WASHINGTON (AP) -- Children could face an increased lifetime risk of developing lung or bladder cancer from using playground equipment made of wood treated with arsenic, the nation's top product safety official said Friday.

Almost all wood playground equipment now in use has been treated with a pesticide called chromated copper arsenate, said Hal Stratton, chairman of the Consumer Product Safety Commission. He said children can get arsenic residue from the treated wood on their hands and then put their hands in their mouths.

Stratton said the agency's scientists recommend that parents and caregivers thoroughly wash children's hands with soap and water immediately after youngsters play on playground equipment made of the treated wood. Children also should not eat while on the equipment, he said.

The safety agency will hold a public meeting next month to consider a proposed ban on the arsenic-based preservative in playground equipment. Advocacy groups petitioned for a ban in 2001.

Last year, preservative manufacturers agreed with the Environmental Protection Agency to stop using the chemical in new wood playsets and other consumer products by December 2003. An EPA report on the risks of the pressure-treated wood is expected later this year.

To figure a child's cancer risk from treated playground equipment, researchers considered factors including how much arsenic is released from wood, the amount picked up on hands and transferred to the mouth and the time a child spends with the equipment. Researchers said an average child visits playgrounds three times each week.

The study found that for every 1 million kids exposed to the treated wood that frequently during early childhood, two to 100 of them might develop lung or bladder cancer later in life because of that exposure. This increase is in addition to other risks of getting cancer.

The range of risk is large because of differing estimates of how likely arsenic is to cause cancer, agency spokesman Ken Giles said. Some of the data came from studies in Taiwan, where there are higher levels of arsenic in drinking water.

Lung cancer is the most common form of cancer; bladder cancer is more rare. The greatest risk factor for both is smoking.

Mike Casey, a spokesman for the Environmental Working Group, one of the groups seeking a ban, said the study supports their position that the treated wood is dangerous.

Wood preservatives containing arsenic and dioxin have been increasingly targeted as unsafe by advocacy groups. Those preservatives have been commonly used in utility poles, wood decks and playgrounds.

The safety commission did not study other products because the ban petition only involved playgrounds, Stratton said.

Arsenic, both manufactured and naturally occurring, is known to cause cancer, but the preservative industry has said the arsenic-based preservative has never been linked to skin disease or cancer in children and its wood is safe when used properly.

The safety commission and the EPA are studying ways to coat treated wood with a sealant to prevent arsenic from coming through.

EPA began requiring consumer warning labels on treated lumber containing arsenic in 2001.

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