The invention provides a mobile work unit for the disposal and recovery of hazardous material, such as asbestos, removed in pieces an particles which would otherwise enter the atmosphere, wherein the pieces and particles are conveyed through a tube from the working zone to an enclosed recovery and disposal cell wherein the particles and pieces are separated from the air and bagged, and the unit has an enclosed entry and exit (or clean) cell, a decontamination cell containing operator washing facilities, the cells being accessible in sequence to operators through sealable connecting doors. The disposal and recovery cell may have further doors to which man entry trunking is connected enabling operators to move along the trunking on the one hand to the working zone and on the other hand to a disposal site for the bags, whereat there may be a skip or other container.