Fixation and leaching characteristics of CCA-treated Douglas-fir was evaluated using the expressate method and the AWPA E11-97 leaching procedure. CCA fixation, as monitored by the chromium reduction, was much faster in heartwood than in sapwood; however, copper and arsenic fixation in heartwood appeared to be incomplete regardless of the extension of fixation time. This poor fixation of copper and arsenic in heartwood samples has been proved by the leaching tests. Based on the results, we may conclude that CCA is not appropriate preservative for Douglas-fir heartwood due to the poor fixation quality along with well-known poor treatability of CCA against refractory species. However, the use of CCA-treated Douglas-fir products in environmentally sensitive areas may be restricted or banned, if this species should be treated with CCA inevitably like our situation.

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