UPDATE, 3 a.m.
The Beltway’s inner loop reopened after cleanup from a crash that took more than 12 hours.
UPDATE, 10:50 p.m.
The Maryland State Highway Administration has revised its estimate for reopening Interstate 495 to 1 a.m.
A tanker truck overturned on Interstate 495 near the American Legion Bridge just after 2 p.m. Thursday, shutting down all northbound lanes of the Inner Loop of the Capital Beltway as fuel leaked from the flipped vehicle.
Though it was not immediately clear what caused the truck to topple over and land on its side, Virginia State Police said that a passenger vehicle had struck the tanker truck as it overturned. Fairfax Fire and Rescue said three cars were ultimately caught up in the crash.
The truck driver was not injured, though the driver of another vehicle suffered a minor injury, Fairfax officials said.
Traffic and police officers advised motorists to find an alternative route around the crash, which happened on the Virginia side of the Montgomery County line. Fairfax Fire and Rescue said it would take at least two hours to reopen the roadway — but more than four hours later, it remained closed.
At about 6 p.m., the Virginia Department of Transportation tweeted that it would take “many more hours” to clear the Beltway, which remained shut down through the evening rush.
A video from a driver heading the opposite direction at the time of the crash captured the truck’s cabin careening off the right shoulder of the road as the truck flipped.
The truck had been carrying 8,500 gallons of fuel at the time of the crash, according to Fairfax Fire and Rescue.
About 150 gallons of fuel spilled onto the roadway, though crews from Virginia and Maryland managed to prevent the gasoline from spilling into the Potomac River, Fairfax Fire and Rescue Battalion Chief John Price said.
The remaining fuel must be transferred to another tanker before the overturned vehicle can be righted and removed from the scene, officials said.
Virginia State Police said an investigation into the cause of the crash is ongoing.