Why is my critter feeder producing germs?

Air pollution bubbles keep coming up from my critter feeder.
I've tried deconstructing the tile underneath in case something trapped in there was producing pollution, nothing.
I've tried making a screenshot but cannot find where the file has been stored.
This has been made as a preparation for my ranching room and is not in use yet.
I don't have a rancher or any critters yet.

What could be causing this?

Solution 1:

There are a couple of items in Oxygen Not Included that "off-gass" - that is to say, solids or liquids that transform mass from items / liquids into gas:

Polluted Oxygen

• Polluted Water
• Polluted Dirt (item form only)
• Slime (item form only)
• Rot Pile

Chlorine

• Bleach Stone (item form only)

Oxygen

• Oxylite

Each of these different gasses has a unique animation too. Since you're encountering the "Air Pollution" visual and germs, that likely means you have either "Slime", "Rot Pile" or "Polluted Dirt" in your critter feeder all three of which are valid food items for the "Sage Hatch". Double-check your critter diet selections and remove the offending off-gassers!