There is economic incentive to operate the ethylbenzene dehydrogenation reaction at low steam/ ethylbenzene ratios. To develop catalysts capable of performing under these conditions, it is necessary to understand the mechanism whereby the concomitant activity loss occurs. A potentially important mechanism is the reduction of the iron oxide. Thermogravimetric analysis in conjunction with X-ray diffraction is used to characterize the reduction properties resulting from potassium addition to iron oxide. The impacts of potassium addition on the temperature required to initiate reduction with hydrogen and on the apparent activation energy of reduction are determined. Reducibility of the potassium/iron oxide system in the presence of other dehydrogenation catalyst promoters is also presented.