Other plants, however, may not be able to adhere to the new standards and could be forced to shut down, Matz said. "It is a legitimate concern that some plants will not be able to meet [the standards] no matter what they do," he said from his Irving, Texas, office.
The EPA estimates that the benefits outweigh the costs, but those costs are high. The estimates for changing the plants to meet the goals range from $222 million to $684 million.
Mercury in the air eventually falls into water, where it changes into methylmercury, a highly toxic form that builds up in fish.
Pregnant women are urged to limit consumption of many fish caught in the Chesapeake Bay because of mercury contamination. Rockfish, for example, should be eatern by a pregnant woman just once a month.
Estimates vary as to how much mercury is emitted by cement kilns nationwide, though the EPA says they are the fourth-largest source of mercury pollution in the country, behind coal-fired power plants, among others.
Aside from reducing mercury emissions by 81 percent, the EPA estimates that the new rules would cut hydrochloric acid by 94 percent, sulfur dioxide by 90 percent and particulate matter by 96 percent.
"These are kind of the forgotten polluters on the American scene right now, and this is finally bringing a spotlight to what they produce out of their smokestacks," said Jim Schermbeck, a board member with Downwinders At Risk, an air pollution advocacy group outside Fort Worth, Texas.
"These guys need to be brought into the 21st century," he said.
