Federal monitors have formed a task force to investigate discharges of radioactive tritium-laced water at several power plants across the nation, including one at the Palo Verde Nuclear Generating Station west of Phoenix, Ariz.
Tritium, a byproduct of nuclear power generation, is a relatively weak source of radiation.
However, authorities say long-term exposure to tritium can increase the risks of cancer, miscarriages and birth defects. It can be ingested or absorbed in human tissue.
Palo Verde vents tritium into the air as a normal byproduct of nuclear power generation, but a leak of contaminated water was recently found.
Nuclear Regulatory Commission officials said the task force of experts will evaluate the health effects of what has happened at least five plants since December and possibly earlier incidents.
But they emphasized the latest reports from all the sites, including Palo Verde, do not indicate any immediate public hazards. The other plants are in Illinois and New York.
The Palo Verde plant, about 50 miles west of downtown Phoenix, is the largest nuclear generating site in the country.
An NRC health inspector has been working during the past week with officials from Palo Verde’s operator — Arizona Public Service — and the state Department of Environmental Quality to pinpoint the source and amount of the contamination.
APS first notified the state on March 2 it found tritium in a maze of underground pipes.
Water samples taken a day before had turned up levels more than triple those considered acceptable by the Environmental Protection Agency for drinking water.
State, federal and Arizona Public Service officials said Wednesday there is no evidence so far that Palo Verde-generated tritium has migrated beyond the boundary of the plant or seeped into aquifers about 70 feet to 200 feet underground that supply water for the area.
A written report summarizing the findings is due by Aug. 31.
Palo Verde supplies electricity to about 4 million customers in Arizona, New Mexico, Texas and California. Public Service Co. of New Mexico is a part owner of Palo Verde.