A metal plating company in St. Louis Park is a likely source of perfluorinated chemicals showing up in fish in Lake Calhoun.
Douglas Corporation said in a news release that the Minnesota Pollution Control Agency notified it that air emissions from the plant may have made their way into storm sewers that empty into Lake Calhoun.
The company says it has eliminated its use of the chemical at all of its five facilities in Minnesota. It used PFOS in making nameplates, faceplates, and membrane switches for circuits.
MPCA Spokesman Ralph Pribble says his agency worked for four years to nail down the source of the contaminant.
"Now we've identified a source, we don't know that it's the only source, but it is a source," Pribble said. "And now we can take steps to make sure that contamination does not continue."
PFOS is not illegal and is not classified as a hazardous substance, but some studies show at high doses it is toxic to lab animals. Pribble says the compound is used in firefighting foams and metal plating, among other industrial uses.
"It reflects, in part, the fact that relatively little is still known about the health and environmental effects of these chemicals," Pribble said. "It's still a new area."
The Minnesota Department of Health has issued advisories for fish consumption for the Minneapolis chain of lakes.