Ram N. Tewari
Director, Broward County Solid Waste Operations Division
Member, APWA Solid Waste Management Committee
Proper usage and safe disposal of chromium copper arsenate (CCA)-treated wood is an important, emerging, and ongoing issue. Recently, Beyond Pesticides (BP) and Communications Workers of America (CWA) filed a federal lawsuit aimed at halting the use of wood preservatives that are considered toxic, such as CCA, pentachlorophenol, and creosote. The above-mentioned chemicals are commonly used to prolong the useful life of wood by protecting it against biological (fungus and insects) deterioration. CCA is the most popular waterborne preservative added to wood, under heat and pressure, to prolong its useful life.
Wood products treated with CCA include lumber, timber, posts, and plywood. The treated wood is widely used in playground (park, school) equipment as well as in structures such as buildings, decks, boardwalks, fences, landscape, highways, utility poles, marine applications (docks, piers, bulkheads) and others.
There are two main issues with CCA-treated wood: its in-service use and its fate upon disposal. The possible adverse impacts from CCA-treated wood structures are soil and water contamination; its effects on workers; and its potential danger (toxic exposure) to children. Although the treated wood industry has reached an agreement with federal regulators to phase out most forms of CCA-treated wood by the end of next year, what about the CCA-treated wood in use and its disposal?
So, exactly what is CCA-treated wood (also known as pressure-treated wood)? In CCA, the arsenic is an insecticide; the copper is a fungicide and the chromium is a fixing agent. Though CCAâ€™s three metalsâ€”chromium, copper, and arsenicâ€”are of major importance from an environmental point of view, arsenic, a known carcinogen, is the most problematic metal from a disposal point of view. Research has shown that arsenic may have a toxic effect on plants or may accumulate in plants, thereby entering the animal and food chains. Because of its carcinogenicity, U.S. Environmental Protection Agency (USEPA) standards for drinking water call for an arsenic content of no more than 10 parts per billion.
The objective is to get rid of CCA-treated wood in a safe manner so that it does not create any environmental problem. There are only three disposal sinks available to usâ€”air, water, and land. The disposal needs to be done in a manner that it does not release toxins and at the same time protects these available environmental sinks. From a waste management point of view, all three disposal methodsâ€”landfilling, recycling, and burningâ€”present some serious environmental and liability concerns, and presently no one knows the best disposal option. Because of the arsenic leaching from CCA-treated wood, the wood must be identified and removed from the waste stream before disposal. Discarded CCA-treated wood, among other materials, is exempt (Code of Federal Regulations Part 261.4) from the regulations and most states handle treated wood just like other wood. However, environmental concerns remain and should be handled accordingly by all stakeholders.
American utilities and railroads discard more than 2.6 million telephone poles (weighing about half a ton each) and more than 14.3 million crossties annually. A 1998 USEPA study estimated that 136 million tons of building-related construction and demolition (C&D) debris were generated in 1996, with wood being the largest component. The report further mentions that there are approximately 500 wood processing/recycling facilities which derive wood from the C&D debris stream. In the 1970s, about 16 percent of treated wood products were treated with CCA; by 1996, CCA was used to treat almost 80 percent of all treated wood products. Wood is the largest component of C&D debris by volume and CCA-treated wood has a large presence in the C&D waste stream. Given that the average service life of a CCA-treated wood is about 25 years, the quantity of CCA-treated wood disposed through the C&D waste stream is forecasted to grow rapidly (the year 2010 volume will equal five times the year 1995 volume).
What is to be done with the used/discarded CCA-treated wood in the C&D debris? What is the proper recycling and/or disposal procedure? The material must go somewhereâ€”but where? The treated wood presents recycling difficulties as well. No one knows what the safest disposal of used CCA-treated wood is; which method will not cause soil, air, or groundwater problems. Can the CCA-treated wood be landfilled (lined or unlined)? Can it be safely (without soil or groundwater contamination) recycled as mulch? Can the wood be burned/incinerated as a fuel in a cogeneration or waste-to-energy plant with the municipal solid waste (MSW)? And if it can be burned, then is there a problem with the resultant ash? Is the ash hazardous? Can it be spread on land or must it be disposed of in a Class C or D (double-lined) landfill? Why do we have to be so concerned with the end-of-life disposal? Is it safe? What about public health, safety, welfare, and environmental (soil, land, groundwater, surface water, air) concerns? There are a lot of questions on this waste issue and, at this point, few answers are known.
The waste industry realized the significance and seriousness of this problem. Waste Age, the business magazine for the waste industryâ€™s professionals, produced a special report on CCA-treated wood entitled â€œPoison Woodâ€ in their August 2001 issue. Various organizations have studied and published their findings in their trade journals as wellâ€”MSW Management, C&D Debris Recycling, World Wastes, Waste Management and Research, and others. The Solid Waste Association of North America (SWANA) conducted a study entitled â€œUrban Wood Wasteâ€ and organized a conference on the topic of â€œUrban Wood: A Waste or a Resource.â€ The Florida Center for Solid and Hazardous Waste Management (FCSHWM) has been sponsoring and supporting research since 1996 on this very significant and timely topic. In Florida, CCA-treated wood disposal is a primary concern because of high rainfall, high groundwater tables, shallow wells, unlined C&D landfills, recycling/processing facilities, and other high-rise landfills.
The mission of FCSHWM (www.floridacenter.org) is to coordinate and engage in research, training, and service activities relating to solid and hazardous waste management issues. Several of the questions on CCA have become the basis of FCSHWMâ€™s sponsored research at the University of Miami (UM), a private university; at the University of Florida (UF) at Gainesville, a public university; and with the creation of a UM/UF CCA research team. Their research (for more information on research reports, visit www.ccaresearch.org) has primarily focused on the adverse environmental effects of discarded CCA-treated wood because its disposal is a problem and will continue to be a problem in the future. Landfilling and combustion of this wood have fallen short as environmentally safe methods for ultimate disposal. Given the drawbacks associated with the current disposal and recycling methods, the UM/UF studies continue to focus on the potential environmental risks, arsenic and chromium speciation, evaluation of detection/identification and sorting/separation technologies, disposal options for CCA-treated wood, and possible alternative chemicals for wood preservation.
Convincing studies and research in Florida show that CCA-treated wood may create a serious disposal problem for local and state governments, the largest consumers of this product. As members of the public works team, it is incumbent upon us to have an appropriate perspective and insight about CCA-treated wood and to learn from the spectrum of opinions held by the various stakeholdersâ€”solid waste managers, recyclers, regulators, researchers, manufacturers, consumers, professional organizations, and the public. It appears that there is a greater awareness of this growing disposal problem, but there are vast differences among state and local environmental agencies in the level of knowledge with respect to disposal options and appropriate permitting process. Local governments may have to pay more attention to this issue because they are the big users of treated woodâ€”in their parks, boardwalks, decks, playgrounds, schools, landscaping, buildings, and other areas. As consumer awareness, regulatory restrictions, and liability cases increase, we have to do more with less. APWA can take a lead to create a nationwide forum for identifying issues, concerns, best-management-practice knowledge, and information exchanges, and for developing goals and guidelines in regard to CCA-treated wood.
Ram N. Tewari is a member of the APWA Solid Waste Management Committee, a member of the ASCE/EWRI Solid Waste Engineering Committee, and a member of the Technical Awareness Group (TAG) for CCA-treated wood research. He can be reached at (954) 577-2394 or by e-mail at email@example.com.