CCA pressure treated wood and arsenic

What is CCA pressure treated wood?

CCA stands for chromated copper arsenate, a pesticide commonly used in pressure treated wood. CCA pressure treated wood is the green-tinged lumber sold in almost every home center and lumberyard in America. It is highly resistant to rot and insects and it protects the wood from deterioration, thus prolonging the life of outdoor wood structures.

CCA treatment leaves about one ounce of inorganic arsenic in each 12 foot 2 x 6. This is enough arsenic, if released, to kill 250 adult humans.

How is arsenic released?

During treatment the boards are dipped into a CCA bath under high pressure. This forces arsenic into the wood but it doesn't seal the wood against the weather. CCA pressure-treated wood contains arsenic can be released from the wood in several ways:

• When the wood burned. Incineration of CCA treated wood does not destroy arsenic. Instead, it concentrates arsenic in the ash, and just one tablespoon of this ash would be toxic to an adult. It is illegal to burn CCA wood in all 50 states.

• Mechanical abrasion, when the wood is sawed, sanded or shaped.

• Direct contact. By contacting, no inorganic arsenic is absorbed through the skin, but it is readily taken up by ingestion. The potential exposure is hand-to-mouth, and thus, young children (under 6 years of age) who play on CCA-treated decks or playscapes are expected to receive the greatest exposure to arsenic leached from wood.

• Leaching from the treated lumber. Recent studies have shown that rainwater leaches (releases) CCA from the treated wood. Another way people may encounter the leached pesticide is when CCA-treated boards are used to frame garden beds. Acid rain and acidic deck washes can speed up release of arsenic from the wood.

Suggestions and Alternatives:

• Coat CCA wood with paints or stains formulated for such use, and recoat as required.

• Keep children and pets out of under-deck areas.

• Follow safe handling and disposal guidelines when using CCA-wood

• Consider use of alternative products on areas that may be contacted by children

• Line interior of raised beds constructed using CCA wood with plastic.

Newer development:

On October 23-25, 2001, the Scientific Advisory Panel of EPA met to discuss issues pertaining to children's exposure from contact with CCA-treated wood playground structures and contaminated soil. A final report announced in an Agency press was released on 12/13/2001. See: http://www.epa.gov/pesticides/citizens/1file.htm