WASHINGTON – Dressed in a somber black pants suit,Raquel Ibarra Mora sat in a dimly lit back corner of the National Transportation Safety Board's hearing room Tuesday,listening to talk of anchor bolts,epoxy and assigning blame.
Her mother,Jamaica Plain,Mass.,resident Milena Del Valle,38,was killed July 10,2006,when ceiling panels in Boston's Interstate 90 connector tunnel fell onto the car in which she was a passenger.
But before Mora,24,could join her family for an evening memorial service at the Iglesia Hispana de la Comunidad church in Jamaica Plain,she was here to learn the official cause of the accident that killed her mother.
“It would have been better to have gone through this process on another day that wasn't the one-year anniversary of the death,” Mora,of Costa Rica,said in Spanish through a translator.
“But the sadness and the overwhelming difficulty of the entire process is kind of saved by the wonderful news of the information of the people who will hopefully be held accountable by the findings of the report,” she said.
The tunnel,a part of a freeway project known as the Big Dig,connects downtown Boston to Logan International Airport. The project was known for being over budget and behind schedule. Two tunnels were closed for a time after the accident but are now open.
The NTSB unanimously approved a staff report that identified the use of Powers Fasteners,Inc.,”fast-set” epoxy as the probable cause of the ceiling collapse.
The material,used as ceiling anchor bolt adhesive,has “acceptable short term strength,” but with time it tends to deform,or “creep” under the pressure,said Bruce Magladry,director of the NTSB's Office of Highway Safety.
“I think it would be fair to say the use of this epoxy would be inappropriate,” said Jim Wildey,an NTSB investigator.
If any of the contractors involved in the Big Dig project had known about the fast-set material's poor creep resistance,a different material or anchoring system likely would have been used,Magladry said.
“We've found a significant lack of understanding in the engineering committee involved in this accident about creep,” he said
The NTSB also recommended that the Federal Highway Administration seek legislation to establish a mandatory tunnel inspection program similar to the national program required for bridges and that departments of transportation throughout the country ban overhead-adhesive anchors in public areas until safety standards have been developed.
The investigation also found the Massachusetts Transportation Authority conducted no formal investigation of the tunnel ceilings between January 2003 and July 2006.
“They should have been ready to go with the tunnel inspection program the minute the tunnel was completed,” said Debbie Hersman,an NTSB board member.
The NTSB report faulted a number of companies and the MTA. The companies,including Bechtel/Parsons Brinkerhoff,should have known an epoxy-adhered design would be susceptible to deformation over time,investigators said.
Investigators said Powers Fasteners released information about its products that failed to highlight the differences between two formulas,”fast set” and “standard set,” which would have been a better choice.
Contractors noticed problems with slipping ceiling bolts in 1999 and again in 2001,investigators said. Powers Fasteners inspected the problem in September and October 1999,but failed to notice the creep or that the wrong product was being used,said Mark Bagnard,an NTSB investigator.
“When Powers was contacted,that was an opportunity to know … however everyone continued to believe it was an installation problem,” he said.
Though investigators said they couldn't determine the degree to which Powers Fasteners was aware of the product's tendency to creep,Del Valle family attorney Brad A. Henry,who watched the hearing with Mora,said it was “certainly,absolutely known by Powers Fasteners in October 1999.”
“There's utterly no reason why it wasn't addressed back then,” he said after the hearing.
A wrongful death lawsuit on behalf of the Del Valle family is pending,and Henry said he found the report's findings helpful.
“It confirmed a great number of things that we weren't certain about. The type of epoxy used in that section we weren't quite certain about,” he said. “We have somewhat more information about what happened prior to the accident,back to 1999. It was in fact very well known creep was an issue between some of the defendants.”