In Kaliforkita is oil a hazmat
Technically yes and no. Actually, I think breathing and exhaling in Kali might be too...
In quantity, waste oil is. You can't just dispose of it in a drain or in your backyard. So when you take it to the re-cycler, they have to handle it as a "hazardous waste". Think of PCB's and other crap that oil once had in it. I imagine now that waste oil is much cleaner than back in the day.