In Oxygen Not Included my greenhouse has a single tile of natural gas that has settled on the bottom. Whenever it moves over a plant, the plant stops growing.
I have a strong force of oxygen coming in from one end of the room, but it is just not blowing the natural gas out for some reason. The pressure inside the room is 1700 and outside is 1400, so there should be good circulation, but for some reason the natural gas does not move.