Post interim study on CCA-treated wood posted
Washington, DC— The U.S.
Consumer Product Safety Commission (CPSC) and the Environmental
Protection Agency (EPA) have posted on their websites interim
results of a two-year study of coatings (i.e., stains, sealants
and paints) for chromated copper arsenate (CCA)-treated wood.
This information update is part
of 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
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).