It is important in the design of future fusion reactors and associated facilities that incorporate passive safety to take account of the possible environmental impact of accidental tritium release. Reliable information on dose consequences can be obtained by evaluating urine samples from persons exposed to tritium. Translating the results of the environmental HT experiment performed in France in 1986 into worst-case exposure conditions, the effective dose equivalent to an individual with highest exposure at a distance of 800 m (typical for site boundaries) is ∼1 × 10−4 Sv per gram of tritium emitted as HT when inhalation and skin absorption are considered. From this value, maximum permissible amounts of accidentally released HT can be derived on the basis of regulatory or anticipated dose limits. A comparison to a tritium release in the form of HTO shows that there is no fixed factor that can be used to convert the dose consequences of an HT release into those of a corresponding HTO release. The factor ranges from at least 10 for worst-case conditions to ∼70.