COVERT TOWNSHIP, Mich. -

A federal safety official says that 79 gallons of "very slightly radioactive water" from a leaky tank at the Palisades Nuclear Power Plant spilled into Lake Michigan.

Operators of the southwestern Michigan plant shut it down Sunday after discovering a growing leak Saturday in a water storage tank.

The plant is 80 miles east-northeast of Chicago in Van Buren County's Covert Township. It's been under heightened Nuclear Regulatory Commission attention for a series of breakdown over two years.

NRC spokeswoman Viktoria Mitlyng told The Associated Press on Monday that investigators determined that 79 gallons entered a basin holding non-radioactive water before entering the lake.

She says there's no human health risk. Read: Michigan nuclear plant under scrutiny for safety.