Tulsa, Oklahoma – The United States imports the majority of its oil from Canada --- not from the Middle East or South America, but from Up North. Canada has one-third of the world's oil source; it comes from the sticky bitumen in the vast oil sands of Alberta. Indeed, much of this so-called "dirty oil" --- accounting for almost 20 percent of America's fuel --- is now being processed in refineries in our Midwest. Our guest on StudioTulsa today says that super-sized refinement makes for an out-of-control oil-production juggernaut that's seriously polluting our air, poisoning our water, and destroying our forests at a rate almost too rapid to be imagined. Andrew Nikiforuk has written about energy, economics, and the West for several Canadian publications; his new book is called "Tar Sands: Dirty Oil and the Future of a Continent."