College of Natural Resources

VIRGINIA TECH TACKLES RECYCLING OF TREATED LUMBER

BLACKSBURG, Feb. 25, 2002 -- The use of Chromated Copper Arsenic (CCA) treated wood has garnered a great deal of media attention over the past few years due to possible environmental and public safety concerns. "Another concern of this material has just recently gained attention from researchers, environmentalists, and government organizations," says Bob Smith, Virginia Tech's wood science and forest products associate professor in the College of Natural Resources. "That is the amount of CCA-treated wood being removed from people's homes and businesses and going to the nation's landfills."

Chromated Copper Arsenate, or CCA as it is commonly known, is the chemical compound used to pressure treat wood in order to resist attack from insects and decay. Smith explains that CCA can typically extend the life of wood in an outdoor environment by 30 to 40 years, thus saving the forest resource. “Since the early 1970's, CCA-treated wood has been used in approximately 80 percent of residential decks built in the United States,” Smith states.

The Environmental Protection Agency (EPA) and the wood preserving industry have voluntary removed the use of CCA for the treatment of wood in residential applications starting in January 2004. "This will end much of the media hype in the possible adverse side affects that CCA may produce because of the arsenic in its formulation," predicts Virginia Tech's wood science research assistant, Dave Bailey. "However, another concern is the amount of CCA-treated wood that could end up in landfills, especially from residential decks. Several researchers across the country have indicated that the amount of discarded CCA-treated wood reaching landfills is increasing and the tonnage is expected to rise substantially over the next several decades."

Research performed at Virginia Tech by the wood science and forest products department and the USDA Forest Service in Blacksburg, Va., have estimated that 1 billion board feet of CCA-treated wood is removed from residential decks and disposed primarily in landfills each year. Researchers from other universities have examined the possible leaching of CCA chemicals from wood in to unlined landfills, in hopes to determine if the rate of CCA chemical leachate will contaminant groundwater supplies. "This research could cause tighter regulations on the disposal of CCA-treated wood, and force the cost of disposing old decks to increase over the next few years," explains Smith.

To help reduce the burden on landfills and the demand of timber harvested for use by the wood industry, research is being conducted at the Brooks Forest Products Laboratory at Virginia Tech to extend the useful life of used CCA-treated material. This research has evaluated the amount of useful material that a deck contains, which instead of ending up in a landfill could be re-used.

'The research has calculated the amount of CCA-treated wood in a residential deck prior to demolition, and then determined the amount of usable CCA-treated material capable of being recycled," notes Bailey. "We have determined that over 80 percent of a discarded CCA-treated deck can be recovered into useable lumber such as 5/4” radius edge decking, 1”x6” boards and 2”x4”, 2”x6”, and 2”x8” lumber."

The physical and mechanical properties of the spent CCA-treated wood were also evaluated, to verify if this used material can perform to needed standards. The chemical retention levels (the amount of chemicals in the wood) of the used CCA-treated wood were similar to that of new CCA-treated wood found in many local home improvement centers. The strength of the old wood was also tested for comparison to new CCA-treated wood. The mechanical tests concluded that the strength properties of the discarded CCA-treated wood, destined for the landfill, were similar as new CCA-treated wood.

A variety of products were made from the used CCA-treated wood that could be easily produced by the deck owner, recycling companies, or local community organizations. Some of the products manufactured included different residential decks and deck components, such as railings, steps, or posts, trellises, trash can containers, pallets, and outdoor furniture such as chairs, benches, porch swings, and utility tables. The new guidelines regarding CCA for treated lumber does not affect wood currently in service. The EPA has suggested that the lumber be coated with a protective barrier if small children will be be exposed to the material. EPA recommends an oil-based transparent stain be applied on a regular basis. For more information on the ruling, visit the website (www.epa.gov/pesticides/factsheets/
cca_transition.htm).

Other products that could also be produced are landscaping components, such as planter boxes, raised flowerbeds, and retaining walls, material for parks and recreation facilities, such as sign posts, trial guides, and walking bridges. Many homeowners, community organizations, and governments could find the products made from used CCA-treated wood of equal quality compared to using new CCA-treated wood, and more cost effective.

Smith says, “We are currently evaluating what it would take for landfill managers to be willing to separate out the CCA-treated wood to sell or donate to parties that could recycle the materials into the useable products we have identified. Our research has helped to recognize the potential of discarded CCA-treated wood. It could certainly reduce the burden on landfills and lessen the demand of our forests by extending the life of current forest products.”