Item #4. There are lots of environmental costs that are caused by burning oil/gasoline. But that goes for most everything in a modern economy - the environment is considered an unlimited source and sink. You can take as much as you want from the earth and the nasty by-products will be absorbed by it. That isn't true of course, but pollution is an externality that is not paid for up front. So of course there are lots of "hidden environmental costs" that are the result of the petroleum business, from air pollution to oil spills, to many secondary effects based on using oil to power our economy.