Chromated Copper Arsenate is used in a wide variety of wood products such as: Poles, posts, piles, timbers and plywood. CCA-C is a pressure-treatment preservative for wood products which have been specified in various applications for over 70 years. CCA-C is effective for wood that may be used in contact with water, soil, concrete or masonry, subject to period wetting, or exposed to moisture or high humidity.
As of December 31, 2003, CCA treated wood products were listed for production only in agricultural, commercial, industrial, marine and limited residential applications.
The Environmental Protection Agency advised that CCA-treated timber products already in use pose no significant threat to health if applied properly, and the current restrictions are precautionary. The more recent research shows that CCA does not pose a risk: This includes a biomonitoring study by K. Lew, S Gabos, JP Acker, and Le XC, University of Albert, Edmonton, Canada (May 2010), which concludes that there was no significant difference in the arsenic concentrations and convergence, distributions in urine and saliva samples of children playing on CCA-treated and non-CCA-treated playground. When used as recommended, CCA-treated wood is harmless to people, plants and animals. Its use provides decades of service and an effective solution to prevent decay and termite attack. CCA-C-treated is for use only in the pressure treatment of certain commodity building materials used in commercial, industrial and agricultural and is not approved for most residential applications.
Examples of CCA Usage
CCA-treated timber is still in widespread use in many countries and remains an economical option for conferring durability to perishable timbers such as pine and other soft wood species. The CCA-C preservative will continue to be used in the US and countries across the world in a wide variety of commercial and industrial applications such as poles, piling, retaining structures, cooling tower material, and many others types of projects.
The following list is taken from the American Wood Preservers’ Association book of standards and its intent is to illustrate examples of the type of wood projects that may be treated with CCA-C. While this list is not exhaustive, it does provide some examples of specific uses.
- Lumber and for Salt Water Use – Bulkheads, Aquaculture timbers, Mariculture lumber and timber, Marine lumber and timbers
- Pilings – Foundation piles, Marine piles (salt or brackish) subject to marine borers, Land or fresh water
- Poles – Building poles, Utility poles, and Agricultural posts and poles
- Plywood – Building construction, Roof, Sub-floor, Decking and Ground contact
Painting and Staining or Natural Weathering
- High quality oil and latex based paints and stains or water-repellant coatings can be applied to improve weathering performance.
- Left uncoated or with a clear water-repellent coating, CCA-C treated wood products will weather to a natural gray color.
- It is important to ensure that the treated wood is dry and clean prior to applying any coating.
Nails, Fasteners and Fittings
Hot Dipped Galvanized (ASTM A-153) or Stainless Steel fasteners and fittings are recommended. Stainless Steel fasteners are recommended for marine and applications or areas that are constantly wet. Anti-corrosion coatings applied to fasteners and fittings in contact with treated wood may enhance long-term performance. We always recommend that current building codes be consulted for up-to-date lists of approved fasteners.
Disposal of large quantities of CCA-treated wastes or spent timber at the end of its lifecycle has been traditionally through controlled landfill sites. Such sites are lined to make them impervious in order to prevent losses to the water table and they are covered to prevent rainfall washing out any contained potential toxicants. These controlled sites handle a range of waste materials potentially more noxious than that posed by CCA-treated timber, e.g. paints, car batteries, etc. Today, landfill sites are becoming more uncommon and disposal of waste materials is becoming economically unattractive. The wood preservation and timber industries are therefore researching better ways of dealing with waste treated timber, including CCA-treated material. Go to WWPI (Western Wood Preservers Institute) website at www.WWPInstitute.org for a current list of approved landfill sites where Treated Wood Waste is accepted.
Handling and Safety Information
CCA-C pressure treated wood is easy to work with, requiring no special precautions other than routine wood working safety procedures. When sawing, drilling, ripping, sanding or manufacturing, the following safety precautions should be followed:
- Gloves should be worn to protect against splinters and abrasions
- Dust masks should be worn when sawing, drilling, ripping, sanding or manufacturing any wood to reduce the inhalation of wood dusts
- Appropriate eye protection should be worn to reduce the potential for eye injury from wood dust or particles and flying debris during machining and construction
- Wash thoroughly with mild soap and water after working with any treated wood product
- Wood scraps should be disposed of by burial in accordance with applicable federal, state, and local regulations
DO NOT BURN TREATED WOOD PRODUCTS