Abstract: A motor-driven pump assembly for hazardous fluids is of the magnetically coupled type wherein drive power from an electric motor is conveyed to a pump drive shaft by rotary magnetic couplings, the pump housing have a containment shell sealed to the motor housing and extending over the interior magnetic drive structure of the coupling to act as a seal against escape of hazardous fluids. A coupling shroud sealingly encloses the driving portion of the magnetic coupling assembly, joining the pump housing at one end and the motor housing region around the motor drive shaft end at the other end to provide containment of hazardous liquids escaping past the containment shell. A sealed reservoir is provided for such fluids, the reservoir communicating with the coupling shroud through a passage. A sensor is provided which reacts to the presence of hazardous fluids in the reservoir to actuate a suitable warning system.