The IGB labs have once-through air flow, exhausted out the large roof stacks. No air in the labs is recycled back to other areas of the building. 

Air comes in through diffusers and is exhausted through chemical fume hoods, exhaust grilles and through any local ventilation that has been set up.

Smoke from fires and vapors from chemical spills can generally be contained by closing doors to the space, except in specific rooms such as tissue culture rooms that are positively pressurized to avoid contamination entering the room.