In a backlash against what environmentalists call “disastrous” new mercury regulations issued by the Environmental Protection Agency (EPA), nine states filed a lawsuit March 29 against the federal government, saying the rules violate the Clean Air Act. One of them, New Hampshire, went further, advancing its own state-level legislation to curb the release of mercury by corporate polluters.

Mercury is a poisonous metal that builds up in the environment, most commonly as a result of the burning of coal. People are exposed to mercury when they eat fish or drink water from polluted lakes and rivers. Ingestion of the metal affects the development of children’s nervous systems and has been linked to cardiovascular problems.

According to Peter C. Harvey, New Jersey’s attorney general and a leader of the lawsuit, scientists estimate that up to 600,000 children are born each year with neurological problems due to exposure to mercury while in the womb. Forty-five out of 50 states have mercury advisories for the consumption of fish in their state. In New Jersey “there are mercury consumption advisories for at least one species of fish in almost every body of water in the state,” he told The Associated Press.

Also included in the lawsuit are California, Connecticut, Maine, Massachusetts, New Mexico, New York and Vermont. “Our ultimate goal is to persuade the court to invalidate the EPA’s rules dealing with mercury emissions,” Harvey said.

The main problem with the new federal rules, environmentalists say, is that the EPA has taken coal-fired power plants — the leading source of mercury emissions — off the list of polluters required to install the “maximum possible control technology” for lowering the release of the poisonous metal.

In addition, the EPA promulgated a “cap and trade” rule, allowing a power company that cuts its mercury emissions by a specified amount to earn “pollution credits.” It can then sell those credits to another company, which can, in turn, release an equivalent amount of the toxic pollutant.

Environmentalists say that while this cap and trade system is bad in general, it is especially bad for mercury. Unlike greenhouse gases, whose harmful effects are widely dispersed, mercury’s fallout is much more localized.

“EPA’s emissions trading plan will allow some power plants to actually increase mercury emissions, creating hot spots of mercury deposition and threatening communities,” Harvey said. “It’s an anti-human health position. The EPA is putting private profit ahead of public health, and it’s a mistake.”

Dr. Richard Nordgren, professor of pediatric neurology at Dartmouth Medical School, told the World, “I wouldn’t eat a fish out of a New Hampshire lake. The FDA says that if there’s one part per million [of mercury] in a fish, pregnant women shouldn’t eat it.” He added that in some fish found in New Hampshire, the level is 250 percent higher.

On March 24, New Hampshire’s Senate passed a bill requiring its two coal-fired power plants to reduce their mercury emissions by 82 percent. It would reduce emissions from the current 130 pounds per year to 24 pounds by 2013, greatly outpacing reduction rates mandated by the EPA.

New Hampshire’s bill, which still has to pass the House, is aimed at the privately owned Public Service of New Hampshire (PSNH), which operates the two plants. Although PSNH has lobbied against the bill, The measure has strong bipartisan support in the Legislature.

“I’m really encouraged,” said Catherine Corkery, spokeswoman for the Sierra Club in New Hampshire. “[The Senate debate] wasn’t about whether or not we should reduce the mercury, it was about when.”

PSNH has argued the proposed state regulation would cause a loss of jobs. Corkery said that upgrading power plants would actually create more jobs.

“It requires a lot of highly educated people who know about energy and energy production, and you’re talking about high-paying jobs,” she said. These new jobs would attract people to the state or employ people already there. The resulting growth in incomes would stimulate the economy and have a ripple effect, she said, creating even more employment.