Recognized cases of amyotrophic lateral sclerosis in automobile workers by the Korean Epidemiologic Investigation Evaluation Committee.

Background: Three automobile company workers (one from Factory D and two from Factory E) were diagnosed with amyotrophic lateral sclerosis. The Korean Epidemiologic Investigation and Evaluation Committee determined that there is considerable scientific evidence supporting the association between amyotrophic lateral sclerosis and combined exposure to heavy metals, organic solvents, and diesel exhaust at the manufacturing plant. Case presentation: Patient A, who primarily engaged in engine processing and completed vehicle inspection at Factory D, was exposed to considerable amounts of heavy metals and organic solvents during medium- and large-engine processing, welding, and painting for over 23 years. Additionally, the patient was likely exposed to diesel exhaust for 33 years from forklifts delivering engines in the workshop. Patients B and C, who were responsible for engine assembly, ignition testing, and engine shipment at Factory E since around 1990, were exposed to lead and benzene from gasoline during engine ignition tests in the engine department for 15 and 16 years, respectively. They also encountered welding fumes, heavy metals, and organic solvents during welding and painting tasks. In addition, Patients B and C were continuously exposed to diesel exhaust from logistics vehicles on standby during work hours for 25 and 30 years, respectively. Conclusions: Although the specific level of lead exposure causing amyotrophic lateral sclerosis remains undetermined, numerous studies have consistently reported a relationship between lead exposure and disease development. Limited evidence suggests that exposure to organic solvents and diesel exhaust may increase the risk of amyotrophic lateral sclerosis. Therefore, the Epidemiological Investigation and Evaluation Committee concluded that the three patients' work-related exposure to heavy metals, organic solvents, and diesel exhaust is significantly supported by scientific evidence as a cause of their amyotrophic lateral sclerosis.