The Gold King Mine spill in Silverton, Colorado, led to the release of 3 million gallons of toxic waste that impacted the Navajo Nation along with Colorado, New Mexico and Utah.
Wednesday, Congress stepped in with a hearing held by the House Science Committee to find out what happened.
Committee Chair Lamar Smith of Texas criticized the U.S. Environmental Protection Agency in his opening statement and Mathy Stanislaus, assistant administrator for the EPA, represented the agency.
