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.