The disclosure relates to a portable apparatus for decontaminating an enclosed room or other space which includes a passageway having an air inlet at one end and an outlet at the other end. A pump causes a flow of air through the passageway from the inlet to the outlet. A heater heats the air flowing through the passageway to a predetermined temperature, a flash evaporator being in communication with the passageway. Liquid decontaminant is pumped from a supply of decontaminant to the evaporator to be evaporated and for the evaporant to be delivered to the air flow in the passage to flow in the air flow from the outlet to the rooms to be decontaminated. A universally rotating nozzle is provided at the outlet to distribute the decontaminant containing air throughout the enclosure.