Induction of micronuclei in cultured human lymphocytes exposed to quartz halogen lamps and its prevention by glass covers.

The light emitted by an uncovered tungsten halogen lamp (12 V, 50 W), equipped with a dichroic mirror, induced time-related and distance-related increases in the frequency of micronucleated lymphocytes following in vitro exposure. Peripheral blood lymphocytes from three healthy donors showed the same degree of sensitivity. This clastogenic effect could be ascribed to the emission of far-UV wavelengths (UVB and UVC) and was prevented by interposing a common glass cover. These results support the findings of our genotoxicity studies in repair-deficient bacteria and carcinogenicity studies in hairless mice, thereby suggesting possible health hazards associated with illumination with halogen quartz bulbs, to which an enormous number of individuals are nowadays exposed. These hazards can be simply avoided by using glass covers.