For nearly 70 years, decks, storage sheds, playground sets, and other outdoor structures were commonly made of pressure-treated lumber--wood infused with chromated copper arsenate (CCA) to make it insect- and rot-resistant. CCA contains known carcinogens and has been shown to migrate to the wood surface, where it can come in contact with people or leach into the surrounding soil.

The outdoor-lumber industry voluntarily halted production of CCA for residential use, effective at the beginning of 2004. Only existing stocks of CCA can be sold.

If you already have a deck or outdoor structure. The withdrawal of CCA lumber does not affect structures already in place. The Environmental Protection Agency doesn’t believe it’s necessary to remove existing CCA structures or the soil under them. The agency has not concluded that CCA lumber poses “any unreasonable risk” but acknowledges that it’s important to reduce exposure to the toxic compounds in CCA. The actual risk posed by CCA depends on many factors--including the type of preservative or deck treatment used, some believe.

We concur with the EPA’s recommendation for reducing the risk from exposure to CCA lumber: Wash your hands after you’ve touched the wood. Removing a CCA structure would be a drastic last resort.

If you have to demolish a structure made of CCA lumber.