In June 1987, an experiment was performed at the Chalk River Nuclear Laboratories in Ontario, Canada, to study the oxidation of HT in the environment. The experiment involved a 30-minute release of 3.54 TBq (95.7 Ci) of HT to the atmosphere at an elevation of one meter. The HTO/HT ratios were shown to slowly increase downwind (∼ 4 × 10−5 at 50 meters to almost 10−3 at 400 meters) as conversion of HT takes place. For several days after the release, HTO concentrations in the atmosphere remained elevated. Freeze-dried water from vegetation samples was found to be very low in HTO immediately after the release suggesting a very low direct uptake of HTO in air by vegetation. The free-HTO concentration in vegetation increased during the first day, peaking during the second day (about 1.5 − 3.0 × 104 Bq/L at 50 meters from the source) and decreasing by the end of the second day. The organically bound tritium continued to accummulate during the period following exposure (about 400 Bq/kg dry weight at 50 meters after two days).