Cognitive impairment and sensory loss associated with chronic low-level ethylene oxide exposure.

A 29-year-old college graduate worked for 10 years adjacent to an ethylene oxide (EtO) chemical sterilizer. When the sterilizer was closed, levels of EtO in the air around the sterilizer were 4.2 ppm (OSHA maximum level, 1 ppm). Seven years after beginning work with EtO, she experienced impaired memory, increased irritability, clumsiness, and falling. Three years later exposure ceased, and symptoms markedly improved over the next few months, but did not disappear entirely. Neurologic and neuropsychological exams 1 year after exposure ceased demonstrated emotional lability, impaired concentration, cognitive slowing, impaired recent and remote memory, and impaired thermal and vibratory sense in distal limbs. Her pattern of relatively preserved learning and profound forgetting distinguished her from most other subjects with memory disorders. No other causes for the condition were identified.