Methane

Methane is an atmospheric resource that can be collected from the atmosphere of certain planets using the Atmospheric Condenser. Its availability varies by planet, with listed concentrations of 75 ppu and 100 ppu on the planets where it appears.

Methane is used as an ingredient in crafting, but no crafting recipes are listed in the available source material here. It is also notably volatile: if it is placed in an active Smelting Furnace, or if Dynamite is detonated nearby, Methane will explode. Because of this, it should be handled away from heat and explosive hazards.

At 100% concentration, Methane has the highest byte value of any atmospheric resource.