A computer glitch led to the spill of hundreds of thousands of gallons of raw sewage into a Massachusetts lake.

The Telegram & Gazette reports that the spill happened in Lake Quinsigamond (kwin-SI'-gah-mond) in Worcester (WUS'-tur) on Tuesday morning.

Philip D. Guerin, director of the city's water and sewer operations, says the glitch caused pumps in a city pumping station to shut down, sending sewage into the lake. He said they had not yet determined how much sewage spilled, but the city said it flowed for over an hour.

A no-swimming order was issued on the lake, part of which is a state park. The water will be tested to make sure it is safe before swimming is allowed to resume.