The areas of greatest safety concern in using hydrogen as a fuel are: the fact that hydrogen is colorless and odorless, hence hard to detect, its wide flammability range compared to other fuels, and its tendency to explode when confined. This paper describes the measures implemented by Ballard Systems to ensure the safety of passengers, transit property and staff and the general public in constructing the six fuel cell-powered demonstration buses for use in Chicago by the Chicago Transit Authority (CTA) and in Vancouver by British Columbia Transit (BCT). Specifically, the paper discusses the System Safety Program Plan for the gaseous hydrogen transit bus, the safety analysis prepared to evaluate bus and facilities designs, the reports concerning the conversion of diesel facilities to hydrogen facilities, and the testing and certification programs used to verify the safety of on-board fuel tanks. The paradigm shift required in the transit authority`s safety culture to ensure the safe maintenance and operations of hydrogen-fuelled vehicles is also investigated. Based the study of the results of one year of operation, the author`s conclusion is that hydrogen can be safely used as an alternative fuel for transit buses.