Mercury Content of Indiana Coals
Maria Mastalerz, IGS coal geologist, in Francisco Coal Mine, Gibson County, Indiana
Inorganic constituents in coal have a significant effect on almost every aspect of coal utilization as well as its impact on the environment. Mercury (Hg) is one of the elements of special environmental concern. Being highly volatile (it vaporizes at temperature as low as 150°C; Finkelman, 1981), mercury poses a special problem for electric utilities. The Clear Air Act of 1990 authorized the U.S. Environmental Protection Agency (EPA) to regulate mercury emissions from electric utilities; on February 24 2004, the EPA proposed a rule supplementing its December 15, 2003 proposal to permanently cap and reduce mercury emissions from power plants. According to this rule, mercury emissions will be reduced by 70 percent when fully implemented. In 2018, the second phase of the mercury program sets a cap of 15 tons. For more information on the Utility Mercury Reduction Rule and updates on the hearing status, visit the EPA Web site.