Chromated Copper Arsenicals (CCA)
and Its Use as a Wood Preservative

USEPA Office of Pesticide Programs 24may01

1. What is CCA, and how is it used?

Chromated Copper Arsenate (CCA) is a chemical mixture consisting of ions of three elements (arsenic, chromium and copper) registered for wood preservative uses. CCA chemical mixtures are also referred to as inorganic arsenicals.

CCA protects wood from dry rot, fungi, molds, termites, and other pests that can threaten the integrity of wood products. Wood treated with CCA lasts at least five times longer than untreated wood. Untreated wood products when used for these scenarios must be replaced more frequently, which can be expensive and resource intensive. The inorganic arsenicals are most commonly applied to wood intended for use in outdoor settings, e.g., decks, walkways, fences, gazebos, boat docks, playground equipment, as well as highway noise barriers, sign posts, utility posts, and retaining walls.

2. Does CCA-treated wood pose risks to human health?

EPA reviewed the use of CCA to treat wood during the 1980s and, at that time, EPA concluded that CCA-treated wood did not pose unreasonable risks. EPA reached this conclusion based on studies that evaluated potential dermal contact (low absorption through the skin) to pressure treated wood. The Agency, however, was concerned about the health effects on people that work with CCA on a daily basis. Based on these concerns, the Agency issued new requirements for protecting workers.

3. What regulatory action has EPA taken with CCA in the past?

In October 1978, EPA initiated a special review of the inorganic arsenicals and two other major wood preservatives, creosote and pentachlorophenol. Following conclusion of the special review in January, 1986 (51 FR 1334 January 10, 1986), the Agency required new protective measures for workers who use inorganic arsenicals to treat wood and imposed restrictions on the use of CCA treated wood. To reduce exposure and potential health risks, the Agency enacted a number of safety precautions:

• CCA is now classified as a "Restricted Use" pesticide, meaning that only certified applicators, or persons under their direct supervision, can purchase and use this chemical; furthermore, the use must be covered by the applicator's certification.
  
  
• Labels must specify protective clothing requirements for workers. Workers who use arsenic to treat wood are required to wear a respirator if the level of ambient arsenic is unknown or exceeds OSHAís Permissible Exposure Limit (PEL) of 10 µg/m³ averaged over an 8-hour work day. Manufacturers and formulators must use a closed system (a sealed container) for mixing powdered inorganic arsenicals. Applicators may not eat, drink, or use tobacco products during the application process. Applicators must also wash thoroughly after skin contact with the pesticide.
  
  
• A Consumer Awareness Program was instituted requiring wood pressure-treaters to provide Consumer Information Sheets (CIS) to all lumber yards and other appropriate retailers. The information sheets give consumers instructions for handling treated wood products, e.g., using protective gloves, coveralls and face masks when sawing treated wood products.
  
  
• When registering new wood treatment products that contain CCAís, EPA requires registrants to create appropriate product labeling. Label instructions must specify that diluted solutions (0.5 - 10%) can only be used in closed, vacuum-pressure treating cylinders. By law, applicators must adhere to these instructions, which are intended to minimize worker exposure and environmental contamination.

4. What precautions should be taken when working with CCA-treated wood?

People working with CCA-treated wood should take a number of precautions, especially when sawdust is generated during handling/fabricating (these precautions are also listed on the Consumer Information Sheets):

• If sawdust accumulates on clothes, wash them separately from other household clothes before reuse. Avoid frequent or prolonged inhalation of sawdust from treated wood. Wear a dust mask when sawing and machining. Always wear goggles to protect your eyes from flying particles when power-sawing and machining.
  
  
• If possible, work outdoors to avoid indoor accumulation of sawdust from treated wood. Wash exposed body areas thoroughly with soap and water after working with CCA treated wood. Clean up thoroughly before eating, drinking or using tobacco products.

5. How should CCA-treated wood be disposed of?

CCA-treated wood may be thrown out with your ordinary trash as long as it was used in accordance with its intended use; it may also be buried. It should never be burned in open fires, stoves, fireplaces or residential boilers because toxic chemicals (such as arsenic) may be released as part of the smoke or remain in the ashes.

6. What action, if any, is EPA taking with CCA?

EPA is concerned that the Consumer Awareness Program has not ensured adequate availability of consumer information sheets on the safe use and handling of CCA-treated wood to consumers purchasing CCA-treated wood products. It is important that consumers are properly informed about the potential risks of working with CCA-treated lumber and how to take proper precautions to minimize those risks. To address this concern, EPA has arranged meetings with representatives of the wood preservative industry, registrants, major retailers, and public interest groups to encourage a constructive dialogue about how to effectively disseminate consumer information on the safe and proper use of CCA-treated wood.

EPA is also reassessing CCA as part of the Agencyís ongoing reregistration program. All pesticides first registered before November 1984 must undergo reregistration review to ensure that the data supporting their use meet current safety standards. As part of the reregistration review process, EPA is requiring registrants to submit additional data, including exposure data on wood treatment plant employees in order to better assess both human and environmental risks. EPA will be following the public participation process. There will be ample time for the public to comment on EPAís preliminary risk assessment (PRA). Once EPA completes its analyses, a Reregistration Eligibility Decision (RED) document will be issued that discusses the Agencyís findings and determines the continued uses of CCA.

7. Are there alternatives to using CCA -treated wood?

We realize that people may not want to use wood that has been treated with CCA. When selecting materials to use for decks, playgrounds, and other outdoor structures, consumers and communities should consider other factors in addition to the environment, such as cost, strength, and durability. There are a variety of alternatives to wood which are available for use in building structures, such as steel, recycled plastic, and concrete. In addition, EPA has registered over one hundred wood preservatives. If you are interested in finding preservatives that do not contain CCA, the California Department of Pesticide Regulation maintains a database of all pesticides registered by U.S. EPA: www.cdpr.ca.gov/docs/epa/epamenu.htm

source: www.epa.gov/pesticides/citizens/1file.htm 5ju01