Society is highly expecting fuel-cell-powered vehicles, which use hydrogen (Hx) as fuel and emit only water. They are considered to be a new generation vehicle with an ability to contribute greatly to the improvement of air quality and the reduction of carbon dioxide (CO2) emissions. In Japan, the government°s target is to commercialize fuel-cell vehicles and put them into practical use from 2005. In order to accomplish this, it is necessary for the government to swiftly establish technical standards (i.e. safety standards) to ensure the safety of and environmental conservation by fuel-cell vehicles. For this purpose, we have been commissioned by the Ministry of Land, Infrastructure and Transport to conduct research in order to establish safety standards that take the unique features of the fuel-cell vehicle system into consideration. It is being undertaken under the framework of an industry-academia-government collaboration in the form of a two-year project commencing from the fiscal year of 2003.