If one of the vials were to break (let's say before you put it into the keychain), would this be detrimental to one's health? Would the radiation emitted cause any short or long term harm to the user? Asking seriously, thank you.
losthumansThe beta emission from tritium is non-ionising meaning it's not strong enough to actually do any damage to you. If you do however break a vial just leave the room for a little while until the gas dissipates into the atmosphere and you'll be fine.