File--In this Wednesday, Aug. 12, 2015, file photograph, water flows through a series of retention ponds after a spill at the Gold King mine near Silverton, Colo. On Friday, Feb. 5, 2016, the Environmental Protection Agency said that the three million gallon spill from the gold mine may have dumped more than 880,000 pounds of metals into the Animas River. (AP Photo/Brennan Linsley, file)

SILVERTON | The U.S. Environmental Protection Agency has promised to involve local officials as much as practical in any decisions about a possible Superfund cleanup around the site of a massive mine spill in southwestern Colorado.

The EPA made the pledge in a letter to the town of Silverton and San Juan County dated Friday.

Local officials are negotiating with the EPA over a Superfund designation for the mountains north of Silverton, where wastewater flows from scores of idle mines into the Animas River.

Last August, an EPA crew inadvertently unleashed 3 million gallons of waste from one of those mines, the Gold King. Rivers in Colorado, New Mexico and Utah were polluted.

The EPA has proposed a Superfund designation to fund a multimillion-dollar cleanup but won’t do so without local support.