SEYMOUR, Conn. — Thousands of gallons of raw sewage have spilled into the Naugatuck River after a siphon carrying the wastewater ruptured on the river’s edge in Seymour, a town in southern Connecticut.

Cyndy Chanaca, a spokeswoman for the state Department of Energy and Environmental Protection, said Thursday that 100 to 200 gallons of wastewater a minute were flowing into the river.

The Republican-American reports that Chanaca says town crews cleaned debris inside the pipe and built a dam of sandbags to contain the spill. The cause is being investigated.

A message left on Thursday after business hours with the answering service for Veolia Water North America, which runs the Seymour plant, was not immediately returned.

Margaret Miner, executive director for Rivers Alliance of Connecticut, an advocacy group, says the sewage is toxic and could harm the river.