EPA and the High Hazard Dams

EPA has recently amended its list of high hazard coal refuse dams, and you can find out more about it here. Some of them are in West Virginia. But it is worth pointing out that these are not dams that present a high hazard because they are likely to fail. The dams in question are generally designed to high standards, and are unlikely to cause damage to downstream property owners. The designation merely means that, if they fail, significant damage or loss of human life could result. By this definition, the Hoover and Columbia Dams, and thousands of others in the country, are high hazard dams. As EPA explains it,

The National Inventory of Dams hazard potential ratings address the potential consequences of failure or misoperation of the dam. A high hazard potential rating indicates that a failure will probably cause loss of human life; the rating is not an indication of the structural integrity of the unit or the possibility that a failure will occur in the future; it merely allows dam safety and other officials to determine where significant damage or loss of life may occur if there is a structural failure of the unit. EPA’s assessment of the facilities that have units with high hazard potential ratings continues to be an Agency priority. EPA plans to make public the results of our assessments as soon as they are completed.

In short, these dams are not listed because coal ash itself presents some particular hazard, but because any liquid piled up behind a dam has potential energy that could cause damage if released to where people are located.