Evaluation and control of worker exposure to fungi in a beet sugar refinery

A study of worker exposure to airborne fungi was undertaken in a sugar beet refinery to evaluate the level of exposure and to determine if controls could be implemented that would lower these exposures. A previous study at this refinery identified one worker who reacted on challenge testing to the moldy but not the fresh sugar beet pulp, had specific Immunoglobulin G to Aspergillus niger, and specific Immunoglobulin E to Aspergillus. Also, two employees were diagnosed with occupational asthma. In the study reported here, two field surveys were conducted, the first during the sugar production campaign (January) and the second during postproduction cleanup and maintenance (June). Approximately 65 personal and area air samples were collected on polycarbonate filters and the culturable fungal spores were identified and enumerated. This study showed high exposure of pellet loaders and pellet silo workers to various species of Aspergillus. Other fungal species that might pose a health hazard were detected. Exposures to fungi during the postproduction cleanup and maintenance phase were much higher than those measured during the production campaign. Engineering controls that would reduce employee exposure are discussed.