Metal oxide area decontamination apparatus (10) is provided which is designed for rapid, emergency situation decontamination of areas contaminated with potentially harmful or lethal chemical and/or biological warfare agents or other hazardous substances. The apparatus (10) preferably includes a pressurizable metallic container (12) equipped with a valve-type delivery nozzle assembly (16), so that upon a manipulation of the assembly (16), a spray of metal oxide and/or metal hydroxide particles is generated; the particles are selected and sized in order to destroy or chemisorb the contaminating agents. The preferred decontamination agent is MgO aggregated to an average aggregate size of from about 50 nm-10 microns. The particles are mixed with a gaseous or liquid propellant within the container (12) allowing rapid and thorough particle cleanout when the nozzle assembly (16) is actuated.