Leftover cooking grease is a hot commodity these days, and restaurants across the country are reporting being hit by slippery-fingered thieves. Biodiesel producers must legally register with the U.S. EPA, but DIY biofuelers are helping themselves to waste cooking oil as its value skyrockets along with the price of diesel. David Levenson, owner of a grease-hauling business in San Francisco, has contracts with local restaurants, but says his drivers too often find empty barrels on their cooking-oil runs. Other grease haulers say oil thievery has lost them thousands of dollars. Says Levenson, “It’s like a war zone going on right now over grease.” We can just hear the thieves now: “I stole grease under sniper fire!”