Ponderosa pine match stick specimens were impregnated with chromated-c
opperarsenate preservative (CCA) and the treated wood subjected to, st
oring under ambient conditions, oven drying or steam treatment. The sa
mples were analyzed by electron spin resonance spectrometry (ESR). Acc
elerated fixation of CCA by steam treatment initially produced a stron
g chromium(V) ESR signal, which quickly decreased. Complete reduction
of Cr(VI) to Cr(III) was achieved in 2 hours by steaming. Samples stor
ed under ambient conditions still exhibited a moderately strong chromi
um(V) signal after 44 days. Oven drying of the CCA-treated samples for
four days, failed to convert all of the chromium(V) intermediate to t
he trivalent form. Leaching of CCA-treated samples, confirmed that fix
ation was best achieved with the steam treatment. Oven drying caused t
he samples to leach large amounts of copper and smaller amounts of chr
omium and arsenic.