Harmful substances on the opera stage: possible negative effects on singers' respiratory tracts

Objective, quantitative information is lacking in the medical community about actual working conditions for professional singers onstage, and moreover, about which conditions are safe. Physicians, speech-language pathologists, and speech scientists focusing on laryngology should have relevant information about the opera as workplace and the medical sequelae of unhealthy environments. We describe five toxic substances to which singers presenting to our clinics were exposed while working professionally on the opera stage: (1) aromatic diisocyanates, (2) penicillium frequentans in cork granulate, (3) formaldehyde in cork granulate, (4) cobalt and aluminum (pigment components), and (5) quartz sand capable of entering the alveolae. Biological considerations and clinical data for some subjects suggest a direct causal link between the exposures and the patients' complaints and findings. Our observations suggest that whenever singers complain about deleterious conditions such as dry and hot onstage climate or suspicion of the presence of harmful substances, the specific conditions existing in the theater in question should be investigated. Harmful substances are not only poorly tolerated by singers, but also they should be preventable.