Update: About 10 a.m., state police said the crashes have been cleared, all lanes are open and "traffic is moving ... slowly."
Original story: Several crashes just inside the Tip O'Neill Tunnel in Boston have significantly delayed traffic as crews work to clear 19 impacted cars.
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State police said three separate crashes involving 19 vehicles occurred just inside the tunnel. Traffic on northbound Interstate 93 was backed up. About 8 a.m. when the first crashes occurred, state police said all of the affected cars were in the left lane, and that the right and middle lanes were still open.
One person was injured enough to possibly be taken to the hospital, state police said.
The cause of the crashes was not immediately clear.
Follow Michael Naughton on Twitter @metrobosmike.