n-Hexane

Abstract

Evaluates the risks to human health and the environment posed by n-hexane, a chemical isolated from natural gas and crude oil and used in food processing to extract vegetable oil from beans, nuts, and seeds. n-Hexane is also used as a solvent, a cleaning agent, in the rubber industry, and in the manufacture of pharmaceuticals. The opening sections review what is known about the behaviour of this highly volatile chemical in the environment and its metabolic fate in experimental animals and in the human body. A review of investigations in experimental animals and in vitro test systems concentrates on testicular lesions and neurotoxicity as the principal effects of repeated exposure to n-hexane. Studies have also shown that neurotoxicity induced by n-hexane is enhanced by co-exposure to methyl ethyl ketone, methyl isobutyl ketone, and lead acetate; co-exposure to toluene decreases the neurotoxic effects of n-hexane. These findings are further supported by observations in humans, which draw upon several reports of peripheral neuropathy in workers exposed to n-hexane and in abusers of glues or solvents containing this chemical. The report notes that the majority of occupational cases have occurred in poorly ventilated small industries. While concluding that n-hexane is not likely to present a hazard to either the general population or the environment, the report stresses the need for precautions in the occupational setting, including the use of suitably designed work processes and engineering controls for reducing atmospheric levels below the recommended occupational exposure limits. The book further recommends the use of protective clothing and the ready availability of respiratory protection for use in enclosed spaces and in emergencies