In an event that has led to health warnings and turned a river orange, the Environmental Protection Agency says one of its safety teams accidentally released contaminated water from a mine into the Animas River in southwest Colorado.

The spill, which sent heavy metals, arsenic and other contaminants into a waterway that flows into the San Juan National Forest, occurred Wednesday. The EPA initially said 1 million gallons of wastewater had been released, but that figure has risen sharply.

Read more of Bill Chappell’s article here: EPA Says It Released 3 Million Gallons Of Contaminated Water Into River