Critics dismiss new rules on mercury as too weak.

Byline: Michael Hawthorne

CHICAGO _ Mercury pollution from coal-fired power plants will gradually drop nationwide under a rule issued Tuesday by the Bush administration, but critics say the limits don't go far enough or fast enough to protect the public from exposure to the toxic metal.

Environmental groups and public-health advocates say it could take decades before states can stop advising people to limit eating fish contaminated with mercury in the Great Lakes and other bodies of water in the Midwest.

The U.S. Environmental Protection Agency billed the long-awaited rule as the first national limit on the largest manmade sources of mercury, a neurotoxin that can irreversibly damage the brain before birth and cause developmental problems later in life. The agency estimates more than 15 percent of the children born in the United States each year are exposed to dangerous levels of mercury in the womb, mostly from fish eaten by their mothers.

Two years ago EPA officials had been on track to require each power plant to reduce mercury emissions by as much as up to 90…