From epidemiological studies the carcinogenic potency factor (slope factor) for benzene was estimated by the EPA in 1988 to be 0.03 [mg/kg-day). On the basis of this estimate, what would be the hypothetical yearly increase in the cancer incidence of the U.S. population from benzene in gasoline due to exposure during filling of gasoline in motor vehicles? Use the following assumptions:   30 million car owners fill the gasoline tank twice a week at self-service stations. Filling averages 3 minutes. The concentration of benzene in the breathing zone is 0.5 ppm. The volume of inhaled air is 14 L/min. The degree of absorption of benzene in the lungs is 50 percent. The annual cancer incidence for the entire U.S. population can be estimated to be about 1 million cases.

From epidemiological studies the carcinogenic potency factor (slope factor) for benzene was estimated by the EPA in 1988 to be 0.03 [mg/kg-day). On the basis of this estimate, what would be the hypothetical yearly increase in the cancer incidence of the U.S. population from benzene in gasoline due to exposure during filling of gasoline in motor vehicles? Use the following assumptions:

• 30 million car owners fill the gasoline tank twice a week at self-service stations.
• Filling averages 3 minutes.
• The concentration of benzene in the breathing zone is 0.5 ppm.
• The volume of inhaled air is 14 L/min.
• The degree of absorption of benzene in the lungs is 50 percent.
• The annual cancer incidence for the entire U.S. population can be estimated to be about 1 million cases.