In 2012, after two decades of resistance from the coal industry, the U.S. Environmental Protection Agency (EPA) finally upheld a rule to control mercury emissions from power plants. Called the Mercury and Air Toxics Standards, or MATS, the stringent new regulations limit not only mercury but also acid gases like hydrochloric acid, heavy metals like arsenic, and other toxic pollutants—and require companies to comply by 2017.
When fully implemented, the standards will eliminate 90 percent of the 53 tons of mercury emitted annually by coal-fired power plants in the United States. Power generation will then finally catch up with medical waste incineration and municipal garbage burning. Twenty years ago those activities contributed similar amounts of heavy-metal pollution but have since drastically cleaned up their acts, leaving power plants as the leading manmade source, by far, of mercury emissions in this country.