An emergency shut off system for a workspace enclosure system, wherein the shutoff system comprises an emergency shut-off module disposed within a workspace enclosure. A plurality of sensors are disposed within the workspace enclosure to detect the presence of undesirable gases or other undesirable conditions within the workspace enclosure. A control module external to the workspace enclosure is coupled to receive output signals from the plurality of sensors, and in response thereto to selective initiate a shut-down of operations taking place within the enclosure. In one example, the control module sends control signals to the emergency shut-off module causing the latter to close one or more valves restricting the flow of gases from external gas supply canisters. A blower is provided to create a flow of air into the enclosure, thereby maintaining a positive pressure within the enclosure. An air intake/sensor module is connected via a closed conduit or the like to the intake of the blower. The intake/sensor module includes a sensor for detecting the presence of gases or other undesirable conditions of incoming air, prior to said air reaching the intake of the blower. The control module is responsive to signals from the sensor in the intake/sensor module to deactivate the blower, thereby preventing undesirable gases to be delivered to the interior of the enclosure. In one embodiment, a baffle is provided within the intake/sensor module for enhancing the effectiveness of the sensing operation by minimizing the amount of incoming air that is not exposed to the sensor prior to being delivered into the enclosure.