There is no risk to human health because the radioactive material was further diluted when it entered a storage basin before flowing into the lake, NRC spokeswoman Viktoria Mitlyng said. She said there is "absolutely" no risk to human health.
The plant located in Van Buren County's Covert Township has been under heightened Nuclear Regulatory Commission attention because of a series of breakdown over two years. It was shut down Sunday after officials discovered a growing leak the day before in a water storage tank.
Safety investigators reported Monday that 79 gallons from the 250,000-gallon tank leaked into a basin holding thousands of gallons of non-radioactive water, Mitlyng said. She said that water from the tank is no longer reaching the lake.
The "very slightly radioactive water" contained small amounts of tritium and may have had trace amounts of cobalt and cesium, Mitlyng said. It was further diluted to the degree that it would have been undetectable at the point where it entered Lake Michigan, she said.