Massive fish kill at Duluth creek under investigation

DULUTH, Minn. — More than 1,000 fish were found dead in a Duluth creek in July after the city released more than a million gallons of disinfected water into it, pollution officials said.

The Minnesota Pollution Control Agency is investigating the massive fish kill , which occurred in Tischer Creek after Duluth drained about 1.7 million gallons of chloraminated water into it.

The drainage does not pose a threat to humans, but "created conditions that were potentially toxic to fish and other aquatic life," the agency said.

Pollution officials counted the dead fish and collected invertebrate samples from the creek in August.

"These samples will provide another biological indicator to determine the impact of the fish kill and the rate of recovery time," the agency said. "Results for those tests will take several months and will inform future choices about what steps can be taken to help the creek recover."

Chloramine is one of two primary disinfectants added to drinking water in the United States, the other being chlorine. The Centers for Disease Control said chloramine is safe to consume in small amounts. It is used as an alternative to chlorine because it "can last longer in the water pipes and produces fewer disinfection by-products," according to the CDC.