Neurophysiological studies of n-hexane polyneuropathy in the sandal factory

Among 93 cases of n-hexane polyneuropathy during a large outbreak in 1968 44 cases were studied by conventional electromyogram and measurement of peripheral nerve conduction velocities, both of which showed remarkable changes, especially in the lower rather than the upper extremities. Over a few years since 1968 most of the cases completely recovered, except for a few with mild sensory impairment, after providing for 100 ppm as the maximal allowable concentration of n-hexane and well equipped ventilation systems in individual houses. During the rescreening in 1981, before which there occurred only 2 patients, 21 cases with mild n-hexane polyneuropathy were clinically and neurophysiologically observed, revealing mostly the same features as in the previous outbreak in 1968. From these data it may be suggested that, in spite of less than 50 ppm of n-hexane concentration in a room, the sandal workers have suffered from neurotoxicity from this organic solvent and the appropriateness of the present regulation on n-hexane has to be reconsidered.