Toxic Cave
From FOnline: 2238 Wiki
Toxic Cave used to be a military warehouse of some sort, now it's a place full of radioactive goo and toxic chemicals.
This place is hidden by default, to find the location you have to talk to trapper Meloy in Klamath. You can retrieve chemical components there, using science skill on a machine located in the warehouse in the cave. Another location where you can get chemical components is Waterworks.