Asthma due to non-occupational exposure to toluene (tolylene) di-isocyanate

The production of asthma by toluene di-isocyanate, aspirated into the ventilating system and emanating from the exhausts of a neighbouring factory, was established in three otherwise non-exposed clerical workers. Occupational-type exposure tests with a polyurethane varnish/toluene di-isocyanate mixture elicited vigorous and prolonged non-immediate asthmatic reactions, thus enabling identification of the otherwise, obscure etiological cause of their asthma.