Oil-filled operational equipment is equipment that includes an oil storage container (or multiple containers and associated piping intrinsic to the operation of the equipment) in which the oil is present solely to support the function of the apparatus or the device.  It is not considered a bulk storage container, and does not include oil-filled manufacturing equipment (flow-through process).

Some examples include, but are not limited to: hydraulic systems, lubricating systems (e.g., those for pumps, compressors, and other rotating equipment including pumpjack lubrication systems), gear boxes, machining coolant systems, heat transfer systems, transformers, circuit breakers, electrical switches, and other systems containing oil solely to enable the operation of the device.