American Tire Reclamation has set out to recycle some of the 2.5 billion scrap tires littering landfills across the nation. Using a patented three-step process, the Detroit start-up will melt discarded tires and refine their by-products into fuel oil, natural gas, and carbon-black substitute. The market for carbon black used in industrial rubber goods already tops $300 million. And with more states restricting tire disposal, and Americans scrapping 200 million more tires each year, the recycling market is nothing short of explosive. The hitch? Passing regulatory muster on emissions.

-- Anne Murphy