Tritium is a radioactive isotope that decays through beta decay, emitting low-energy electrons that are typically contained within vials, such as those used in glow sticks and watches. The energy from tritium's decay is converted into visible light, making it useful for luminescent applications. Concerns about its safety focus on the amount of tritium present and its comparison to natural radioactivity levels, with some users questioning the longevity and efficiency of tritium's luminescence over time. Tritium has a half-life of about 12.5 years, leading to discussions about its effectiveness after several years of use. Overall, while tritium is considered safe in contained applications, its long-term viability and safety compared to natural radiation sources remain points of interest.