## Facts

- EPA promulgated new-source performance standards for corn wet milling plants under § 306 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. § 1316.
- The standards set 30-day average effluent limits of 20 lbs BOD₅ and 10 lbs TSS per 1,000 standard bushels of corn processed, premised on deep bed filtration as the best available demonstrated control technology.
- In an earlier proceeding, the court found the record inadequate to support the new-source standards and remanded for EPA to supply support or set achievable standards and to update cost projections.
- On remand, EPA reconsidered the record and reissued essentially the same numerical BOD₅ and TSS standards, again relying heavily on data from a Clinton, Iowa corn wet milling facility and, particularly for TSS, on data from other industries.
- Industry petitioners challenged the reissued standards, arguing EPA did not fairly reconsider them, overstated deep bed filtration performance, inadequately accounted for modified starch waste loads, relied on non-comparable cross-industry TSS data, and misjudged compliance costs and economic feasibility.

## Issues

1. Whether EPA’s reissued § 306 new-source standards for BOD₅ and TSS for corn wet milling were supported by the administrative record and were not arbitrary or capricious.
2. Whether EPA reasonably treated deep bed filtration as the best available demonstrated control technology and reasonably relied on the Clinton plant and other-industry data.
3. Whether EPA adequately accounted for increased waste loads associated with modified starch production in setting the BOD₅ standard.
4. Whether the TSS standard had an adequate evidentiary basis given EPA’s reliance on cross-industry data of disputed comparability.
5. Whether EPA’s technology and cost analyses were arbitrary or capricious.

## Decision

- The court granted the petition in part and denied it in part.
- The court upheld the BOD₅ standard, finding it supported by record evidence and not arbitrary or capricious.
- The court set aside the TSS standard as arbitrary and capricious and remanded it for further proceedings.
- The court rejected petitioners’ broader challenges to EPA’s technology and cost assessments, finding no arbitrariness or caprice.

## Legal Principles

- Review of technology-based effluent standards proceeds under the APA “arbitrary and capricious” standard; courts require a rational connection between record evidence and the agency’s choice and will not substitute judicial judgment for agency expertise.
- Under § 306, new-source standards must be based on “best available demonstrated control technology”; a “leading” plant’s demonstrated performance may support a standard when the record shows achievability for a properly designed and operated new source.
- EPA may use models and extrapolation, but numerical limits must rest on reliable, comparable evidence showing the standard is achievable; speculative transfer of technology across industries without adequate support is insufficient.
- EPA must consider costs and economic impact, but the statute does not require strict cost–benefit balancing; disagreements in cost estimates do not alone establish arbitrariness.

## Conclusion

The Eighth Circuit sustained EPA’s BOD₅ new-source limit for corn wet milling because the record, anchored in demonstrated performance at a corn wet milling facility using deep bed filtration and accounting for modified starch loads, supported achievability. It vacated and remanded the TSS limit because EPA relied largely on non-comparable cross-industry data and did not show the TSS level had been demonstrated as achievable in the relevant industry, rendering that portion of the rule arbitrary and capricious.


CPC Int'l, Inc. v. Train, 540 F.2d 1329 (8th Cir. 1976)