Q & A Library

You're right. There is arsenic in lumber that has been used for years to make decks, fences, picnic tables and even some playground equipment. Technically speaking, the lumber is treated with chromium copper arsenate (CCA), a preservative used to prevent the wood from decaying. The good news is that since the beginning of this year, lumber manufacturers are no longer selling wood impregnated with CCA. But that isn't much comfort if you have young children and an old deck or old yard and porch furniture.

Although arsenic is a carcinogen, manufacturers insist that the old, treated wood is safe for people, plants and animals when used as recommended. However, advocacy groups maintain that the chemical can rub off on contact and that the lumber remains dangerous for 10 to 15 years. And a staff report to the United States Consumer Product Safety Commission concluded that children exposed to the treated wood may face an increased lifetime risk of lung or bladder cancer.

If you have a deck made with CCA-treated lumber, you can test it for arsenic by ordering test kits online for about $20. Results will tell you how much arsenic is in wood. You can then decide if you want to replace the furniture or insist that your kids wash their hands well after playing on it, especially before eating.

You can also protect your family by applying a sealant to CCA-treated wood. Pigmented deck stains provide the most protection, but you'll have to reseal frequently, as often as twice a year. If you decide to use a sealant, be sure not to sand the deck beforehand 'sanding will release arsenic-laden sawdust. Be sure to wear a protective mask! And don't pressure-wash your deck before sealing - the high pressure water can loosen arsenic-contaminated particles and release them into the air. You can learn more about this issue through the Washington-based Environmental Working Group at www.ewg.org.

Andrew Weil, M.D.