by ArchitectureWeek

When the U.S. Environmental Protection Agency (EPA) issued a report last year on the safety of pressure-treated lumber, they acknowledged the danger of arsenic, a poison and carcinogen, which is used widely in wood preservatives like chromated copper arsenate (CCA). They announced a phase-out of some uses of the preservative by the end of 2003.

Unfortunately, this phase-out will not affect existing outdoor wooden structures in the United States, an estimated 90 percent of which are treated with arsenic-based preservatives. The EPA may have misled the public when it asserted that it "does not believe there is any reason to remove or replace arsenic-treated structures."

Contradicting stated EPA beliefs is a recent study by the independent organization Environmental Working Group (EWG)*. The EWG report concludes that millions of people, especially children, remain at risk from older decks, picnic tables, and play structures, which continue to leach out high levels of arsenic for years after construction.

Findings reported in EWG's "All Hands on Deck" indicate that arsenic easily wipes off the surfaces of old wood structures. Their study was based on samples nationwide from 263 structures and the arsenic-contaminated soil beneath them. The samples were analyzed by the University of North Carolina - Asheville's Environmental Quality Institute.

The EWG study shows that pressure-treated wood up to 15 years old exposes people to as much arsenic as newly treated wood. The amount of arsenic that testers wiped off a small area of wood about the size of a four-year-old's handprint (15 square inches, or 100 square centimeters) typically far exceeds what the EPA allows in a glass of water under the Safe Drinking Water Act standard. Arsenic in the soil from 40 percent of test sites exceeds the EPA's Superfund cleanup level of 20 parts per million.   >>>

Natural materials in a pristine setting may appear benign, but a report from the Environmental Working Group warns of dangers from arsenic in pressure-treated wood. Photo: www.clipart.com Children routinely play in soil so contaminated with arsenic as to far surpass Superfund cleanup levels. Image: Environmental Working Group and UNC-Asheville Environmental Quality Institute Home Testing Program, 2001-2002   Click on thumbnail images to view full-size pictures.