Benzene History
“A large number of Americans could be exposed to measurable concentrations of benzene in the ambient air, and while these ambient levels are substantially lower than those affecting workers, there is reason to believe that ambient exposures may constitute a cancer risk and should be reduced.” - Douglas Costle, Environmental Protection Agency Administrator, May 31, 1977.
It has been known for a long time that Benzene has caused cancer. This dates back to the early 1900’s when the first strong connections were made. The first major industrial use of benzene was in the rubber industry when they used the carcinogen as a solvent before World War I.
Review articles as early as 1926 mentioned reports of fatal cases of benzene poisoning. In 1909, there were three girls in Maryland that had been exposed to benzene for a period of 4-5 months and died within 1 month. The girls’ exposure to benzene came from vapors of a commercial grade of benzene that was used as a rubber solvent in sealing tin cans. In 1920, chronic benzene poisoning was reported in two men who had been spreading balloon fabric with rubber. The reports were made in England by Legge, which provided the first measurements of benzene levels in workroom atmospheres for workers exposed on a chronic basis determined by a chemist. Legge concluded that though the range of benzene exposure levels were measured to range from 210-800 ppm, the fact that the spreading room contained such poor ventilation could have made the concentration as high as 16,800 ppm. Cases of chronic benzene poisoning continued to increase in number due to the use of benzene beginning to be used in a wide array of industries. These reports of benzene poisoning also began to appear in more literature and investigations resulted due to the serious and deadly effects benzene poisoning was having on those exposed. As more and more people learned of the dangers of exposure to benzene, eventually it began to become replaced with other solvents.
During the WWI, toluene in the manufacture of explosives increased the production of benzene greatly. Soon benzene was being used readily as a solvent in artificial leather, rubber goods, and rotogravure printing industries, and as a starting material in organic synthesis. The expanded use of benzene in industry following WWI found that the number of reports of chronic benzene poisoning of workers began surfacing in literature. The growing knowledge of the hazardous conditions associated with benzene due to the seriousness of the health effects that resulted, led to a gradual substitution of benzene with other solvents. Thus, there was soon a noticeable decrease in the number of benzene poisoning cases reported. In 1967, just about 800 million gallons of benzene was produced in the U.S., and by 1969, it had increased to 1,185 million gallons with about 16% of the production coming from coal.
Benzene mainly comes from the petroleum industry today as it is produced as a petrochemical from paraffinic hydrocarbons. There are estimates that more than 3 million workers are still potentially exposed to benzene every year, and industries and processes using benzene include coke and gas, chemical, printing and lithography, paint, rubber, dry cleaning, adhesives, petroleum, and coatings. Chemical laboratories use benzene as a solvent and a reactant in many various chemical applications. Benzene is one of the largest volume chemicals produced in the U.S. used in many different chemical and industrial processes and in automobile gasoline.
Benzene is responsible for emitting as much as 260 million pounds into the atmosphere of the 11 billion pound manufactured in 1976. The benzene emissions are the result of chemical manufacturing facilities, petroleum refineries, gasoline storage handling and marketing facilities, coke ovens, and automobiles.
The EPA has put benzene on the lists of hazardous air pollutants based on scientific reports that strongly suggest human exposed to benzene can suffer from leukemia. Listing benzene is the first step to regulate the organic chemical under the Clean Air Act.
OSHA is trying to reduce the amount of allowable workplace benzene exposure levels.