Gases are transported, generated, mixed or split via ventilation. Based on Duplicant needs they can be sorted into breathable and unbreathable. There are currently four Unbreathable gases in Oxygen Not Included:

Carbon Dioxide Edit

Denoted by a black color, Carbon Dioxide is heavier than Oxygen and will sink to the lowest levels of the duplicants' colony. It is exhaled by duplicants upon consuming Oxygen and as a byproduct of the Coal Generator.

Algae Terrariums will consume Carbon Dioxide instead of Water to produce Oxygen. Carbon Skimmer will also filter Carbon Dioxide while consuming Water and emitting Polluted Water as a byproduct.

Hydrogen Edit

Denoted by a pink color, Hydrogen is a lighter-than-air gas which rises above all other gases. It is found in abundance in the Crystal Biome and is a byproduct of the Electrolyzer.

Hydrogen can be harnessed as a power source through the use of a Hydrogen Generator.

Chlorine Edit

Chlorine is a fluorescent green gas and heavier than Hydrogen and Oxygen. It can be found in the Crystal Biome aka purple biome(?), sometimes with patches of Bleach Stone.

Chlorine is emitted when Duplicants use Bleach Stone.


Chlorine with a Morb. Note the greenish hue of the gas.

Natural Gas Edit

Natural Gas is an orange gas. It can be used as a power source with the Natural Gas Generator.

Natural Gas is emitted when Fertilizer Maker is turning Contaminated Water into Fertilizer.

Vacuum Edit

This is in areas void of Oxygen or Carbon Dioxide. The Vacuum is also a common area for Creatures to lurk in. The Void Biome that surrounds the map contains no gasses except a vacuum.