Questions and Answers
CCA-Treated Wood
Prepared by CPSC Staff
February 2002

What is chromated copper arsenate?

Chromated copper arsenate or CCA, is a chemical preservative that is used to protect wood from being destroyed by microbes, termites, or other wood-boring insects. CCA contains forms of the chemicals chromium, copper, and arsenic. CCA is largely used to pressure treat lumber intended for outdoor uses such as home, school, and community playgrounds; decks; and landscape timbers. CCA-treated lumber is also used in building structures.

What work is CPSC doing related to CCA-treated wood?

In May 2001, CPSC was petitioned by the Environmental Working Group and the Healthy Building Network to ban the use of CCA-treated wood for playground equipment. In response to this petition, and to define the risk to children, the CPSC staff is evaluating the amount of CCA (in particular, arsenic) that a child might be exposed to while playing on CCA-treated playground equipment.

CPSC staff is currently evaluating the amount of CCA released from both newly purchased, unused CCA-treated wood that might be used for building playground structures and from "used" or "older" wood. CPSC staff is particularly interested in knowing the amount of arsenic that children can be exposed to when they play on CCA-treated wood playground equipment. CPSC staff studies are being conducted by wiping the surface of the wood to measure the amount of arsenic on the wood's surface. The wipe samples are used to estimate the amount of arsenic that might be accessible to children when they rub their hands on the wood surfaces while playing.

In addition to evaluating the amount of the chemical available on the wood surface, CPSC staff is considering product-specific human use characteristics in its assessment. CPSC staff is evaluating the reasonably foreseeable use of the product by considering the age of the child using the product, the type of exposure (hand-to-mouth), the frequency and period of exposure, accessibility, extent of exposure (area contacted), and use environment (exposure to heat and sunlight). The relationship between exposure and adverse health effects will then be considered.

Staff review of these and other data, along with its review of public comments received, will be incorporated into a briefing package for Commission consideration as to what action to take regarding CCA-treated wood.

What types of wood are used to make home playground equipment?

There are several types of wood that are used to make playground equipment. They include cedar, redwood, untreated lumber, and CCA-treated wood. Playground equipment can be built by the consumer with CCA-treated lumber purchased from lumberyards, hardware stores, or other retailers. Consumers can use their own playground designs, purchase design plans, or purchase pre-manufactured kits with design plans plus swings and slides. Some pre-manufactured playground equipment kits may also contain CCA-treated wood. Some playground manufacturers who are not currently using CCA-treated wood in their equipment may be advertising the use of arsenic-free wood. Consumers can verify with the manufacturers before purchase whether this wood is being used.

CPSC staff is also aware of arsenic-free wood preservative chemicals, such as ammoniacal copper quat (ACQ). Consumers may wish to consider using wood treated with these preservatives for new construction.

Do public wood playground structures contain CCA?

School and public playgrounds can be made with a variety of materials, including CCA-treated wood. Many older playground structures have been constructed using CCA-treated wood. In the past year, some playground manufacturers have begun moving away from the use of CCA-treated wood for playground equipment and are using either untreated wood or wood that has been treated with chemicals that do not contain arsenic.

What does CPSC staff know about the amount of CCA that children are exposed to when playing on CCA-treated wood playground equipment?

CPSC staff is currently evaluating the amount of CCA released from both newly purchased, unused CCA-treated wood that might be used for building playground structures and from "used" or "older" wood. CPSC staff is particularly interested in knowing the amount of arsenic that children can be exposed to when they play on CCA-treated wood playground equipment. CPSC staff studies are being conducted by wiping the surface of the wood to measure the amount of arsenic on the wood's surface. The wipe samples are used to estimate the amount of arsenic that might be accessible to children when they rub their hands on the wood surfaces while playing.

The amount of arsenic present in different samples of CCA-treated wood appears to vary and limited test data do not allow staff to define the mechanism by which the amount of available arsenic changes as the wood ages. It may depend in part on the environmental conditions to which the wood is exposed (for example the amounts of heat, sun, and rain), as well as the chemical composition of the wood.

How are children exposed to arsenic from playground equipment?

Children can be exposed to arsenic from playground equipment primarily through hand-to-mouth contact when they touch the wood and then place their hands in their mouths. Minimal exposure to arsenic can occur through their skin.

What are the health effects of exposure to arsenic and is there a risk to my child playing on CCA-treated wood playground equipment?

In order to define the risk, the CPSC staff is currently evaluating the amount of CCA, and in particular, the amount of arsenic, that a child might be exposed to while playing on CCA-treated wood playground equipment.

According to the National Academy of Sciences, long-term exposure to arsenic increases the risk of lung, bladder, and skin cancer over a lifetime. The risk to children playing on CCA-treated playground equipment depends on the amount of available arsenic on the wood surface, how children are exposed to the arsenic (orally or through skin contact), and the length of time children spend using the equipment. Studies suggest that children may be exposed to arsenic from playing on some CCA-treated wood playground equipment.

The amount of arsenic present in different samples of CCA-treated wood appears to vary and limited test data do not allow staff to define the mechanism by which the amount of available arsenic changes as the wood ages. It may depend in part on the environmental conditions to which the wood is exposed (for example the amounts of heat, sun, and rain), as well as the chemical composition of the wood.

In addition to evaluating the amount of the chemical available on the wood surface, CPSC staff is considering product-specific human use characteristics in its assessment. CPSC staff is evaluating the reasonably foreseeable use of the product by considering the age of the child using the product, the type of exposure (hand-to-mouth), the frequency and period of exposure, accessibility, extent of exposure (area contacted), and use environment (exposure to heat and sunlight). The relationship between exposure and adverse health effects will then be considered.

Consumers may wish to take steps to reduce this exposure. These steps are described in the following question and answer.

What can I do to decrease my child's exposure to chemicals found in CCA-treated wood?

CPSC staff is aware that various trade and consumer groups, some state governments, and a Science Advisory Panel (SAP) recently convened by the U.S. Environmental Protection Agency's Office of Pesticides, have made suggestions concerning surface coating of CCA-treated wood to reduce potential exposure to chemicals found in this wood.

Based on the limited available data, these groups have suggested that applying certain penetrating coatings (for example, oil-based semi-transparent stains) on a regular basis (for example, once a year or every other year depending upon wear and weathering) may reduce the migration of chemicals in the wood preservative from CCA-treated wood. However, in selecting a finish, in some cases, "film-forming" or non-penetrating stains (latex semi-transparent, latex opaque, and oil-based opaque stains) on outdoor surfaces such as decks and fences are not recommended as subsequent peeling and flaking may ultimately have an impact on durability as well as exposure to the preservatives in the wood.

CPSC staff has not completed its assessment of the effectiveness of these mitigation measures. However, consumers desiring to reduce potential exposure to chemicals found in CCA-treated wood may wish to consider using them.

It is also important to have children wash their hands after playing on playground equipment.

CPSC staff is aware of alternatives to CCA-treated wood. These include both non-arsenic wood preservative chemicals such as ammoniacal copper quat (ACQ) as well as other wood (for example cedar and redwood) and non-wood materials (for example metal and plastic). Consumers may want to consider using these alternatives for new construction.

How can I tell if my playground equipment or deck contains arsenic?

Freshly treated wood, if not coated, has a greenish tint, which fades over time. Historically, CCA has been the principal chemical used to treat wood for decks and other outdoor uses around the home. Generally, if you know that your deck has not been constructed with redwood or cedar, then it is likely that the deck was probably constructed with CCA-treated wood. Alternatively, if you know who the building contractor or wood retailer was, you may want to call and ask.

The CPSC staff is aware that arsenic test kits are available to consumers. The kits, if used properly, might be useful for determining whether wood was ever treated with CCA. However, the CPSC staff has not evaluated these kits and therefore, does not know how accurate they are.

In 1990 the CPSC looked at the release of arsenic from playing on wood playground equipment treated with CCA. What's different now?

Since that study was conducted, additional health effects data are available. At the time of the 1990 study, skin cancer was the only carcinogenic effect of arsenic ingestion that was considered. New data reviewed by the National Academy of Sciences (NAS) suggest that long-term exposure to arsenic increases the risk of lung and bladder cancer, as well as skin cancer, and that the health risks posed by exposure to arsenic may be more than previously believed.

Can you explain the recent action taken by the CCA chemical manufacturers concerning CCA-treated wood and how does it affect CPSC's work?

Pesticides must be registered with the U.S. Environmental Protection Agency (EPA) for certain uses before they can be sold or used in the U.S. CCA has been registered for many uses, including use in dimensional lumber (2 x 4s, etc.) sold to consumers.

In early February, 2002, the manufacturers of CCA asked EPA to remove from their registration many applications of CCA for residential use, including playground equipment, decks, and landscape timbers. According to EPA, manufacturers are phasing out the production of CCA over the next 22 months to allow enough time for wood treatment facilities to convert to alternative chemicals and to ensure the availability of enough wood preservative during the transition time. It thus appears that after December 31, 2003, CCA will no longer be available to treat wood used in residential settings.

The results of this action will likely impact the work that the Commission staff undertakes in the future, particularly in the area of mitigation.