CPSC/EPA Post Interim Study on CCA-Treated Wood

May 11, 2005
Release Number: 05170

The U.S. Consumer Product Safety Commission (CPSC) and the Environmental Protection Agency (EPA) have posted on their Web sites today interim results of a two-year study of coatings (i.e., stains, sealants and paints) for chromated copper arsenate (CCA)-treated wood.

- CPSC staff study of new CCA-treated wood (1st year results)

- EPA study of old CCA-treated wood (1st year results)

This press release is part of an ongoing activity at the CPSC studying possible mitigation measures to decrease the amount of dislodgeable arsenic from CCA-treated wood. If consumers are concerned with potential exposures that may result from contact with CCA-treated wood, they may treat the structure with a sealant. Available data suggest that application of penetrating coatings to your deck or other residential CCA-treated structures can be effective in reducing dislodgeable arsenic. Oil- or water-based stains that can penetrate wood surfaces are more effective in this regard than products such as paint, which forms a film on wood surfaces. This is because paints and other film-formers can chip or flake, requiring scraping or sanding for removal which can increase a consumer's exposure to arsenic. By selecting the proper coating for the initial application and re-coating, consumers can help minimize the potential arsenic exposure caused by scraping, sanding and power washing.

This information is based on first-year results from two-year studies initiated by CPSC staff and EPA in 2003, to determine if stains, sealants and paints are effective in reducing potential arsenic exposure from existing CCA-treated structures. EPA tested the performance of 12 coatings on older wood and CPSC tested eight coatings (seven were the same as those tested by EPA) on new (as of August 2003) CCA-treated wood.

CCA was a chemical treatment commonly used in the past to prevent deck and playground wood from rotting. Effective December 31, 2003, the use of CCA to treat virtually all residential uses of wood was eliminated following an agreement between EPA and the wood treatment industries. EPA and CPSC staff developed an externally peer-reviewed research protocol to study the performance and effectiveness of wood coatings. The joint study, which is slated to end in August 2005, continues to evaluate the performance of commercially available products, a combination of film-forming (e.g., paints) and non film-forming products (e.g., stains).