The Environmental Protection Agency, which accidentally spilled three million gallons of toxic wastewater from an abandoned mine in Colorado, lacks the technical skills to handle such tricky projects, a government assessment reported on Thursday. The big accident could have been averted if the agency had had greater expertise and acted more prudently, the report said.
The E.P.A. had intended to gradually drain and capture contaminated water that was seeping out of the Gold King Mine and poisoning local streams in the area, which is high in the Rocky Mountains in the southwestern part of the state. Instead, on Aug. 5, workers caused a blowout, releasing a yellow-red torrent into Cement Creek and then into the Animas River. The agency has conceded that its people underestimated the volume of water collected in the mine and how much pressure it was under. It requested a separate inquiry by the Interior Department, which released its 132-page report by a team of engineers on Thursday.
At the E.P.A., the report said, “abandoned mine guidelines and manuals provide detailed guidance on environmental sampling, waste characterization and water treatment, with little appreciation for the engineering complexity of some abandoned mine projects that often require, but do not receive, a significant level of expertise.”
In particular, it said, the E.P.A. does not adequately “analyze the geologic and hydrologic conditions of the general area” or comprehend how, in a region honeycombed with tunnels, changing conditions in one affect the others.
The E.P.A. said it was reviewing the report and offered no immediate response to the specifics in it. The accident occurred in a remote area, at an elevation of 11,500 feet, where a mine entrance had been plugged with rocks and soil that held back the water. The E.P.A., working with the state Department of Natural Resources, pushed a pipe horizontally through the top of the plug, expecting to find a pocket of air. Instead, water began to gush out.
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.