May 12, 2005
Homeowners with decks or playground equipment made of treated wood should take note of a federal study that finds yearly application of oil- or water-based stains or sealants can reduce the amount of arsenic released by the wood.

The data show that oil- or water-based sealants or stains that can penetrate wood surfaces are preferable to products such as paint, because paints and other film-formers can chip or flake, requiring scraping or sanding for removal, which can increase exposure to arsenic.

Consumers should consider the required preparation steps -- sanding, power washing, etc. -- before selecting a product to minimize potential exposure to arsenic, both for initial application and re-coating, the study said.

The results are from a study of chromated copper arsenate (CCA)-treated wood conducted by the Environmental Protection Agency (EPA) and the Consumer Product Safety Commission (CPSC).

The information is based on first-year results from two-year studies initiated by CPSC and EPA in 2003 to determine which stains, sealants and paints are most 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 the EPA group) on new (as of August 2003) CCA-treated wood.

CCA was a pesticide treatment commonly used in the past to prevent deck and playground wood from rotting and insect damage. Effective Dec. 31, 2003, the use of CCA to treat virtually all wood intended for residential use was eliminated.

Key points for parents and consumers:

  • If you are concerned about potential exposure to arsenic, sealants, when applied at least once a year, have been shown to reduce dislodgeable arsenic from the wood.
  • Oil or water-based, penetrating sealants or stains are preferred.
  • As always, parents and other caretakers should follow these precautions for children who play on or near decks. Always wash hands thoroughly after contact with treated wood, especially prior to eating and drinking, and ensure that food does not come into direct contact with any treated wood.
  • At this time, EPA and CPSC said they do not believe there is any reason to remove or replace CCA treated structures, including decks and playground equipment.
  • Consumers should follow manufacturer recommendations when handling the wood, including the same precautions that workers should take: wear gloves when handling wood, wear goggles and dust masks when sawing and sanding, always wash hands before eating, and never burn CCA treated wood.
  • The majority of exposure that is estimated to occur to children is from hand-to-mouth activities (i.e., children touching the surface of CCA-treated wood and then putting his/her hand in his/her mouth). This activity is most prevalent in children aged 1 to 6 years of age.