On August 5, an Environmental Restoration company crew, supervised by U.S. Environmental Protection Agency officials, used a backhoe to dig away tons of rock and debris that were blocking the entrance portal of Colorado’s Gold King Mine, which had been largely abandoned since 1923. Water had been seeping into the mine and out of its portal for decades, and the officials knew (or should have known) the water was acidic (pH 4.0-4.5), backed up far into the mine, and laced with heavy metals. But they kept digging – until the greatly weakened dam burst open, unleashing a 3-million-gallon (or more) toxic [...]