A device and method for inactivating infectious biological or chemical agents using microwave-activated diazoluminomelanin (DALM). The agents are typically vacuumed into a load cavity, which is at least partially filled with DALM. The load is irradiated with microwaves via a cylindrical waveguide disposed under the load cavity, thereby inactivating or destroying the agents. The system is preferably temperature controlled and operation is preferably automated.