The oil pools on this planet are definitely unnatural. Trying to understand their origin, I crawled

The oil pools on this planet are definitely unnatural. Trying to understand their origin, I crawled through one of the empty pipes only to find a tough metallic screen that stopped me from progressing. There was a sign behind it that said "Waste Disposal Source". I drilled through the pipe to go around the screen, but the pipe stopped abruptly. It has to be connected to something from our old home, but I don't understand how. That sign keeps worrying me. Did the humans want to dispose of us too?