The risk of squamous cell carcinoma (SCC) from ultraviolet radiation (UV) emitted by unfiltered fluorescent lamps was assessed. The assessment employed a mathematical power model based on human epidemiological data, which relates the SCC incidence in the United States white population to ambient solar UV. The annual numbers of new SCC on anatomical sites chronically exposed to solar UV (head/face/neck and hands) were estimated for indoor workers. Then the number of SCC that may be caused by additional UV exposure from indoor fluorescent lighting was estimated: the lifetime exposure of indoor workers to typical fluorescent lighting (if unfiltered) may add 3.9% (1.6-12%) to the risk from solar UV, resulting in the induction of an additional 1500 (600-4500) SCC per annum in the United States. This calculated projection must be compared with the 110,000 SCC caused by solar exposure. Thus, this analysis suggests there may be a small increased risk of SCC from exposure to UV-emitting fluorescent lamps.