Interesting bit about watch lume that I ran across on another forum:
"Actually there are studies that show that wearing a tritium lume watch is detectable in your urine. In addition, the problem with radium lume in old watches is that the substrate crumbles leaving radioactive dust which can leak out, especially if you open the watch as many WIS do and make its way into your lungs through breathing. from whence it may make its way into your bones, displacing calcium and happily spewing out beta radiation for the next 1600 years (to half life).
Now you can say what you want about 'safe doses' of radiation but the risk of starting a cancer is, as far as I understand it, both cumulative and probabilistic. In other words the more exposure you have the more 'tickets' you buy and the more tickets you buy the more likely you are to get 'lucky'. Now I know that there are dietary, environmental and genetic components, but these are just modifiers.
In short, if you happen to know for certain that a certain gene on the short arm of your 17th chromosome is doing a really sharklike job then you can gamble in the radiation lottery.
If not, or if the gnomic sentence above means nothing to you, then it really isn't worth the risk."