Early uses of commercially produced benzene varied widely.
At the turn of the century, a process for decaffeinating coffee was invented that utilized benzene as a primary tool. Benzene-driven coffee decaffeination led to the production of Sanka, a very popular instant decaffeinated coffee throughout Europe and the United States. During the early 20th century, European and North American gentlemen were also know to use benzene as a splash of aftershave, owing to its sweet, pleasant, but not overly flowery, scent. However, the primary use of large quantities of benzene prior to around 1920 was as an industrial degreaser.
As concerns about benzene’s potential toxicity arose mid-century, most non-industrial uses like coffee and aftershave were discontinued. But beginning in the 1950s, the nascent polymer industry began drastically increasing the manufacturing demand for larger and larger volumes of benzene as they discovered it could be used as an intermediate ingredient for many of the chemicals necessary for polymer and plastics production. This dramatic rise in demand could not be met by the standard coal distillation processes in place prior to this point in history. Benzene production shifted to extracting the hydrocarbon from petroleum on a much larger, much more productive scale instead via steam cracking and catalytic reformation. Benzene also proved to be a highly valuable gasoline additive, producing higher octane ratings in automobile fuels.
We are still producing benzene via petroleum and using it as an intermediate in the production of several other chemicals which feed into the plastics, polymers, resin, & synthetic fiber industries. The primary chemicals produced with benzene include ethylbenzene, cumene, and cyclohexane. Around half of all the benzene commercially produced today winds up as ethylbenzene, which will eventually be made into an assortment of plastics and polymers like polystyrene. One fifth of benzene production currently becomes cumene, which is a major ingredient in many resins and adhesives, and one tenth makes its way into nylon fibers as cyclohexane.
Benzene is still found
in gasoline and accounts for much of the signature odor of a service station, however, in the United States, the EPA now limits benzene to a 0.62% concentration of automobile fuels. In other locations around the world, benzene remains a much more concentrated additive and therefore a significant avenue for increased exposure risk.
Benzene exposure typically takes place via inhalation, ingestion or dermal absorption. Large and long-term exposure most commonly occurs at workplaces where benzene is produced or utilized. A smaller percentage of unhealthful exposure takes place via consumer products.
Inhalation is the most common long-term exposure avenue. The most common avenue of inhalation exposure to benzene is via cigarette smoke - first or second hand. About half of all benzene exposure in the United States happens via inhalation of cigarette smoke, as the one smoking or via second hand exposure.
Dermal, or topical, exposure
is less common and less severe in smaller quantities because benzene evaporates off the skin so quickly. It may still cause tissue irritation, redness, or blistering, but much less benzene enters the bloodstream in this fashion. Anyone experiencing dermal exposure to benzene should immediately wash the affected area with soap and water. Also, remove and wash any clothing that came in contact with the liquid benzene.
Ingestion and high levels of immediate inhalation
result in acute benzene poisoning which creates significant central nervous system impairment. Dizziness, drowsiness, headaches, confusion, tremors, a feeling of intoxication, and loss of consciousness may occur. If ingested, individuals may experience vomiting, convulsions, and a dangerously increased heart rate. Anyone experiencing acute benzene poisoning via inhalation must be moved to fresh air immediately and should receive emergency medical attention. For ingestion exposures, seek medical help immediately and do not induce vomiting.
Certain jobs typically experience elevated benzene exposure risk.
Painters, printers, oil refineries (drivers, drillers, service personnel), auto mechanics, service station employees, rubber industry workers, shoe manufacturers, and steel workers are all much more likely to suffer from cytotoxic levels of benzene exposure than other fields. Widespread studies across populations of workers in oil refineries, chemical production facilities, and shoe manufacturers demonstrate significantly elevated leukemia rates, especially Acute Myeloid Leukemia. Regular benzene exposure for a year or more creates genotoxicity in the bone marrow and abnormal blood counts, priming the body for development of assorted blood production-related cancers like leukemia.
FOR THE AVERAGE AMERICAN
limiting benzene exposure begins with quitting smoking and encouraging any individuals one lives with to quit as well. Also, caution with fueling your vehicles is required to limit skin contact with gasoline. Individuals can also strive to eliminate the use of solvents, paints, pesticides, or other chemicals containing benzene in their homes and workplaces. If exposure to benzene is part of an individual’s daily work, they should speak to their employers about minimizing the use of benzene products or at a minimum, containing those products safely in order to make sure exposure levels are below required WHO and OSHA limits. All employees working in environments with a high risk of potential benzene exposure should also use personal protective equipment when working with benzene.