a can, container, drum tank etc is something to use caution on. I'll admit that I'm out of my league on the volatility of fumes from different petroleum products but to me no one in their right mind should weld, use a cutting torch, grind or saw on an old fuel oil storage tank and likewise engine oil fumes can't be much be much different then fuel oil. I do believe the lighter petroleum fumes may be more explosive and anytime you start pulling a vacuum on a mixture of petroleum products the lighter products are liberated first. Is a tank filled with gasolene fumes any different then a tank filled with oil fumes I don't know? ............
Re: "I'd want to run explosive fumes through it like gas, methane etc, but oil fumes should not cause much concern."