On August 5, a U.S. Environmental Protection Agency (EPA) crew and contracting company conducting an investigation of the inactive Gold King mine north of Silverton, Colorado, accidentally breached an earthen wall holding back built-up, polluted water in the mine, discharging an estimated 3 million gallons into Cement creek and downstream into the Animas river. The mine was last worked in 1923.

Pollutants in the spill included arsenic, lead, copper, aluminum and cadmium. The discharge turned the color of Cement creek and the Animas river orange to mustard yellow as the pollution spread downstream.

Major communities impacted by the spill included Silverton (population 630); Durango, Colorado, (population 17,000) about 50 miles downstream; and Farmington, New Mexico, (population 45,000) about 100 miles downstream.

The Animas River flows into the San Juan River at Farmington. The San Juan flows generally west and somewhat north until it empties into Lake Powell in southern Utah. The Colorado River is the major tributary to Lake Powell and flows from Lake Powell through the Grand Canyon in northern Arizona into Lake Mead in southern Nevada.

Lake Powell has a maximum water storage capacity of more than 24 million acre ft and currently holds more than 13 million acre ft. This huge volume of water was expected to fully dilute and render harmless the pollutants from the Gold King mine spill.

Immediately following the spill, communities along the Animas shut off drinking water intakes, and the river was closed to recreational use. Colorado Gov. John Hickenlooper on August 10 declared a state of emergency in Durango; however, by August 16, the Animas and San Juan rivers had cleared up and were declared safe for irrigation, recreation and pumping into municipal water treatment facilities.

Short-term environmental damage, including impacts on fish in the Animas river, appeared to be limited.

On August 11, EPA Administrator Gina McCarthy issued statements accepting EPA responsibility for the spill and saying she was “deeply sorry” for the damage it caused.

Three past-operating mines in the immediate vicinity of the Gold King mine—the Sunnyside, Mogul, and Red and Bonita mines—were cited as possible contributors to the Gold King spill and as ongoing sources of polluted mine drainage water. How responsible authorities will deal with pollution from these mines in the future remained an open question.

While the condition of the Animas and San Juan rivers appeared to be back to near normal by mid-August, the political fallout from the spill was only beginning and may be long-lasting. Environmental nongovernmental organizations (NGOs), especially Earthworks, leveraged the wide-spread news coverage of the spill to draw attention to their agendas, including fixing hazards represented by abandoned mines throughout the western United States and renewed calls for replacement of the Mining Law of 1872. (For additional details, see p. 66-68.)