Site of the Crane Collapse (Photo: Brian Zumhagen/ WNYC)

(New York, NY -- Brian Zumhagen, WNYC) Authorities on Wednesday were focusing on what caused a construction boom crane to crash to the ground at a Manhattan work site Tuesday evening, killing one construction worker and seriously injuring another.

Michael Simmermeyer, 30, of Burlington, N.J. was pronounced dead following Tuesday's accident at the No. 7 subway line extension construction site. One other person was hospitalized in serious condition and three people were treated for minor injuries.

According to the MTA, "a Manitowoc 4100 crane owned and operated by Yonkers Contracting Company Inc., collapsed striking a worker below.  The worker, employed by subcontractor J & E Industries LLC succumbed to his injuries.  Another worker, employed by Yonkers Contracting Company Inc., suffered a leg injury."

The MTA says  all work on the construction site has been suspended until further notice. The NYC Department of Buildings -- which regulates cranes --  as well as OSHA personnel, NYPD and the Manhattan District Attorney’s Office are on site today.

The MTA it has ordered the inspection of all cranes at all MTA Capital Construction work sites.

Simmermeyer worked at the site with his father, his co-workers said.

"Both great guys to work with and hang out with. It's just horrible," said Joe Travers, an ironworker from the Rockaways. Simmermeyer was "one of the nicest guys I've ever worked with," he said.

Worker Chazz Brown, one of about 50 ironworkers sent home Wednesday from their day shift, said danger is part of the job.

"It's tragic," he said. "Nobody wants to lose a life on a job site. We come here, we expect to be secure. But it's always stuff flying over our head. All you got to do is just look up, and once it's passed, you just get back to work."

The crane was set up on the second of three levels on the construction site on Manhattan's West Side, city officials said. The FDNY said the boom came apart in two pieces - one 80 feet long and the other 40 feet long.

The NYPD said that the investigation would be jointly conducted by the Department of Buildings and police.

Jack Sullivan, deputy chief for the FDNY EMS, said it was possible one of the workers had been struck by the crane's boom. The crane operator and someone who worked with him were among those who were injured.

He described the removal of the workers from the construction site, about 60 feet below street level, as "extremely dangerous."

"We had construction material that wasn't stable," he said.

Dozens of first responders came to the accident site.

Standing on a sidewalk, one construction laborer collapsed in tears into the arms of another worker. A laborer could be heard saying: "I can't take it."

Thomas Rushkin, a retired city police officer and private investigator, said he was on his way home when he saw emergency vehicles heading over and got a glance at the pieces of the crane.

"The arm is broken in half," he said, adding that it appeared that one part of the crane was on a level below the street.

Another witness, Kennon Murphy, of Charlotte, N.C., said he was on his way to the nearby Javits Convention Center when he heard "a big boom." He said of the crane: "We noticed it was down."

The Metropolitan Transportation Authority released a statement saying they plan to work with all proper authorities to conduct a thorough investigation into the incident.

"On behalf of the entire MTA, we pray for the recovery of the workers injured as a result of this tragic accident," the statement said.

The MTA says the cumulative lost time injury rate for the No. 7 Extension project overall is 1.6 and is 1.3 for Site J, which is below the Bureau of Labor Statistics national standard for heavy and civil construction of 2.2.In May 2008, a construction crane collapsed on Manhattan's East Side, killing the crane operator and a fellow worker. The crane's owner is currently on trial for manslaughter.