This document addresses the use of germicidal ultraviolet radiation for disinfection of room air and surfaces; potential dangers for humans; potential effects on materials and plants; UVGI technologies; and safety measures and precautions. It does not address photobiological safety with respect to emission or exposure limits; those topics will be addressed in an update to ANSI/IES RP-27-20, Recommended Practice: Photobiological Safety for Lighting Systems.