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The Complete Beginner's Completely Incomplete Guide to Oxygen Not Included



Once upon a time (and when a story starts like that you know it was a long time ago) if a dupe got infected with slimelung, death was at your colony's door. Every green puff of germs a sick dupe exhaled could spread the disease to others and every dupe that got infected could die.

I have vague memories of stopping everything I was doing if a dupe got infected, to instead focus solely on micromanaging the quarantining and medical care of infected dupes for as long as it took to rid the colony of infection.

These days slimelung is more of a nuisance than a threat, but it is a nuisance that is largely avoidable. So thanks for indulging me in my trip down memory lane; now let's look at some ways of dealing with slimelung.

A crash course in slime

Slimelung is found in a biome I have trouble remembering the official name of because we all just call it the slime biome.

  • To see slimelung germs select the germ overlay (click on the germ icon in the top right or press F9)

Slimelung is bright green. It is most commonly found in slime tiles. However, not all slime tiles are infected, and tiles other than slime can also be infected.


Gases (i.e. the air) can also be infected with slimelung germs. This is most commonly seen in polluted oxygen. On a "new" map, meaning a new playthrough, slimelung in the polluted oxygen in the slime biome is possible but uncommon. (I can't remember ever having seen slimelung in other gases at the start of a game.)

Slimelung germs don't spread between natural tiles, like from a slimelung-infested slime tile to another natural tile next to it. So an area of slimelung tiles won't "grow" or expand. However, slimelung can spread from a natural tile to a dupe-constructed tile it touches. (This also includes the tiles of pre-built structures.)

Slimelung doesn't transfer from a tile to the air around it. Meaning you can dig out tiles around a slimelung-infested tile and the slimelung won't start spreading to the oxygen (or other gases) around it.

Slime can begin to spread when you dig out a slimelung-infested slime tile. This happens because the slime begins to offgas polluted oxygen and that polluted oxygen is contaminated with slimelung germs.


Slimelung germs don't spread from either natural tiles or debris (meaning a tile you have dug up) to liquids. So a slimelung-infested tile in a liquid won't cause the liquid to become slimelung-ridden.

How to cure a dupe with slimelung




Sick bay

In the top left of the screen there is small germ icon. On the right of that icon there is a number. That is the number of sick dupes you have. You can mouseover the germ or number to see a list of dupes and sicknesses.

A dupe that becomes infected gets a Slimelung debuff which lasts for 3 cycles. The debuff causes a -3 penalty in athletics and coughing. (Basically, slimelung slows dupes down.)

Curing slimelung isn't difficult, but it does require a dupe with the Bedside Manner skill. This means you need a dupe with two points in the Doctoring skill tree.

Curing slimelung:

  • Slimelung is cured with a Medical Pack

  • Medical packs are made using an Apothecary

  • To administer a medical pack you need to have a building called a Sick Bay

  • A dupe needs to have the Bedside Manner skill to administer a medical pack

All the relevant buildings are built under the Medicine build tab.

To manufacture a medical pack you will need balm lily flower and phosphorite. Balm lily are those plants that grow in chlorine, found in the same biome you find dreckos in. Phosphorite can be dug up on the map and it is also produced by dreckos.

Options for dealing with slimelung

One approach to dealing with slimelung is to ignore it. Not avoid it - ignore it. Dig and build and go about your business without giving slimelung a second thought or ever even opening the germ overlay.

I don't recommend this approach; I mention it more as a way to underline that slimelung isn't actually dangerous for your dupes. So if you have been avoiding slimelung out of fear, you can stop being afraid :-)

As far as actually dealing with slimelung, you have two options: containment or eradication. In the first option you make sure slimelung germs don't spread. In the second option you get rid of slimelung germs entirely.


If you are content just containing slimelung so it doesn't spread in your base, then all you need to do is submerge slimelung-infested slime in liquid so it can't offgas any polluted oxygen.

One way to do this is to have storage bins submerged in liquid. Another way is to have an automatic dispenser that dumps debris into liquid. How you do it doesn't matter, it's just a matter of getting infected debris submerged.


There are various ways in which you can kill off germs, some quicker some slower.

The Ore Scrubber

There is a building called an ore scrubber. I used to use it to rid my base of slimelung, but don't use it anymore and don't really recommend it either. But since it can do the job I'll go over it.


Ore scrubber

If a dupe carries something with germs on it past an ore scrubber, they will automatically put it in the ore scrubber. The ore scrubber will then remove a lot of germs from it.

  • Note: you need to pump chlorine to an ore scrubber's gas input pipe for it to work

However, slime tiles can have more slimelung germs than a single use of an ore scrubber will remove. Also, if an ore scrubber is in use and a dupe carries a slimelung-infested tile past it, then they won't stop and wait to put it in the ore scrubber. They just run past, carrying the germy tile.

So you will need to have several ore scrubbers in a row, and then also keep an eye on all dupes that pass by to make sure all slimelung germs are killed off. This makes it a very labour-intensive approach.


You can kill off germs by having germy debris in chlorine. The tricky part, depending on how you do this, is likely to be that chlorine is lighter than carbon dioxide. So any dupes that exhale carbon dioxide in your chlorine pit will cause the chlorine level to rise, which might mess with the design.

(Clean) Oxygen

The easiest (but not fastest) way to kill off slimelung germs is to just have slimelung-infested tiles in oxygen (regular oxygen, not polluted oxygen). Slowly but surely, the slimelung germs will die off.

Cold temperatures

This has become my standard approach (as long as I have a cold biome). Slimelung germs die quickly in cold temperatures. Slimelung in natural tiles, meaning slimelung-infested tiled that you haven't dug up, begin dying off at temperatures below +20C.

I used to be scared of slimelung, even after it was nerfed. I would have intricate systems with lots of ore scrubbers and chlorine and whatnot. These days, I just put some storage bins in a cold biome and set them to accept slime and algae (the most common tiles slimelung is found in). Then I just dig up any slimelung I want to get rid of. Dupes put it in the storage bins and the slimelung dies off.

This is a messy process - there will be slimelung germs in your base, on ladders, etc. And whenever dupes put new slimelung-infested slime in the storage bin, the bin will become infested with new germs. (I turn off auto-disinfect during this process to not waste time on pointless disinfections.) But once all slime is in the storage bins, it won't take long before slimelung germs will be a thing of the past.

If you don't like the idea of digging up slimelung, and if you only want to get rid of a limited amount of slimelung germs, then you can also bring the chill to the slime. Dig out the tiles around a slimelung-infested tile (or several) and then put a storage bin next to the slimelung tiles. Then fill the storage bin with ice (or anything cold). As long as the chill can spread to the slimelung, it will kill it.


If you are playing the DLC, then you can use radiation to kill slimelung germs. This is perhaps most convenient on other asteroids than your starting one, where you can mine out the top of a smaller asteroid so radiation from above can get at the germs.

Cleaning up

Regardless of approach, you are likely to get some (or a lot of) slimelung infested polluted oxygen. Cleaning that up is mainly a matter of just placing lots of deodorizers wherever needed. You can do this while you're digging out slime tiles.

When placing deodorizers, remember that polluted oxygen mainly moves horizontally (left and right) and not much vertically (up and down).


Operation slimelung. Digging out a slime biome and placing deodorizers. Storage bins in the ice biome make quick work of slimelung germs.

Before you break (or dig) into an area with polluted oxygen, mousover a tile or two in there. Some pockets of polluted oxygen can have a lot of polluted oxygen per tile.


Your base is likely to be at somewhere between 1-2K of oxygen per tile. If a pocket of polluted oxygen has 5K per tile, then a lot of polluted oxygen will rush out into your base (or other areas) when you open up a way for it to do so. You can prepare for this by having a lot of deodorizers by where you will dig up a passage.

You can save dupe travel time if you build ladders out of a material you have nearby. There is a lot of sedimentary rock in slime biomes. If you don't need it for hatches (to turn regular hatches into stone hatches) then you can build ladders out of it. (But it's not a big deal if you forget, or just don't bother with it. It just means a bit more travel time.)

Buddy Bud flowers (floral scents)


Buddy Bud

What to do with slime?

Tiles can only contain one type of germ. Slimelung is a germ, but so are floral scents. Meaning if there are floral scents, slimelung can't infect that tile or move past it.

Buddy Bud flowers give off floral scents. So planting buddy bud flowers is an effective way of limiting where slimelung germs can spread (in gases).

If you want to (slowly) get rid of your slime, one use for it is to feed it to mushrooms. You can also turn slime into algae and polluted water using a building called an Algae Distiller. I would recommend ridding the slime of slimelung germs first, as otherwise you will get slimelung-infested algae.

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