MTA officials said Wednesday that the explosion at the Upper West Side site of Second Avenue subway construction may have been caused by the improper attachment of an 1,800-pound protective plate, and diagonal drilling to build an escalator.
The Tuesday blast, which terrified passersby, shattered windows and sent smoke billowing to the street "should not have occurred," said MTA Capital Construction President Michael Horodniceanu. at a news conference. "I'm really upset and angry that what happened put the residents in the area in [that] situation."
Drilling is normally done vertically, and the diagonal drilling performed Tuesday may have contributed to the blast, Horodniceanu said.
The MTA also said it planned to hire an independent consultant to monitor procedures at the Second Avenue subway's 72nd Street work site.
Work remained halted there Wednesday.
On Tuesday, MTA chairman and CEO Joseph J. Lhota called the incident at Second Avenue and 72nd Street "unacceptable" and said work will not resume at the site until he receives "a full explanation for what happened and a plan to make sure it does not happen again."
"The safety of the community is the MTA's utmost priority," Lhota said. "We will continue working with the community to ensure their concerns are heard and acted upon."
Something went wrong as contractors were blasting a tunnel for the Second Avenue subway at about 1 p.m, said MTA spokeswoman Marjorie Anders.
"I heard 'boom!' Then I heard people screaming, 'Call 911, call 911!'" said a 12-year-old girl named Eve Secilmis, who was home alone for several minutes when she heard the boom. "I was really, really scared, and I was crying. I didn't know what to do."
Officials were trying to figure out what happened at the construction site, beneath East 72nd Street and Second Avenue.
A vacate order was issued as a precaution for the ground floor of one building that had several windows blown out, said Tony Sclafani, spokesman for the city's buildings department.
Bystander Eric Guzman said he was struck in the back of the head by concrete, but FDNY officials reported no serious injuries in the blast.
"I saw rocks coming down around me and I was like 'Oh, please don't let me get hit,'" Guzman told NBC 4 New York.
FDNY chief James Esposito said, "We did have some collateral damage involving some windows on the adjoining structures, but it was relatively minor from what we’ve seen."
Witnesses described a hectic scene as they ducked for cover.
"There was a small cloud coming from 72nd and 2nd, and a lot of people were running from it," said Sabrina Ramdyal, who works at Sharkey's Cuts for Kids on East 72nd. "They didn't know what was going on."
"We're used to the explosions, the rattling and the shaking of the floor," she said. "Sometimes it's not so bad, sometimes it's really really bad. Today was bad. This one was a little bit harder than the rest.”
Venancio Arvizo, a worker at a cafe near the construction site, also said that blasting was common at the site, but the explosion Tuesday afternoon was much louder than usual.
"It shook the entire building," he said. "The windows shook and shattered. It shot up almost like a volcano out of the street."
The Kolb Art Gallery, which sells custom paintings and furniture, is located on the ground floor. Workers were removing pieces of art off a desk in the gallery after the blast.
Diana Mighiu, an employee at the gallery, said flying rocks flew through the door after the explosion, which damaged some store merchandise, including lamps and vases.
"The cement floor broke and went up in the air. We saw all this smoke," she said. "It was really scary."
There was no structural damage to any surrounding buildings, Sclafani said. There were no reported problems with electric, steam or gas lines after the blast.
The first phase of construction on the project began in April of 2007. In September, the project reached a milestone as two miles of new tunnels were completed, linking the start of digging on 92nd street to an existing tunnel at 63rd Street.
The first phase of the project will provide service from 96th Street to 63rd Street as an extension of the Q train. The first phase is planned to go into service around December 2016.
The MTA says the subway eventually will serve more than 200,000 people per day. It will reduce crowding on the packed Lexington Avenue line. The neighborhood lost its Second Avenue Elevated in 1940.
While the new subway line will return much needed service to neighborhood, construction has caused a host of problems. Air samples taken from the construction site had dangerous levels of toxic dust, containing three times the allowable amount of silica, according to a federal report released in March. Business owners along the construction route have also complained that sidewalk closures and construction fallout along the route has hurt their business.
Hortense Bernard, a manager at Mellesima Wine Shop on 2nd Avenue, between 71st and 72nd street, said workers for the MTA had installed sensors in the building where her store is located to monitor potential damage caused by blasting.
“They’re really cautious with their work,” Bernard said. “I trust them, but you never know.”
She added, “Sometimes when they’re blasting we’re scared.”
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