It's also a low-energy beta emitter, not dangerous externally, and has a short biological half-life in the human body (days), so it there is not a long term bio

It's also a low-energy beta emitter, not dangerous externally, and has a short biological half-life in the human body (days), so it there is not a long term bioaccumulation risk. https://en.wikipedia.org/wiki/Tritium https://en.wikipedia.org/wiki/Tritium