## Facts

- NEPA requires federal agencies to prepare an environmental impact statement (EIS) for major federal actions significantly affecting the environment.
- In licensing nuclear power plants, the Nuclear Regulatory Commission (NRC) must consider environmental effects of the nuclear fuel cycle, including disposal of spent fuel and other wastes.
- The NRC addressed certain fuel-cycle impacts through generic rulemaking rather than requiring repetitive, plant-by-plant litigation.
- The NRC adopted “Table S-3,” a numerical table estimating resources used and effluents released by fuel-cycle activities supporting a typical light-water reactor’s annual operation.
- For long-term storage of transuranic and high-level waste, Table S-3 included a “zero-release” assumption, treating permanent storage as having no significant environmental impact for licensing purposes.
- In promulgating the rule, the NRC acknowledged uncertainty in long-term geologic storage, summarized major uncertainties, characterized intrusion probability as small, and found the evidence “tentative but favorable” that suitable storage sites could be developed.
- Environmental organizations and others challenged the rule; the D.C. Circuit set it aside as arbitrary and capricious and inconsistent with NEPA, reasoning that uncertainty in the zero-release assumption was not integrated into licensing in a manner that could affect outcomes.

## Issues

1. Whether the NRC’s generic “Table S-3” rule, including the zero-release assumption for long-term waste storage, satisfied NEPA’s requirements of environmental consideration and disclosure.
2. Whether the rule was arbitrary or capricious under the Administrative Procedure Act (APA) based on the NRC’s treatment of scientific uncertainty and predictive judgments.

## Decision

- The Supreme Court reversed the D.C. Circuit and upheld the NRC’s rule.
- The Court held that the NRC complied with NEPA because it considered the relevant environmental factors and disclosed the uncertainties and assumptions underlying the rule.
- The Court held that the zero-release assumption was not arbitrary or capricious where the NRC articulated a rational connection between the record evidence, the acknowledged uncertainties, and the agency’s predictive judgment.
- The Court emphasized that judicial review is especially deferential when an agency makes scientific predictions within its technical expertise, particularly at the limits of available knowledge.

## Legal Principles

- NEPA is primarily procedural: it requires agencies to take a “hard look” by considering and disclosing environmental consequences; it does not mandate particular substantive outcomes.
- Under APA arbitrary-and-capricious review, a court asks whether the agency considered relevant factors and explained a rational basis for its choice; courts may not substitute their judgment for the agency’s on technical matters.
- When an agency evaluates complex scientific data and makes predictive judgments within its expertise, judicial review is at its most deferential.
- An agency may use generic rulemaking to resolve recurring NEPA issues applicable across many proceedings, so long as the rulemaking record adequately addresses the environmental effects and uncertainties relevant to the generic determination.

## Conclusion

The Court sustained the NRC’s generic fuel-cycle environmental rule, concluding that NEPA was satisfied by reasoned consideration and disclosure of uncertainties and that the agency’s technical, predictive judgment about long-term waste storage was entitled to strong deference under the APA.


Baltimore Gas & Electric Co. v. Nat. Res. Def. Council, Inc., 462 U.S. 87 (1983)