Is it actually that dangerous? I thought beta and alpha emitters were pretty safe as long as you don't get them inside your body. If you opened a vial of one of

Is it actually that dangerous? I thought beta and alpha emitters were pretty safe as long as you don't get them inside your body. If you opened a vial of one of these and dumped it out on the workbench and stood there for an hour, how bad would that be?