An underground explosion at the Second Avenue subway project at 72nd Street in Manhattan sent a wave of panic down the streets of New York City on Tuesday, as windows were shattered above ground and a thick later of debris covered the area.

The blast occurred at around 1:00 p.m., at which time work at the site was suspended and the street was shut down.

“What happened at the Second Avenue subway construction site today is completely unacceptable,” said Joseph J. Lhota, chairman of the transportation agency.  “The M.T.A. is investigating what went wrong and will not resume work at the 72nd Street site until we receive a full explanation for what happened.”

Six windows were damaged at 260 East 72nd Street, at the corner of Second Avenue, including a nearby art gallery. No injuries were reported.

James Esposito, an assistant fire chief, said property damage appeared to be confined to some windows and to the construction site itself, but that utility crews found no damage to gas or water lines, The New York Times reported.

Venancio Arvizo, a worker at a cafe near the said that blasting was common at the site, but that Tuesday’s explosion was louder than usual.

“It shook the entire building,” he said, according to The Wall Street Journal.

“The windows shook and shattered,” said Arvizo. “It shot up almost like a volcano out of the street.”