The better approach, the Interior Department’s engineers concluded, would have been to drill a hole from above first to gauge conditions and, if necessary, relieve pressure. In its own review, in August, the E.P.A. argued that a drilling operation would have been too costly and slow. It concluded that the plug would have collapsed eventually, and that a “blowout was likely inevitable.” The Interior Department acknowledged that the plug “may have failed on its own,” but said smarter intervention could have averted that.
The mountains in the region have veins of gold and silver, but also lead, copper and zinc. Mining operations can accelerate the leaching of metals from the soil, add other toxins and create especially concentrated pools of poisoned water. Contaminated water continually seeps from mines into nearby streams, and environmental regulators have tried to slow or stop that process.
But instead of fixing the problem at Gold King, the E.P.A. temporarily made it much worse, incurring the wrath of residents downstream.