in a method and apparatus for decontaminating biomedical waste , the waste is introduced with moisture into a flexible , polymeric bag defining an internal volume and having a bursting point in response to expansion of the internal volume . the waste and moisture is then sealed within the bag , and the sealed bag is introduced into a decontamination chamber and subjected to microwave radiation within the chamber at a predetermined level and time sufficient to sterilize the waste . the decontamination chamber defines an internal surface spaced a predetermined distance from the flexible bag with the bag at about ambient temperature . the predetermined distance is large enough to permit expansion of the bag within the space when the bag is subjected to the microwave radiation , and small enough to permit the internal surface to engage the bag and thereby prevent further expansion of the bag prior to reaching its bursting point in order maintain the bag in its sealed condition throughout the microwaving and decontamination process .