Tritium is indeed a hydrogen isotope. H3 to be exact. :wink:
Due to the (weak) radioactivity it was always discussed for use in consumer products. In several countries products containing radioactive materials are banned. Here in Germany the situation is not 100% clean. For example tritium torches are sold only to government, police and such. The small keyrings with tritium vials have however appeared on the german market, claimed to be illegal but none actions have been done to prevent further spreading.
The general concerns are less for the consumer himself - the radioactivity is not very strong while properly built into the watch, but the disposal is often regarded as a problem. As all consumer product, watches tend to be "thrown away" when broken or batteries died. While this for sure does not apply to collectors like us this is how many normal consumers treat watches, especially "cheap" ones. If a product becomes a "hit" and millions of tritium loaded products land on the trash dump it could arrise to a problem.
Here's some beautifull examples of Tritium usage in watches today:
http://ballwatchusa.com/technology/trit ... nology.htm
http://ballwatchusa.com/collection/Trai ... JNight.htm
Unfortunately there are no digital watches of today that are using tritium light sources.