CHICAGO — Looking to bolster the fight against childhood lead poisoning, the Environmental Protection Agency last month approved a tough new rule aimed at clearing the nation's air of the toxic metal.
But at the last minute, federal documents show, the Bush administration quietly weakened a key provision, exempting dozens of polluters from scrutiny. A new network of monitors that is to track lead emissions from factories has been scaled back.
Critics say the change undermines a rule that otherwise has been widely hailed as a powerful step in protecting children's health.
The federal rule was prompted by compelling research showing lead is more dangerous than had been thought. Even low levels of the toxic metal in young children have been linked to learning disabilities, aggression and criminal behavior later in life. Many scientists say there is no safe level of exposure.
Faced with a court order to act more aggressively, the EPA last month lowered the maximum amount of lead allowed in the air. The new standard, 0.15 micrograms per cubic meter, is 10 times more stringent than the standard set in 1978.
To help meet the new limit, the EPA had planned to require lead monitors next to any factory emitting at least half a ton of lead a year. But after the White House intervened, the agency raised the threshold to a ton of lead or more, according to e-mails and other documents exchanged between the EPA and the Office of Management and Budget.
As a result, dozens of factories won't be checked regularly. Federal and state officials debate the exact number, but a review of EPA records found the number of U.S. plants monitored could drop by nearly 60%, from 203 to 87.
"This sleight of hand by the administration ignores major sources of a dangerous neurotoxin," said S. William Becker, executive director of the National Assn. of Clean Air Agencies.
The Obama administration could try to amend the lead rule, but that process would take months.
National lead emissions have dropped 97% under the old standard, largely because lead was removed from gasoline. But cement plants, smelters, steel mills and other factories still emit about 1,300 tons of lead into the air each year, the EPA said.
After tiny lead particles settle to the ground, they can stay there for years. Exposure can occur when people, especially children, handle or play with contaminated soil and then put dirty hands into their mouths.
"If we can keep bringing down blood-lead levels in kids, there could be considerable benefits over the years to a wide swath of our population," said Bruce Lanphear, a researcher at Simon Fraser University in British Columbia, Canada, and a member of a scientific panel that urged the EPA to set tougher lead standards.
Dozens of monitors scattered across the country already check lead levels in the air, but the EPA estimated that it would take dozens more to track emissions from polluters releasing at least half a ton of lead.
Industry lobbyists waged a fierce battle against the new standard and the additional monitoring. They argued that lingering dust from leaded gasoline and lead paint are a much bigger threat to children than ongoing industrial emissions.
In written comments filed with the EPA and the Office of Management and Budget, lead battery manufacturers and recyclers said many of their facilities would fail to comply with the tougher standard. If factories had to reduce lead emissions, they said, companies would be forced to move operations to countries with lax environmental policies.
The Assn. of Battery Recyclers wrote in comments to the Office of Management and Budget that a tougher lead rule would lead to "environmental and human health risks attributable to mishandling, improper disposal and illegal export of millions of spent lead acid batteries."
A related organization, the Battery Council International, told the EPA that the more stringent monitoring standards would be "unjustifiably low."
Last month, two weeks after lobbyists from the industry met with Bush administration officials, the White House ordered the EPA to raise the monitoring threshold to a ton or more, federal records show.
An industry lawyer declined to comment, saying the publicly filed comments "speak for themselves."
EPA officials said states could add lead monitors if they thought it was necessary.
"We selected an approach that would still ensure monitoring around those sources that have the potential to contribute to a violation of the standards," Cathy Milbourn, an EPA spokeswoman, said in a statement.