(Photo courtesy of Environmental Protection Agency)

On Aug. 5, 2015, the EPA spilled contaminated wastewater from the Gold King Mine in San Juan County, Colorado.

In the summer of 2015, a massive spill from an abandoned mine contaminated rivers in three Western states. The federal government has now released a report on the metals that were released during the 3 million-gallon spill.

The U.S. Environmental Protection Agency says over the course of nine hours, nearly 540 tons of metals — mostly iron and aluminum — poured into Colorado’s Animas River. The EPA report says the total amount of metals entering the river was comparable to levels during one or two days of high spring runoff.

An EPA-led contractor inadvertently triggered the spill while doing preliminary cleanup work at the old Gold King Mine. The blowout turned rivers yellow in Colorado, New Mexico and Utah – including parts of the Navajo nation. Last year, the tribe sued the EPA over the incident.

The Associated Press contributed to this report.