October 2003

Texas Cooperative Extension, College Station, Texas


Pressure-treated Wood Under Pressure

By David S. Jones, Real Estate Center, Texas A&M University, College Station, Texas

Pressure-treated wood popular in vegetable gardens
Pressure-treated wood is popular in vegetable gardens

Here in the termite belt, pressure-treated lumber has for years been the wood of choice for just about anything built outdoors. Decks, fences, landscaping, raised gardens and even playground equipment. All that will end officially on Dec. 31, 2003.

In February, the U.S. Consumer Product Safety Commission (CPSC) released results of a study regarding chromium copper arsenate (CCA)-treated decks and play sets. The research concludes that out of every one million children exposed to CCA-treated lumber an average of three times per week for five years, between two and 100 have an increased risk of developing lung or bladder cancer.

In March, the U.S. Environmental Protection Agency (EPA) reached agreement with producers of pressure-treated lumber to discontinue sales of CCA-impregnated wood by the end of the year.

The agreement affects lumber used to build anything children might come in contact with - decks to picnic tables to playground sets. EPA officials do not recommend removal or replacement of CCA-treated structures or surrounding soil. The CPSC does recommend homeowners take steps to protect children from coming in contact with arsenic that may leach from the lumber.

Pressure-treated lumber resists rot, decay and insect infestation. It typically has a greenish tint. It usually has a stamp that identifies it as pressure-treated or rot- and insect-resistant. It is sold under many brand names.

Although the lumber has come under increasing attack in recent years, the significance to homeowners in unclear. Unclear or not, it won't be manufactured for residential building or consumer products after 2003. Industrial and commercial products or those used in saltwater marine applications are expected to continue.

The copper in CCA is the major preservative, protecting against fungi and insects. The arsenic is a second line of defense. The chromium fixes the treatment so it doesn't easily leach from the lumber.

"CCA is controversial," say experts at Criterium Engineers in Portland, Maine. "However, in negotiating with the timber industry, the EPA stopped short of calling it dangerous. Instead, they said any reduction in the amount of arsenic in the environment is desirable. We are not aware of any credible studies that quantify the actual safety risk."

Some have wondered why the EPA did not call for removal or replacement of CCA-treated structures if such lumber is dangerous enough to be phased out.

The debate seems certain to continue for some time. The new non-arsenic lumbers - alkaline copper quaternary or ACQ, copper boron azole (CBA) and Tanalith E - cost as much as 20 percent more. Many major building supply outlets have yet to stock the non-arsenic treated alternatives.

In lieu of removal, the EPA says that applying an oil-based, semitransparent stain once a year may reduce the levels of arsenic on the surface. Children playing on CCA-treated wood should wash their hands before eating; food should not be allowed to touch the wood. Use gloves when handlng CCA-treated wood. Do not burn it.

For more information about CCA-treated wood, go to www.epa.gov and use their search engine to search for "CCA."

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