Today I learned that it is illegal to sell tritium in the us but it is not illegal to buy it in the us…so here is a website selling tritium trinkets that come from taiwan!
They are like glow sticks that last for 10 years, it is perfectly safe unless maybe you were drinking liquid tritium for a few weeks.
Actually now that you mention it I think you are half right after looking into it more.
It does seem like it is actually heavily regulated and not necessary illegal, but I guess this would mean illegal for unlicensed people to sell.
If I had to guess most sellers in the us with tritium in their products aren’t selling tritium but rather selling procured items with tritium and thats probably a legal workaround for that.