Abstract: A positive-pressure respirator hood assembly comprising, a gas-impermeable hood made of a flexible material, formed with at least a transparent visor portion; a gas treatment unit, comprising a filter and a power-operated blower to force air through the filter and generate a positive pressure within the hood; a one-way purge valve for facilitating the exhaust of exhaled gases and moisture from the hood; and a sealing portion for sealingly securing the hood over a body portion of the user; the respirator hood assembly is designed to be compactly received in a container and to be deployed into an operative state automatically, whereby a user is provided protection from toxic gases and particulate material.