## Facts

- Industrial dischargers, utilities, and a municipality petitioned for review of an EPA NPDES permitting rule under the Clean Water Act (CWA).
- States set water quality standards for surface waters, using either numeric criteria (pollutant-specific numbers) or narrative criteria (general prohibitions such as no toxics in toxic amounts).
- Permit writers had sometimes failed to implement narrative criteria by omitting pollutant-specific, enforceable limits in permits.
- EPA adopted 40 C.F.R. § 122.44(d)(1)(vi), directing permit writers to translate narrative criteria into chemical-specific effluent limitations when a discharge has “reasonable potential” to cause or contribute to an excursion above a narrative criterion.
- The rule allows three translation approaches: (1) state-derived numeric criteria shown to protect the designated use, (2) EPA national criteria developed under CWA § 304(a), or (3) case-specific calculation procedures or models.

## Issues

1. Whether EPA lawfully required NPDES permit writers to translate state narrative water-quality criteria into numeric, pollutant-specific effluent limits.
2. Whether the rule impermissibly intruded on state authority over water-quality standards and reallocated responsibilities between states and EPA under the CWA.
3. Whether the rule exceeded EPA’s authority by effectively making EPA guidance and recommended criteria binding in permitting.

## Decision

- The court denied the petitions for review and upheld 40 C.F.R. § 122.44(d)(1)(vi).
- The CWA requires NPDES permits to contain limitations necessary to ensure compliance with applicable water quality standards, including narrative criteria.
- Requiring translation of narrative standards at the permitting stage did not force states to adopt new standards and did not unlawfully displace state standard-setting.
- EPA could require use of rational translation tools, including state-developed methods, EPA § 304(a) criteria, or site-specific models, to produce enforceable permit limits.

## Legal Principles

- NPDES permits must include effluent limitations sufficient to assure attainment of applicable water quality standards, even when those standards are expressed narratively.
- EPA may require permit writers to derive numeric, pollutant-specific limits from narrative criteria when there is reasonable potential for a discharge to cause or contribute to exceedances.
- The CWA preserves state primacy in adopting water quality standards, but EPA may ensure those standards are implemented through enforceable permit limitations.
- EPA may rely on § 304(a) recommended criteria and technical translation methods as permissible tools for implementing state narrative criteria in permitting.

## Conclusion

The D.C. Circuit sustained EPA’s rule requiring NPDES permitting authorities to convert state narrative water-quality criteria into numeric, chemical-specific effluent limits using specified translation methods, holding this approach consistent with the Clean Water Act and compatible with state control over standard-setting.


Am. Paper Inst., Inc. v. U.S. Env't Prot. Agency, 996 F.2d 346 (D.C. Cir. 1993)