Our residential underground transformers from time to time end up being waste oil storage tanks.Cool Starry time:
I had a friend who lived in low income .Gov apartments in east San Jose by Story Rd and Capitol Expressway. He pointed out the sewer (storm drain) gratings in the parking lot were all black with orl from the residents there pulling up on the curb over the drains to drain their orl right into the sewer when changing orl in their cars.
It plays hell on the rubber components.