Inorganic mercury intoxication reminiscent of amyotrophic lateral sclerosis

Two employees in a mercuric oxide manufacturing plant developed neurologic changes not previously reported from the exposure to inorganic mercury or elemental mercury vapor. The symptoms, physical findings and laboratory studies resembled those found in amyotrophic lateral sclerosis (ALS) and organic mercury intoxication. Nineteen employees are reported who precipitously developed signs and symptoms which may be regarded to be the early onset of a symptom complex of mercury intoxication that would likely have progressed to the ALS-like syndrome if the progression had not been interrupted by removal of the individuals from exposure to mercury. All symptoms, signs, and laboratory findings returned completely to normal after approximately three months in a mercury free work environment.