The EPA was trying to clean up an old mine in Durango, Colorado this week. Instead, they released more than one million gallons of pollutants into the Animas River.

Heavy metals such as lead, cadmium, and arsenic are now flowing through the river, which runs 126 miles and is one of the sources of drinking water for towns surrounding it.

Professor Asish Basu, who specializes in geochemistry at the University of Texas in Arlington, says the impact goes way beyond just the look of the river. “All these metals, in excessive amounts, are dangerous to human life,” Basu said.

For more on this story, visit Toxic sludge turns river in Colorado orange at CBS News.