ATLANTA (AP) -- Some childhood lead poisonings in Maine last year came from an unusual source -- lead dust tracked into the family car.

Government health officials said Thursday the six cases are the first ever attributed to lead dust on childhood safety seats. The car seats themselves weren't the source; the inside of family cars were contaminated through a parent's workplace.

Parents got lead dust on their clothes at work and then shed it in the cars, said Tina Bernier of the Maine Department of Health and Human Services.

Adults who work in paint removal should change and shower before getting in their cars to go home. However, the Maine families with lead-poisoned children said their employers didn't provide places to do that, Bernier said.

Lead -- a metal that for years was common in paint and gasoline -- can harm a child's brain, kidneys and other organs. Severe exposures can cause coma, convulsions and death. Lower levels can reduce intelligence, impair hearing and cause other problems, according to the Centers for Disease control and Prevention.

In 1978, the government banned lead in paint. But more than 30,000 new cases are still detected each year through doctor's office blood tests. Health officials think as many as 240,000 children have the problem, many of those undiagnosed.

Usually, the victims are children living in old homes that are dilapidated or under renovation, who pick up paint chips or dust and put it in their mouths. But sometimes an obvious source of the lead poisoning is never found.

The CDC report looked at 66 cases of childhood lead poisoning in Maine in 2008. In six cases, no contamination was found in the child's home.

Investigators then checked family vehicles, and found high levels lead on the seats and floors of the cars, trucks and vans. In each case, a father or the mother's boyfriend worked at businesses that did metals recycling or removed paint from old buildings.

The dust also got on the child car seats.

"Kids chew on the sides of those seats... Or they put a cookie down" on the seat and then eat it, said Mary Jean Brown, chief of the CDC's Lead Poisoning Prevention Branch.

Maine officials said they now include checks of cars and child safety seats in their lead investigations.

Parking close to a worksite with the windows open could be another way lead dust can contaminate a car, Brown said. But Bernier said there was no evidence that was what happened in the Maine cases.

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