WASHINGTON — Nearly 540 tons of metals — mostly iron and aluminum — contaminated the Animas River over nine hours during a wastewater spill from an abandoned Colorado gold mine, the Environmental Protection Agency said Friday in a new report on the 2015 blowout.
The EPA said its research supports earlier statements that water quality in the affected river system has returned to pre-spill levels.
An EPA-led contractor inadvertently triggered the 3-million-gallon spill while doing preliminary cleanup work at the old Gold King Mine near Silverton, Colo.
The EPA said in its report that only 1 percent of the metals came from inside the mine, while 99 percent were “scoured” from waste piles on nearby hills and stream beds.
The EPA said last month that it will pay $4.5 million to state, local and tribal governments for their emergency responses, but the agency rejected $20.4 million in other requests for expenses.