LAUREL — State workers on Tuesday set fire to an oil-tainted logjam on an island along the Yellowstone River, the last of dozens of debris piles smeared with crude from an Exxon Mobil pipeline break that dumped 42,000 gallons of oil into the waterway.
Two employees of the Montana Department of Natural Resources and Conservation, Derek Yeager and Matt Wolcott, used drip torches to ignite the woody debris as Exxon Mobil contractors looked on.
With a blast of heat and a spiral of smoke, the fire spread quickly through the oil-soaked logs. Just a few hours later, the last of the flames were extinguished with a water hose that had been brought in to keep the blaze from spreading beyond the island.
"Whatever was there is gone now," Wolcott said of the oil in the logjam.
Elsewhere along Yellowstone, black stains from the July 1 spill near Laurel still can be found on trees and rocks near the shoreline and on islands. Environmental regulators have warned that more damaging crude could re-appear next spring, when high waters stir up any oil trapped in river bottom sediments.
But after more than four months of cleanup work — an operation that involved more than 1,000 people at its peak — Exxon Mobil representatives and state officials said Tuesday that the emergency response to the July 1 spill is largely over.
"At this point we're just dotting the i's, making sure it's all right," said Rick Lavold, an Exxon Mobil contractor supervising the cleanup.
As he spoke, Lavold was working with another contractor to pull charred pieces of wood from Tuesday's burnout of the river. Stuffing the black material into trash bags in case any oil remained, Lavold added that remediation and reclamation work by the company will continue, including for agricultural areas marred with oil where farmers have worried about long-term damage to their land.
Additional soil and water monitoring is planned, said Exxon Mobil spokeswoman Claire Hassett. She said the company had made a "start to finish" commitment to see the cleanup through.
The Environmental Protection Agency has been gone from the spill response since September, after most areas of moderate or heavy oiling had been addressed. That left the state Department of Environmental Quality as the chief oversight agency for the spill.
DEQ officials said they appreciated Exxon Mobil's cooperation but that some of the damage from the spill could not be undone.
"The difficulty is you can't get everything, and you can't put it back to the condition it was before the spill," said DEQ deputy director Tom Livers.