Looking Ahead – Air Toxics Regulatory Activity

The last few years have seen a flurry of revisions to air toxics regulations, due primarily to a court case referred to as “LEAN” where the court determined that the U.S. Environmental Protection Agency (U.S. EPA) should have set more comprehensive emissions standards when it first promulgated many of its rules under 40 CFR Part 63. U.S. EPA has been revising National Emission Standards for Hazardous Air Pollutants (NESHAP) to include additional hazardous air pollutants (HAPs) and additional emissions sources. More stringent requirements have also been added to the NESHAP for some source categories due to an update in the risk value for ethylene oxide. Sectors affected by significant rule changes include coke ovens, iron and steel, tire manufacturing, lime manufacturing, and chemicals. The recent changes often include not only new emissions standards but also more stringent monitoring requirements, including fenceline monitoring. U.S. EPA is obligated to review their NESHAP on a certain schedule, so even without decisions like LEAN, the work never ends. What might be coming in 2025?

First, we are likely to see the new administration ask U.S. EPA to reconsider some of its more recent actions. With respect to air toxics rules, this could include a stay of the requirements while the NESHAP is being reconsidered. Litigation on NESHAP that U.S. EPA reconsiders is likely to be paused during the reconsideration, especially if a stay is put in place. Any significant regulatory changes as a result of reconsideration could result in new compliance dates for the final requirements. In the first Trump administration, we did not see any new fenceline monitoring requirements in any final NESHAP; this could be an area where requirements change.

There are a few NESHAP where we expect proposal activity in 2025. The stationary combustion turbine NESHAP proposal is expected and is one where U.S. EPA has been working to fill regulatory gaps. There are subcategories of combustion turbines that do not currently have any emissions standards. We also expect to see proposed changes to the NESHAP for Industrial Boilers and Process Heaters in 2025 to address a recent court decision around the 2022 changes to the standards for new sources. U.S. EPA is also expected to issue a supplemental proposal requesting additional input on the Plywood and Composite Wood Products NESHAP, another rule where significant gap filling was proposed during the Biden administration. Other NESHAP scheduled for proposal according to the Fall 2024 semiannual regulatory agenda are those covering chemical manufacturing area sources, secondary lead smelting, and marine vessel loading. We may also see final rule revisions for the polyvinyl chloride (PVC) NESHAP. (See our chemical and power sector lookaheads for more insight on regulatory activity specific to those sectors.)

We may see litigation around whether U.S. EPA has correctly interpreted the LEAN decision. In the gap-filling rules that we’ve seen since the LEAN decision, the agency has included many new requirements for additional HAPs and additional equipment, even where the results of the residual risk review were acceptable and additional controls are not cost effective. Will the court determine that U.S. EPA should only be setting additional standards if they are necessary to address risk and are cost effective to implement? We shall see.

We are not likely to see the proposed revisions to the Air Emissions Reporting Requirements (AERR) Rule finalized. The revisions would have required thousands of facilities to report HAP emissions to the U.S. EPA. The 2023 proposed additions to the rule were extremely burdensome and U.S. EPA quantified no benefits. Although the final rule went to the White House Office of Management and Budget for review in 2024, it is not expected to be finalized. It remains to be seen if the 2023 proposal that addressed regulatory issues around additions to the HAP list (e.g., 1-bromopropane) will be finalized soon.

ALL4 monitors air toxics regulatory activity and can help you or your industry association develop technical comments on regulatory proposals or evaluate impacts of final rule revisions on your facility or industry. Please contact your ALL4 project manager or Amy Marshall for assistance.