## Facts

- EPA, acting under the Resource Conservation and Recovery Act (RCRA), regulates hazardous waste under a “cradle to grave” scheme with stringent management requirements.
- RCRA defines “hazardous waste” as a solid waste (or combination of solid wastes) that may cause serious illness or pose a substantial present or potential hazard to health or the environment if improperly managed.
- RCRA directs EPA to develop criteria for identifying hazardous waste characteristics and for listing hazardous wastes, considering factors such as toxicity, persistence, degradability, and related hazardous properties.
- EPA promulgated and maintained a rule treating any waste “mixed with” or “derived from” a listed hazardous waste as hazardous waste subject to RCRA Subtitle C.
- The American Chemistry Council (ACC), a trade association, petitioned for review, arguing EPA lacked statutory authority to regulate mixtures and derivatives categorically absent separate proof that each resulting waste independently satisfies RCRA’s definition of hazardous waste.

## Issues

1. Whether RCRA authorizes EPA to treat substances mixed with or derived from a listed hazardous waste as “hazardous waste” without an individualized showing that the resulting material independently meets the statutory definition.
2. Whether EPA’s interpretation of RCRA embodied in the mixture and derived-from rule is reasonable and entitled to Chevron deference.

## Decision

- The D.C. Circuit denied the petition for review and upheld EPA’s mixture and derived-from rule.
- The court concluded RCRA does not unambiguously bar EPA from regulating mixtures and derivatives of listed wastes as hazardous.
- The court held EPA reasonably construed its listing authority to include mixtures and derivatives that may retain hazardous constituents or pose similar risks.
- The court deferred to EPA’s technical and policy judgment that a categorical rule is an appropriate preventive measure within RCRA’s comprehensive regulatory scheme.
- The court rejected ACC’s interpretation as an unjustified statutory limitation that could permit evasion of hazardous-waste controls through mixing or processing.

## Legal Principles

- Under RCRA’s broad delegation, EPA has substantial discretion to identify and list hazardous wastes using criteria tied to the statutory definition and protective purpose.
- A statute’s silence or ambiguity on the precise regulatory mechanism may permit an agency, under Chevron, to adopt reasonable categorical rules implementing Congress’s aims.
- EPA may treat wastes mixed with or derived from listed hazardous wastes as hazardous where the agency reasonably determines those wastes may remain hazardous and where the approach prevents regulatory avoidance.
- Courts generally defer to EPA’s technical and risk-based judgments when the agency acts within delegated authority and provides a rational connection to the statutory standard.

## Conclusion

The D.C. Circuit upheld EPA’s authority under RCRA to regulate as hazardous wastes that are mixed with or derived from listed hazardous wastes, holding the categorical approach a reasonable construction of the statute and a permissible exercise of EPA’s delegated judgment.


Am. Chem. Council v. EPA, 337 F.3d 1060 (D.C. Cir. 2003)