A mobile deactivation apparatus for deactivating contaminants within a defined region that includes a source of a vaporous deactivating agent, a gas handling system, a support member, a drive means, a control system, and a power system is disclosed. The gas handling system dispenses the vaporous deactivating agent to the defined region. The support member is movable in the defined region and supports the source of the vaporous deactivating agent and the gas handling system. The support member can be propelled by the drive means. The control system is programmed to control the operation of the gas handling system and the drive means. A power system is provided to supply power to the mobile deactivation apparatus.