Nearly 40 million lb. of arsenic is used in this country every year, and most of it goes into the pressure-treated wood that we use to build decks and playgrounds. But that all changes Jan. 1, 2004. The Environmental Protection Agency (EPA) is banning chromated copper arsenate (CCA) as a preservative for wood intended for residential use (except for the lumber that is used in permanent wood foundations). CCA-treated lumber will still be available for industrial and agricultural use, however.
By the way, there's no need to panic about existing CCA-treated structures. The EPA says that they're fine. But if you're nervous about the chances of leaching chromium and arsenic, you can make your deck or swing set safer by coating it with an oil-based penetrating stain every couple of years.
Taking CCA's place as a preservative are two waterborne compounds: alkaline copper quat (ACQ types B and D) and copper azole (CBA-A, CA-B). Sold under the trade names Preserve, NatureWood, and Natural Select, they have been used around the world for up to 15 years. These EPA-approved low-toxicity pesticides resist bugs, mold, and rot as effectively as CCA. (See How much safer? for more on quat and azoles.)