EPA’s Worst-Case Discharge NPRM
Substantial Harm
This is the next post in my series on the recent notice of proposed rulemaking (NPRM) from the EPA for “Clean Water Act Hazardous Substance Worst Case Discharge Planning Regulations”. Earlier posts in this series were:
EPA Publishes Worst Case Discharge NPRM (Subscription version)
EPA’s Worst-Case Discharge NPRM – Affected Facilities (Subscription version)
Substantial Harm Requirement
Any facility that meets the threshold quantity and proximity to navigable waters screening thresholds of the rule then needs to determine if they meet the substantial harm standards that would lead to the facility being subject to the worst-case discharge planning requirements. Facilities meet the substantial harm standards if they fill any one of the following conditions:
Ability to cause injury to fish, wildlife, and sensitive environments (FWSE),
Ability to adversely impact a public water system,
Ability to cause injury to public receptors, or
Reportable discharge history
Ability to Cause Injury - FWSE
In this rule, the EPA is using the FWSE rule similar to that used in the Facility Response Plan (FRP) requirements for oil spills (40 CFR 112.20(f)(1)(ii)(B)). The definition of ‘fish, wildlife, and sensitive environments’ in the new 40 CFR 118.2 is the same as used in the existing oil spill planning requirements of §112.2. It specifically includes “areas that may be identified by their legal designation or by evaluations of Area Committees (for planning) or members of the Federal On-Scene Coordinator's spill response structure (during responses) [emphasis added].” This means that facts developed during a spill response could require subsequent response planning for any facilities that could impact that area.
To determine if a facility spill could cause harm to FWSE would use the toxic endpoints process outlined in the new §118.10. This includes:
Determination of worst case discharge quantity,
Planning distance determination,
The EPA is seeking comments on two alternative toxic end point methods discussed here and here.
Impact Public Water System
Because of different water treatment capabilities and the effects of different chemicals on those capabilities, the EPA is not able to concisely provide methodologies to determine if a worst-case spill will adversely affect a public water system. For this reason, facilities “would be required to coordinate with the public water system to determine whether concentrations from a worst case CWA hazardous substance discharge would result in scenarios adversely impacting the public water system.” That facility would determine, based on the worst-case spill information provided, whether the spill would:
Violate Federal and state drinking water standards (e.g., Maximum Contaminant Levels (MCLs)),
Compromise the ability of a public water system to produce water that complies with Federal and state drinking water standards,
Result in adverse health impacts in individuals exposed to contaminated drinking water,
Contaminate public water system infrastructure, and/or
Cause a public water system to issue water use restrictions.
The EPA is seeking comments on two alternative methods of determining public water system affects discussed here and here.
Ability to Cause Injury – Public
The definition of the term ‘public receptors’ used in this final rule is similar to that found in the Clean Air Act (CAA) Risk Management Program, at 40 CFR 68.3, but the version in the new §118.2 emphasizes the association of the location with a worst-case discharge to a navigable waterway. The determinations of substantial harm would use the same processes described in reference to FWSE.
Reportable Discharge
The final substantial harm criteria is the easiest to determine: “If a facility that meets the screening criteria has had a reportable discharge [under 40 CFR 117.21] within the last five years that reached water, the facility would be considered a facility that has the potential to cause substantial harm in the event of a worst case discharge.”
The EPA is seeking comments on three alternative methods of determining a reportable discharge quantity that are discussed here, here, and here.