The fungicidal substance pentachlorophenol (PCP) had been used commonly for wood protection and leather impregnation in Germany until 1989, when this substance was prohibited by law. Hence, the body burden in the general population in Germany has been steadily declining. The reference values (95th percentiles) in blood plasma decreased from 20 micrograms PCP/l in 1991 to 12 micrograms/l in 1996. In 1998 the current exposure in a large residential population was investigated. 623 persons with an average age of 34.6 years (0-62 years) were investigated. For all of them there was neither evidence of occupational contact with PCP nor of the presence of PCP in the residential indoor environment. The mean PCP concentration in the plasma samples was 2.4 +/- 3.9 micrograms/l, the median 1.7 micrograms/l, and the 95th percentile 6.1 micrograms/l, the maximum value was 59.3 micrograms/l. In children and adolescents higher median and 95th percentiles were obtained than in adults (median 2.5 vs. 1.5 micrograms/l and 95th percentile 7.7 vs. 5.9 micrograms/l). All values above 20 micrograms/l were checked again individually: relationships with the level of PCP in household dust could not be detected. In one family leather clothing containing PCP, however, was found to be the cause of unusually high PCP values in the blood. Our investigations confirm a trend observed in recent years: exposure to PCP in the population in Germany decreases steadily and leads to an actualized reference value of 6.1 micrograms PCP/l plasma. In individual cases, however, greatly increased PCP levels in blood can still occur today, for example due to leather clothing treated with PCP.