Neurotoxicity associated with occupational exposure to acetone, methyl ethyl ketone, and cyclohexanone

The neurotoxic effects of acetone, methyl ethyl ketone (MEK), and cyclohexanone on Romanian workers and the impact of those effects on industry environmental standards have been controversial subjects. To scientifically substantiate the standards, a study was conducted on three groups of workers to determine the changes induced by ketone solvents on the central and peripheral nervous systems. Groups of exposed workers and matched controls were studied for each solvent: acetone, 71 exposed and 86 controls from a coin printing factory; MEK, 41 exposed and 63 controls from a cable factory; and cyclohexanone, 75 exposed and 85 controls from a furniture factory. The subjects' mean age was 36 years. The mean length of exposure was 14 years. Study participants completed a questionnaire, responded to questions about alcohol consumption, submitted to a clinical examination, submitted samples for identification of biological exposure markers, and underwent motor nerve conduction velocity and neurobehavioral tests. Results showed that workers exposed to acetone were most affected in terms of human performance and evidence of neurotoxicity, followed by workers exposed to MEK and workers exposed to cyclohexanone. On the basis of the results, it was proposed that the 6-hr permissible exposure limits for acetone, MEK, and cyclohexanone be reduced to less than 500, 200, and 150 mg/m3, respectively.