Oxygen plays now a major role in your ship, previously oxygen was distributed evenly in your spaceship but now oxygen flows from the life support units to all the modules in your ship slowly and between modules when no doors are available. So if there is a fire the amount of oxygen in that module will be depleted and eventually the fire may extinguish itself if lucky, but if it the module on fire is connected to other modules without doors it will start to pull oxigen from those modules and fire will propagate through your ship. Fire also damages your valuable equipment or it may destroy it completely so it is always better to run and extinguish it, in case of hull breachs oxygen will go into the vacuum of space and if the breach is not closed you may even run out of oxygen! and eventually die. You can purchase more oxygen, or mine it, though the mining process is still under development.
Also at this moment all crew members wear space suits but the amount of oxygen is limited so while in ship they can extract oxygen from the ship at any time, whenever a crew member is in a module the amount of oxygen available will decrease, if your life support systems do not provide enough oxygen to those modules eventually your crew may face some problems and try to find another place with enough supply, so if for example 10 crew members are located in just one module and if the supply is not fast enough some may experience some life problems or may even die. Also if working on a module with fire with low oxygen your crew member will start to suffer after a few minutes without the needed supply of oxygen and he/she may eventually pass out or die.
Green areas have enough supply of oxygen, while red are very low or almost depleted, fire in red areas will extinguish itself after a few minutes but if the supply of oxygen continues it will still spread around.
