The type of radiation emitted by Tritium is easily stopped by the outer layer of dead cells on your skin. If you broke open the tritium capsule and inhaled the contents that probably wouldn't be good for you--but the amount you'd be inhaling is ridiculously small. As long as you don't TRY to hurt yourself with it it's perfectly safe.
http://www.epa.gov/radiation/underst...l#affecthealth