Final Revisions to SOCMI NESHAPs and NSPS and the NESHAPs for Group I and II Polymers and Resins

On April 9, 2024, the U.S. Environmental Protection Agency (U.S. EPA) released a pre-publication version of final revisions to several National Emission Standards for Hazardous Air Pollutants (NESHAP) and New Source Performance Standards (NSPS) applicable to facilities in the Synthetic Organic Chemical Manufacturing Industry (SOCMI) and Group I and II Polymers and Resins (P&R I and II) Industries. These rules include 40 CFR Part 63 Subpart F, G, H, and I (the HON), Subparts U and W (P&R I and II), and 40 CFR Part 60, Subparts VVa, VVb, III, IIIa, NNN, NNNa, RRR, and RRRa.

Chris Ward, a Technical Manager here at ALL4, wrote a comprehensive 4 The Record article covering the changes to the rules that were proposed  in April 2023. For the most part, U.S. EPA finalized the provisions as proposed, and made only a few changes. This article provides a summary of the major changes from the proposal that U.S. EPA included in the final rules.

Storage Vessels

In the proposed rule, U.S. EPA indicated that they intended to remove the pressure vessel exemption from the HON and P&R I such that pressure vessels with an operating pressure of greater than 204.9 kilopascals (kPa) would no longer be exempt from the storage vessel control requirements. U.S. EPA is clarifying in the final rule that only pressure vessels that would otherwise be classified as a group 1 storage vessel would be subject to control and as proposed, U.S. EPA is finalizing changes to lower the group 1 storage vessel volume and maximum true vapor pressure control thresholds.

U.S. EPA has also finalized the provisions that require owners and operators to control emissions from the use of sweep air, purge air, or inert blankets at internal floating roof tanks. However, in a change from the original proposal, control is only required if the use of the purge, sweep, or blanket results in continuous emissions of one pound per hour (lb/yr) or more of total organic HAP.

Sources of Ethylene Oxide and Chloroprene

Two important changes to note are related to the requirements for emissions of ethylene oxide (HON) and chloroprene (P&R I). In the proposed HON rule, U.S. EPA included a restriction on the mass of ethylene oxide that could be routed to a flare in any given year. For P&R I, the Agency proposed that site-wide emissions of chloroprene from P&R I facilities could not exceed 3.8 tons per year. However, U.S. EPA did not finalize either requirement.

Fenceline Monitoring

U.S. EPA’s proposal to require fenceline monitoring of six target analytes at HON and P&R I facilities took center stage in the proposed rules and U.S. EPA is finalizing the fenceline monitoring provisions with a few key changes from proposal. Three major changes are described below.

First, the Agency is clarifying that the fenceline monitoring requirements apply if the “affected source” (instead of the “site”) uses, produces, stores, or emits one or more of the target analytes. The use of the term “site” in the proposed rule created confusion as to whether use, production, storage, or emissions of one of the analytes outside of the HON or P&R I affected source would trigger monitoring requirements. It’s important to note, however, that U.S. EPA makes it clear in the preamble to the proposed rule that if a facility determines an exceedance of the action level is under their control, they are obligated to address the emissions, regardless of whether they originate from the HON or P&R I affected source.

Next, with the exception of P&R I sources producing neoprene and emitting chloroprene, U.S. EPA is allowing sources more time than proposed to begin data collection. Most sources now have two years instead of one to begin data collection, and three years to comply with the root cause and corrective action requirements. P&R I sources producing neoprene must begin monitoring for chloroprene within 90 or 150 days of publication of the final rule in the Federal Register (U.S. EPA states 90 days in the preamble, but also states 150 days elsewhere in the preamble and in the regulatory text included in the prepublication version).

Finally, U.S. EPA added provisions for reduced sampling frequency in the proposed rule for all compounds except ethylene oxide and chloroprene. If an individual sampling site is consistently 10 times below the action level, the sampling frequency can be reduced from either 14 days or 5 days to monthly, quarterly, semi-annually, or annually.

NSPS Standards

U.S. EPA is finalizing the new and revised NSPS as proposed with a few changes from proposal. First, U.S. EPA is finalizing Subpart IIIa, NNNa, and RRRa as proposed without the total resource effectiveness (TRE) concept for determining which vent streams must be controlled, but in the final rules, U.S. EPA added a mass-based control threshold criterion to Subparts IIIa and NNNa. Second, U.S. EPA is incorporating changes to correct errors in the definition of “capital expenditure” in Subpart VVa, as noted by commenters.

What’s Next?

We are currently awaiting publication of the final rules in the Federal Register which will begin the compliance timeline clock. Existing sources generally have three years to comply with the non-risk related changes to the NESHAP, but sources must begin compliance with the fenceline monitoring data collection and ethylene oxide control requirements in two years. P&R I sources of chloroprene must comply with the fenceline monitoring requirement and chloroprene control requirements within 150 days (see note above about U.S. EPA’s mention of 90 days in the preamble). New sources (those for which construction or reconstruction began after April 25, 2023) must be in compliance with the new NESHAP requirements 60 days after publication or upon startup, whichever is later. Sources that began construction, reconstruction, or modification of an affected source after proposal of the new NSPS regulations must be in compliance with those provisions within 60 days after publication of the final rules or upon startup, whichever is later.

We suggest facilities start reviewing the regulatory changes now to understand the differences from what was proposed and to begin planning for any capital investments and process improvements necessary to come into compliance with the new requirements. It’s a good idea to reach out to your industry associations and your ALL4 project manager if you need assistance understanding the new rule requirements. ALL4 can work with your facility to identify applicable regulatory changes, develop options for process and control changes, scope required monitoring system upgrades, and design and implement a fenceline monitoring program.

ALL4 is hosting three upcoming in-person workshops for regulated industry professionals that will provide an opportunity to learn more about recent chemical industry rule changes (including updates to the Risk Management Program rules and the recently revised National Ambient Air Quality Standards for PM_2.5). These workshops will be a combination of presentations and group discussions and will be held in Cherry Hill, NJ, on May 2, Columbus, OH, on May 7, and Houston, TX, on May 9. Check out the registration link for more information on the workshops.