Vaporized hydrogen peroxide is used for decontamination of enclosed and sealed areas. It is capable of destroying all forms of microbial life. It is commonly produced from a solution of liquid H2O2 and water, by means of generators specifically designed for the purpose. The present invention provides a combined source for heating steam and vaporized hydrogen peroxide and a method for simultaneously supplying steam and vaporized hydrogen peroxide. A device according to the invention comprises a chamber adapted for receiving water through an inlet and expelling steam through an outlet. A vessel for receiving and vaporizing hydrogen peroxide solution is provided in close contact with the chamber. Heat from the water vapor in the chamber is allowed to supply the required energy for producing hydrogen peroxide vapor in the vessel from an aqueous solution.