Neuropsychiatric symptoms in workers occupationally exposed to jet fuel--a combined epidemiological and casuistic study.

Some aircraft personel and airline industry workers are exposed to jet fuel, a mixture of aliphatic hydrocarbons (petroleum 80%) and some organic solvents (petroleum 80%) and some organic solvents (aromatic hydrocarbons 20%). In order to evaluate the possible neuropsychiatric sequeale of such long-term occupational exposure, we examined 30 workers exposed at about 250 mg/m3 for 4-32 years at a jet motor factory. They were compared with two control groups (2 x 30) of matched non-exposed workers. The medical history was first assessed by standardized interviews and examination of medical records kept by the factory physician. The exposed subjects had, after their employment, much more often sought medical advice because of emotional dysfunctions, such as depression and anxiety, than had the control groups (P less than 0.005). When the prevalent mental symptoms, indicative of brain lesion, later were rated by psychiatrists, the exposed workers scored higher than did the controls (P less than 0.001). 14 subjects showing most symptoms were then selected for a thorough neuropsychiatric clinical investigation comprising psychosocial inquiries, psychological testing, personality assessment and neurological/neurophysiological examination. Seven were judged to suffer from mild organic brain syndrome (i.e. "organic neurasthenia") of which one subject was a severe case. The subjects had all undergone a slow but steady personality change over the years--starting from an ordinary strength without neurotic traits and moving towards an asthenic state with fatigue, anxiety and vegetative hyperreactivity. No other cause for this change could be identified as an alternative to the occupational exposure to jet fuel. It is concluded that personality changes and emotional dysfunctions are the foremost effects of such long-term exposure to petroleum products.