Highlights of the North Carolina Manufacturers Alliance 2025 Environmental, Energy, Health & Safety School

The 2025 North Carolina Manufacturers Alliance’s (NCMA) Environmental, Energy, Health & Safety (EEHS) School, hosted in Raleigh, NC, provided timely and relevant EEHS presentations, panels, and discussions with leaders in industry, consulting, and government. Attendees of the school learned about the latest air regulatory updates, the latest water quality regulatory updates, workplace safety hot topics, and what’s new around energy and waste.

Regulatory and program highlights at the NCMA EEHS School regarding the latest activities at the United States Environmental Protection Agency (U.S. EPA), Occupational Safety and Health Administration (OSHA), the North Carolina Department of Environmental Quality (NCDEQ), and other relevant government bodies are summarized below.

Air Quality Regulatory Updates

U.S. EPA announced a long list of deregulatory actions in March 2025 that are currently the focus of their reduced staff. These include rolling back several greenhouse gas (GHG) regulations, the recently tightened fine particulate National Ambient Air Quality Standards (NAAQS), and several recent revisions to National Emission Standards for Hazardous Air Pollutants (NESHAP).

U.S. EPA is no longer focused on environmental justice (EJ)-related policies or actions. Each state may have its own EJ policy or rule.

U.S. EPA is currently ending the Good Neighbor Plan (the ozone transport federal implementation plan [FIP]) and advancing the concept of cooperative federalism by working with states on approvable State Implementation Plans (SIP) to address ozone transport.

The Congressional Review Act (CRA) was used to repeal 2024 revisions to two hazardous air pollutant (HAP) rules: 40 CFR Part 63, Subpart XXXX (Tire Manufacturing Maximum Achievable Control Technology [MACT] for mixing operations) and the Major MACT to Area (MM2A) provisions in 40 CFR Part 63, Subpart A. This was the first time the CRA has been used to repeal a Part 63 rule change, so the path forward is not clear.

U.S. EPA has rescinded its 2024 proposed revisions to the New Source Review (NSR) Rule provisions related to project emissions accounting (PEA).

NCDEQ is finalizing changes to their air curtain incinerator rules to provide support for Hurricane Helene recovery efforts.

Other NCDEQ proposed rules approved by the Environmental Management Commission (EMC) that are currently in the rulemaking process include:

• Permit issuance timelines rule (90 days for minor modifications and 270 days for major modifications).
• Pre-permitting construction activities rules at 15A NCAC 02Q .0114 (generally, construction activities you can undertake for a minor project prior to receiving your permit).
• Periodic rules review for 15A NCAC 02D (Air Pollution Control Requirements) and 15A NCAC 02Q (Air Quality Permits Procedures).

North Carolina Division of Air Quality (NCDAQ) is adding the following condition to permits: Disclosure of Information Relating to Emissions of Fluorinated Chemicals [15A NCAC 02Q .0308(a); 15A NCAC 02Q .0309(b)]:

The Permittee shall have an ongoing duty to disclose the presence of materials containing fluorinated chemicals at the facility that have the potential to result in the emission of fluorinated chemicals to the environment. Such disclosures shall be in writing and submitted to the Regional Office Supervisor within thirty days of the Permittee becoming aware of such information, unless such information has already been disclosed to NCDAQ by the Permittee. The disclosure shall describe the identity, quantity, and use of such material to the extent known. NCDAQ may require the permittee to conduct analysis or testing of fluorinated chemical emissions as necessary to properly evaluate emissions sources at the facility. As used in this condition, the term “fluorinated chemicals” includes but is not limited to per- and polyfluoroalkyl substances (PFAS).

Water Quality

Proposed groundwater standards for PFAS compounds have an effective date, if approved, of November 1, 2025 in 15A NCAC 02L .0200.

The interim maximum allowable concentrations (IMAC) for eight PFAS compounds in groundwaters were made effective October 15, 2024.

15A NCAC 02B .0512 (Direct Dischargers) and 15A NCAC 02H .0923 (Significant Industrial Users): PFOS, PFOA, and Gen X (PFAS) Monitoring and Minimization rules are due to be effective April 2026. The start of baseline monitoring will begin September 2026, and minimization plan implementation will be July 2029.

Energy

In 2024, the North Carolina Utilities Commission accepted the Duke Energy Consolidated Carbon Plan and Integrated Resource Plan (CPIRP). Duke proposed significant investments in solar, energy storage, and nuclear, more hydrogen-capable natural gas facilities, and 2,400 megawatts of offshore wind by 2035, saying this all-of-the-above strategy was needed to meet increased energy demand and keep costs low for customers, while enabling a transition out of coal to meet Executive Order No. 80.

Waste

North Carolina House Bill 600 amends North Carolina General Statue 130A-309.10 to ban the disposal of lithium-ion batteries in landfills. The effective date is December 1, 2026.

Workplace Health and Safety

Effective October 15, 2024, the OSHA Memo for Inspection Guidance for Animal Slaughtering and Processing Establishments established inspection guidance for North American Industry Classification System (NAICS) 3116.

Hazard Communication changes to the classification of health and physical hazards, and provisions related to labeling and safety data sheets will be effective January 1, 2025.

Effective January 13, 2025, changes to design and selection criteria of personal protective equipment (PPE) in the construction industry.

OSHA Part 1904 (Recordkeeping Policies and Procedures) Directive Number CPL 02-00-172 updated inspection procedures and policies will be effective January 13, 2025.

North Carolina minimum and maximum civil penalties associated with occupational safety and health standard violations increased will be effective July 1, 2025.

Effective July 17, 2025, OSHA Directive Number CPL 02-01-067 updates instructions on site-specific targeting and does not include construction worksites or public sector sites.

Conclusion

ALL4 is tracking state and federal regulatory developments related to these and other environmental, health, and safety (EHS) topics. If you have questions about how these regulatory changes might affect you or need help with EHS permitting and compliance in North Carolina, please reach out to Alex Ges at ages@all4inc.com or Claire Corta at ccorta@all4inc.com.

What Are Scope 3 Greenhouse Gas Emissions?

Greenhouse gas (GHG) emissions are becoming an increasing consideration for companies and organizations due to state regulations and business goals to address and mitigate emissions. The European Union (EU) is phasing in GHG reporting requirements for companies based in the EU or doing business there. GHG emissions are broken into three different categories according to the GHG Protocol: Scopes 1, 2, and 3. Scope 1 emissions are direct emissions generated at the facility and by sources under the direct control of the organization, such as company-owned vehicles, while Scope 2 emissions are indirect emissions resulting from purchased utilities such as electricity, steam, or chilled water. Finally, there are Scope 3 emissions, which are also indirect emissions, but include sources across the entire supply chain. But what exactly are Scope 3 emissions, and why are they becoming more of a concern to companies? This blog will outline Scope 3 emissions and why they are important to understand.

What Are Scope 3 Emissions?

Scope 3 emissions, or value chain emissions, are indirect GHG emissions that result due to the activities of a company or organization, but from assets or sources the company does not own or control. Scope 3 emissions are often difficult to quantify because value chains are complex and consist of both upstream and downstream activities, but these emissions typically make up the majority of a company’s total GHG emissions.

The GHG Protocol provides the most widely used GHG accounting standards and has defined 15 categories of Scope 3 emissions, eight upstream and seven downstream, from the company’s operations. It should be noted that not every category will be relevant for every company, but to meet GHG Protocol standards, emissions from every material category must be reported. The 15 categories are:

1. Purchased goods and services
2. Capital goods
3. Fuel- and energy-related activities
4. Upstream transportation and distribution
5. Waste generated in operations
6. Business travel
7. Employee commuting
8. Upstream leased assets
9. Downstream transportation and distribution
10. Processing of sold products
11. Use of sold products
12. End of life treatment of sold products
13. Downstream leased assets
14. Franchises
15. Investments

Figure 1 from the Scope 3 Standard of the GHG Protocol provides an excellent illustration of how Scope 3 emissions fit within a company’s structure and with Scope 1 and Scope 2 emissions.

Figure 1. Overview of GHG Protocol scopes and emissions across the value change.

Why are Scope 3 Emissions Important?

As Scope 3 emissions typically comprise the majority of a company or organization’s GHG footprint, having a good understanding of the full GHG impact requires a thorough and accurate accounting of Scope 3 emissions and provides the biggest opportunity for GHG emissions reductions. This can have a larger overall impact on a company by providing insight into the different types of risk they may be subject to both upstream and downstream of their direct activities. Understanding Scope 3 emissions also allows for a company to have a robust understanding of their supply chain and assist in engagement with stakeholders both upstream and downstream of the process. One example of this is identifying supply chain costs and reliability issues due to higher energy- or emissions-related costs or business interruption risks in the supply chain. This can ultimately lead to reductions in costs, increased efficiency, and better risk mitigation, which are beneficial to the health and success of a company.

There are also regulatory pressures, starting with the California Climate Corporate Data Accountability Act (SB-253) which is requiring companies doing business in California with $1 billion or more in gross annual revenue to report their Scope 3 emissions by 2027. It is important to understand how to quantify these emissions now to ensure that your company has the necessary information to meet the reporting requirements of the rule. For more details on state regulatory requirements, please see Evan Mia and Louise Schaffer’s 4 the Record Article posted on April 9, 2025.

How Can a Company Start a Scope 3 Emissions Inventory?

Scope 3 emissions calculations are complex, so it is important to first create a plan for these calculations. Developing a Scope 3 emissions inventory can be a daunting task, but can be broken down into three stages:

1. Determining material Scope 3 categories
2. Estimating GHG emissions in each category
3. Improving and expanding emissions data over time

The initial stage allows a company to identify the Scope 3 categories that are material through examining the Scope 3 Standard’s descriptions. Starting small and identifying the top three to five categories can be a great way to begin the process. The second stage relies on available data to estimate the GHG emissions within the identified categories. This requires engagement with suppliers and other stakeholders.

Finally, the Scope 3 emissions inventory should be a work in progress that improves and expands over time. This may include developing more accurate sources of data, expanding to other relevant categories that are harder to quantify, or expanding plans to reduce Scope 3 emissions. With an increase in mandatory reporting and disclosure in different states, Scope 3 emissions inventories are becoming an important part of a company’s management and business strategy. Developing a full Scope 3 emissions inventory can be a slow and iterative process, so it is important to start early to get the best results.

Helping Companies with Scope 3 Emissions Inventories

ALL4 can help your company develop its Scope 3 emissions inventory and provide Scope 3 playbook assistance, GHG reporting, tracking, and mitigation services to companies or organizations that need to comply with state regulations or are interested in better understanding and developing strategies to reduce their GHG emissions. For inquiries about the impact of Scope 3 emissions and how ALL4 can assist, contact Staci McGill at smcgill@all4inc.com, Daryl Whitt at dwhitt@all4inc.com, or your ALL4 project manager.

What You Should Know About CMAS Applicability Testing

If you are a chemical manufacturer and have been keeping a pulse on the federal air quality rules, you may have heard about the CMAS rule.

What is CMAS? It is the National Emission Standards for Hazardous Air Pollutants (NESHAP) for chemical manufacturing area sources (CMAS) that is codified under 40 CFR Part 63, Subpart VVVVVV. The rule was originally finalized in 2009 and changes were proposed in January 2025. If you own or operate a chemical manufacturing process unit that is located at an area source of hazardous air pollutants (HAPs) or a HAP is used as a feedstock for your chemical process, CMAS may apply to you.

If you think that your facility may be subject to the CMAS rule, what are the next steps? To tell whether your facility is subject to the CMAS rule, you must have analytical data to assess whether your facility is or is not subject to the rule. To get this analytical data, you must collect and analyze samples. To execute the measurements, you must develop a test plan. Finally, you must assess and summarize the data and draw a conclusion. The first step in assessing the CMAS rule’s applicability to your facility is to create a test plan.

CMAS samples often differ from other environmental samples in key ways. Oftentimes, established environmental sampling and analytical methods don’t apply to the process streams. These methods were not developed with complex chemical process streams in mind, and the sample matrices can be very complex. There may be instances where the sampling and analysis methods will need to be modified to obtain meaningful measurements. Not all laboratories will be able to accept the sample due to safety concerns, and not all laboratories will be capable of implementing the necessary method modifications. It’s important to communicate what is being sampled and how the data are to be used to make sure that the lab is able to analyze the samples as collected for the specified analytes. Sometimes samples will have many related compounds in a stream that can muddy the analytical results, so it’s important for the facility and the lab to continue communicating as the program moves from sampling to analysis.

A successful test plan should consider a few different aspects of the testing program. Any test plan should have a clearly defined goal. That will make sure that as other considerations and challenges come into play, decisions are made to best achieve the goal. For the purpose of this article, the goal is to determine CMAS applicability. Understanding the complexity of the task in front of you, the test plan will want to reflect input from the facility, a sampling team, and an analytical laboratory.

The selection of a testing firm and/or an analytical laboratory are key. This selection should be a dialogue between the facility, the tester, and the analytical laboratory. The facility should be able to communicate the expected analytes to be found in the material and any expected challenges or considerations. This assessment of expected analytes is essential for test plan development. While in many cases a test plan can be developed without input from a sampling or analytical group, that is not the case for CMAS applicability.

This leads us to finally detailing our comprehensive plan for the actual sampling and analysis of the samples. In our example, a CMAS applicability consideration would require both the chemical process feed streams and the exhaust gas streams to be sampled. As the details are hammered out, the following questions are addressed:

• Are there any hazards associated with gathering samples at either location?
• What methods will be used?
• Will the samples need to be preserved, either chemically or thermally?
• Will the samples be stable enough to be analyzed in the time it takes for the lab to receive it?
• Are there any transportation hazards that need to be accounted for?

ALL4’s chemical sector team is well-versed in all aspects of evaluating applicability of the chemical sector air rules, preparing gap analyses, and developing compliance plans. If you need help putting together a test plan for your applicability determination, or if you’ve already started working through your testing program and want assistance on how to navigate the ongoing dialogue between your facility, your testing firm, and your laboratory, feel free to contact me at tcunningham@all4inc.com.

South Coast AQMD Proposed Amended Rule 1107: Key Updates and What You Need to Know

The South Coast Air Quality Management District (AQMD) is proposing to phase out the use of para-ChloroBenzotrifluoride (pCBtF) and tertiary-Butyl Acetate (t-BAc) in metal coating operations regulated under Rule 1107, with a final prohibition date of July 1, 2029. The preliminary draft rule 1107 is currently available for review.

A Working Group Meeting will be held on August 27, 2025, offering stakeholders the next opportunity to provide feedback before the rule is finalized. This public engagement point follows prior working group meetings held in August 2024, December 2024, and May 2025.

The proposed phase-out schedule for pCBtF and t-BAc in the preliminary draft rule is as follows:

• July 1, 2026: Final date to manufacture coatings containing pCBtF or t-Bac within AQMD’s jurisdiction.
• July 1, 2027: Final date to sell, supply, market, distribute, package, or repackage such coatings within AQMD’s jurisdiction.
• July 1, 2029: Final date to apply, blend, or possess such coatings at stationary source regulated with AQMD’s jurisdiction.

In addition to phasing out pCBtF and t-BAc, proposed changes in Rule 1107 include:

• Revised definitions to be aligned with Rule 1151 and clarification in the definition of “REDUCER OR THINNER”.
• Requirement that multi‑category coatings must meet the lowest Volatile Organic Compounds (VOC) limit among applicable categories.
• Prohibition of cadmium, hexavalent chromium, and Group II exempt compounds in regulated coatings.
• New labeling and administrative requirements for manufacturers, distributors, and sellers.

The preliminary draft rule does not propose changes to Table 1 VOC limits in Rule 1107; instead, AQMD is phasing out the use of the VOC “EXEMPT COMPOUNDS” pCBtF and t-BAc based on toxicity concerns identified by California’s Office of Environmental Health Hazard Assessment (OEHHA).

AQMD Regulatory Phaseouts for Use of pCBtF and t-BAc:

Historically, pCBtF and t-BAc have been used in metal coating operations to enhance coating performance and improve drying times. OEHHA assessed pCBtF and t-BAc for environmental and human health risks in 2018 and 2020. OEHHA toxicological assessments determined that both pCBtF and t-BAc have carcinogenic endpoints which prompted AQMD to evaluate the VOC “EXEMPT COMPOUND” status and/or initiate phaseout procedures for both compounds. AQMD did not reclassify pCBtF and t-BAc from their current status as a VOC “EXEMPT COMPOUND” under Rule 1107 and Rule 102. Instead, the proposed amended rule will phase out the use of pCBtF and t-BAc in metal coating operations.

The phaseout of pCBtF and t-BAc proposed under Rule 1107 is the latest phase out under a multi-rule initiative that includes:

• Rule 1168. Amended in November 2022 with an established phaseout timeline for the manufacture, sale, distribution, and use of pCBtF and t-BAc in adhesives and sealants following the OEHHA toxicological assessments.
• Rule 1151. Amended in November 2024 with a phaseout schedule for use of pCBtF and t-BAc in motor vehicle coating similar to that found in Rule 1107.
• Rule 1171. Amended in June 2025, solvent cleaning activities using pCBtF and t-BAc subject to the provisions of Rule 1171 subject to a tiered phase out with a final prohibition date of July 1, 2028.

What This Means for Your Facility:

If your facility performs metal coating operations subject to Rule 1107, it is important to:

1. Review your current materials to identify any coatings that contain pCBtF or t-Bac requiring action by your facility to comply beginning as early as 2026.
2. Participate in the August 27, 2025 workshop to engage with AQMD on feasibility, transition timelines, and sell-through provisions.
3. Consider subscribing to the AQMD Advisor Newsletter to stay up-to-date on rule updates.

By taking proactive steps now, your facility can better navigate the compliance challenges of the pCBtF and t-BAc phaseout under the amendments in preliminary draft Rule 1107.

If you have any questions about air quality compliance in the South Coast region of California, contact your ALL4 project manager, our California Office at 909.483.3300, or all4inc.com.

U.S. EPA Proposes a Reconsideration of 2009 Endangerment Finding and Greenhouse Gas Vehicle Standards

Introduction

On July 29, 2025, the U.S. Environmental Protection Agency (U.S. EPA) proposed to rescind the 2009 Greenhouse Gas (GHG) Endangerment Finding, which has served as a foundation for regulating GHG emissions from motor vehicles for over a decade. With this rescission, U.S. EPA proposed to eliminate all existing GHG vehicle emission standards for light-, medium-, and heavy-duty on-highway vehicles. If finalized, this proposal would represent a significant shift in Federal climate and transportation policy, affecting automakers, regulatory agencies, and consumers of America.

What is the Endangerment Finding?

The 2009 Endangerment Finding established a formal determination by U.S. EPA, under the Clean Air Act (CAA) Section 202(a), that GHGs – carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF₆) – constitute air pollutants that ultimately pose concern for both public health and welfare. This finding gave U.S. EPA the legal authority to regulate GHGs, laying groundwork for vehicle GHG emissions standards implemented over the past 15 years.

If the 2009 Endangerment Findings were rescinded, U.S. EPA would lose its authority to regulate climate change-related emissions under the CAA. This action would be predicated on the assertion that GHG emissions standards do not advance public health and welfare.

What are the GHG Vehicle Standards?

Following the 2009 finding, U.S. EPA issued multiple rules to limit GHG emissions from vehicles, including:

• The 2010 and 2011 rules establish progressively more stringent GHG standards for light-, medium-, and heavy-duty vehicles (see 40 CFR § 86.1818‑12 and 40 CFR Part 1037),
• Requirements for technologies like start-stop systems, air conditioning improvements, and hybridization, and
• Coordination with the Department of Transportation’s Corporate Average Fuel Economy (CAFE) standards ( see 49 CFR Part 531 and 49 CFR Part 533).

These rules were developed to reduce transportation sector emissions while also improving fuel efficiency and encouraging innovation in vehicle technologies.

Why is U.S. EPA Reconsidering 2009 Endangerment Finding Now?

U.S. EPA’s reconsideration is part of the broader deregulatory agenda aligned with President Trump’s energy policy initiatives. The proposal was delivered by Administrator Lee Zeldin during an event in Indiana, highlighting the agency’s position where the original 2009 Endangerment Finding was based on misinterpreted legal findings and insufficient scientific findings.

Citing recent Supreme Court rulings, including West Virginia v. U.S. EPA and Loper Bright Enterprises v. Riamondo, U.S. EPA argues that major policy decisions, like GHG regulation, should be made by congress, not administrative agencies. The agency also referenced new scientific and economic data that challenge the assumptions behind the 2009 Endangerment Finding. The proposed rule seeks to remove this and the resulting vehicle GHG standards entirely. This includes control, measurement, and reporting obligations for GHG emissions.

What Are the Potential Implications of This Reconsideration?

The proposal seeks to repeal all regulatory provisions relating to GHG emissions of the following rules:

• 40 CFR Part 85—Control of Air Pollution from Mobile Sources
• 40 CFR Part 86—Control of Emissions from New and In-Use Highway Vehicles and Engines
• 40 CFR Part 600—Fuel Economy and Greenhouse Gas Exhaust Emissions of Motor Vehicles
• 40 CFR Part 1036—Control of Emissions from New and In-Use Heavy duty Highway Engines
• 40 CFR Part 1037—Control of Emissions from New Heavy-Duty Motor Vehicles
• 40 CFR Part 1039—Control of Emissions from New and In-Use Nonroad Compression-Ignition Engines

If finalized, U.S. EPA’s proposal would eliminate all Federal GHG emissions standards for new highway vehicles, effectively:

• Removing CO₂ and other GHG emissions requirements for cars, trucks, and engines,
• Eliminating related compliance obligations for vehicle manufacturers, and
• Undoing the Federal basis for current and future electric vehicle (EV) mandates.

However, U.S. EPA’s goal is to retain standards related to criteria pollutants and fuel economy testing. While states such as California, New York, and Oregon currently maintain independent GHG programs, recent federal actions—including challenges to state climate initiatives and efforts to rescind U.S. EPA waivers under the CAA—signal a potential shift toward limiting states’ authority to impose standards stricter than federal requirements. Such conflicts could influence whether a fragmented national vehicle market persists.

The agency claims the proposal will reduce hidden regulatory costs for consumers and restore decision making to elected lawmakers. On the other hand, critics warn it could stall progress on vehicle electrification and climate goals, while triggering legal challenges and prolonging regulatory uncertainty.

What’s Next?

We expect this proposed regulation to be finalized quickly after the public comment period. Nonetheless, it is anticipated that U.S. EPA’s final decision will be subject to litigation, and a court may issue a stay on any action that removes the GHG emissions standards while legal proceedings are ongoing. Automative manufacturers will need to assess both state and Federal regulatory requirements to ensure compliance with the changing regulatory landscape.

U.S. EPA is accepting public comments on the proposed rule through September 15, 2025, under Docket ID No. EPA-HQ-OAR-2025-0194. Comments can be submitted at https://www.regulations.gov/ or via email a-and-r-Docket@epa.gov with the docket number EPA-HQ-OAR-2025-0194 in the subject line. A virtual public hearing is scheduled for August 19 through 21, 2025, depending on demand. Stakeholders- including automakers, environmental groups, and state regulators are expected to actively participate in the process.

Need help understanding how this affects you?

If you are wondering how this proposal will affect your facility or ongoing projects directly, please reach out to your ALL4 project manager or contact Louise Shaffer at lshaffer@all4inc.com

U.S. EPA Releases Significant Update to AP-42 Section 2.4 for Solid Waste Landfills

In May 2025, the United States Environmental Protection Agency (U.S. EPA) released a significant update to AP-42 Section 2.4 for Municipal Solid Waste Landfills and the associated LandGEM model for estimating air emissions from solid waste landfills. AP-42 Section 2.4 was last updated in November 1998 (with a draft update in 2008 that was not finalized). The 2025 updates reflect advancements in data collection, regulatory frameworks, and a continued focus on refining methane emissions calculation methods. This article provides an overview and comparison of the key differences between the new and previous versions.

1) Methane Generation Rate Equation:

1998 Version: Used a first-order kinetic equation with specific “k” (methane generation rate) and “L₀” (potential methane generation capacity) values derived from older datasets for solid waste landfills in the U.S. EPA database.

May 2025 Update: Removes the original first-order kinetic equation and replaces it with the Mandatory Greenhouse Gas Reporting Program (GHGRP) equation HH-1 from 40 CFR 98.343(a)(1) (Subpart HH). This update is designed to ensure consistent methane generation values across various U.S. EPA programs, particularly aligning AP-42 with the GHGRP, which is a mandatory reporting program for large sources of greenhouse gas (GHG) emissions. This is not merely a technical adjustment but a strategic policy choice by U.S. EPA to standardize methane generation calculations across its different regulatory programs. This harmonization streamlines compliance for facilities that must report emissions under both Federal air permitting programs that require use of AP-42 Section 2.4 procedures and the GHGRP, reducing the potential for discrepancies in emissions estimates and administrative burden, thereby fostering a more consistent and efficient national approach to landfill emissions quantification. This change also implicitly elevates the importance of GHGRR methodologies for all landfill emissions calculations.

While the equation itself is updated, the New Source Performance Standards (NSPS) under 40 CFR Part 60 and Emissions Guidelines (EG) under 40 CFR Part 62 still reference the older k and L₀ values from the previous AP-42 section, which may cause some confusion when preparing calculations for regulatory applicability analyses. ALL4 is not aware of a planned effort by U.S. EPA to update these rules in alignment with Subpart HH as of the date of this article.

Additionally, Equation 3 of AP-42 Section 2.4 was updated to allow for the incorporation of a site-specific fraction of methane volume in landfill gas. This change provides greater flexibility and accuracy when site-specific data is available, moving towards more tailored emissions estimates. The default average collection efficiency of 75% has been replaced with a directive for the reader to refer to Table HH-3 of Subpart HH for Landfill Gas Collection Efficiencies. This change emphasizes reliance on specific regulatory tables for gas collection and control systems (GCCS) efficiency calculations, ensuring consistency with other Federal requirements.

2) Non-Methane Organic Compound (NMOC) and Volatile Organic Compound (VOC) Default Concentrations:

1998 Version: Default NMOC/VOC values were based on older, smaller datasets (e.g., 18 landfills for no/unknown co-disposal sites). A 39% ratio of VOC to NMOC was used to adjust calculations for regulatory applicability purposes.

May 2025 Update: Updated default NMOC concentrations for co-disposal sites (prior to 1992) use 2,400 parts per million by volume (ppmv). NMOC concentrations for non-co-disposal sites opened before 1992 use 600 ppmv (previously 595 ppmv) while NMOC concentrations for sites opened during and after 1992 use 550 ppmv.

The May 2025 update clarifies that NMOC emissions are a good surrogate for VOC emissions, with less than a 50 ppmv difference, and removes the previous reference to a 39% ratio of VOC to NMOC. This reflects a more accurate understanding of the relationship between these compounds in landfill gas. U.S. EPA reviewed existing test reports for these updates, while addressing previous critiques regarding the data used for the original AP-42 section. The May 2025 update incorporates a larger and more complete dataset which includes 242 complete test reports from 116 landfills used for the 2019 Residual Risk Assessment conducted for proposed revisions of the 40 CFR part 63, Subpart AAAA National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Municipal Solid Waste Landfills¹.

3) Emissions Factors for Combustion Sources:

1998 Version: Provides less-detailed or specific emissions factors for various combustion devices such as flare control devices and landfill gas-fired engines.

May 2025 Update: Adds six new emissions factors and revises five existing emissions factors for landfill gas flares, engines, and fugitive emissions sources. This update also combines emissions factors for pollutants from open flares and enclosed combustors and provides additional NMOC emissions factors for engines at various loads. Emissions factors for nitrogen oxides (NO_X) and carbon monoxide (CO) from these sources are also generally lower than the factors in the 1998 version.

Notably, the May 2025 Update provides new emissions factors with a “Highly Representative” emissions factor rating for enclosed flares, including for NO_X, NMOC, and CO. This is a new inclusion and a significant change for enclosed flare emissions factors, which had previous been given only a “C” rating in the 1998 Version.

4) Organization and Structure:

The May 2025 update also includes minor organizational changes, such as adding Section 2.4.5 for Source Classification Codes for municipal landfills and updated references to more recent federal regulations like NSPS/EG and 40 CFR Part 63 NESHAPs.

See the table below for a side-by-side comparison of the major updates to AP-42 Section 2.4:

 Updates to U.S. EPA LandGEM Model

The Landfill Gas Emissions Model (LandGEM) is designed to calculate emissions rates for total landfill gas, methane, carbon dioxide, NMOC, and hazardous air pollutants (HAP) from MSW landfills. In general, both AP-42 Section 2.4 and LandGEM work together to provide the emissions factors and methods and a tool that implements a model based on those principles. Both the May 2025 update to AP-42 Chapter 2.4 and LandGEM itself, as of its most recent publicly available version (LandGEM Version 3.1, 2024, with a User Guide from December 2024), have replaced the previous first-order kinetic equation with equation HH-1 from Subpart HH.

Here are the key aspects of the LandGEM Version 3.1 updates:

1. Core Functionality: LandGEM continues to be a macro-enabled Microsoft Excel file that allows users to calculate emissions using either site-specific data or default parameters.
2. Model Parameters: LandGEM relies on key parameters like the methane generation rate (k), potential methane generation capacity (L₀​), assumed NMOC concentrations, and methane content of landfill gas.
3. Equation Differences: LandGEM Version 3.02 (which predates 3.1) introduced a revised first-order decomposition rate equation that integrates emissions over a 0.1-year time increment, improving accuracy, especially for higher k This resulted in slightly lower emissions for typical k values compared to earlier versions. Version 3.1 continues with this improved calculation method.
4. Default Parameters: LandGEM continues to offer two sets of default parameters:

1. 1. Regulatory defaults: Based on federal Clean Air Act (CAA) regulations for MSW landfills, used for determining regulatory applicability.
   2. Inventory defaults: Based on AP-42 Section 2.4 emissions factors, used for emissions inventories and air permits.

5. Alignment with AP-42 Section 2.4: LandGEM now uses a first-order decay model based on equation HH-1 from Subpart HH, and its default parameters are intended to align with AP-42 Section 2.4. The updated default NMOC concentrations from the May 2025 update to AP-42 Section 2.4 are expected to be reflected in the latest LandGEM versions, or at least be the recommended inputs for users.

Ongoing Development/Considerations:

U.S. EPA is exploring a transition from an NMOC emissions threshold to a methane emissions threshold for requiring GCCS in future solid waste landfill regulations. This could influence how LandGEM is used for regulatory compliance in the future. There is ongoing discussion and research into improving methane emissions quantification, including the use of advanced monitoring technologies (like aerial monitoring) which may, in the long term, influence how models like LandGEM are refined or supplemented. However, this effort to refine both the regulatory applicability methodology and supporting tools such as AP-42 and LandGEM may be limited or halted altogether if U.S. EPA’s pending proposal to eliminate most subparts in 40 CFR Part 98 is adopted by the Federal government. This pending decision would separate both AP-42 Section 2.4 and LandGEM from their recently established basis in the GHGRP equation HH-1 from Subpart HH. This decoupling could create uncertainty over the appropriate emissions quantification methodology between regulatory agencies and affected facilities and would nullify U.S. EPA’s effort to streamline compliance for facilities that must report emissions under both Federal air permitting programs that require use of AP-42 Section 2.4 procedures and the GHGRP.

In summary, AP-42 Section 2.4 has made a direct shift to the GHGRP equation for methane generation, and LandGEM, as a modeling tool, has been updated to reflect the new default parameters and emissions factors provided in AP-42 Section 2.4. The key takeaway is that the latest LandGEM version incorporates the application of the newly updated values from AP-42, particularly for NMOC concentrations and potentially other parameters influencing emissions calculations. As the May 2025 update to AP-42 Section 2.4 and the LandGEM model are more widely utilized, it is possible that users will encounter other bugs, issues, or have more suggestions for improvements. If you have any questions about these updates or encounter an issue, feel free to reach out to Daniel Brese at dbrese@all4inc.com or your ALL4 project manager.

¹Residual Risk Assessment for the Municipal Solid Waste Landfills Source Category in Support of the Risk and Technology Review 2019 Proposed Rule. EPA’s Office of Air Quality Planning and Standards Office of Air and Radiation May 2019.

Optimizing Air Emissions Calculations with Digital Solutions: Identifying Air Emissions Templates

What is an Air Emissions “Template”? Templates are used to group similar emissions calculations within digital solution platforms. The way templates are handled varies depending on the software used, but templates are a common concept and approach across software systems.

What is the value proposition? The set up of digital tools for air emissions can be time consuming, but by investing in developing air templates the solution can be more easily maintained, ongoing updates to the system are easier and more consistent, and training/knowledge transfer is more straightforward.

When trying to scope and cost setting up digital tools for air emissions calculations, the primary driver of cost and schedule is the number of air emissions calculation templates required. A very common question is how to tell if two emissions sources should be one calculation template or two calculation templates. This blog post will walk through some checks that can help you determine whether two emissions sources could be the same calculation template, providing guidance for project scoping and scheduling.

You may be tempted to think that equipment types will tell you how many air emissions calculation templates will be needed. However, equipment type is not the only indicator of whether you will need one or multiple emissions templates. Below are some scenarios where equipment type is not the sole criteria:

• Furnaces, process heaters, and boilers are considered different types of process equipment. However, if they are all calculated using the same AP-42 emissions factors and data frequence, they can be one shared emissions template.
• If one process heater has CEMS that determine emissions and another process heater uses heat input and emissions factors, they would be two different emissions templates.
• If a combustion source’s calculated emissions are based on fuel consumed or hours of operation, then these are separate methods and will typically require separate templates.

Emissions Source to Air Emissions Calculation Template Checklist

Step through the following checklist to identify whether an emissions source matches an existing template or requires a new template. Each question should be answered for the emissions source in question against one existing calculation template at a time. If you answer “No” to a question, start the checklist over against another existing calculation template. If you do not find a match by comparing to each existing template, this source requires a new calculation template.

• Do the operating or usage data inputs match the same type of input in an existing template with matching units of measure (UoM) and input frequency (i.e., Monthly Operating Hours (hr) or Daily Diesel Fuel Usage (gal))?

*Note: Daily Diesel Fuel Usage and Daily Natural Gas Usage are not the same input type, even though they are both considered fuel inputs. Different fuel types require different emissions factors, so the template would be different.

• If Yes, next question, if No → it’s a new (or different) template

• Do the emissions that need to be calculated match the same emissions calculated in an existing template (i.e. NOx, PM, VOC)?
  • If Yes, next question, if No → it’s a new (or different) template

• Do the emissions calculations use the same emissions factor (EF) source and UoM (i.e., PM from AP-42 Table 1.3 in lb/kgal)?
  *Note: if the EF is from a source test it’s OK that the value is different for each emissions source as long as both sources use a source test and the same UoM.
  • If Yes, next question, if No → it’s a new (or different) template

• If the emissions calculations use equipment properties in the formula, is the property type the same and the same UoM (i.e., Rating in hp)?
  • If Yes, next question, if No → it’s a new (or different) template

• Does each emissions calculation (per contaminant) match the formula used for the same emissions calculation in the template (i.e., Input*EF or Input*EF*Attribute)
  • If Yes, next question, if No → it’s a new (or different) template

If you have answered “Yes” to each item above, there’s a good chance this emissions source matches the existing calculation template you’re comparing against and does not require a different template.

Some emissions templates may include more source specific information, like a template for chemical usage or paint booth sources. Templates like these may require more time to configure due to their need to include customized data, such as chemicals used for each specific source.

Determining the number of emissions templates in an air emissions configuration project can help to understand the needed effort and how to break the effort into manageable phases. By following the guidelines provided in this blog post, you can make informed decisions about whether two emissions sources should share a single calculation template or require separate ones. If you have more questions about how to turn emissions calculations in a spreadsheet into emissions calculations in a digital solution, please contact Kaitlin George at 716-238-3706 or kgeorge@all4inc.com or Julie Taccino at 281-201-1247 or jtaccino@all4inc.com.

New York Proposed Rulemaking – 6 NYCRR Part 253 (Mandatory Greenhouse Gas Reporting)

The State of New York passed the Climate Leadership and Community Protection Act (CLCPA) in July 2019. This regulation requires the New York State Department of Environmental Conservation (NYSDEC) to evaluate statewide greenhouse gas (GHG) emissions and to promulgate regulations to reduce those overall GHG emissions. As part of these promulgated regulations and to work towards the emissions reductions targets set by the CLCPA, NYSDEC has proposed to establish 6 NYCRR Part 253 (NY GHG Rule), requiring emitters of GHG to report annual emissions. This article outlines what facilities are required to report under the NY GHG Rule and the differences between the NY GHG Rule and Federal GHG reporting requirements.

Who Must Report?

According to the proposed regulations, facilities meeting and exceeding the following source category definitions would be subject to these regulations:

1) Owners and operators of facilities within New York that emit over 10,000 metric tonnes (MT) or more of carbon dioxide equivalents (CO₂e) per year

2) Fuel suppliers, which includes both fuel suppliers in New York and suppliers importing fuel into New York State, including:

1. Suppliers of natural gas, who must report the cubic feet of natural gas necessary to generate any GHG emissions per emissions year
2. Suppliers of liquid fuels and petroleum products, who must report the gallons of affected liquid fuel necessary to generate any GHG emissions per emissions year
3. Suppliers of liquified natural gas and compressed natural gas, who must report the cubic feet of liquified natural gas and/or compressed natural gas to generate any GHG emissions per emissions year
4. Suppliers of coal, who must report tonnage of coal necessary to generate any GHG emissions per emissions year

3) Waste haulers and transporters with estimated emissions from solid wastes transported to landfills or combustion facilities outside of New York exceeding 10,000 MT CO₂e per year

4) Electric power entities who must report any GHG emissions or imported megawatt hours (MWh)

5) Suppliers of agricultural lime and fertilizer, who must report the quantity of agricultural lime and fertilizer necessary to generate any GHG emissions per emissions year

6) Anaerobic digestion and liquid storage of waste facilities who must report the wastes imported to or generated at the facility if they are in excess of at least one of the following:

1. 1×10⁶ gallons of aqueous industrial food waste,
2. 7×10⁸ gallons of municipal wastewater,
3. 1,500 MT (wet mass) of food scraps, commercial food waste, or industrial food waste,
4. 430 MT (dry mass) of food scraps, commercial food waste, or industrial food waste,
5. 1,100 MT of stover, yard trimmings, or other plan biomass,
6. 1,100 MT of paper or paper pulp,
7. 290 MT of fats, oils, or grease,
8. 600 MT of any other waste that contains degradable organic carbon, or
9. A combination of (i)-(viii) over their threshold with the sum exceeding 1 (i.e., gallons of aqueous industrial food waste/1×10⁶ + gallons of municipal wastewater/7×10⁸ + …)]

If a facility’s annual GHG emissions meet or exceed the limits listed above in any emissions year from 2023 through 2025 or any year after, the facility must report its emissions to NYSDEC starting in the first reporting period, which will start January 1, 2026 and end December 31, 2026. Affected facilities can also be subject to more than one of the source categories listed above depending on the nature of their operations. Along with these requirements, these sources are also subject to third party verification, unless meeting a specific exemption or meeting the cessation requirements for reporting and verification.

This rule is not just applicable to facilities located in New York State, but also upstream electricity and fuel suppliers that provide electricity or fuel into New York State. Electricity providers and fuel suppliers outside of New York State need to evaluate their supply chain to understand their applicability to the NY GHG Rule.

What Are “Large Emission Sources”?

Under the NY GHG Rule, facilities defined as large emissions sources also have additional reporting requirements. “Large emission sources” are defined as those meeting the following criteria:

1) Owners and operators of facilities (within New York) that emit 25,000 MT CO₂e or more per emissions year

2) Fuel suppliers

1. Natural gas suppliers: 15,000,000 cubic feet or more of natural gas per emissions year
2. Liquid fuels and petroleum product suppliers: 100,000 gallons or more of affected liquid fuels per emissions year
3. Liquified and compressed natural gas suppliers: 15,000,000 cubic feet or more of liquified natural gas and/or compressed natural gas per emissions year
4. Coal suppliers: 500 U.S. short tons of coal per emissions year

3) Waste haulers and transporters that emit 25,000 MT CO₂e or more per emissions year

4) Electric power entities: Not applicable (N/A) unless they meet the thresholds defined under category (1)

5) Suppliers of agricultural lime and fertilizer: N/A unless they meet the thresholds defined under category (1)

6) Anaerobic digestion and liquid storage of waste: N/A unless they meet the thresholds defined under category (1)

With the thresholds for large emitters being over 25,000 MT CO₂e, any facility subject to 40 CFR Part 98 will be considered a large emitter under the NY GHG Rule and subject to the additional reporting requirements.

General Reporting Requirements

Facilities exceeding their source category’s applicable emissions thresholds must report annual GHG emissions and develop and retain for review a GHG Monitoring Plan (GHGMP). Additional annual report requirements include general facility information, with the specific requirements listed in Section 253-1.5 of the rule. The first reporting period is 2026 and the first report will be due June 1, 2027. Emissions reporting requirements are outlined for each type of facility in Section 253-2.

GHGMP

The GHGMP must be electronically submitted to NYSDEC by December 31, 2026, or by the end of the first calendar year in which the source first meets or exceeds the applicability thresholds. The GHGMP must be resubmitted any year in which a revision is made. The GHGMP contains similar requirements to the written GHG Monitoring Plan required by U.S. Environmental Protection Agency (U.S.EPA) under 40 CFR Part 98, Subpart A, but will need to include all additional reporting requirements listed under Part 253.

The GHGMP must contain the following:

• Identification of positions of responsibility (i.e., job titles) for collection of the emissions data;
• Explanation of the processes and methods used to collect the necessary data for the GHG calculations; and
• Description of the procedures and methods that are used for quality assurance, maintenance, and repair of all continuous monitoring systems, flow meters, and other instrumentation used to provide data for the GHG reported under Part 253.

Additional source category-specific requirements are also specified within the proposed regulation.

Methane generating sources such as anaerobic digester/liquid storage and solid waste landfill with over 300,000 MT CO₂e must also complete an Emissions Monitoring and Measurement Plan (EMMP). The EMMP, which will be due March 1, 2026, will be the first report that will be submitted for this rule.

Third Party Verification

Facilities that meet applicability requirements that are not exempt under Section 253-1.2(l)(2) must obtain third-party verification services for the annual report. This verification must be completed by an accredited verification body. New York State will offer an application for companies to obtain verification body accreditation or will accept verification bodies accredited by American National Standard Institute (ANSI) or California Air Resource Board (CARB). Note that a verification body can only be contracted for NY GHG Rule third-party verifications for six-years, after which time the facility will need to contract another verification body.

The verification will include (but is not limited to) the following:

• A verification plan
• Planned meetings with the facility
• Site visits, review of the facility’s operations and information
• Sampling plan
• Data checks
• Emissions data report modifications
• Log of issues
• Material misstatement assessment
• Review of missing data substitution
• Review of product data, as applicable.

The verification body will then complete a verification statement/report in accordance with the requirements listed in Subpart 4 of Part 253. The third-party verifications are on a three-year verification cycle, with a more thorough verification in the first year, and with a positive verification there is the potential for a less intensive verification for the remaining years in the cycle. The initial verifications must be submitted by the verification body to NYSDEC by August 10 of each year.

How is Part 253 Different Than 40 CFR Part 98?

The New York Part 253 GHG reporting has some significant differences from the Federal GHG reporting requirements of 40 CFR Part 98. It is important to identify these differences to see what needs to be modified to prepare both reports. Some of these key differences are summarized below:

One key difference in applicability is the different source subcategories subject to these rules. Source category applicability for 40 CFR Part 98 is located at 40 CFR §98.2 and may differ from the sources required to report per the proposed New York regulations. Another important difference is the reporting deadline – for NY Part 253, the emissions data report is due on June 1 of each emissions year, while for 40 CFR Part 98, reports must be submitted by March 31.

Another factor that may increase the facility’s emissions reported is the use of CO₂e Global Warming Potential (GWP) on a 20-year basis instead of the 100-yearr GWP basis under 40 CFR Part 98. Biomass combustion will also use different calculations methods, with Tier 3 or 4 requirements for New York under Part 253, while 40 CFR Part 98 allows for Tier 1-4 calculation methods. These required methods require monthly testing of the carbon content of samples per 40 CFR 98.34(b)(3)(ii)(D) and 253-2.7 (e)(2). Equipment calibration requirements may also vary by source type, with a higher calibration frequency than required by 40 CFR Part 98.

Additional reporting requirements are imposed in the proposed New York rule which differ from 40 CFR Part 98, including fuel supplier information for fuel used in combustion equipment and different fugitive refrigerant thresholds and requirements. Emergency equipment (i.e., emergency generators or fuel combusting equipment) must report per the New York rule, while 40 CFR Part 98 exempts certain emergency equipment. If exceeding the specified reporting requirements, any electricity generated onsite must be reported, while 40 CFR Part 98 only requires certain EGU to report.

What Should My Facility do to Prepare?

Facilities should start identifying their applicability to the rule as soon as possible. This would involve the calculation of GHG emissions from 2023-2025 and understanding the new monitoring, recordkeeping, and reporting requirements that need to be implemented by 2026. This proposed rule does not completely align with the Federal GHG Reporting Rule, so it is important to understand how this will impact monitoring and recordkeeping at your facility. ALL4 can help with developing a compliance strategy and preparing GHG emissions inventories.

ALL4 will continue to monitor the proposed Part 253 rules and updates for a final rule. Public comments were submitted July 1, 2025, and we are now awaiting the final rule. For inquiries about ALL4’s services or follow-up questions regarding the proposed Part 253 regulations, please contact ALL4 Consulting Engineer Louise Shaffer at lshaffer@all4inc.com and/or Consulting Engineer Corey Prigent at cprigent@all4inc.com.

NESHAP Extensions: A Look at Two Recent Relief Notifications

Over the last few weeks, the United States Environmental Protection Agency (U.S. EPA) and the White House took actions related to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Coke Oven Facilities and the Hazardous Organic NESHAP, also known as the HON Rule, for the Synthetic Organic Chemical Manufacturing Industry. For both actions, extensions were issued for upcoming deadlines for each industry sector and this article presents a brief update.

Coke Oven Facilities

On July 5, 2024, U.S. EPA published final amendments to the NESHAP for Coke Oven Facilities in the Federal Register at 40 CFR Part 63, Subparts L and CCCCC. These regulations establish Maximum Achievable Control Technology (MACT) standards for emissions from Coke Oven Batteries (COBs) and associated processes like Pushing, Quenching, and Battery Stacks (PQBS) for Coke Ovens. The amendments were a result of the Clean Air Act (CAA) mandated risk and technology review (RTR). As part of that review, U.S. EPA identified a need to address previously unregulated hazardous air pollutants (HAPs) and HAP emissions sources.

As part of the 2024 revisions, U.S. EPA established compliance deadlines for new requirements, including fenceline monitoring, new MACT standards, requirements for oven doors at Heat and Non-Recovery (HNR) facilities, and opacity limits for HNR bypass/waste heat (B/W) stacks. On July 8, 2025, U.S. EPA revised the deadlines for the new requirements through an interim final rule as follows:

Benzene fenceline monitoring (COBs):

• Original Deadline: July 7, 2025.
• Revised Deadline: July 5, 2027.

New MACT emission standards [PBQS, battery stacks, HNR heat recovery steam generator (HRSG) main stacks, and HNR B/W]:

• Original Deadline: January 6, 2026.
• Revised Deadline: July 5, 2027.

Lower leak limits and revised pressure monitoring at HNR facilities (COBs):

• Original Deadline: July 7, 2025.
• Revised Deadline: July 5, 2027.

A 20% opacity limit for HNR B/W stacks (PBQS)

• Deadline: July 7, 2025.
• This deadline was not revised and remains unchanged.

U.S. EPA granted these extensions to allow additional time based on petitions for reconsideration that requested they reevaluate the modeled benzene action level and feasibility of real-time sampling techniques for fenceline monitoring, reevaluate the calculations for the new MACT standards, and reevaluate the work practice standards for the lower leak thresholds. U.S. EPA announced they would reconsider the 2024 rule revisions in March 2025 as part of its deregulatory agenda. Proposed changes as a result of their reconsideration are forthcoming.

Chemical Manufacturing Industry

On May 16, 2024, U.S. EPA published final amendments to the HON Rule for the Synthetic Organic Chemical Manufacturing Industry (SOCMI) and the Group I & II Polymers and Resins (P&R I and II) Industry under 40 CFR Part 63, Subparts F, G, H and I (HON), 40 CFR Part 63, Subpart U (P&R I), and 40 CFR Part 63, Subpart W (P&R II) as a result of its required periodic technology review and a second risk review that it elected to perform. These amendments addressed HAPs from heat exchange systems, storage vessels, process vents, transfer racks, wastewater, and equipment leaks, and established new fenceline monitoring requirements.

As part of the 2024 amendments, U.S. EPA set the following compliance deadlines:

• July 15, 2026: Conduct fenceline monitoring for ethylene oxide, benzene, 1,3-butadiene, ethylene dichloride, vinyl chloride, and/or chloroprene at sites that use, produce, store, or emit these compounds.
• July 15, 2026: Comply with the new ethylene oxide control requirements.
• July 15, 2027: Initiate corrective actions for fenceline monitoring exceedances and comply with revised regulations for heat exchange systems, process vents, tanks, transfer operations, wastewater systems, and equipment leaks.

On July 17, 2025, President Trump issued a proclamation extending all compliance dates under the HON Rule by two years from the original required deadlines for approximately 25% of all facilities subject to the HON and P&R I and II revisions, with the remaining facilities still under the original compliance schedule. The rationale behind the proclamation was based on a request made by facilities under section 112(i)(4) of the Clean Air Act and a determination by the White House that testing and monitoring technologies cannot be implemented to meet the original compliance dates and enforcement could lead to supply chain disruption due to shutdowns and/or decreased production.

Additionally, the White House noted that these disruptions could impair the nation’s ability to respond in a time of crisis and the need for maintaining the operations of these facilities is a priority for national security. We note that the Presidential Exemption only applies to compliance with the new requirements and does not relieve facilities of any compliance obligations with respect to current applicable requirements. As with the Coke Ovens NESHAP, U.S. EPA will reconsider certain elements of the 2024 amendments to the HON and P&R I and II NESHAP, and we anticipate a regulatory proposal later this year.

Moving Forward: How Can ALL4 Help?

As the administration continues with its deregulatory agenda, ALL4 monitors environmental regulatory and policy changes or updates, publishes articles such as this one to keep everyone informed, and we are available to answer any questions you have. For facilities that are still subject to the original compliance deadlines, ALL4 would be glad to assist with gap assessments to help you understand your compliance obligations and short-term fenceline pilot studies ahead of the compliance date to characterize ambient impacts and identify opportunities to reduce fugitive emissions.

We have assisted several facilities with these assessments and studies, with valuable information collected from both to help you make informed decisions. Although U.S. EPA will reconsider some of the revised requirements, the changes will be limited, and not all of the new requirements are expected to be eliminated. Therefore, it makes sense to evaluate gaps now and then adjust your compliance approach when we understand which requirements will change. For more information, please reach out to me, Kyle Hunt, or your ALL4 project manager to start a conversation.