My take on this comes from growing up on a dairy farm. Over time, raw milk sours, ferments and turns into a cheese and you can still consume it. My mother kept a jar of leftover milk on the counter all the time. I dont know how many sour milk pancakes I have eaten that have contained bits of this “cheese” that didnt get mixed in nor were fully cooked. Pastuerized milk on the other hand would just go bad. She would never put any of that in the jar. What is leaking is not refined oil that we think of like the motor oil we put in our cars.
Wasn’t the Exxon Valdez refined oil? So it was thick. This oil is a natural substance. Aren’t there naturally occurring oil leaks all the time?