The reactive property between steam and the iron carbide, which was industrially produced by the two-step fluidized beds, was investigated at the heating rate of 0.167 K/s by thermal analysis with a mass spectrometer. The purpose of this short paper, thus, is to rapidly report the hydrogen generation of the active iron carbide with steam at a much lower temperature than thermodynamically expected. It was quite natural that hydrogen, carbon monoxide and carbon dioxide were released over 873 K due to the reaction of Fe(3)C + H(2)O = CO + H(2) + 3Fe and following oxidation of the reduced iron (Steam Iron method), as we can expect from the theory of thermodynamics. An even more surprising result was that an unexpected, hydrogen generation was observed from as low as 573 K in temperature, together with exothermic heat. This temperature is as much as 500 K smaller, in comparison to the conventional Steam Iron method. These results revealed the possibility of an innovative cost-effective transportation process of not only steelmaking material but also hydrogen using iron carbide, because hydrogen generation from the iron carbide is possible before the oxidation at high temperature. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.