## Facts

- In the 1980s, the Environmental Protection Agency (EPA) found high levels of tetrachlorodibenzo-p-dioxin (TCDD), a toxic pollutant, in fish from the Columbia River basin.
- Studies connected a significant portion of the TCDD to upstream discharges associated with pulp and paper mills.
- States regulating water quality in the Columbia River Basin used a numeric water-quality criterion for TCDD of about 0.013 parts per quadrillion (ppq).
- EPA determined that TCDD concentrations in the river exceeded that permissible level.
- The basin states designated affected river segments as “water quality limited” waters under Clean Water Act (CWA) § 303(d) because applicable water-quality standards were not being met.
- Following the listings, EPA developed and issued a total maximum daily load (TMDL) for TCDD for the relevant river segments to implement the states’ water-quality standards.
- Environmental organizations (Dioxin/Organochlorine Center and Columbia River United) challenged the TMDL as unlawfully weak and not sufficient to meet the states’ standards.
- A group of pulp and paper companies (the mills), participating as intervenors, challenged EPA’s authority to issue a TMDL for TCDD without first issuing technology-based effluent limits for TCDD under other CWA programs.
- The U.S. District Court for the Western District of Washington granted summary judgment to EPA and rejected both the environmental groups’ and the mills’ claims, and the challengers appealed.

## Issues

1. Whether CWA § 303(d) authorizes EPA to establish a TMDL for a pollutant even if technology-based effluent limitations for that pollutant have not been promulgated.
2. Whether EPA’s TCDD TMDL violated the CWA because it allegedly failed to meet, or ensure attainment of, the applicable state water-quality standards.
3. Whether EPA’s technical choices in setting the TMDL were arbitrary or capricious under the Administrative Procedure Act (APA).

## Decision

- The Ninth Circuit affirmed the district court’s summary judgment in favor of EPA.
- The court held that § 303(d) permits EPA to issue TMDLs without first establishing pollutant-specific technology-based effluent limits.
- The court rejected the environmental groups’ argument that the TMDL was unlawfully insufficient, concluding EPA’s TMDL conformed to the states’ water-quality standards as implemented through the TMDL.
- The court rejected the mills’ statutory argument that EPA was required to proceed first through technology-based limits before issuing a TMDL.
- Applying APA review, the court upheld EPA’s technical and scientific judgments, finding EPA’s approach reasoned and supported by the record.

## Legal Principles

- CWA § 303(d) TMDLs are a water-quality-based control mechanism that can operate independently of technology-based effluent limitation programs.
- When the Clean Water Act does not clearly dictate the timing or sequencing between water-quality-based tools and technology-based controls, courts generally accept a reasonable agency reading of the statute.
- Under the APA, courts set aside agency action only if it is arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law; disagreement with an agency’s technical choices is not enough.
- Courts give significant weight to an agency’s scientific and technical determinations so long as the agency considered the relevant factors and explained a rational connection between the record and its decision.
- A TMDL is upheld when it reasonably implements the applicable state water-quality criterion (here, the 0.013 ppq TCDD target) and the agency’s analysis is adequately supported.

## Conclusion

The Ninth Circuit upheld EPA’s Columbia River Basin TCDD TMDL against challenges from both environmental groups and pulp-and-paper mills, ruling that § 303(d) allows EPA to set TMDLs even before pollutant-specific technology-based effluent limits exist and that EPA’s application of the states’ 0.013 ppq water-quality criterion and supporting technical analysis satisfied the Clean Water Act under deferential APA review.


Dioxin/Organochlorine Center v. Environmental Protection Agency, 57 F.3d 1517 (1995)