The Environmental Protection Agency at Gold King Mine waste water spill releases 3 million gallons of heavy metal toxin tailings and waste water into the Animas River in Colorado.

The 2015 Gold King Mine waste water spill was an environmental disaster that began at the Gold King Mine near Silverton, Colorado, when Environmental Protection Agency (EPA) personnel, along with workers for Environmental Restoration LLC (a Missouri company under EPA contract to mitigate pollutants from the closed mine), caused the release of toxic waste water into the Animas River watershed. They caused the accident by breaching a tailings dam while attempting to drain ponded water near the entrance of the mine on August 5. After the spill, the Silverton Board of Trustees and the San Juan County Commission approved a joint resolution seeking Superfund money.Contractors accidentally destroyed the plug holding water trapped inside the mine, which caused an overflow of the pond, spilling three million US gallons (eleven thousand cubic metres) of mine waste water and tailings, including heavy metals such as cadmium and lead, and other toxic elements, such as arsenic, beryllium, zinc, iron and copper into Cement Creek, a tributary of the Animas River and part of the San Juan River and Colorado River watershed. The EPA was criticized for not warning Colorado and New Mexico about the operation until the day after the waste water spilled, despite the fact the EPA employee "in charge of Gold King Mine knew of blowout risk."The EPA has taken responsibility for the incident, but refused to pay for any damages claims filed after the accident on grounds of sovereign immunity, pending special authorization from Congress or re-filing of lawsuits in federal court. Governor of Colorado John Hickenlooper declared the affected area a disaster zone. The spill affected waterways of municipalities in the states of Colorado, New Mexico, and Utah, as well as the Navajo Nation. It is estimated that acidic water spilled at a rate of 500–700 US gal/min (1.9–2.6 m3/min) while remediation efforts were underway. The event drew attention to toxic drainage from many similar abandoned mines throughout the country.