Possible Household Sources of Radiation Posted on April 17, 2018October 10, 2018 Smoke Detectors: Some smoke detectors contain a sealed radioactive isotope as part of the smoke sensing mechanism. There is no danger to the individual if the container in sealed. They are labeled. Camping Lantern Mantles: In recent years this has changed but some lantern mantles are made with radioactive Thorium. Be especially careful not to inhale or ingest the fine ash that is left when they are burned out. Clocks, Watches, and Timers: Many old timepieces have dials painted with radium to make them glow in the dark. Tritium is now commonly used to obtain the same effect. Tritium is also radioactive but emits low energy radiation which cannot penetrate the lens of the timepiece. Jewelry: Some gold used to encapsulate radium and radon for medical purposes was improperly reprocessed and entered the market as radioactive rings and other types of gold jewelry. Some imported cloisonné being glazed with uranium oxide exceeds U.S. limits. Some gems are irradiated by an electron beam or in an accelerator to enhance their color. Irradiated gems typically are held until there is no residual activity remaining. Rock Collections: Many natural formations contain radioactive materials. Hobbyists who collect such things should vent the rooms in which these items are stored and be careful to avoid inhaling the fine dust particles from these samples. Pottery: Some types of pottery are glazed with uranium oxide, such as Fiesta ware. To the best of our knowledge, this process has been discontinued, although some of these pieces are still in circulation.