Occupational asthma due to oil mists.

Twenty five patients who were exposed to oil mists at their place of work were investigated for possible work related asthma. Serial peak expiratory flow recordings showed 13 to have definite work related asthma, seven equivocal work related asthma, and three asthma unrelated to work; two had normal recordings. Subjects with work related asthma often produced different patterns of peak flow response during the working week; patterns also varied between patients. Six of these patients had bronchial tests with oil from their place of work. Three had asthma induced by exposure to unused (clean) soluble oil and one reacted to used but not to clean oil. The challenge tests in the remaining two gave inconclusive results. It is concluded that occupational asthma due to oil mists is common, the peak flow response is heterogeneous, and the provoking agent within the oil may vary from worker to worker.