In 2015, one of the worst environmental disasters in Colorado and New Mexico's history occurred when the Gold King Mine near Silverton experienced a massive wastewater spill. The accident occurred when the U.S. Environmental Protection Agency was attempting to drain contaminated water that had built up at the entrance of the mine. More than 3 million gallons (11,400 m3) of highly acidic waste spilled into the Animas and San Juan Rivers, turning the water a bright yellow-orange color. The spill temporarily threatened irrigation and domestic water supply as far downstream as the Navajo Nation, and contaminated sediment with heavy metals including lead and zinc. The EPA asserted it would take "full responsibility" for the spill.