NTSB Report on Big Dig Collapse

Last summer’s death of Milena del Valle under 26 tons of concrete that fell from the ceiling of a Big Dig tunnel raises a complex web of potential liability. I’ve posted about this over the past year as investigators pore through a mountain of evidence to fix the cause of the ceiling’s collapse. See Big Dig, Big Liability, Massachusetts Sues for Big Dig Negligence, and Big Dig Litigation Update. The National Transportation Safety Board (NTSB) recently identified use of the incorrect epoxy as the culprit. In the words of an NTSB member “[i]t’s kind of ironic in a $14 billion project . . . About $1.50 per anchor is what ended up bringing the ceiling down.”

According to the NTSB this is what happened. Bechtel/Parsons Brinkerhoff, which oversaw all Big Dig construction, reviewed the epoxy specifications prepared by Gannet Fleming, one of six subcontractors and suppliers who worked on the ceiling. The NTSB says that Bechtel/Parsons did not consider the fast-set epoxy’s long-term strength. The epoxy’s supplier, Powers Fasteners, stated in project documentation–“in the fine print”–that fast-set epoxy was not for long term use but apparently no one acted on this language. A Powers spokeswoman says that Powers supplied its standard-set epoxy, an order valued at $1,287, and assumed it was used. Big Dig contractors were aware that the bolts supporting the massive concrete ceiling panels were slipping and devised theories as to the cause, but the nature of the epoxy securing the bolts in their holes was not among them. Despite knowledge that these bolts were loosening the project’s overseers and the tunnel’s managers never instituted regular inspection of them. Reporting on the NTSB’s findings The Boston Globe stated “[t]here were no regular inspections in the more than three and a half years between the completion of the tunnel and the collapse . . . But after the disaster, investigators found that other ceiling panels were in imminent danger of falling.”

Expect more details over the coming months as other investigations continue, including one by Massachusetts Attorney General Martha Coakley to determine whether to file criminal charges in connection with del Valle’s death.