Clean Water Act Hazardous Substance Planning


You’ve probably heard about the new rule the EPA proposed this year. In it, the agency states its intention to enforce facility response planning, or FRPs, for worst-case discharges of Clean Water Act harmful substances. The rule is the result of a consent order (resolved in March 2020), which required the EPA to sign a proposed regulation within two years and release a final version 30 months after publication. This means that we can expect the rule to become law around September 2024.

It’s better to plan ahead now than wait until the last minute. For example, you can keep a comprehensive list of all chemicals at your site. This will allow you to prepare for the FRPs before the final rule is published and your preparations are crammed into one year. We’ve read the Federal Register Notice in its entirety and distilled the most important information into the answers you will need when it comes time to submit.

Before you read on, please note that the following information was taken from the proposed regulation (published March 28th, 2022). It is subject to change when the final rule is published.

Which Substances Are Hazardous Under the CWA, and What Are Their Reportable Quantities?

You should check this intuitively, but if you need confirmation, here is the complete list of hazardous substances designated pursuant to 33 U.S.C. If you are unsure, the list of hazardous substances as defined by 33 U.S.C. is available for your reference. 1321(b), also known as

Substances… that, when discharged into waters under jurisdiction, pose an immediate and substantial threat to the public’s health or welfare including, but without limitation, fish, shellfish and wildlife, shorelines and beaches (Federal Register notice section 3B).

You can find the CWA category of each substance–X or A–as well as its corresponding RQ (reportable quantity) in pounds (1, 10, 100 or 1,000). The EPA will consider your facility “reasonably likely to cause substantial damage to the environment” if it stores or works with hazardous substances that are at or above RQ and is near navigable waterways (see the next section).

After achieving this distinction, you can now proceed to the criteria for applicability specific to the worst-case discharges of these substances.

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What is the EPA’s definition of a CWA worst-case discharge?

The Federal Register notice states that a worst-case discharge is the “largest discharge foreseeable in adverse weather conditions including a discharge resulting from a fire, explosion or other incident” (Section 4.A.3.b).

It is the same as discharging the container or group of containers with the highest capacity for a single dangerous substance (that meets or exceeds threshold quantities at the facility). This is what the EPA calls a “worst-case discharge scenario,” and facilities use it to evaluate and determine hazards.

If you combine those two, we can imagine a worst-case discharge as a hypothetical scenario where your container or containers with the most hazardous substance in your facility (when full capacity) are discharged in navigable water or into a conveyance in navigable water as a result of bad weather or a fire or explosion.

Do I have to submit a Facility Reaction Plan (FRP)?

You must submit a FRP if your facility meets the EPA screening criteria as well as any of the four criteria for substantial harm.

Screening Criteria

1. Is there a limit to the amount of hazardous substances that can be stored in your facility?

Maximum capacity on site is defined as:

The total container capacity (excluding permanently sealed containers) of hazardous substances present in all locations throughout the entire facility (section IV.a.1.A.II).

2. Your Facility is within a half mile of navigable waters or conveyances to navigable waters?

You should only proceed to the criteria for substantial harm below if both of these criteria are “Yes.”

Substantial harm criteria:

  • Has your facility discharged a hazardous substance that exceeded its RQ in the last five years (not at 10,000 times its RQ)?
  • Have you located far enough away from your facility that a worst-case discharge could cause harm to fish, wildlife, and sensitive environments?
  • Your facility is located far enough away that a worst-case discharge could negatively impact a water system for the public.
  • Are you located in a location where a worst-case discharge could cause harm to public receptors? These are areas that the public may be exposed to, like offsite residences or office buildings or parks, or any other place that the public can occupy or inhabit at any time without restriction from the facility.

You may be confused about how to determine whether you meet these criteria. The EPA expects facilities to need help, so owners and operators of facilities that meet the two screening criteria are asked to fill out the Substantial Harm Certification Form. (Federal Register notice, Appendix A), regardless of whether they think they meet the four criteria. The EPA makes the final decision.

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It’s also worth noting that, under the rule, the Regional Administrator has the authority to demand FRPs for facilities that don’t meet the criteria above. The rule will apply to facilities that do not have passive mitigation measures or are vulnerable to climate change in the future (for example, because of flooding). Facilities that may cause harm to local communities who are concerned about environmental justice or those that exhibit other site-specific concerns can also expect to be included. The facility owner/operator can always appeal the decision by requesting reconsideration.

What should I include in my Hazardous Substance Facility Reaction Plan (FRP), as required by the CWA?

The following is only a brief summary of the major components of a FRP. For more information, please refer to Section III.B.4 in the Federal Register notice.

Facilities that are regulated will be required to identify all hazardous substances onsite with a maximum volume exceeding or equaling the threshold quantity (that’s 10,000 times their RQ) and plan accordingly. They must calculate one planning quantity.

This calculation has three components. First, the amount itself. This is also known as the worst-case discharge quantity. It corresponds to the maximum foreseeable amount that can be discharged in a worst-case discharge scenario. After establishing the quantity, the facility owner/operator must determine the endpoints to which the hazardous substance will be discharged and calculate their distance. The EPA defines the “distance to an endpoint” as follows:

The distance a hazardous substance travels before dissipating, to the extent that a worst-case discharge does not cause injury to public receptors, FWSE, or negatively impact a public drinking water system (Federal Register Notice section IV.A.4).

Remember that the rate of dissipation depends on the endpoint. There are lower and upper toxicity levels available. 

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