The Case of CCA Wood
Weighing Science Against Precaution
Addressing environmental health issues in schools can be a challenging task, considering that the science is not always clear. Take, for example, the issue of CCA wood, or pressure treated wood as it is referred to. Chromated copper arsenate (CCA) is a chemical preservative that is used to protect wood from rotting due to insects, mildew, and fungi. It is also 22 percent pure arsenic. In the United States, CCA wood has been used for decades in outdoor structures such as decks, playground equipment, and picnic tables.
The U.S. Environmental Protection Agency (EPA) has regulated CCA as a restricted-use pesticide since 1986. Since 2001, in response to groups concerned about increased cancer risks associated with CCA wood, the EPA has been evaluating the human and environmental risks of the pesticide as part of the re-registration process required under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).
As children repeatedly come in contact with playground and other outdoor equipment made of CCA wood, there is concern that daily play activity may result in significant exposure to arsenic, a known carcinogen, because of the skin-contact and frequent hand-to-mouth behaviors prevalent particularly among young children. Studies suggest that, over time, arsenic may seep out of pesticide-treated wood (referred to as leaching), making it easier to pick up. The wood sometimes develops a greenish discoloration, which may be mistaken as mold or mildew (see the photos below).
On February 7, the Consumer Product Safety Commission (CPSC) released a report linking arsenic-treated lumber to increased cancer rates in children. The study concluded that 2 to 100 children out of 1 million will get bladder and lung cancer from their exposure to arsenic-treated wood playground equipment.
On February 12, 2002, the EPA and industry announced a voluntary phase-out of arsenic-treated wood intended for such residential use as play structures, decks, picnic tables, gazebos, landscaping timbers, fencing, patios, walkways, and boardwalks. The industry’s agreement will take effect beginning January 2004. However, it only applies to new products, so wood treated with CCA prior to this date can still be sold.
At the same time, the EPA concluded that the pressure-treated wood did not pose unreasonable public risk that required ordering the removal of playground and backyard structures. However, the agency recommended always washing hands, especially prior to eating and drinking, and warned food should not come into direct contact with any CCA-treated wood.
On November 4, the CPSC denied a petition to ban the use of CCA-treated wood in playground equipment, citing the EPA’s cancellation of the registration of CCA as a pesticide beginning 2004 as having the same effect. The EPA and CPSC are conducting a risk assessment of wood sealants that may be most effective in containing the arsenic within pesticide-treated wood, such as oil-based, semi-transparent stains.
We should expect to hear more about CCA wood. Last November, the EPA released preliminary results of a study that indicates that children between 1 and 6 face an increased risk of cancer from contact with CCA-treated wood. The draft study found a risk of 1 in 100,000, which suggests that 90 percent of children repeatedly exposed to arsenic-treated wood face a risk greater than one in 1 million, the EPA’s threshold of concern. For southern states, where children tend to spend more time playing outdoors, the risk is higher. According a review of the EPA data by the Environmental Working Group, 10 percent of all children face a cancer risk 100 times higher than the children in the general population. The EPA study is being reviewed by a scientific advisory panel.
So, given all the mixed signals, this is an issue that school boards and administrators should monitor closely, and in some cases, consider being proactive. This is particularly relevant for schools with pre-school and kindergarten programs, especially in states where children spend more time outdoors.
For starters, you might consider having the soil and wood tested for contamination. Contamination may be present through the ground and runoff water, even after structures are removed. Test kits are sold for a nominal fee at www.ewg.org or www.healthybuilding.net.
Consider sealing the wood on a regular basis with an oil-based, semi-transparent stain as a temporary measure. Keep in mind that sealing the wood may prevent further aboveground leaching (bleeding) of CCA but will not address ground contamination and potential problems due to splinters. The number of applications is another important consideration.
The following precautions should also be taken:
Be aware of some of the symptoms of arsenic poisoning, which is difficult to diagnose. Depending on the level of poisoning, some of the symptoms that can occur are vomiting, fatigue, diarrhea, nausea, and the decreased production of red blood cells.
The United States Conference of Catholic Bishops is tracking this issue to ensure that current legislation on arsenic-treated lumber provides all schools with technical assistance and grants that would assist them in removing existing structures and equipment built with CCA wood.
For additional information, visit the following sites:
U.S. Environment Protection Agency at www.epa.gov
U.S. Consumer Protection and Safety Commission at www.cpsc.gov
Environmental Working Group at www.ewg.org
Healthy Building Network, Inc. at www.healthybuilding.net
Roxana U. Barillas
Project Administrator, Children's Health and the Environment, Department of Social Development and World Peace, U.S. Conference of Catholic Bishops
From Issue-Gram, Vol. 13, No. 4, Fall 2003
Copyright NCEA
