Occupational laryngitis caused by formaldehyde: a case report.

Formaldehyde is commonly accepted to be an allergen and irritant. However, specifically diagnosed occupational respiratory diseases caused by formaldehyde are relatively rare. Occupational laryngitis was diagnosed in a 47-year-old dairy foreman. He had been exposed for 9 years to formaldehyde emitted from a milk-packing machine situated underneath his office. His exposure level varied considerably. Under normal process conditions, the measured formaldehyde level was 0.03 mg/m3. The patient was examined by different specialists over 1 1/2 years. It was concluded that he had psychogenic dysphonia. However, a specific laryngeal provocation test with formaldehyde carried out at the Finnish Institute of Occupational Health was positive. His laryngitis was so serious that he was pensioned. During the 3 years of follow-up his condition gradually worsened. He now reacts especially to tobacco smoke and other air impurities known to contain formaldehyde.