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Presidential Green Chemistry Challenge: 2002 Designing Greener Chemicals Award

Chemical Specialties, Inc. (now Viance)


ACQ Preserve®: The Environmentally Advanced Wood Preservative


Innovation and Benefits: ACQ Preserve® is an environmentally advanced wood preservative designed to replace chromated copper arsenate (CCA) wood preservatives, which have been phased out because of their toxicity. ACQ Preserve® will eliminate the use of 40 million pounds of arsenic and 64 million pounds of hexavalent chromium each year. It also avoids the potential risks associated with producing, transporting, using, and disposing of CCA wood preservatives and CCA-treated wood.

Summary of Technology: The pressure-treated wood industry is a $4 billion industry, producing approximately 7 billion board feet of preserved wood per year. More than 95 percent of the pressure-treated wood used in the United States is currently preserved with chromated copper arsenate (CCA). Approximately 150 million pounds of CCA wood preservatives were used in the production of pressure-treated wood in 2001, enough wood to build 435,000 homes. About 40 million pounds of arsenic and 64 million pounds of chromium(VI) were used to manufacture these CCA wood preservatives.

Over the past few years, scientists, environmentalists, and regulators have raised concerns regarding the risks posed by the arsenic that is either dislodged or leached from CCA-treated wood. A principal concern is the risk to children from contact with CCA-treated wood in playground equipment, picnic tables, and decks. This concern has led to increased demand for and use of alternatives to CCA.

Chemical Specialties, Inc. (CSI) developed its alkaline copper quaternary (ACQ) wood preservative as an environmentally advanced formula designed to replace the CCA industry standard. ACQ formulations combine a bivalent copper complex and a quaternary ammonium compound in a 2:1 ratio. The copper complex may be dissolved in either ethanolamine or ammonia. Carbon dioxide (CO2) is added to the formulation to improve stability and to aid in solubilization of the copper.

Replacing CCA with ACQ is one of the most dramatic pollution prevention advancements in recent history. Because more than 90 percent of the 44 million pounds of arsenic used in the United States each year is used to make CCA, replacing CCA with ACQ will virtually eliminate the use of arsenic in the United States. In addition, ACQ Preserve® will eliminate the use of 64 million pounds of chromium(VI). Further, ACQ avoids the potential risks associated with the production, transportation, use, and disposal of the arsenic and chromium(VI) contained in CCA wood preservatives and CCA-treated wood. In fact, ACQ does not generate any RCRA (i.e., Resource Conservation and Recovery Act) hazardous waste from production and treating facilities. The disposal issues associated with CCA-treated wood and ash residues associated with the burning of treated wood will also be avoided.

In 1996, CSI commercialized ACQ Preserve® in the United States. More than one million active pounds of ACQ wood preservatives were sold in the United States in 2001 for use by 13 wood treaters to produce over 100 million board feet of ACQ-preserved wood. In 2002, CSI plans to spend approximately $20 million to increase its production capacity for ACQ to over 50 million active pounds. By investing in ACQ technology, CSI has positioned itself and the wood preservation industry to transition away from arsenic-based wood preservatives to a new generation of preservative systems.

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