Clear oil spills and access Biomutant Deadzone area - Biomutant Wiki
There's a way to clean up oil spills in Biomutant. You'll need to help gizmo repair a giant robot that you can ride, it's a Biomutant mount. This will let you access the deadzone and pick up and oil that gets in your way. This Biomutant Guide will explain it to you, and the video above.
To help gizmo you'll need to go to the trainyard north of the Jagni's home. Then clear the enemies, take the rocket and smash it into a wall and take the elevator down to Gizmo. Then go through the hypoxia area to get the Wrekton Parts and complete Gizmo's quest. Afterwards you'll have the Biomutant robot mount and be ready to run through the deadzone.