On August 5, 2015,  contractors working for U.S. EPA at the Gold King Mine near Durango, Colorado, triggered the release of more than 3,000,000 gallons of highly contaminated water into the Animas river.  More specifically, U.S. EPA contractors were in the process of conducting an investigation of the Gold King Mine to assess on-going water releases from the mine. While excavating materials around the entrance to the mine, loose material gave way allowing water from the closed mine to spill into the nearby river.  As of Sunday afternoon, the mine continued to discharge approximately 500 gallons per minute although U.S. EPA notes that the polluted water is being contained and treated in two ponds near the site.

The release has resulted in a visible plume that extends almost 80 miles down the Animas River.  According to preliminary water quality tests, arsenic levels in the Animas River are more than 300 times normal levels and lead had peaked at 3,500 times normal levels.  U.S. EPA is working cooperatively with Region 6 and Region 9 and the states of Colorado, New Mexico, Utah and the Southern Ute tribe to address the contamination in the Animas river.  The Navajo Nation, however, has declared an emergency and shut down its drinking water systems that rely upon water from the Animus river.  Navajo President Russell Begaye has already indicated that the Navajo Nation intends to sue U.S. EPA for damage to the Navajo Nation’s natural resources.  In addition, Colorado Governor John Hickenlooper has declared a disaster emergency for the Animas river which makes $500,000 from Colorado's Disaster Emergency Fund eligible to be used to remediate the contamination.  

It is unknown at this time what long-term impacts this release might have on the Animas river which ultimately discharges into the San Juan and Colorado rivers.  U.S. EPA has acknowledged that metals are likely to settle down to the bottom of the river bed and long-term monitoring will be required.