Firefighters practice fighting a gas fire at a training exercise at the Lancaster County Public Safety Training Center in 2007. LNP File Photo Print The state is investigating a fish kill in a Columbia stream that was caused by firefighting foam from a training session by the Columbia Fire Department. The state Department of Environmental Protection is investigating the Thursday, Sept. 20, fish kill near Columbia High School, where the fire department was training.

The agency determined the cause was a fire retardant foam, said DEP spokesman John Repetz. The foam, as well as dead fish, could be seen the next day floating in the stream.

Columbia Borough Manager Jeff Helm said the fire suppressant was supposed to be environmentally friendly but that a high concentration may have proved lethal to the fish.

The small, unnamed tributary is near North Ninth Street.

Based on the outcome of the investigation, DEP will determine whether further action will be taken by the department, Repetz said.