## Facts

- EPA issued final pretreatment regulations defining “interference” and “pass through” for industrial discharges into publicly owned treatment works (POTWs) under 40 C.F.R. § 403.3(i), (n).
- The regulations implement statutory authority requiring pretreatment standards to prevent pollutants from interfering with, passing through, or otherwise being incompatible with POTWs.
- The definitions linked “interference” to discharges that inhibit or disrupt POTW treatment processes and result in permit violations or sewage sludge use/disposal problems.
- The definitions linked “pass through” to discharges exiting a POTW in quantities or concentrations that cause violations of the POTW’s NPDES permit or applicable water-quality requirements.
- An Arkansas poultry industry trade association petitioned for appellate review, arguing the definitions exceeded statutory authority and were impermissibly vague.

## Issues

1. Whether EPA’s regulatory definitions of “interference” and “pass through” are inconsistent with the Clean Water Act’s pretreatment provision authorizing standards to prevent pollutants from interfering with or passing through POTWs.
2. Whether the definitions are unconstitutionally vague because they fail to give regulated industrial users fair notice of prohibited or regulated conduct.

## Decision

- The court denied the petition for review and upheld the challenged definitions.
- Applying Administrative Procedure Act review, the court held EPA’s action could be set aside only if arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.
- The court deferred to EPA’s reasonable interpretation of the statute and gave substantial deference to EPA’s interpretation of its own regulations.
- The court concluded the definitions were consistent with statutory text and purpose because they focus on preventing industrial discharges from causing POTW operational disruption, permit noncompliance, or sludge-related problems.
- The court rejected the vagueness challenge because the definitions use technical, program-based criteria and objective benchmarks (e.g., causation of NPDES permit violations or demonstrable disruption of treatment processes).

## Legal Principles

- Under APA § 706(2)(A), courts reviewing national regulations set aside agency action only if it is arbitrary, capricious, an abuse of discretion, or otherwise contrary to law.
- An agency’s reasonable construction of a complex environmental statute it administers is entitled to judicial deference.
- An agency’s interpretation of its own regulation is entitled to substantial deference and is upheld unless plainly erroneous or inconsistent with the regulation.
- Regulatory language in technical programs is not unconstitutionally vague when it provides regulated parties adequate notice through objective, operational standards tied to measurable consequences (such as permit violations or identifiable treatment disruption).

## Conclusion

The Eighth Circuit upheld EPA’s 1987 pretreatment definitions of “interference” and “pass through,” holding they reasonably implement statutory authority to protect POTWs and provide sufficient notice to regulated industrial users, defeating both statutory and vagueness challenges.


Arkansas Poultry Fed’n v. U.S. Env’t Prot. Agency, 852 F.2d 324 (8th Cir. 1988)