Michigan Limits Mercury From Coal-Fired Plants

Michigan's coal-fired power plants will be required to make drastic cuts in mercury emissions under regulations announced Monday.

The rules developed by the Department of Environmental Quality are designed to implement a policy Gov. Jennifer Granholm announced three years ago to slash the generators' mercury output 90 percent by 2015. Coal-fired plants produce 60 percent of Michigan's electricity.

"Mercury is a serious health concern, and Michigan is eager to see a major reduction in mercury air emissions," DEQ Director Steven Chester said.

A powerful toxin, mercury can damage the human nervous system and cause learning disabilities in fetuses and young children. Coal-fired electric plants are the nation's leading source of mercury pollution.

Mercury pumped into the atmosphere from their smokestacks can fall into waterways and convert to methylmercury, a form that moves up the food chain and accumulates in fish.

Michigan is the 19th state to regulate mercury emissions from coal-fired plants.

Not every plant will have to reduce emissions by 90 percent. But the regulations will require each company to cut overall emissions by 90 percent from their 1999 levels, which environmental groups said would reduce mercury pollution in the state by 3,600 pounds a year.

The rules give existing plants several options.

They can install equipment that will produce a direct 90 percent drop-off in mercury output. One such system injects carbon into gas produced by plants, isolating the mercury in ash that can be hauled to landfills.

Or companies can use advanced scrubbers that target other pollutants, such as nitrogen oxide and sulfur dioxide. Such devices have been found to also reduce mercury emissions by nearly three-quarters.

Small plants that don't emit much mercury will be allowed to try other methods that the DEQ will evaluate on a case-by-case basis.

New plants will have to use best-available technology to meet state standards.