BOSTON (WHDH) - A Boston Water and Sewer Commission worker was hospitalized after a dump truck rolled over inside the Thomas P. O’Neill Tunnel in Boston on Monday morning, causing lengthy delays for commuters.

The dump truck rolled over just after exit 23 northbound around 8 a.m., sending gravel across all lanes of the highway.

Crews worked for more than an hour removing the gravel before all lanes were reopened around 9:45 a.m.

The driver, a 30-year-old Mattapan man, was taken to Massachusetts General Hospital with non-life-threatening injuries.

The crash resulted in delays of nearly two hours on Interstate 93 from the Braintree Split to the Tunnel.

7NEWS videographer Dave Heikkila got stuck in the traffic, describing it as “unbelievable.”

“Once you hit about the Dorchester line, standstill,” he explained. “Complete standstill.”

The road reopened around mid-morning.

The cause of the crash remains under investigation.

State Police: Boston water and sewer commission dump truck driver suffered non life threatening injuries when his truck flipped in the O’Neil tunnel #7news pic.twitter.com/fzTQvPDlOI — Steve Cooper (@scooperon7) March 2, 2020

Passenger video shows the earlier dump truck and spill inside the tunnel.

XWAY NB is barely moving, though all lanes are open. #7News https://t.co/l1ZRpYTUuG pic.twitter.com/NsDe13Woig — Alaina Pinto (@alainapinto) March 2, 2020

ALL LANES open inside O'Neill Tunnel after dump truck rollover. A sweeper will come through soon to get the last of the gravel that spilled. Expect delays on XWAY NB #7News https://t.co/VJksyJRMK2 — Alaina Pinto (@alainapinto) March 2, 2020

9:30AM: TWO LANES are now open inside the O'Neill tunnel after a dump truck rolled over spilling gravel on the roadway… big delays on XWAY NB and Pike EB/WB

#7News https://t.co/SMJ9Fhnkh9 — Alaina Pinto (@alainapinto) March 2, 2020

8:55AM: Dump truck rollover inside the O'Neill Tunnel, spilling gravel all over the road, is causing the worst commute ever for the XWAY NB and the PIKE EB. Details on #7News https://t.co/dZ3NSHJxmf — Alaina Pinto (@alainapinto) March 2, 2020

This is a developing news story; stay with 7NEWS on-air and online for the latest details.

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