There are lots of types of oils.
I know that, and you know that. But reality is not relevant. Nor is the half-used bottle of canola oil you show the inspector.
The day that some bureaucratic *#&$^%^ comes to your house or farm and cites you for spilling hydrocarbons, potentially polluting the water table, forcing you to spend thousands of dollars on a phase I assessment or even remediation of your land to prove that you didn’t spill any hydrocarbons, you will hate life. In fact, they do not have to even come to your property. All they have to do is to send you a letter implying their suspicion of groundwater pollution occurring on your land and your property becomes effectively unsalable. I do not exaggerate. You could have an employee or even an acquiantance who gets into some piece of heartburn with you and decides to blab to the town.
In California, the Polanco act is used to bludgeon property owners into performing these tests and/or remediations and is absolutely brutal, because it has very short time-to-perform limitations (60-90-120 days) that are typically less than the amount of time it takes to perform and write up such tests in the real world. I am very familiar with the instance cited at the posted link wrt Emeryville, because I know very well an attorney engaged in the litigation. The town, in collusion with a developer, had their eye on a particular cluster of parcels. They merely had to send on city letterhead to the property owners, a letter that they “suspected” the subject properties may be contaminated AND THEY WERE TOAST. The properties immediately became effectively unsalable, because those suspicions became mandatory disclosures. No testing, no certification, no nothing except a piece of city letterhead and a stamp. Total cost: Under $10 to the city. Total loss in property values to the owners: At least $10 million. It is a backdoor method of eminent domain seizure. In the case I am familiar with, a $3 million property (housing a nice high-tech business and performing very well as a rental for the owners) the city wanted to redevelop was declared “potentially polluted” and subsequently razed, with the owners offered about $200K, which was the estimated yield on sale after remediation of the suspected pollution.
Don’t think it can happen? Forget not the fourth branch of government, my FRiend, the administrative branch. You and I may rail on about Dodd and Frank and Pelosi, but I will assure you that your local building or health & safety inspector can make your life absolute hell far worse than your congressperson, should they find good reason.