Last year, the Union of Concerned Scientists, joined by environmental organizations and members of the public (including the author), filed a petition with the United States Nuclear Regulatory Commission (NRC). The petition requested that the NRC take a single action: that it utilize its enforcement authority to demand information from its licensees concerning the nature and extent of tritium contamination of groundwater. The scope of this request was extremely narrow, considering the ubiquity of tritium contamination at every link in the nuclear fuel chain. Tritium contamination has become a marker for the varieties of radioactive contamination left in the wake of producing what the nuclear industry likes to call “safe and clean” energy. Yet mining, milling, processing, enrichment, fuel fabrication, fuel utilization and storage at nuclear reactors, disposal of radioactive waste, and attempted reprocessing of nuclear fuel have resulted in massive amounts of tritium- (and other radionuclide) contaminated groundwater.