Since chromated copper arsenate (CCA) was technically introduced into Japan in 1963, CCA was used for extending service life of various wood commodities, especially sill plates (dodai) in Japanese houses. However, the problem on the disposal of CCA-treated wood waste became public and related industry concern, and questionnaire survey conducted by Japan Wood Preservers’ Industry Association indicated that Japanese treatment plants could not meet the new strict criterion (tolerance limit) of arsenic (<0.1 mg/) in the discharged water in the revise regulation, Water Pollution Prevention Act in 1995.
In addition, on the basis f the fact that alternatives to CCA were domestically standardized in 1995 (JUS K 1570, 1995), Japanese wood preserving industry came to a self-imposed decision to restrict the use of CCA. Alternatives actually appeared in the marketplace in 1991, and a drastic increase in their use has been prominent since 1996.
They account for over 85% of total amount of wood produced by pressure-impregnation with preservatives.
Keywords: Disposal of CCA-treated wood, incineration, water pollution prevention act, alternatives to CCA