The EPA finalized 40 CFR Part 118 on March 28, 2024. It took effect on May 28, 2024. It is the first federal rule to require Facility Response Plans for facilities that hold hazardous substances near navigable water, and it pulled roughly 5,400 new facilities into scope.

The rule has been on the books for over a year. Atlantic hurricane season is now ramping into its statistical peak. And the Arkema Crosby settlement, closed in 2024 for events that began during Hurricane Harvey in 2017, is the sitting reminder that the Clean Water Act does not have a short memory.

Any facility whose plan predates May 2024 has a compliance verification to run before the next named storm makes landfall.

What the Rule Actually Requires

40 CFR Part 118 applies to facilities that meet all three criteria: they hold a listed CWA hazardous substance at or above 10,000 times the reportable quantity of that substance, they sit within one-half mile of navigable water or a conveyance to navigable water, and they meet at least one of the substantial-harm criteria such as proximity to public drinking water intakes or fish and wildlife populations.

Facilities in scope must prepare a Facility Response Plan covering worst-case discharge scenarios, response equipment inventory, notification procedures, personnel training, and drills. Initial FRP submission to the EPA was due June 1, 2027, and existing facilities that came into scope must submit within the same window.

The Piece Most Plans Miss: "Worst-Case Discharge" Now Includes the Weather

The single most consequential shift in the 2024 rule is how "worst-case discharge" gets defined. The final rule requires facilities to account for climate-driven extreme weather in the discharge scenario, not only mechanical or process failures.

A 2015-era plan that modeled a worst case around a stationary tank rupture is not covering the 2026 scenario. The 2026 scenario is a Category 4 storm surge lifting drums out of a bermed containment area, or a monsoon flash flood pushing product past a containment lip that was sized for a 25-year event. Both are now scenarios the plan is expected to address.

The Anchor Case: Arkema Crosby

The Arkema chemical plant in Crosby, Texas lost power and backup refrigeration during Hurricane Harvey's Houston-area flooding in August 2017. Volatile organic peroxides in the plant's cold storage warmed and combusted over a 72-hour window. The EPA and the state of Texas settled the resulting Clean Water Act and related claims in 2024 for $1.1 million. Seven years from event to settlement.

The Crosby record is the case behind the rule. It is why the "worst-case discharge" language now names extreme weather, and it is the reference point for how long a facility's storm-related exposure can sit open.

The Pre-Storm, Mid-Storm, Post-Storm Workflow

A working FRP built for the current rule reads as three distinct workflows, not one plan.

Pre-storm (72 hours out). Verify perimeter containment integrity. Stage absorbent socks and containment booms at every potential runoff path from tank farms, drum storage, and transfer areas. Confirm secondary containment volumes against the current inventory. Move mobile assets out of surge-projected zones.

Mid-storm (during the event). Personnel are typically off-site. The plan is what runs. Automated sensor systems, if present, must be live and reporting. Pre-staged containment must hold. Communications with the National Response Center pre-programmed and tested.

Post-storm (first 48 hours). The rule's notification cascade is tightest here. Any discharge above the reportable quantity requires immediate NRC notification, followed by written follow-up. On-site response teams deploy hazardous chemical spill kits matched to the substances actually released. Documentation of every action, every hour, is the record the EPA will review.

Where the Old Plans Break

Common gaps in plans that have not been refreshed against the 2024 rule:

• Worst-case discharge modeled against a single equipment failure, not a compound climate event.
• Response equipment inventory that reflects the facility at last audit, not current process.
• Personnel training records that show initial training but no annual refresher and no drill documentation.
• Containment strategy that assumes secondary containment volumes remain effective in a flooded environment. In a flood, secondary containment overtops.
• No pre-staged surface containment at grade level, meaning hazardous chemical mats and pads for surface control are sourced reactively, not stocked in place.

What to Verify This Month

1. Confirm applicability. Pull your hazardous substance inventory. Cross-reference against the CWA HS list at 40 CFR 116.4. Compare to the 10,000-times-RQ threshold. Confirm whether you sit inside a one-half-mile navigable-water buffer. Applicability is a binary answer.
2. Read your existing plan against the current rule. If it was written before May 2024, work through the worst-case discharge section first. It is almost certainly the part that needs the largest rewrite.
3. Inventory your response equipment against current process. The plan's equipment list has to match what is on the shelf and what the shelf can respond to. A plan that references sock types no longer stocked will fail on inspection.
4. Run one tabletop drill before the peak of hurricane season. Two hours of walk-through with the response team is the highest-yield compliance and readiness activity a facility can run in July.

One Stock List, Every Storm

The regulatory scope changed. The physical work of containment did not. A facility whose plan is rewritten to the current rule, whose equipment is pre-staged against the surge path, and whose response team has walked the drill in the last 90 days is a facility that survives both the storm and the inspection that follows it.

The rule changed in 2024. The storm season did not wait. The absorbents, containment, and spill kits ship from Absorbents For Less.