CCA wood preservative: Trust with destiny

IRG/WP 19-30731

S Kumar

This paper traces the history of Copper-Chrome-Arsenic (CCA) and its current status in India and worldwide. CCA was invented as ASCU at the Forest Research Institute, Dehra Dun in 1933 by Dr. Sonti Kamesam. Although its efficacy was doubted by the British colonial rulers resulting in several hiccups at home, the patent rights were purchased by US Bell Telephone Co. and it was adopted by the US wood industry. Indian wood industry never took up preservation of wood seriously. Original CCA composition was changed to yield various oxide based formulations more due to commercial aspects rather than any technical advantages. Many countries around the world adopted it and CCA became the most used wood preservative among the water-borne preservatives. Commercial aspects started playing roles to push out CCA, as pesticide industry was striving hard to recover money spent on new molecules and formulations and wood preservation industry held a huge potential. This culminated in hate ‘arsenic campaign’ and media played a major role in the same. Despite the fact that several studies could not reveal any positive report for ill effect of CCA treated wood on humans (even children) and animals, Environmental Protection Agency of USA succumbed to media pressures advising wood-treatment industry to move away from CCA. Some wood scientists in USA do feel that there is no virtual replacement for CCA in performance as well as cost-effectiveness. Technology has become available to process CCA treated wood to reuse residual wood/chemicals effectively. This can make more wood available negating processing costs. The substitutes currently available are not only less effective and more costly; these may subsequently be found to pose different types of problems as has been observed in TCMTB and Chloripyrifos. If the current attitude towards effective formulations continues to make room for less effective new molecules/formulations, the requirement of wood as well as preservatives will increase over time resulting in diversion of farm land to tree plantations, which may have serious implications/repercussions.

Keywords: CCA, Arsenic, Chloripyrifos, TCMTB, EPA, health hazards, playground equipment, safety

Conference: 19-05-12/16 Quebec City, Canada

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