There are many general statements here which are misleading or simply incorrect when applied to tritium. Look at the following study done by the State of California in 2006:
In particular, around Page 25: "For tritium, the experimental evidence for carcinogenicity is rather weak." It emits a beta carrying only 6 keV of energy, about 1/10 the energy used for dental X-rays. Tritium primarily occurs in water, so it rapidly gets diluted from the concentrations described here as "on-site". Water passes through the body quickly; its "biological half-life" is about 2 days.
Furthermore, the notion that the smallest amount of radiation is still dangerous is being discredited by modern molecular biology and our knowledge of the mechanisms for cancer formation, DNA repair, and cellular adaptive responses to stress. Look at this presentation:
for a comparison of the relative risks of nuclear power with other forms of power generation which are widely thought to be safer. You may be surprised.