Abstract: The disclosure relates to a closed working cabinet (1) for toxic or sterile material comprising a work station (9) within the cabinet to receive toxic or sterile material, means to enable an operator to conduct contactless operations on the toxic material, means (47) to provide a flow or filtered air through the cabinet at an elevated pressure above ambient to prevent ingress of contaminant material to the cabinet and means to cause said pressurised air to flow over the work station in a direction away from the side of the cabinet which the operator functions to protect the operator from exposure to toxic material.