[Assessment of occupational exposure to p-tert-butylphenol in synthetic resin factories].

Two cases of occupational vitiligo were observed in a resin factory where p-tert-butylphenol (PTBP) has been used as a starting material or an intermediate of synthetic resin. In this resin factory (A shop) and another resin factory (B shop), occupational exposure to PTBP was assessed in workers charging this chemical into the reaction vessel by means of a gas-chromatographic measurement of the environmental PTBP concentration and their urinary PTBP excretion. Assessment in A shop was made after the working condition was partly improved. Geometrical mean values of 8 h-time-weighted-average (8 h-TWA) of PTBP in air near the charger's breathing zone (personal air) were 0.215 mg/m3 in A shop and 2.12 mg/m3 in B shop. Continuous measurements of PTBP concentration in some stationary air of the shops showed that the maximum environmental PTBP values occurred during charging. Urinary PTBP concentration was increased to the maximum values 2 to 4 h after charging of this chemical and then rapidly decreased. Biological half-lives of urinary PTBP were estimated as 4.4 h in A shop and 4.8 h in B shop. The urinary PTBP concentration was correlated to 8 h-TWA of PTBP in the personal air. In particular, PTBP in urine collected at the end of the shift showed an excellent correlation to PTBP in the personal air (r = 0.84, n = 9, A shop; r = 0.88, n = 11, B shop). These results indicate that biological monitoring using urinary PTBP concentration is a suitable means of assessing exposure to this alkylphenol and the urine collected at the end of shift is the best sample for monitoring. In addition, the present environmental and urinary PTBP values were compared with those described in the literature and the relation of the occupational vitiligo with PTBP exposure is discussed.