## Facts

- The Clean Water Act (CWA) prohibits discharging pollutants to navigable waters without a National Pollutant Discharge Elimination System (NPDES) permit containing technology-based and, when required, water-quality-based limits.
- EPA issued final NPDES permit regulations implementing aspects of an earlier settlement and addressing: the definition and timing of “new sources,” the CWA § 306(d) ten-year “new source” exemption, permit application disclosures (including on-site toxics), and limits on “bypasses” of treatment systems.
- Environmental groups (including NRDC) and multiple industry petitioners filed consolidated petitions for review challenging discrete provisions as exceeding statutory authority or being arbitrary and capricious under the Administrative Procedure Act.
- One challenged provision asserted EPA authority to bar construction of new sources pending issuance of an NPDES permit.
- Other challenges focused on when “new source” status attaches relative to proposed and final New Source Performance Standards (NSPS), the scope of the ten-year exemption, the breadth of required toxic-chemical disclosures, and the legality of EPA’s bypass restrictions.

## Issues

1. Whether the CWA (or NEPA) authorizes EPA to impose a blanket moratorium on construction of new sources while an NPDES permit application is pending.
2. How to define “new source” under CWA § 306 with respect to the timing of NSPS proposal and finalization.
3. Whether CWA § 306(d)’s ten-year exemption shields new sources from later-adopted water-quality-based limits, or only from later technology-based standards reflecting advances in technology.
4. Whether EPA may require NPDES applicants to disclose toxic pollutants used or manufactured on-site even if not expected to be discharged.
5. Whether EPA’s bypass prohibition is within its permitting authority or instead an unauthorized effluent limitation requiring additional statutory justification.

## Decision

- The court granted the petitions in part and denied them in part.
- EPA lacked authority under the CWA or NEPA to impose a blanket prohibition on construction of new sources pending issuance of an NPDES permit; that provision was invalidated.
- The court upheld substantially all remaining challenged NPDES regulations.
- “New source” under § 306 covers facilities whose construction begins after NSPS are proposed only if the NSPS become final within 120 days of proposal.
- The § 306(d) ten-year exemption applies only to more stringent technology-based standards tied to advances in technology, not to water-quality-based limits.
- EPA may require disclosure of on-site toxic pollutants used or manufactured at the facility, even absent an expected discharge, as part of its information-gathering and permit-conditioning authority.
- EPA’s bypass restrictions were upheld as part of the statutory permitting and effluent-limitation framework aimed at preventing circumvention of permit limits.

## Legal Principles

- EPA’s CWA authority is broad but functionally limited to regulating pollutant discharges (including issuing/denying permits, setting effluent limits, and obtaining information relevant to discharge control).
- NEPA is procedural and does not supply substantive authority to halt construction where the CWA does not confer that power.
- For § 306, “new source” status depends on construction commencing after NSPS proposal, coupled with NSPS finalization within 120 days, to balance regulatory notice and enforceability.
- The § 306(d) ten-year protection insulates new sources from later, more stringent technology-based standards driven by technological advances, but does not bar water-quality-based limitations required to meet receiving-water goals.
- CWA §§ 308 and 402 support expansive information demands in NPDES applications, including disclosure about toxic substances present on-site to address risks of accidental releases and to support preventive permit conditions.
- Bypass prohibitions may be used to preserve the effectiveness of effluent limits by limiting diversion around treatment systems to narrow, defined circumstances.

## Conclusion

The D.C. Circuit upheld nearly all of EPA’s NPDES permit regulations, confirming wide authority to regulate discharges through permits, standards, and information-gathering, but held EPA may not impose a categorical construction moratorium for new sources absent explicit statutory authorization.


Natural Res. Def. Council, Inc. v. EPA, 822 F.2d 104 (D.C. Cir. 1987)