The Environmental Protection Agency filed a brief in the U.S. Court of Appeals for the District of Columbia Circuit January 22 saying that its decision to regulate mercury and air toxics emissions from power plants is based on exhaustive scientific evidence showing mercury’s health hazards. A 2000 finding triggered the February 2012 final rule establishing emissions limits for mercury, filterable articulate matter as a surrogate for toxic metals, and hydrogen chloride as a surrogate for acid gases. The mercury rule is expected to cost industry $9.6 billion annually, but create $90 billion in health benefits.