Treated Wood Is Cancer Risk For KidsMay 16, 2004 | KNIGHT RIDDER NEWSPAPSERS
With spring weather drawing people outdoors, the chemical arsenic, a carcinogen, is giving families a new worry: Are decks, swing sets, playgrounds, and picnic tables made from treated wood hazardous to children's health?
The Environmental Protection Agency last fall warned that children regularly exposed to pressure-treated wood have a greater chance of cancer due to the arsenic-based preservative in the wood. A final study isn't due until this winter, but the initial report put the risk at 10 times the agency's usual limit for toxic chemicals.
The agency has not recommended that these decks and swing sets be torn down, and manufacturers insist the worries are overblown. But with billions of board-feet of treated lumber in back yards and playgrounds across the nation, parents and public officials have been left with questions.
"It's definitely a concern," said Christina Rau, a New Jersey mom with two daughters and a suddenly suspicious swing set in her back yard. "They're your children. You don't want anything to happen to them."
Until January, most wood used for outdoor and recreational purposes in the country was treated with chromated copper arsenate, or CCA, a preservative used to ward off insects, mildew, fungi and other attackers. Activists had pushed for years to stop the use of the chemical, for fear that arsenic was rubbing off wood, leaching into surrounding soil and ending up in children's bodies.
Bowing to public pressure, manufacturers finally agreed to stop using CCA as of last Dec. 31 and switched to preservatives thought to be less toxic.
But what about the arsenic-treated decks and swing sets in back yards? Government regulators, and even environmental activists, don't advise ripping out your deck or junking your play set. Instead, they say, regular staining or sealing of wood, and washing hands after touching it, should be enough of a safeguard.
CCA had been the preferred preservative for outdoor lumber for decades. The federal government first used it in the 1930s to treat wood pilings in a Missouri swamp, said Chris Hale, executive director of the Wood Preservative Science Council, an industry group. Seventy years later, the pilings are still standing.
Durable and cheap, pressure-treated wood became the standard for decks, playgrounds, stadium bleachers, picnic tables, fence posts, and landscaping. The wood mostly yellow pine in the eastern United States was processed in high-pressure chambers that forced the preservative into the core of the lumber.
But as evidence of arsenic's long-term dangers mounted in the '90s, pressure rose on manufacturers to stop using the compound. Chronic exposure to arsenic has been linked to bladder, lung and skin cancers; increased risk of diabetes; and other health problems.
Arsenic isn't absorbed readily through the skin, so simply touching a deck or climbing a jungle gym is no great concern, experts say. But children's hands inevitably end up in their mouths, taking the chemical with them. They touch a banister, then grab a hamburger. Adults can be exposed, but children, still developing and more susceptible to smaller doses, are more vulnerable.
Studies have also found higher arsenic levels in dirt around CCA-treated wood, prompting concerns about tainted playground soil and arsenic-tinged tomatoes from backyard gardens. Last fall, Massachusetts researchers found arsenic levels above state limits at 10 Boston playgrounds. City officials promised to remove dirt and lumber from the three most contaminated spots.
While research shows arsenic doesn't travel beyond a foot or two in soil, the EPA recommends against using treated lumber to create raised vegetable gardens.
Four studies found varying effects of exposure to arsenic-treated wood from one extra case of skin cancer among 1 million people to 2000 additional lung and bladder cancers per million.
At the EPA, preliminary results of a study found CCA-treated wood may cause 10 additional cancers among 1 million children over their lifetimes, said David Deegan, a spokesman. The government typically raises concerns when chemicals cause more than one extra cancer in a million.
Toxicologists with the U.S. Consumer Product Safety Commission, put the additional cancers at between 2 and 100 per million, said spokesman Ken Giles.
There has never been an actual cancer case tied to exposure to arsenic in wood, Giles acknowledged. Still, he said, warnings are based on well-known effects of arsenic, the amounts that rub off wood and the rate at which children put hands in mouths.
Some CCA-treated wood is still available as the companies sell off their remaining stock.
The wood has a greenish tint when new, though that can fade over time. Pieces may be marked with a black stamp. If there's a doubt, it's safe to assume your playground or backyard lumber has the chemical, Giles said.
"We believe every wood playground built over the last 20 years used CCA-treated wood," he said.
For homeowners wondering about the wood in their back yard, what should be done depends on how much risk and uncertainty you can accept.
"It's a personal choice," said Lauren Sucher, a spokeswoman for the Environmental Working Group. "I would suggest that an unnecessary exposure to a human carcinogen is a choice that a lot of people would not make."
Hale, of the industry group, had a different take, blaming the phase-out of CCA on "hyperbolic nonsense" from environmentalists and trial lawyers.
"Any arsenic that might be associated with the wood preservative is so minuscule that it does not pose any health risk," he said.
The EPA agrees there's no "unacceptable" risk from leaving CCA-treated wood where it is, Deegan said. Still, the agency and the Consumer Products Safety Commission recommend washing children's hands after they touch the wood and not placing food on treated lumber.
The agencies have launched separate studies on the effectiveness of various stains and sealants at trapping the arsenic. Neither is complete, but Giles said other researchers have found that oil-based penetrating seals are better than water-based versions.