Subjective Estimation of Toluene Exposures: A Calibration Study of Industrial Hygienists

Abstract The ability of a group of industrial hygienists to predict exposures based on experience and professional judgment was evaluated. Eight-hour time-weighted average toluene exposures for a group of batch chemical process workers were measured over a three-week period. These 134 personal measurements comprised the empirical distribution of exposures. Twenty-four industrial hygienists with expertise in assessing exposures in batch chemical processing operations were randomly selected for the study after a formal nomination process. Each industrial hygienist participated in a three-hour personal interview which followed a standard protocol. During the interview, each expert reviewed chemical process information and then subjectively assessed the distribution of exposures and the average exposure among the workers. After limited historical exposure data were presented, elicitations of the subjective distribution and the average exposure were repeated. Industrial hygienists estimated the average exposur...