Mutagenic compounds in wood-chip drying fumes.

The mutagenicity of fumes from the heating of freshly cut spruce and birch chips was measured with Salmonella typhimurium strains TA98, TA100 and TA102. The bacteria were exposed directly and indirectly to the fumes. Wood chips were also extracted with solvents. No mutagenicity was found in wood extracts or the fume samples measured indirectly. The results from the direct exposure experiments indicate, however, that drying spruce and birch at 170 degrees C emits mutagenic compounds, which are short-lived and/or volatile. One of the mutagenic compounds of the fumes is probably 3-carene. These results are consistent with previous epidemiological findings, which suggest that these fumes are carcinogenic.