Weaver, NK; Gibson, RL; Smith, CW
In reviewing occupational exposure to benzene (71432) in the petroleum and chemical industry, it was noted that almost all of the benzene produced was used as starting material for the manufacture of other chemical products such as ethylbenzene, cumene, cyclohexane, nitrobenzene, dodecylbenzene, alkylbenzene, chlorobenzenes, and maleic-anhydride. Analytical methods for measurement of benzene, important for obtaining accurate assessments of exposure levels, have been refined so that the minimum level of detection was currently 3 parts per billion, using infrared absorption from carbon-monoxide and carbon-dioxide lasers. Exposure could also be detected by measuring excretion products of benzene in the urine of workers. In the petroleum industry, production, refining, transportation, and marketing were listed as areas of exposure. Levels of exposure varied between 0.01 and 2.9 parts per million (ppm), and the highest exposure occurred during the loading at bulk marketing terminals. In the petrochemical industry, where essentially all benzene was being used in closed system operations, most of the benzene exposure has occurred during the use of solvents containing benzene. Printing and shoe manufacturing plants were mentioned as examples of industries where exposure levels of up to 1000ppm been reported. The authors conclude that, under normal conditions, the current level of exposure will not result in deleterious health effects.