From a USA Today report at the link below
The Environmental Protection Agency took responsibility Friday for inadvertently polluting a Colorado river with 1 million gallons of toxic orange wastewater while trying to clean up an abandoned gold mine.
The spill occurred Wednesday morning at a long-closed Gold King Mine near Silverton and fouled the Animas River, a 126-mile-long tributary of the San Juan River, part of the Colorado River system.
"We are very sorry for what happened. This is a huge tragedy," Dave Ostrander, who handles emergencies for the EPA's Denver-based Region 8, told the Durango residents.