Feds finish Boston Big Dig investigation

BOSTON, July 11 (UPI) -- Builders and suppliers are to blame for a tunnel collapse that killed one woman beneath Boston Harbor in Massachusetts, said federal investigators.

The Big Dig consortium, led by Bechtel Corp., should have known the epoxy glue used to hold ceiling panel bolts in place could slip over time, the National Transportation Safety Board concluded.

The NTSB Tuesday, in a summary of its investigation, said "Big Dig" workers should have monitored the concrete panels after bolts were discovered to be sliding out of place in 1999.

Milena Del Valle, 39, was crushed to death a year ago when panels weighing 26 tons fell on her car in a tunnel beneath Boston Harbor.

The accident followed years of cost overruns and complaints about shabby construction at the Big Dig, a maze of highway tunnels beneath Boston's downtown. The cost of the project stands at $14.6 billion.

Del Valle's family is suing Bechtel and a decision is expected within several weeks on whether the Massachusetts' attorney general will file criminal charges.