Safety guidelines outline protecting workers from radon exposure by identifying risky workplaces and applying justified, optimized radiation protection. This Safety Guide provides recommendations on the protection of workers against exposure due to radon in existing exposure situations and planned exposure situations. It focuses on the identification of workplaces of concern and the implementation of requirements for radiation protection through the application of a graded approach and the principles of justification and optimization of protection and safety. This includes exposure in workplaces such as buildings, underground locations and industrial premises involving the processing of naturally occurring radioactive material (NORM). The recommendations provided in this Safety Guide are aimed at governments, regulatory bodies and other relevant authorities, employers, workers, and service providers.