Elevated levels of tritium — a radioactive form of hydrogen — have been found at the shuttered San Onofre Nuclear Generating Station, but pose no risk to public health or safety, officials from Southern California Edison said on Thursday, Sept. 5. The Environmental Protection Agency has set a “maximum contaminant level” of 20,000 picocuries per liter for tritium in drinking water. Routine monitoring at San Onofre found a low concentration of 3,430 picocuries per liter in one well, and a higher concentration of 19,100 picocuries per liter in an adjacent well. Neither, however, is a drinking water well, officials said.