An economical and reliable system for the contained transfer of particulates by means of a series of transfer containers facilitates the particulate transfer without either exposure of the operating personnel and the environment to the particulate, or environmental contamination of the particulate itself. The system employs a multiple o-ring canister assembly which can be attached to either the discharging port or charging port of a piece of processing equipment. The canister has a series of circumferential o-ring grooves which allows the attachment of a series of individual transfer containers. In a charging mode, once the particulate is charged to the processing equipment, a first transfer container is collapsed and a second transfer container is placed in the next o-ring groove, thereby containing the remaining contaminated section of the first transfer container. The first transfer container is removed through a bag-out sleeve which is an integral part of the second transfer container. The process is repeated in a stepwise fashion by moving to the next groove in the canister until the process equipment is completely charged in a particulate contained manner.