Abstract: A negative pressure control system for protection from airborne asbestos particles, gases and the like from a work space includes an enclosure formed of portable rigid doorway panels and doors with transoms communicating with the work space and defining an air intake and decontamination chambers, an exhaust unit having a blower and HEPA filter is positioned in the work space and discharges to the atmosphere and maintains a suitable negative air pressure in the work space and a substantial flow of air through the work space and the decontamination chambers. The enclosure may comprise a room divider and/or a temporary room in communication with the work space. The doors are normally closed as by spring action and the transom closures open responsive to air flow towards the work space and closes with the loss of negative air pressure within the work space.