An oil spill you’ve never heard of could become one of the nation’s biggest disasters

In 2010, the Deepwater Horizon oil tragedy commanded the nation's attention for months. Eleven lives were lost and communities around the Gulf of Mexico ground to a halt under hundreds of millions of gallons of oil. Yet, lurking underneath the fresh disaster, an older spill was spewing ever faithfully forth: A leak that began when another oil platform was damaged six years earlier.