Wood preservatives are pesticides that protect wood against attack by fungi, bacteria, or insects. The active ingredients found in wood preservatives may include pentachlorophenol (penta or PCP), creosote, copper, zinc, chromium, arsenic, and other compounds. Preservatives may be injected into the wood before purchase (pressure-treated wood) or applied by the user. If wood-preservative chemicals are incorporated into a paint or stain, that product is considered a pesticide.

Wood preservatives perform a useful function and may be required by building codes in some applications. In other cases, there is a choice of whether to treat or which chemicals to use. Wood preservatives are hazardous materials, and health and environmental hazards should be considered in making these decisions. If you must use a wood preservative, compare labels and look for the least-toxic products that will do the job. Some preservative ingredients that are less toxic include copper compounds, zinc compounds, and borates, but individual product hazards vary widely.

On this page you will find links to sources of information on a variety of chemicals that are used to treat wood, some of their environmental and health effects, sealants for treated wood, and some alternative building material suggestions.

Fact sheets with basic information on CCA-treated wood and its alternatives:

• What You Need to Know about Pesticides Used in Pressure-Treated Wood. Connecticut Department of Public Health, 2001. 4 pp.
• Arsenic Wood Fact Sheet. Healthy Building Network.
• Paints and Wood Preservatives: Protecting your Wood and Your Health. (36kb PDF file) Washington Toxics Coalition.

Toxicity information on metals found in CCA-treated wood:

Public Health Statements from the Agency for Toxic Substances and Disease Registry (ATSDR):

• Arsenic
• Chromium
• Copper

Reports on toxicity of and exposure to arsenic in CCA-treated wood:

• Poisoned Playgrounds: Arsenic in Pressure-treated Wood. Environmental Working Group and Healthy Building Network, 2001. 23 pp.
• Poisonwood Rivals: the Dangers of Touching Arsenic-treated Wood. Environmental Working Group and Healthy Building Network, 2001. 18 pp.
• All Hands On Deck: Nationwide Consumer Testing of Backyard Decks and Playsets Shows High Levels of Arsenic on Old Wood. Environmental Working Group, 2002. 44 pp.

Scientific report evaluating leaching of metals from decks made of CCA-treated wood:

• New Lines of CCA-Treated Wood Research: In-Service and Disposal Issues. Florida Center for Solid and Hazardous Waste Management, State University System of Florida Report #00-12. March 19, 2001. 206 pp. (696kb PDF file)

Scientific report evaluating leaching and toxicity of CCA-treated and alternative-treated wood products (including ACQ-, CBA-, CC-, and CDDC-treated wood):

• Leaching and Toxicity of CCA-Treated and Alternative-Treated Wood Products. Florida Center for Solid and Hazardous Waste Management, State University System of Florida, Draft Report. February 7, 2003. 151 pp. (4352kb PDF file)

Information on phase-out of residential uses of CCA-treated wood:

• Whitman Announces Transition from Consumer Use of Treated Wood Containing Arsenic. U.S. Environmental Protection Agency, February 12, 2002.

Sealants for CCA-treated wood:

• All Hands Off the Deck: Preventing Exposure to Arsenic from Treated Wood. Philip Dickey.  Washington Toxics Coalition Alternatives Newsletter, Spring 2004. (340kb PDF file)
• Identifying Effective Sealants for CCA-treated Wood. Philip Dickey, Washington Toxics Coalition, 2004.  24pp.

Alternatives to CCA-treated wood:

• Organic Alternatives to Treated Lumber. National Sustainable Agriculture Information Service, ATTRA (Appropriate Technology Transfer for Rural Areas). July 2002.
• Alternatives to Chromated Copper Arsenate (CCA) for Residential Construction. Forest Products Laboratory, USDA Forest Service. 2004.
• Recycled Material Suppliers, King County Environmental Purchasing Program

Pentachlorophenol:

• Pentachlorophenol. A Washington Toxics Coalition Fact Sheet. February 2004. 2 pp. (PDF)