I've seen several videos of people burning potato chips. The inference is that because they're flammable, there must be something wrong/toxic with them. The reason the chips burn, of course, is the oil they're cooked in. Vegetable oils to be precise, not petroleum. So the question is, is there something toxic about vegetable oils. I'm not so sure, though I know of at least one doctor that considers all oils to be carcinogenic, even olive oil.
That all foods cooked in oil is toxic is a tough sell in today's world. Oil is everywhere. It's so ubiquitous in our food that you can pretty much write off all processed and prepared food as having oil. If you don't want to consume added oil, eating raw food is the way to go.