Burnisher's asthma--a case due to ammonia from silverware polishing

A 39-year-old man with no past or family history of asthma developed asthmatic symptoms five months after working as a burnisher in a hotel. He polished brass or silverware using "brasso" or "silvo" respectively. He noticed symptoms only when using "silvo". Specific bronchial provocation testing (BPT) to "brasso" was negative. Specific BPT to "silvo" produced a dual asthmatic reaction. Ammonia was present in both polishes. The ammonia-in-air levels during polishing was 8-15 ppm with "silvo" and less than 1 ppm with "brasso". A specific BPT to 12 ppm of ammonia produced an immediate asthmatic reaction. Our opinion is that he had occupational asthma from the ammonia liberated while polishing silverware with "silvo". Ammonia has been reported to cause asthma. However, there have been no previous reports of occupational asthma among burnishers doing silver polishing.