Chromated copper arsenate (CCA) wood preservatives contain a mixture of chromium, copper, and arsenic. CCA wood preservatives have been used to pressure-treat lumber in the United States since the 1940s. For more information, visit our page about different kinds of treated wood.
Before 2004, CCA-treated wood was widely used around homes to build decks, playsets, picnic tables, and fences. However, regulators grew concerned over arsenic residue on the treated wood and exposure to children who played on treated wood structures, in addition to workers in wood treatment facilities. The U.S. Environmental Protection Agency (EPA) and the lumber industry agreed to stop using CCA-treated wood in residential settings starting in 2004. This included playground equipment, decks, picnic tables, landscaping, fences, patios, and walkways.
The EPA concluded that existing CCA-treated wood structures such as playsets do not pose unreasonable risks to the public, and do not need to be removed. However, you may still consider taking steps to reduce exposure if you have a CCA-treated wood deck or playset at home. Wooden structures with unknown wood built before 2004 were likely built with CCA-treated wood.
Today, wood treated with CCA is used for commercial, industrial, and some agricultural purposes. It may still be used in residential construction as shingles, shakes, and foundations.
For more information, visit our page about the regulation of treated wood products.
The arsenic in CCA-treated wood can leach to the surface and get on the skin if you touch it. You could accidentally swallow residues if you eat, smoke, or put your hands in your mouth after touching the treated wood. Children are at higher risk because they are more likely to put their hands in their mouths without washing their hands first.
Using recycled CCA-treated wood in garden beds can leach chromium, copper, and arsenic into the surrounding soil. Residues could get on plants, especially root vegetables. Plants may take up arsenic or other chemicals through their roots and into their tissue, although the amount is typically low. You can be exposed if you eat vegetables grown in contaminated soil, especially if you do not wash them first.
CCA residues on your skin do not get in your body. However, they may cause redness and swelling. Ingesting low levels over the long-term can lead to hair loss and skin changes including thickening or darkening of the skin. It can also increase the risk of skin, bladder, liver, and lung cancer over a lifetime.
For more information, visit our page about chromium, copper, and arsenic.
The chromium, copper, and arsenic in CCA-treated wood may leach onto the wood’s surface, and into the surrounding soil and water. The age, size, and type of the wood, moisture in the area, and type of soil all affect how much CCA will leach. Wood sealants may reduce or prevent leaching.
Once chemicals are in the soil, they may change their form, a process known as speciation. The final chemical form can affect the chemical’s toxicity and how easily it moves in the environment. Factors such as soil pH, temperature, soil type, and soil moisture can affect whether and how speciation occurs.
The chemicals in CCA-treated wood mostly accumulate in soil closest to the wood. Under some conditions, they can travel farther. In general, they move least in organic soils, slightly more in clay soils, and the most in sandy soils and water. CCA movement in soils can range from less than 6 inches to up to 8 feet from the source.
Wash hands after touching CCA-treated wood. Have children wash their hands after playing on equipment made of treated wood, especially before eating. If you have an old deck or playset made with CCA or other treated wood, you may consider coating it with a wood sealant. This can reduce the amount of residue leaching to the surface of the wood, where it could transfer to skin or clothing when touched. Coatings should be reapplied on a regular basis to minimize the risk.
If you have garden, consider placing it away from treated wood structures. You may also consider building a raised-bed garden and filling it with clean soil.
Reusing treated wood comes with risks. You may not know what chemicals were used to treat the wood if the original end tag is missing. Avoid cutting and sanding CCA-treated wood. If you must work with CCA-treated wood or any treated wood, consider wearing protective equipment to avoid inhaling the sawdust or getting it on your skin and eyes. Wear long sleeves, pants, shoes and socks, gloves, a dust mask, and eye protection. Wash work clothes separately from the rest of the household laundry.
Treated wood, including CCA-treated wood, should never be burned in stoves, fireplaces, burn piles, or in any other way. The smoke and ash can be toxic. CCA-treated wood should not be chipped or used in landscaping. This can expose people and the environment to the wood preservative chemicals. The laws regarding proper disposal of CCA-treated wood may vary by state. Some states do not allow disposal in the trash. Check with your local waste management agency before placing treated wood in the municipal trash.For more information, visit our pages about treated wood.
Understanding the risks to treated wood can be complicated. If you have questions about this, or any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email us at firstname.lastname@example.org.