In certain locations, radon gas can seep up from the ground into buildings. Other sources of background radiation in the UK are shown in the diagram.Storage of radioactive materials should be in lead-lined containers, thick enough to absorb gamma radiation. Radioactive substances should be kept locked away and records should be kept pertaining their use. No source should be allowed to come into contact with the skin. Tongs, a glove box or robots should be used to handle the substances. Liquid, gases or powders should always be kept in sealed containers. Radioactive substances should not be used for longer than necessary.