In connection with an investigation of state-owned buildings for wood preservatives, human monitoring on pentachlorophenol (PCP) was performed on 484 subjects from Northern Bavaria and 299 persons from Southern Bavaria during the period November 1994 to October 1995. Altogether, a similar pattern of concentrations resulted, the 95th percentile amounting to 15 (Northern Bavaria) and 20 micrograms PCP/l blood plasma (Southern Bavaria), respectively. An inquiry of the exposure conditions of the subjects studied in Southern Bavaria revealed that 28% had been exposed to wood containing 5-100 mg PCP/kg (slightly elevated) and 61 % to wood with > 100 mg PCP/kg (definitely treated). One-third each of the subjects had been exposed to dust containing 5 mg PCP/kg (normal), 5-10 mg/kg (slightly elevated) and > 10 mg/kg (clearly elevated), respectively. The mean exposure period was approx. 10 years with a mean daily stay of 8 hrs. No statistically significant correlations were found between the human monitoring data and PCP concentrations in wood or dust or the stated complaints.