The Animas River near Durango on Aug. 9, 2015. Orange sediment is still visible along the river’s banks.

(Grace Hood/CPR News)

More than a week after 3 million gallons of wastewater escaped an abandoned mine near Silverton and turned it a filthy golden yellow, the Animas River has been opened again to recreational boaters.

La Plata County Sheriff Sean Smith said he based his decision on recommendations from the Colorado Department of Public Health and Environment. The agency says its data shows "levels of contamination are below what would be a concern for human health during typical recreational exposure."

The river was closed Aug. 6, a day after the Gold King Mine blowout.  A team of three contractors and a supervisor and bulldozer had gone to the abandoned mine to install a pump to drain it, with the eventual goal of plugging the mine for good.  

The team apparently underestimated the volume of water backed up behind fallen debris -- the water level turned out to be about 12 feet high. As they began moving the unstable debris, it collapsed and the pressurized, filth-laden water spewed out and down into Cement Creek, a tributary of the Animas.

The shocking yellow color of the water, caused by iron, is gone, and the state has already cleared the water for use by water treatment plants. However, it's not known how much danger remains from other heavy metals, such as lead, that are trapped in the river bed.

When he ordered the river closed, Smith said his main concern was "the public health and safety of our community." On Friday, a sheriff's office statement said, in part:

The Colorado Department of Public Health and Environment does not anticipate adverse health effects from exposure to contaminants detected in the water and sediment during typical recreational activities.

On the statement, the Agency for Toxic Substances and Disease Registry issued this cautionary note:

  • Don’t drink untreated water from the river.
  • Wash hands with soap and water after contact with the sediment and surface water.
  • Avoid contact in areas where there is visible discoloration in sediment or river water.
  • Wash clothes after contact with sediments and surface water.

The Environmental Protection Agency, which is conducting its own tests, had earlier recommended the river remain closed until Aug. 17.

Officials in northwestern New Mexico have lifted the precautionary ban on the use of private well water throughout the Animas River valley after a toxic mine spill.