That's one big "oops."
The MTA has blamed Tuesday's blast at a Second Avenue subway construction site on workers who pointed explosives in the wrong direction and a metal covering meant to contain blasts that wasn't properly anchored.
The explosion of rubble had caused minor damage to buildings but didn't injure any workers or pedestrians.
Michael Horodniceanu, who heads the MTA's megaprojects, said Wednesday he was "really upset and angry" about the botched job by the subcontractors doing the work on what will be the 72nd Street entrance of the subway line, and thankful that nobody was hurt.
"What happened was completely unacceptable and should have not occurred," Horodniceanu said. "I truly would like to apologize to the residents of the area that have been exposed to numerous problems throughout the construction with this project."
The workers were supposed to be setting off a blast 40 feet underground to create a space for an escalator, but directed the explosives at a 30 degree angle, instead of vertically, which led to the upward eruption. On top of that, the 1,800 pound, inch-thick steel plates that cover the hole at street level to keep in dust and rubble were not anchored.
"The cover was supposed to absorb all of this pressure. It did not," Horodniceanu said, calling the system in place "inadequate." He said all other metal plates on MTA construction sites were being checked.
Because the cover wasn't welded down, it lifted up "like a trap door," MTA spokesman Adam Lisberg said. That cover was not welded down because it wasn't expected to be affected by the blast.
Dorrie Elk, a contracts manager for Schiavone Construction, one of the three subcontractors on the project, rejected the MTA's explanation for the explosion, saying, "The cause of the incident is not known at this time."
Spokesmen from J.F. Shea Co. and Kiewet, the other two companies working on the subway line, were not available for comment last night.
The MTA has halted work at the site until it figures out exactly how the work went awry.
The agency also said it will hire an outside safety consultant for the $4.45-billion project and use a blasting consultant more frequently. Pedestrians and cars will also be kept farther away when blasts are going off.
Tuesday's explosion at the site was the second felt on street level so far this month, officials said, though they said the first one was much smaller.
MTA spokesman Kevin Ortiz said the cause of the Aug. 8 explosion, which was across the street from Tuesday's blast, was a "shift in wooden beams at the surface," which let "minor" debris fly out.
He said the other beams were inspected and "found to be in sound condition," adding that all of the beam attachments were replaced with stronger anchorages.