Milestone Report on Mercury Emissions

By ANDREW C. REVKIN

A prestigious panel of scientists declared yesterday that levels of the most hazardous form of mercury in the environment posed an unacceptable health risk to children born of women who eat fish during pregnancy, and should be reduced.

That finding by the 10 experts, convened by the National Academy of Sciences, means that after long delay, the way is now cleared for the Environmental Protection Agency to write new regulations forcing electric power plants, the last large source of unregulated emissions of mercury, to cut them.

The panel's conclusion essentially ends a rancorous debate waged between industry and environmental officials for more than a decade. At issue was how to deal with methylmercury, a toxic metal that occasionally taints popular seafood like tuna and by now has also prompted 41 states to issue warnings against eating fish caught in many rivers and lakes.

In unambiguous terms, the panel said yesterday that warnings did not suffice. "The long-term goal," its report said, "needs to be a reduction in the concentrations."

Coal-burning power plants release more than 40 tons of mercury a year, about a third of the total entering the environment.

The environmental agency was poised two years ago to write new mercury rules for plants, but met heavy resistance from members of Congress, who in turn were encountering intense lobbying from the electric power industry. The industry pushed hard for an independent study on the risks of methylmercury, created in nature by the interaction between mercury and bacteria, and Congress responded by directing the E.P.A. to commission it. The work was undertaken by the 10 scientists, brought together by the academy's National Research Council.

Representatives of the power industry yesterday accepted the panel's conclusions, thereby effectively ending their opposition to the E.P.A.'s plans and shifting the debate over mercury regulation from if to how.

"We wanted this issue about mercury to be settled based on the best science available, and that's essentially what the academy has done," said Paul Bailey, vice president for environmental affairs at the Edison Electric Institute, a trade group representing companies that generate three-fourths of the country's electricity.

"We expect the E.P.A. to decide that they are going to regulate mercury from us," he said. "What we're focused on is working with them to fashion a program that makes sense."

Mr. Bailey said the industry would favor a system of pollution credits much like that which now governs industrial emissions of sulfur dioxide. Environmental groups would oppose that approach.

The panel of scientists estimated that 60,000 children are born each year who were exposed during pregnancy to methylmercury levels that could cause neurological and learning problems. Most of the exposure comes from fish in their mothers' diet. Through rain and runoff, methylmercury tends to concentrate in bodies of water, where it accumulates in fish as it passes up the food chain.

E.P.A. officials said they felt vindicated by the report and intended to press ahead with a decision by Dec. 15 on limiting mercury emitted by power plants.

That date was set in settlement of a lawsuit brought by some private environmental groups to force the agency to consider mercury cuts under provisions of the Clean Air Act.

The report "underscores and reinforces the science that will go into that policy decision and others that will follow with regard to controlling mercury," said David Cohen, a spokesman for the environmental agency.

Environmental groups said the end of the scientific debate over power plants was long overdue, noting that they were the last large uncontrolled source of mercury emissions.

David Hawkins, director of air and energy programs for the Natural Resources Defense Council, pointed out that as a result of government regulation already in effect, owners of incinerators, another big source, were adding filters and other equipment to capture the metal before it leaves smokestacks.

The debate now shifts to how best to cut the flow of mercury from coal to power-plant smoke and on into the environment. Last year the E.P.A. initiated the first significant study of the problem, requiring not only that all power plants measure the amount of mercury in coal through 1999 but also that several dozen measure the amounts emitted from smokestacks before and after the installation of filters.

The report issued yesterday, after the scientists' 18-month review of the E.P.A.'s risk calculation for mercury, concluded that the most important hazard by far lay in the threat to developing fetuses.

It emphasized that the risk to most people was very small, and that the primary goal was to cut the exposure in young women who frequently eat fish in which the highest levels of mercury tend to accumulate -- generally predatory sea fish like tuna and swordfish but also some freshwater fish in places with high mercury levels.

Federal officials said the report could also be an influence in whether the Food and Drug Administration tightens its standards for fish. The food agency now uses a much less aggressive risk calculation than the E.P.A. calculation endorsed by the scientists yesterday.

F.D.A. officials said they had not yet had time to review the mercury report.