It's possible to build a machine that converts one gas into another. The machine is 100% reliable, allowing basically pure alchemy in the game. This makes pretty much breaks all game mechanics. The exact same mechanic shows up in tons of places that are unexpected. I've been calling it "matter conversion" for quite a while now, and I know that @Ipsquiggle has seen it and marked "thanks" on one of the update threads in the game forums.
The bug has been known for a long time. @FIXBUGFIXBUGFIX posted about this more than a year ago. It got marked as fixed, but was still in the game. He posted about it again, and I added lots of things to bug report, trying to show you where the bug appeared all over the game (explainig phenomenon that people post about all over the web). Unfortunately he removed all his bug reports when he left the game, so all my work got deleted as well. This bug kills game designs, for newbies and veterans alike. It needs to be removed.
Here is how to build the thing.
Here is a possible fix (I've been thinking about it for a long time, and this is the first option that seems reasonable... maybe).
Good luck with fixing it. Your game is my favorite game of all time. Thanks for all you do Klei.
Build the machine above. Build a water fall anywhere. Put some gas heavier than steam near a geyser. Put less than 1800g of chlorine near slime. The list goes on. Tons of ways to reproduce it. I see posts on it every week in the forums and reddit.