An outbreak of N-hexane induced polyneuropathy among press proofing workers in Taipei

The objective of this study was to determine the prevalence and the etiology of polyneuropathy observed among press proofing workers in Taipei. Neurological examinations of 59 workers, from 16 press proofing factories, were conducted. Fifty-four of those workers subsequently underwent studies of nerve conduction velocities. Samples of bulk solvent from the involved factories were analyzed for their contents using gas chromatography. Fifteen (25%) of the study group were found to have polyneuropathy. All 15 patients with polyneuropathy were from factories in which solvents containing n-hexane were regularly used, and there was a significant association between n-hexane concentration in the bulk samples and prevalence of polyneuropathy. The air concentration of n-hexane in one factory in which all six employees developed polyneuropathy was 190 ppm. Workers who were exposed to n-hexane at air levels of less than 100 ppm but who frequently worked overtime showed a significant slowing of motor nerve conduction velocities on median, ulnar, and peroneal nerves. Of 13 workers who regularly slept in the factory, 12 (92%) had polyneuropathy compared to three (7%) of 46 workers who did not sleep in the factory. The outbreak of polyneuropathy was attributed to a combination of the use of solvents with high contents of n-hexane, poor ventilation, and the practice of sleeping in the factories between shifts.