While the federal government has banned lead in paint, gasoline and plumbing, among other products, the EPA has ignored an estimated 3.5 million pounds of lead weights that drop off tire rims and onto U.S. roads every year, according to a coalition of environmental groups that filed the petition.

Once the lead weights hit the road, they can be picked up by children or eaten by wildlife. They are run over by other vehicles and broken down into dust, which can be inhaled or end up in runoff that taints water and wetlands, the groups say.

Lead has been shown to cause serious neurological problems, affecting development, intelligence and behavior, particularly in children.

The environmental groups asked EPA Administrator Lisa Jackson to prohibit the manufacture and sale of the lead weights in the petition submitted Thursday under a provision of the federal Toxic Substances Control Act.

"We found in our research that this was one of the last unregulated sources of lead into the environment," said Charles Margulis, a spokesman for an Oakland nonprofit, the Center for Environmental Health, which last year filed a separate California anti-toxics lawsuit to stop the sale of the lead weights. "Massive amounts of lead come off every year from wheel weights dropping to the side of the road."

The Center for Environmental Health is part of the coalition of a dozen environmental groups and scientists petitioning the EPA, including the Sierra Club and Alliance for Healthy Homes. They want the EPA to act immediately, arguing that the European Union has banned the lead weights in favor of lead-free steel weights, and Asian governments have instituted both mandatory and voluntary controls of lead weights.

Cathy Milbourn, an EPA spokeswoman, said the agency would review the petition and respond within 90 days.

In 2005, the Bush administration’s EPA turned down a similar petition by the Ecology Center in Ann Arbor, Mich., asking for a lead wheel weight phase-out, citing harmful exposure from urban grit, hobby activities and using the weights as ballast in ships. The EPA denied the ban in favor of a voluntary program by manufacturers, saying that there wasn’t enough evidence to show there was a problem.

"We think the decision ignored the facts," said Jeff Gearhart, an environmental scientist at the Ecology Center who has been warning of the lead problem for 10 years. He also cautions about the widespread lead use in batteries.

The Department of Defense and the U.S. Postal Service have stopped using lead wheel weights, Washington state has banned them, and several states including California are considering similar measures, he said.

At least three manufacturers of lead wheel weights – Henessy-Bada, Perfect Equipment and Plombco Inc. – have indicated that they would welcome a federal policy, to protect them from cheap foreign imports, Gearhart said.

In 2008, these three companies and Chrysler settled a lawsuit alleging that their wheel weights presented an unsafe exposure to a substance that can cause cancer and birth defects. The companies don’t sell the weights in California but other manufacturers continue to do so.

Lead weights account for 80% and lead-free weights make up 20% of the U.S. market, according to Michigan’s Ecology Center. One or two small weights the size of a fingertip typically go on every new and serviced tire, adding up to a half-pound per car. (Tire Review/Akron)