Here are some more pictures from the Mass. State Police.UPDATE: All lanes are back open on I-495 after the accident.
UPDATE: Dave Avery has posted pictures on Twitter.
Here is the previous post from earlier:
Massachusetts State Police and fire and rescue teams are at an accident on I-495 North in the area of Tadmuck Road Bridge.
The accident was first reported about 30 minutes ago.
Teams arrived a few minutes later to assist with an entrapment with a patient reportedly pinned in the vehicle that had driven off the highway into the woods.
A Medflight team arrived about 15 minutes ago to assist as well.
State Police are warning on Twitter that commuters should expect delays.
Westford Patch will update this post when more information becomes available.