Exposures to respirable, airborne Penicillium from a contaminated ventilation system: clinical, environmental and epidemiological aspects.

Symptoms compatible with hypersensitivity pneumonitis (HP) in two of fourteen employees in a clerical office prompted an investigation of their work environment. Forced-air heater-cooler units which had not been properly maintained were implicated when they were found to be grossly contaminated with predominantly Penicillium molds. Air-sampling for viable, respirable-size particulates in the affected office and an unaffected office in the same building demonstrated a 50- to 80-fold excess in the number of colony-forming-units per cubic meter of air in the affected office. Persistent alveolitis was documented by repeated bronchoalveolar lavage, gallium scan, and other studies in one affected worker whose peripheral lymphocytes underwent blast transformation in response to Penicillium antigens obtained by air-sampling in the work environment. The other affected worker had asthma, presumably exacerbated by exposures to a variety of inhaled environmental irritants and antigens. Despite a documented reduction of airborne fungi to background exposure levels after clean-up of the forced-air units, the worker with persistent alveolitis has had occasional recurrences of symptoms consistent with HP. Further research is needed to establish health guidelines for control of occupational and non-occupational exposures to respirable fungal organisms which may contaminate cooling, heating and humidifying systems in these settings. A multidisciplinary method of approach to such research is described.