Complex chlorinated hydrocarbons: occupational exposure in the sawmill industry.

Exposure to chlorophenols occurs in the vicinity of the lumber treatment area in sawmills and in subsequent work phases where treated lumber is handled. Measurements from several countries indicate that the concentration of chlorophenols in the workroom air is generally below 0.5 mg/m3, the occupational exposure limit of chlorophenols in many countries. Inhalation usually leads to relatively low concentrations of chlorophenols in urine of exposed workers. Frequent skin contact with chlorophenol solution or with freshly treated lumber can produce urine concentrations 10-100 times higher than among those with inhalatory exposure only. In addition to chlorophenols, exposure to toxic polychlorinated dibenzodioxins and dibenzofurans may occur in some tasks carried out in sawmills. Jobs with potentially heavy exposure include the treatment of dipping-vat sludge and processes involving heating of chlorophenols, such as burning of treated waste wood and welding of metal structures contaminated by chlorophenols.