The federal investigation into the July 10 collapse of part
of a tunnel in Boston’s Big Dig project that left a woman dead is focusing on a
variety of possible explanations for what caused the three-ton concrete panels
to come loose from the ceiling.
The Associated Press reported that one avenue being
examined by the National Transportation Safety Board is whether vibrations from
nearby construction could have played a role in loosening the bolts that held
the ceiling panels in place. The NTSB is also examining whether freezing
temperatures, faulty installation or other factors could have contributed to
the deadly collapse.
Rep. Michael Capuano, D-MA, told The AP that, while
federal officials remained skeptical that the construction could be a cause,
they weren’t ruling anything out at this point.
Federal officials issued 12 subpoenas to people involved in
the Big Dig including contractors and subcontractors. The AP reported
that the subpoenas mirror those sent out by Massachusetts Attorney General Tom
Reilly in his criminal investigation.
Reilly told The AP on Thursday, July 27, that his
investigation is focusing on Bechtel/Parsons-Brinckerhoff, the main contractor
for the project.
Meanwhile, Matthew Amorello, head of the Massachusetts
Turnpike Authority, agreed to step down on Thursday, July 27, amid mounting
pressure from Gov. Mitt Romney and others involved in the Big Dig
Amorello came under fire following the fatal July 10
collapse. In the days following the accident, Romney filed emergency
legislation to assume control of the investigation and scheduled a hearing to
remove Amorello from his position.
That hearing was to have taken place on July 27, but
Amorello resigned before it got started.
The $14 billion Big Dig project – which buried portions of
Interstates 93 and 90 beneath downtown Boston and extended the Massachusetts
Turnpike to Logan Airport – has been plagued with problems through much of its
15 years, including leaks, faulty concrete, missed deadlines and political
scandals among those involved in its management.
The section of Interstate 90 where the collapse occurred,
which connects Interstate 93 to the Ted Williams Tunnel, is still closed
A second part of the tunnel, a mile-long ramp that connects
Interstate 90 west with Interstate 93 north and south, is also still shut down
as repairs continue.
The tunnel closures have brought more traffic to the surface
on Boston’s streets. The Massachusetts Turnpike Authority has posted
information on alternate routes and closures on the Big Dig Web site at masspike.com/bigdig.