2026-06304RuleWallet

EPA Tightens Leaks in Chemical Factories for Cleaner Air

Published Date: 4/1/2026

Rule

Summary

The EPA is updating rules for chemical factories to catch and fix leaks faster, keep an eye on pressure devices, and report pollution data electronically. These changes start April 1, 2026, and help keep the air cleaner without big costs. If you run or work with chemical manufacturing equipment, these new rules affect you and make sure pollution stays in check with smarter tech and better reporting.

Analyzed Economic Effects

12 provisions identified: 2 benefits, 10 costs, 0 mixed.

New LDAR instrument monitoring rules

If you own or operate a chemical manufacturing process unit, you must perform annual instrument monitoring of pumps in light-liquid service, valves in gas/vapor and light-liquid service, and connectors in gas/vapor and light-liquid service using EPA Method 21 with a leak definition of 10,000 parts per million by volume (ppmv). These monitoring rules are finalized as part of the CMAS NESHAP technology review.

Heat exchanger quarterly testing

If you operate a heat exchange system in organic HAP service with flowrates greater than or equal to 8,000 gallons per minute (gpm), you must conduct quarterly monitoring (after an initial six months of monthly monitoring if not already completed) using the Modified El Paso Method and repair leaks at or above 6.2 ppmv total strippable hydrocarbon concentration (as methane).

Pressure vessel no-detectable emission rule

Pressure vessels in organic HAP service must meet a no-detectable-emissions requirement: each potential emission point must have an instrument reading less than 500 ppmv, with initial and annual monitoring using EPA Method 21, and organic HAP must be routed through a closed vent system to a control device.

Continuous APCD performance testing required

The final rule requires continuous performance testing/monitoring of non-flare air pollution control devices (APCDs) as part of the CMAS NESHAP amendments.

Effective/compliance dates and cost estimate

This final rule is effective April 1, 2026. Existing affected sources must comply with the amendments no later than April 1, 2029, or upon startup, whichever is later. The EPA estimates present value (PV) costs of $72 million at a 3% discount rate and $56 million at a 7% discount rate over 2027–2041, with equivalent annualized values of about $6.1 million and $6.2 million per year (2024 dollars).

PRD monitoring, recording, and root-cause steps

Owners/operators must monitor pressure relief devices (PRDs) in organic HAP service for leaks after placing a PRD into service following a pressure release, record the time and duration of each pressure release, perform root-cause analysis and corrective action if a PRD releases directly to the atmosphere, and implement preventative measures.

No bypassing of control devices allowed

For closed vent systems with bypass lines, owners/operators may not bypass the air pollution control device (APCD) at any time; doing so is a deviation. Using a cap, blind flange, plug, or second valve on open-ended valves or lines is sufficient to prevent a bypass. The exemption for gas streams exiting analyzers is removed.

Five-year recurring performance tests

Owners/operators must conduct subsequent performance testing once every five years to demonstrate compliance with emission limits for certain process vents.

Affirmative defense provisions removed

The EPA is eliminating the affirmative defense provisions in the CMAS NESHAP (specifically 40 CFR 63.11501(e) and the definition of 'affirmative defense' in 40 CFR 63.11502(b)), in line with court precedent.

Alternative monitoring option for exchangers

Owners/operators may use the current heat exchange monitoring requirements at 40 CFR 63.104(b) instead of the Modified El Paso Method only if 99 percent by weight or more of organic compounds that could leak are water soluble and have a Henry's Law constant less than 5.0E-6 atm·m3/mol at 25°C.

Electronic reporting via CDX/CEDRI required

Owners/operators must submit certain reports electronically: notification of compliance status (NOCS) as a PDF upload, performance test reports in the EPA Electronic Reporting Tool (ERT) format or XML schema, and periodic reports using the CEDRI spreadsheet templates via the EPA's Central Data Exchange (CDX).

EtO area-source action deferred

The EPA is not finalizing the proposed listing and regulation of ethylene oxide (EtO) from area sources (NAICS code 325) at this time; the Agency will take additional time to consider comments and coordinate with EtO regulation for major sources.

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Key Dates

Published Date
Rule Effective
4/1/2026
4/1/2026

Department and Agencies

Department
Independent Agency
Agency
Environmental Protection Agency
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