EPA sets new rules on mercury emissions

WASHINGTON — The Environmental Protection Agency released its final rule on mercury emissions from power plants on Tuesday, asserting that allowing companies to buy and sell the right to pollute would encourage control of the biggest sources of mercury first.

Mercury from smokestacks poses a hazard, especially to children and developing fetuses, because it eventually ends up in rivers and lakes, where it is absorbed by fish that are then caught and eaten by people.

Some environmentalists said the agency should have simply required uniform emission limits, to reduce concentrations everywhere. They say the new rule means that some plants would end up doing nothing to curb emissions, allowing mercury "hot spots" to persist, affecting the health of people living nearby.

Jeffrey R. Holmstead, the EPA's assistant administrator for air and radiation, defended the "cap-and-trade" system, already used for a pollutant that causes acid rain.

"The highest deposition is in areas where there are concentrations of very large power plants," he said. "Because of the economies of scale when it comes to pollution control, all of our analysis and experience with acid rain shows the largest plants are the ones that control the most, and control the soonest."

Economists say the cost of eliminating a ton of pollution is lower under cap and trade than under a blanket rule.

Some environmentalists disagreed, though, that the cap-and-trade concept would work for mercury. Fred Krupp, president of Environmental Defense, which is based in New York, said that while other pollutants are regulated under a cap-and-trade system, they are also regulated with "a cascade of other clean air programs to ensure that health standards are met everywhere." In contrast, he said, mercury is a highly potent neurotoxin and this would be the only rule that applied to it.

"In this case trading is just completely inappropriate because of the nature of the pollutant and the lack of other safeguards," he argued.

But Holmstead said the cap-and-trade system gives companies an incentive to start controls early, so they can save up credits and delay final compliance. He predicted that emissions by 2010 would fall to 31 tons, lower than the target of 38 tons. The current emission level is 48 tons per year.

On March, 10 the EPA announced a "Clean Air Interstate Rule" that will further limit emissions of sulfur dioxide and nitrogen oxides, and in controlling those two pollutants, power plants will also be filtering out mercury.

The rule calls for mercury emissions of no more than 15 tons in 2018, although under cap and trade, the actual date that the target is reached could be years later because companies could reduce emissions more than required in the early years and accumulate "credits" to emit more later. The phase-in effect is deliberate; it helps avoid national deadlines that create crash programs and drive up the cost of pollution control equipment.

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Contributing: Felicity Barringer