A follow-up study in 1994 of all inhalation accidents reported to the Surveillance of Work-related and Occupational Respiratory Disease project (SWORD) found that in 11 (3%) of 406 cases reported by occupational physicians and in 39 (18%) of 217 cases reported by chest physicians the patients had developed asthma-like symptoms. In a further follow-up in 1995, physicians who had reported these 50 cases were asked whether they still considered that their patients had developed asthma as consequence of the inhalation accident and further details were sought. Of the 11 cases reported by occupational physicians, seven were considered due to the inhalation accident, compared with 27 of 39 from chest physicians. The majority (88%) of diagnoses were supported by respiratory function tests. Accidents with prescribed sensitizing agents more frequently resulted in asthma than those with other agents. Of 34 cases, only six had recovered when last seen, so it was unlikely to have been due to transient bronchial hyperreactivity. The positive predictive value of respiratory symptoms increased with the number and duration of symptoms but was low for occupational physicians.