Arsenic in Wood — Dangers Persist
Other studies have shown that arsenic sticks to children's hands when they play on treated wood and is absorbed through the skin and ingested when they put their hands in their mouths. Exposure to arsenic is known to cause acute poisoning as well as lung, bladder, and skin cancer in humans, and it is suspected as a cause of other cancers.
Arsenic-treated wood may be difficult to identify visually. Some wood treated with arsenic compounds sports a characteristic faded green color, and/or rows of tread-like puncture marks. However, more recent CCA treatment processes, including the "Wolmanzing" of the "Outdoor Wood" brand of lumber, can leave wood with a pleasant, natural brown color. After weathering, "Wolmanzed" wood is even less distinguishable from untreated wood.
More than a year after the EPA phase-out announcement, and with only about nine months remaining to the final date, large amounts of CCA-treated wood apparently still flow through the U.S. lumber supply chain, representing a continuing source of potential toxic exposure to builders and building occupants.
According to an EPA publication, "Your local hardware store or lumberyard can provide more information on available alternatives." Such vague advice may not be adequate for concerned design and building professionals, who may want to carefully conduct their own literature survey on alternative preservative treatments like Alkaline Copper Quaternary (ACQ).
A quick survey of home improvement superstores showed mixed progress. A large independent outlet had a mixture of CCA or "Wolmanized" arsenic-treated wood shelved together with hopefully safer lumber treated with non-arsenic ACQ. However, their free "How-To Booklet #82: Preserved Wood" still includes discredited if not dangerous statements like "no chemicals can leave the wood or enter the ground water or your body."
Home Depot has received some credit in the green-building community for stating a corporate commitment to stopping distribution of CCA-treated wood. At a local Home Depot, we found relatively up-to-date consumer safety tear-sheets, in accord with current EPA recommendations for handling arsenic-treated wood, posted at most of the pressure-treated lumber racks. The racked wood, however, was all CCA-treated, presenting no direct alternative for customers at that store.
According to Ontario activist Deborah Elaine Barrie, CCA-treated lumber can contain a large amount of arsenic, on the order of one ounce (28 grams) per board. California State Senator Gloria Romero (Democrat, Los Angeles) introduced legislation in February, 2003 to ban the use and production of three dangerous wood preservatives, CCA, pentachlorophenol (penta), and creosote. This legislation would allow arsenic-treated wood in California to receive the more careful disposal appropriate for toxic materials.
Experts say that boards in high-contact areas such as handrails should be replaced with arsenic-free alternatives. In light of the documented risks, removal of arsenic-treated wood from all areas of contact with people, water, or weather may be prudent.
Short of replacing their decks, families may be able to lower their arsenic exposure somewhat by sealing the wood at least every six months and by washing hands thoroughly after contacting the wood. Additional safety tips are available at the EWG Web site, and in the references below.
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Whitman Announces Transition from Consumer Use of Treated Wood Containing Arsenic — EPA Press Release, 2002.0212
Questions & Answers:What You Need to Know About Wood Pressure Treated with Chromated Copper Arsenate (CCA) — EPA Fact Sheet, 2002.0212
Consumer Safety Information Sheet: Inorganic Arsenical Pressure-Treated Wood (CCA, ACA, ACZA) — EPA Product Safety Sheet - updated 2003.0227
October 23 - 25, 2001 - CCA treated wood — FIFRA Scientific Advisory Panel (SAP) Meeting Agenda and Report
All Hands on Deck (PDF file) — Environmental Working Group Report
To guard environmental health and avoid potential liability, design professionals may want to immediately update all architectural, remodeling, and landscape projects and specifications to ensure that CCA-treated wood is prohibited from use where it may be exposed to human contact, water, or weather.
To guard environmental health and avoid potential liability, builders may want to actively substitute safer alternatives where contracts allow, and request allowance of safer equivalents where specifications are restrictive. Special safety procedures should be specified for all work involving CCA-treated wood, wood scraps, and wood dust.