Thousands of dead fish were reported Tuesday near the Streator Dam on the Vermilion River in Livingston County, prompting a review by state and local agencies that is still ongoing.

The fish were found at the dam and along 3150 N Road, south of Lentman Lake. The cause has not yet been determined.

Illinois American Water, which operates the nearby Streator water treatment plant, said its water supply has not been affected.

“Illinois American Water is aware of the fish at the dam. The water intake for the Streator water treatment plant is located away from the area of concern and there is no risk to water quality,” the company said in a statement. “Illinois American Water continues to monitor conditions and laboratory testing indicates the water leaving Illinois American Water’s Streator water treatment plant meets all state and federal drinking water standards.”

“Providing safe drinking water to our customers is our foremost priority,” Terrance Ragusa, superintendent of water operations for Illinois American Water, said in the statement. “We continue to provide our customers in Streator with safe drinking water.”

The company said it has contacted the Illinois Environmental Protection Agency and the Illinois Department of Natural Resources and is working with both agencies.

As of Tuesday evening, neither the IEPA nor IDNR had responded to requests for comment.