The U.S. Consumer Products Safety Commission (CPSC) and the Environmental Protection Agency (EPA) have posted interim results of their two year joint study focused on reducing the amount of dislodgable arsenic from chromated copper arsenate-treated wood. Chromated copper arsenate (CCA) was widely used as a treatment against rot and insect damage until it was eliminated from use on residential wood on December 31, 2003.
Available data from the study suggests that application of penetrating oil- or water-based stains is more effective in reducing arsenic exposure rather than application of paint. Paint, which forms a film on wood surface, can chip or flake. Consumers then would have to sand or scrape them to refinish, and ultimately, this would increase their exposure, the study said.
CPSC and EPA started this two-year study in 2003 to determine if stains, sealants and paints are effective in reducing potential arsenic exposure from existing CCA-treated structures. EPA is testing the performance of 12 coatings on older wood and CPCS tested eight coatings on new CCA-treated wood. Seven of the products tested were the same.