPA's right to take enforcement actions, as appropriate. The NPL is designed primarily for informational purposes and to assist EPA management. Section 300.425(e)(3) of the NCP states that the deletion of a site from the NPL does not preclude eligibility for future response actions, should future conditions warrant such actions.

The site to be deleted or partially deleted from the NPL, the location of the site, and docket number with information including reference documents with the rationale and data principally relied upon by the EPA to determine that the Superfund response is complete are specified in table 1. The NCP permits activities to occur at a deleted site, or that media or parcel of a partially deleted site, including operation and maintenance of the remedy, monitoring, and five-year reviews. These activities for the site, or portion of the site being deleted, are entered in table 1, if applicable, under Footnote such that; 1 = site, or portion of the site, has continued operation and maintenance of the remedy, 2 = site, or portion of the site, receives continued monitoring, and 3 = site, or portion of the site, five-year reviews are conducted.

Table 2 includes information concerning whether the full site is proposed for deletion from the NPL or a description of the area, media or Operable Units (OUs) of the NPL site proposed for partial deletion from the NPL, and an email address to which public comments may be submitted if the commenter does not comment using https://www.regulations.gov.

EPA maintains the NPL as the list of sites that appear to present a significant risk to public health, welfare, or the environment. Deletion from the NPL does not preclude further remedial action. Whenever there is a significant release from a site deleted from the NPL, the deleted site may be restored to the NPL without application of the hazard ranking system. Deletion of a site from the NPL does not affect responsible party liability in the unlikely event that future conditions warrant further actions.

The North Atlantic right whale is listed as endangered under the Endangered Species Act (16 U.S.C. 1531 et seq. ), with an estimated population size of about 380 individuals at the start of 2024 (Linden, 2025). The main threats to North Atlantic right whale survival include entanglement in fishing gear and collisions with vessels. In 2008, NMFS implemented seasonal, mandatory vessel speed restrictions in designated areas along the U.S. East Coast to reduce the risk of vessel collisions with North Atlantic right whales (73 FR 60173, October 10, 2008, “speed rule”). NMFS subsequently modified the speed rule by removing the original 5-year “sunset” provision (78 FR 73726, December 9, 2013; 79 FR 34245, June 16, 2014).

The speed rule requires most vessels equal to or greater than 65 feet (19.8 m) in length to transit at speeds of 10 knots or less in designated Seasonal Management Areas (SMAs). See 50 CFR 224.105. Along with the speed rule, in 2008 NMFS implemented a voluntary Dynamic Management Area (DMA) program (also referred to as Slow Zones since 2020) to enhance protections for North Atlantic right whale aggregations that may form outside designated SMA boundaries (73 FR 60173, October 10, 2008).

Information on the speed rule and DMA/Slow Zone programs may be found at: https://www.fisheries.noaa.gov/national/endangered-species-conservation/reducing-ship-strikes-north-atlantic-right-whales.

NMFS requests information to inform a possible deregulatory-focused modernization of the speed rule and the development of alternative vessel strike-reduction programs. The agency intends to craft durable programs that consider both conservation and the economic vitality of coastal communities. To this end, we specifically seek information concerning the following topics.

The Effectiveness of Technologies to Reduce Vessel Strikes with Whales: NMFS supports the development and use of technologies, engineering approaches, and other advanced tools to reduce the risk of vessel strikes with large whales. As part of an ongoing partnership with The MITRE Corporation, NMFS recently released a Technology Readiness Level (TRL) report, which assesses the maturity level ( i.e., research and development stage) of certain technologies in relation to vessel collision avoidance. MITRE's report may be accessed at https://www.fisheries.noaa.gov/s3/2026-02/Vessel-Strike-Risk-Reduction-TRLReport.pdf. NMFS seeks comment, especially technical information, on the readiness of technologies to effectively reduce vessel strikes, following the TRL framework as applied in the MITRE report ( e.g., table 2-2). In addition, NMFS seeks data on available and upcoming technologies, engineering approaches, onboard vessel adaptation capabilities, and other relevant practices/protocols, with a particular interest in the capacity of these approaches to trigger automated, real-time DMA/Slow Zone notifications that could replace static seasonal measures.

Vessel-size-specific Risk Assessment: NMFS seeks scientific and commercial data and/or analysis distinguishing the strike risk posed by various vessel size classes, including comparing the draft and maneuverability of smaller recreational vessels versus large ocean-going ships and how those factors affect strike risk.

Alternative Management Areas: NMFS seeks information on using dynamic approaches for speed zones based on whale detections (sightings, acoustic or other forms of detection) communicated to mariners via real-time electronic notification as a primary management tool in place of static SMAs. NMFS also welcomes perspectives from impacted parties on the use of voluntary DMAs/Slow Zones and the effectiveness of these temporary zones.

Safety Deviation Provision Improvements: NMFS seeks recommendations for updating the speed rule safety deviation provision (50 CFR 224.105(c)) to provide greater flexibility for vessel operators. We welcome information regarding potential safety risks ( e.g., swamping, capsizing, or loss of steerage) of a 10-knot speed limit on smaller vessels in open ocean conditions or adverse weather.

Efficacy of the Speed Rule: NMFS seeks comments assessing the effectiveness of the speed rule in reducing the risk of vessel strikes with right whales, and input on vessel compliance with the speed rule. We further seek suggestions on technological interventions that could improve these results relative to the current speed rule.

Economic Impacts on Industry: NMFS seeks quantifiable data on the economic consequences of the speed rule, especially where it may have impacted operations for shipping, fishing, tourism, or other industries. NMFS also seeks relevant information that informs potential economic impacts of technology adoption, including technologies discussed in the MITRE report, and other relevant technologies. This includes but is not limited to information about the impacts of the speed rule on small businesses and small governmental entities. Furthermore, we seek data on the economic and safety benefits of maintaining the current regulated vessel size threshold at 65 feet (19.8 m) relative to a less restrictive threshold. In addition, NMFS seeks comment on how a revised speed rule safety deviation provision may affect costs to industry.

Outreach: NMFS seeks information regarding successful models for mariner outreach and collaborative monitoring programs that incentivize voluntary strike avoidance through technology, education, and private sector partnerships.

Linden D., 2025. Population size estimation of North Atlantic right whales from 1990-2024. US Dept Commerce Northeast Fish Sci Cent Tech Memo 338. 14 p.