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New Rules for Pressure Treated Wood
By Paul Bianchina
Treated lumber has been around for decades, and is generally considered to be a very safe product. Recently, however, some controversy has arisen around CCA – Chromated Copper Arsenate – one of the most common chemical compounds used in the pressure-treating process. As a result, on February 12, 2002 the Environmental Protection Agency (EPA) announced a voluntary decision by the pressure-treatment industry to move away from CCA to other types of preservatives by the end of 2003. By January, 2004 CCA-treated lumber – which currently accounts for about 90 percent of the pressure-treated materials on the consumer market – will no longer be available for residential use.
CCA is a blend of three chemicals: Chromium, which binds the chemicals to the wood fibers; Copper, which makes wood decay-resistant and also acts as a pesticide for certain types of insects; and Arsenate, a derivative of arsenic, which acts as a pesticide to stop wood-destroying insects.
The EPA has long maintained – and continues to do so today – that CCA-treated wood is completely safe. However, in light of some data that indicates arsenic may leach out of the wood and become a potential source of soil and ground water contamination, they have deemed it prudent to reduce this potential as much as possible.
What's taking its place?
Even with the removal of CCA from the residential marketplace (it will still be used in some commercial applications), pressure-treated lumber will still be readily available in lumberyards and home centers. The only difference will be new chemical compounds used in the treatment process – and an estimated 10 to 20 percent jump in price.
Two new compounds will be, at least for the time being, the preservatives of choice for pressure-treating lumber. The most common is ACQ – Amine Copper Quat – which will still utilize copper as its primary ingredient. Gone will be the chromium and arsenic, which are being replaced by a solution of ammonia. Manufacturers state that ACQ-treated lumber will look very much the same as CCA-treated wood, with perhaps a slightly browner color.
The second, copper-azole, has been used in Europe and Japan for some time but is fairly new in the United States. As with ACQ, copper-azole compounds do not contain any chemicals that are listed with the EPA as carcinogens, and are in fact utilized by some growers for the treatment of fruit. Wood treated with copper-azole will have a slightly greenish tint that manufacturers say weathers to a brownish tone.
Three manufacturers are currently moving to market with these next generation pressure-treated woods. These include "NatureWood" and "Preserve," both of which use ACQ for their preservative, and Wolman's "Natural Select," which is currently the only product using copper-azole compounds.
What about the CCA-treated stuff I already have?
The EPA has stated repeatedly that CCA-treated wood "does not pose any unreasonable risk to the public or the environment". As such, the EPA is not recommending that you do anything with currently existing structures made with pressure-treated lumber containing CCA.
Since it was the potential risk to children that was of primary concern to the industry and that helped prompt the voluntary changeover, the EPA does offer a few common-sense tips for dealing with CCA-treated lumber. These include not burning treated wood, keeping food out of direct contact with it, and thoroughly washing hands after working with treated lumber or playing on structures that are built with it. For even more protection, you can coat CCA-treated lumber with exterior paint or exterior clear sealants.
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