CWA Hazardous Substances FRP: Advanced Notice of Proposed Rulemaking for Potential Rule Amendments

ALL4 has been tracking developments with the Clean Water Act (CWA) Hazardous Substances Facility Response Plan (FRP) Rule since the 2022 draft. Since the rule was finalized in 2024, ALL4 has been digging into the rule requirements, unanticipated differences from the original and proposed rule, guidance (or lack thereof) from the United States Environmental Protection Agency (U.S. EPA) and its announcements around delays and potential changes. Though we have yet to see details about a proposed compliance date delay that completed inter-agency review at the White House Office of Management and Budget (OMB) earlier this year, on Friday, February 13, U.S. EPA gave an to the FRP-regulated community – an announcement of an advanced notice of proposed rulemaking (ANPRM) to seek feedback on potential changes to the rule “to address implementation challenges and clarify requirements from the 2024 final rule.” This ANPRM quickly hit the Federal Register on February 18, 2026, starting the 30-day clock to submit comments. Read on for highlights from the ANPRM.

The ANPRM is seeking feedback on both applicability determinations and implementation of the FRP rule in two series of questions starting on Pages 17 of 21 and 20 of 21, respectively, of the prepublication version. These questions are summarized below:

Applicability Determination

• How should thresholds be set? Thresholds are currently set at 1,000 times the Reportable Quantity (RQ) at 40 CFR Part 117.3, but U.S. EPA is opening the door to another multiplier, a static value for all CWA Hazardous Substances (rather than being based on the RQ for each substance), or some other method.
• Could a de minimis for container size or concentration be established? The 2024 rule includes neither, requiring all container sizes and all concentrations of CWA Hazardous Substances to be included in applicability evaluations.
• What opportunities are there to simplify the criterion for distance to navigable waters? Should “conveyance” be more clearly defined?
• What changes to the substantial harm criteria or what alternative demonstration approaches should be considered? This is the big one. The substantial harm criteria require complex modeling under a variety of scenarios. To date, U.S. EPA has given minimal guidance on how this modeling is to be conducted and no indication of whether a commercially available model exists to perform it.
• What exemptions should be considered, and how should this rule account for or specifically exempt CWA Hazardous Substances in oils that are already subject to 40 CFR Part 112 FRP requirements? There is already an exemption for wastewater treated by Publicly Owned Treatment Works (POTW) – should that be extended to privately-owned treatment works under NPDES permits?

Program Implementation Issues

• What existing tools or alternative approaches should be considered in determining planning distances? (See previous bullet on substantial harm criteria – the same modeling for determining applicability plays into implementation for subject facilities.)
• How should chemical reaction intermediates and byproducts be handled?
• What requirements of this program overlap with other existing U.S. EPA programs (e.g., 40 CFR Part 68 Risk Management Program)?
• What other external resources would assist with FRP coordination with potentially affected entities (such as public water systems)?
• How else can the FRP requirements be simplified but “retain readiness to protect human health and the environment”?

For more background on the CWA Hazardous Substances FRP Rule, check out our previous blogs and webinar recording. If you have any questions or would like support in providing comments to U.S. EPA in response to this ANPRM, please reach out to Lizzie Smith at lsmith@all4inc.com.