The Brooklyn Bridge reopened to traffic late Tuesday, a couple of hours after a crane towed by a barge hit some protective sheeting on the span's underside.
The accident happened shortly after 8:30 p.m. and the bridge was open to traffic again shortly before 11 p.m.
The crane was being towed by a southbound barge, which kept going past the bridge.
About 20 feet of the bridge's scaffolding were damaged.
"I heard the bottom of the bridge, it got ripped by the crane as it was going by. I saw debris falling from the bridge and everything," said one teenager who saw the accident. "It sounded like a building collapsing."
"I turned around and I saw little bricks falling down under the bridge. The crane just kept moving," said another teenaged eyewitness.
About 100 firefighters, police and staff from the Office of Emergency Management responded to the sign.
Police shut down the bridge as Department of Transportation workers assessed the condition of the bridge.
"Could have been a lot worse. A little bit higher, and it could have damaged the bridge," said FDNY Deputy Chief Vinny Mandala. "If the crane was a little bit bigger, if they didn't wait for low tide, whatever, it could have been a lot worse."
Fire officials said no one was hurt and that the bridge was still safe to cross.
Coast Guard officials caught up with the barge and was questioning those on board late Tuesday.