Cement plants emit mercury from the kilns used in the cement manufacturing process. Cement kilns operate at high temperatures, and are, in fact used to destroy many types of toxic substances. The rule, proposed on August 9, 2010 also applies to total hydrocarbons (THC), and particulate matter (PM) from new and existing kilns located at major and area sources, and for hydrochloric acid (HCl) from new and existing kilns located at major sources. The standards for new kilns apply to facilities that commence construction, modification, or reconstruction after May 6, 2009

The U.S. Environmental Protection Agency (EPA) issued final rules to cut emissions of mercury, particle pollution and other harmful pollutants from Portland cement manufacturing, the third-largest source of mercury air emissions in the United States. EPA calculates that the rules will yield $7 to $19 in public health benefits for every dollar in costs.