The story of Factio tells that the character must prepare an alien planet for the colonists. But how many planets are similar to the Earth and at the same time have a human atmosphere? So this planet probably has an atmosphere not suitable for breathing, and we will need oxygen in order to survive.

Added:
Oxygen
Breathing Oxygen Cylinders
Oxygen separator
Electrolysis oxygen production recipes
Gas masks
Oxygen dispensers

The mod is not mine, I just updated and slightly modified it. I will not refuse help on refinement and improvement.

Original found here:
https://mods.factorio.com/mod/Oxygen_Patched
https://mods.factorio.com/mod/Oxygen