At least 40 injured in Manhattan blast

Rescue teams work at the scene of the blast.

NEW YORK (CNN) -- An explosion Thursday in the Chelsea neighborhood of Manhattan damaged adjoining high-rise buildings housing a technical school, offices and residential units and injured at least 40 people, the mayor's office said.

Authorities said no foul play was suspected, and the explosion appeared to be an accident.

"There's absolutely no reason to think this is anything other than a tragic accident," said New York City Mayor Michael Bloomberg.

Ten of the injured were in critical condition, the mayor's office said. At least six people had life-threatening injuries, according to a spokesman with St. Vincent's Hospital.

CNN NewsPass VIDEO An explosion Thursday in the Chelsea neighborhood of Manhattan damaged adjoining high-rise buildings and injured at least 50 people. (April 25) Play video   EXTRA INFORMATION Gallery: Scenes from the blast

The explosion, according to the fire commissioner, involved volatile chemicals used in etching work by a company in one of the buildings, but few details about the nature of the explosion were available. Earlier, a police spokesman said a boiler in the basement was involved, but authorities later said that was not the case.

The commercial-residential building where the blast occurred houses lofts and businesses, including Kaltech Industries Group, an architectural sign company.

"It was just a loud, thunderous noise," said Jeff Gross, who works in the building. "As soon as the explosion came, it seemed like a hurricane came through the building."

Students were evacuated from the eight-story Apex Technical School adjoining the building which houses Kaltech, located at 123 W 19th St. The streets in the area around 19th St. and Sixth Ave. were closed to traffic.

'If I didn't duck, I would have died'

"I just ducked because all the glass and flames and fire was coming toward me," said Steve Jaisingh, who works in the basement of the building. "If I didn't duck, I would have died."

The explosion blew out windows and sent debris raining down on to the street. Several people, some bleeding from cuts and lacerations, were treated at the scene. Others were taken away on stretchers.

At least 50 people were injured in the explosion.

"I was on 20th Street in the rear of the building and I was literally directly across the street when the explosion happened," said witness John Heffernan. "Two huge windows blew out and glass shattered all around me. I ran underneath an awning and the glass just came down all around me."

While the incident initially raised fears of some kind of attack -- coming seven months after the September 11 terrorist attacks against the World Trade Center in lower Manhattan -- officials quickly ruled that out.

"We do have people from the Joint Terrorism Task Force on the scene. As of right now, there's nothing to indicate a terrorist connection to the explosion," said FBI spokesman Joseph Valliquette.

Police, fire and rescue units responded to the blast, and some rubble was visible on the street. But no fire or smoke was evident.

More than 100 firefighters were on the scene, fire officials said.