LAUREL, Mont. -- Montana officials have set fire to an oil-tainted logjam along the Yellowstone River – the last of dozens of contaminated debris piles from a 42,000-gallon Exxon Mobil pipeline spill.Regulators say the logjam was too precarious to be hauled away but needed to be removed to prevent future wildlife damage from the July 1 pipeline break near Laurel.Read More... More on Environment