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The PPM Blog

CWA Worst-Case Discharge Rule: A Surprising Slowdown—What It Means for Industry

a man wearing a suit and tie smiling at the cameraContributed by Zane Hood, Principal, PPM Consultants

Some of you may have read my blog last year entitled “Buckle Up – EPA Expands the FRP Rule to Include ‘Hazardous Substances”. Well, you may be able to loosen the buckle a bit but do so with caution. If you’ve been tracking the Clean Water Act (CWA) Hazardous Substances Facility Response Plan (FRP) rule with the same urgency as many of us in the environmental compliance field, you may have noticed that May 28, 2024, has come and gone—and the much-anticipated enforcement of the rule appears to be in a holding pattern. Despite the final rule’s publication in the Federal Register on March 28 and its stated effective date just two months later, implementation activity has been curiously quiet. So, what’s going on?

The Rule Recap: Why It Mattered

As a quick refresher, this new rule expanded the FRP universe beyond oil facilities to include those storing or handling certain hazardous substances listed in 40 CFR 117.3. Facilities that store these substances above the “1,000 times Reportable Quantity (RQ)” threshold and are located within 0.5 miles of a navigable waterway were suddenly on the hook for preparing worst-case discharge plans—modeled scenarios, emergency response coordination, and initiating extensive training requirements.

The rule was designed to fill what some consider a long-standing regulatory gap, and it signaled EPA’s renewed commitment to environmental justice (EJ) and climate resilience. The industry response? Cautious concern, a bit of scrambling, and a lot of consultants dusting off their FRP templates.

So… Where’s the Follow-Through?

Despite the Final Rule’s effective date of May 28, 2024, we’ve seen little evidence of rollout activity—no updated EPA guidance documents, no webinars or workshops, no formal implementation memos from the individual EPA Regions, and (perhaps most notably) no proactive outreach to facilities that are now theoretically covered under the rule. Several possible reasons may explain the delay:

  1. Legal and Political Pushback: The rule’s broad scope, aggressive thresholds, and ambiguous language (e.g., “navigable waters” and “adverse climate impacts”) may be ripe for litigation. It’s not uncommon for rules of this magnitude to get tied up in judicial review.
  2. Lack of Guidance Tools: The rule requires modeling of worst-case discharge scenarios and planning distances, yet EPA has not released any standardized methods or approved models. That’s a recipe for confusion—and inconsistency.
  3. Internal Administrative Reassessment: With the Trump administration’s recent shift in regulatory priorities, it’s likely that EPA is internally reevaluating rollout strategy or timing.

What Does This Mean for Industry?

If you’re a facility potentially subject to the rule, this delay brings both questions and options.

On the one hand, it gives you some breathing room. If your inventory of CWA-listed hazardous substances is minimal or far below the threshold, or your facility is clearly not within a half-mile of a navigable waterway, a wait-and-watch approach may be entirely reasonable. It allows you to observe how this rule evolves without prematurely investing significant time and resources. There definitely seems to be a lack of zeal or interest in regulatory enforcement of this rule.  So, if you are on the edge of applicability, this approach may be ideal for your facility.

On the other hand, if your facility is near the threshold—or if you’re in a region known for environmental justice concerns—it may be worth keeping your foot on the gas, at least lightly. Starting with a desktop screening to identify your chemical inventory and proximity to navigable waters is a smart first step. From there, you can gauge the potential scope and impact before committing to more intensive modeling or plan development.

Most importantly, facilities should document any applicability determinations, particularly if they conclude the rule doesn’t apply. A well-supported conclusion is your best defense if regulators eventually come knocking.

PPM’s Balanced Recommendation

At PPM, we’re helping clients evaluate their next steps based on where they sit on the spectrum. For some, this rule might be a non-issue. For others, it could carry real implications—especially as EPA continues to stress climate resilience, spill prevention, and equity in enforcement.  The political and regulatory winds can shift quickly so considering all angles are important.

Here’s a practical approach:

  • Start with an applicability screen: Inventory your CWA hazardous substances and assess potential exceedance of the 1,000x RQ threshold.
  • Map your site: Evaluate proximity to navigable waters or conveyances (keeping in mind the gray areas here).
  • Document your findings: Whether you proceed or pause, make sure your rationale is on paper.
  • Stay plugged in: Monitor EPA and industry updates for potential movement on guidance, litigation, or state-specific implementation.

If you have any questions or want to discuss the rule and/or implications to your facility, feel free to reach out to me at zane.hood@ppmco.com.

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