EPA releases final NESHAP for area source chemical manufacturers

The Environmental Protection Agency (EPA) published a final rule on April 1, 2026, amending the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Chemical Manufacturing Area Sources (CMAS). The NESHAP controls hazardous air pollutant (HAP) emissions from facilities that manufacture a range of chemicals and products, such as inorganic chemicals, plastics, and synthetic rubber.

Who’s impacted?

The final rule applies to nine area source categories in the chemical manufacturing sector that are regulated by the CMAS NESHAP (40 CFR 63 Subpart VVVVVV).

What are the changes?

EPA’s final rule:

• Establishes leak detection and repair requirements for equipment leaks and heat exchange systems in organic HAP service,
• Adds detectable emissions monitoring standards for pressure vessels in organic HAP service and emission management practice standards for pressure relief devices (PRDs) in organic HAP service,
• Prohibits closed vent systems in organic HAP service from bypassing an air pollution control device (APCD), and
• Requires recurring performance testing of non-flare APCDs to demonstrate compliance with process vent and storage tank provisions.

The final rule also mandates electronic reporting for notifications of compliance status (NOCs), performance test reports, and periodic reports. Facilities must submit these reports through the Compliance and Emissions Data Reporting Interface (CEDRI) on EPA’s Central Data Exchange.

What didn’t change?

Significantly, the final rule doesn’t add previously proposed regulations for area sources that use ethylene oxide (EtO) to produce materials described by code 325 of the North American Industry Classification System (NAICS).

EPA states that it intends to address the regulation of EtO from area sources and major sources in one final action.

What are the compliance timelines?

Existing facilities must comply with the amendments by April 1, 2029.

New facilities (those that begin construction or reconstruction after January 22, 2025) have to comply with the changes by April 1, 2026, or upon startup, whichever is later.

Additionally, facilities must start electronically submitting:

• Performance tests by June 1, 2026;
• NOCs by August 31, 2026; and
• Periodic reports by April 1, 2029.

Key to remember: EPA’s final HAP emissions rule for chemical manufacturing area sources adds new requirements for certain processing equipment and systems.