Black light induction of skin tumors in mice

Albino inbred mice (A/J strain exposed to 40-w black light fluorescent lamps (BLB) for 12 hr a day for up to a year developed inflammatory and hyperplastic responses on hairless ear and tail skin, but not on back skin covered by hair. After 1 year of such exposure, many individuals developed papillomas, carcinomas, and sarcomas on their ears and tails. It may be concluded that black light is a skin carcinogen for A/J mice.