In one of the most closely reasoned of its many end-of-term environmental law decisions, the Supreme Court held on June 1, 1976,¹ that Congress did not intend the 1972 Federal Water Pollution Control Act Amendments (FWPCA)² to transfer regulatory authority over nuclear materials in nuclear power plant effluents from the Nuclear Regulatory Commission (NRC)³ to the Environmental Protection Agency (EPA).

The Atomic Energy Act of 1954⁴ gave the NRC broad regulatory authority over what it called "source materials,"⁵ "special nuclear materials,"⁶ and "by-product materials,"⁷ in short, all the substances involved in the nuclear fuel process for nuclear power plants. The FWPCA empowered the EPA (and states acting under its control) to regulate, through a permit program, discharges of all "pollutants" into the nation's waters, and it defined pollutants to include, inter alia, "radioactive materials."⁸ When the EPA Administrator issued regulations establishing the permit program, he explicitly excluded the NRC-regulated nuclear materials, citing the legislative history of the FWPCA.⁹