The latest fight over environmental pollution in the United States focuses on mercury, a highly toxic substance that's dangerous to wildlife and humans.
Under a court agreement, the Environmental Protection Agency issued regulations Tuesday sure to generate controversy, particularly since a new study focusing on the Northeast warns that mercury levels are higher than earlier thought. Adding to the political tension here, the new mercury regulations - like the Bush administration's general approach to reducing air pollution - include a cap-and-trade program that allows some power plants to buy and sell mercury pollution credits.
It's an approach favored by coal-burning utilities and other industries who oppose what officials call "traditional command-and-control approaches." But environmentalists say it delays the kind of protection provided under the Clean Air Act of 1990.
Mercury, a highly toxic substance that can poison wildlife and cause brain and nervous system damage in children and fetuses, is a difficult issue for several reasons. Unlike some other air pollutants, such as carbon dioxide, mercury tends to concentrate in dangerous "hot spots." So merely reducing overall levels leaves some areas vulnerable. Also, 40 percent or more of the mercury polluting the US comes from abroad - mainly coal-burning power plants in places like China.
The border issue works the other way as well: Ten percent of mercury in the Canadian environment comes from the US - as much as 38 percent in the Great Lakes region, home to more than 9 million Canadians. Canadian officials have expressed concern that both cap-and-trade as well as the tougher measures some say are called for in the Clean Air Act "fall short of the emissions reductions that are achievable with current and emerging control technologies."
Mercury is the only metal that is in liquid form at room temperature, which means that it evaporates easily and thus spreads throughout the environment. It tends to concentrate in fish, birds, and other wildlife. Among the largest emitters of mercury pollution: coal-fired power plants, factories that produce chlorine, and automobile scrap yards. About 115 tons of mercury is emitted in the US each year, 48 tons of which come from power plants.
According to the Natural Resources Defense Council, a research and advocacy group, mercury pollution in the US has contaminated 12 million acres of lakes, estuaries, and wetlands (30 percent of the total), and 473,000 miles of streams, rivers, and coasts.
Forty states have issued fish advisories in recent years, and 14 states - mostly in the Northeast and Midwest - have statewide advisories for some or all sport fish from rivers or lakes. Americans get most of their exposure to mercury from eating tuna fish.
The Government Accountability Office recently took the EPA to task for underplaying the danger. Meanwhile, the EPA's inspector general says agency scientists have been pressured to align themselves with the industry approach in addressing mercury.
For their part, industry and administration officials say the cap-and-trade method will reduce mercury levels more and at a faster rate than government- mandated regulations. Still, industry spokesmen say, reaching the goal envisioned in the new rule won't be easy.
"There is no mercury control technology that exists today that can achieve the reduction levels finalized in the [EPA] mercury rule, let alone the 90 percent reductions advocated by some" says Scott Segal, director of the industry-funded Electric Reliability Coordinating Council. "The cap-and-trade mechanism creates substantial economic incentives for superior mercury control but remains sensitive to real technological constraints."
One option, according to the Electric Power Research Institute, is to inject materials into flue gases or inject chemicals into the boiler to absorb mercury and produce solids that can be captured. But in all cases, says an EPRI paper, "field experience is needed to determine the emission levels that these technologies can sustain over the long term ... [and] any secondary emissions that may arise."
Environmentalists say that allowing individual power plants to acquire pollution credits would have the effect of creating "hot spots" and exposing local residents to unsafe levels of mercury.
"The cap-and-trade approach sounds great unless you are one of those people who live near a power plant that chooses to spend money on paper credits instead of making real mercury reductions," says Sierra Club executive director Carl Pope. "We know that for every six women of childbearing age in the US, one of them has mercury levels in her blood high enough to put her baby at risk."
The new rule is intended to reduce power plant mercury emissions from 48 tons a year nationwide today to 38 tons by 2010, followed by additional reductions to less than 25 tons by 2018.