Exposure to fluorotrichloromethane (R-11).

Three volunteers were exposed to fluorotrichloromethane (R-11) under experimental conditions. Solvent levels in ambient and alveolar air, in blood and urine were measured. The mean concentration of R-11 in ambient air was 657 ml/m3. The average values of pulmonary retention and solvent levels in alveolar air and blood were 18.2%; 537 ml/m3 and 2.8 mg/l. Inter-individual variations of these parameters are negligible. R-11 concentrations in urine--in contrast to blood or alveolar air--depend on the dose taken up. After termination of exposure, R-11 concentrations in alveolar air and in blood are excreted with biological half-lives of seven and eleven minutes respectively during the first phase of elimination and with 1.8 and 1.0 h respectively during the second phase of elimination. Though ambient monitoring should, in most cases, be sufficient for the prevention of occupational diseases, the R-11 concentration in alveolar air seems to be the best parameter if biological monitoring seems to be necessary.