Several techniques are available for predicting the strength of the blast wave produced by an unconfined vapor cloud explosion (UVCE), as a function of distance from the vapor cloud. In this manuscript, three of the most widely used UVCE prediction models (TNT, TNO and BST models) have been used to study the consequences of an explosion of hydrogen that occur in a lab where investigation on fuel cells is carried out. Moreover, the vulnerability of persons, expressed as the number of individuals who can possibly be affected by eardrum rupture or death from lung hemorrhage have been estimated using the Probit units. The TNT model predicts higher values of overpressure than the other two models at the same distances. Some structural damages can be expected at distances up to 50 m, the four closer labs to the lab where the explosion occurs suffer destruction. In the case of people, important injuries or casualties can be expected to the people in the CICAT but not to the people in the library or in the lecture room building. This paper shows an easy tool to give the first step in the study of hazards of explosion of hydrogen. © 2006 International Association for Hydrogen Energy.