with control device 60 in a preferred embodiment control device 60 is a ferrous scrubber capable of absorbing cl 2 gas control device 60 operates under negative pressure which creates a partial vacuum within evaporator platform 50 and dome 22 the maximum vacuum pressure provided by control device 60 is preferably 10 inches of water relative to the ambient pressure by generating this vacuum control device 60 pulls in any hazardous material vapors leaked in dome 22 or platform 50 control device 60 also includes a status monitor 62 which is coupled to signal bus 58 in the event of a failure or malfunction within control device 60 status monitor 62 will generate a control signal this control signal is transmitted over signal bus 58 to valve 34 see fig2 and either causes valve 34 to close or prevents valve 34 from opening a predetermined vacuum level must be maintained within dome 22 and platform 50 for valve 34 to be opened otherwise one or more vacuum gauges 38 will generate a control signal transmitted over signal bus 58 that will either close valve 34 or prevent valve 34 from opening dome 22 allows for rapid leak detection because of the relatively small space enclosed by dome 22 and container 26 any leaked material will rapidly reach a sensor 36 within either dome 22 or platform 50 sensors 36 will then generate a control signal transmitted over signal bus 58 that closes valve 34 as described above this rapid response limits the volume of material leaked from container 26 therefore control device 60 need only be powerful enough to absorb or deactivate the largest amount of the hazardous material that could have escaped before valve 34 closes sensors 36 can.