We conducted an epidemiological survey to inquire into an outbreak of acute pneumonitis after two reported cases of interstitial lung disease.

The study subjects were 45 workers from a compound metal alloy factory. We reviewed the factory's industrial hygiene data along with the results of a special health examination, including pulmonary function tests, simple chest X-rays, and high resolution computed tomography.

The air concentrations of beryllium ranged from 0.42 microgram/m3 to 112.3 microgram/m3, and the mean concentration of urinary beryllium were 1.53±0.79 microgram/g of creatinine in the molding workers, 1.41± 0.50 microgram/g of creatinine in the casting workers, and 1.16±0.53 microgram/g of creatinine in the sorting workers. The rates for cough (p=0.054), dyspnea (p=0.030), and the use of medical services (p=0.018) were higher in the molding workers than in the non-molding workers. The incidence rate of acute interstitial lung disease was higher for the molding process (32.0%) than for the non-molding process (5.0%) (p=0.012). The time of employment for all patients was prior to December 1st, 2002.

Since most of the patients were molding workers, and all of the patients had worked without a ventilation system, this outbreak of acute interstitial lung disease was regarded as acute beryllium disease. Although the direct cause of the epidemic was the beryllium fumes, the fundamental cause was improper control of the work environment. Therefore, the means for preventing avoidable epidemics of occupational diseases are discussed.