Debris from surface construction rains on vehicles inside Big Dig tunnels

| 4/7/2005

The day after officials officially released a report declaring the tunnels of Boston’s Big Dig were safe, a construction mishap rained rocks and dirt on at least five vehicles inside the Interstate 93 tunnel, local media outlets reported.

Construction workers were demolishing supports for the old, above-ground I-93 roadway and a small building over a ventilation shaft Wednesday, April 6, when some of the construction debris fell into the shaft, making its way down to the tunnel road surface far below. Media outlets said the rocks and dirt struck five passenger vehicles, one of which was an ambulance.

The incident – which officials said was not caused by or related to the tunnels’ integrity – led the Massachusetts Turnpike Authority, which operates the Big Dig, to suspend work by the construction firm whose activities led to the material dropping on the highway.

One day earlier, the Federal Highway Administration released a report in which it concluded that the tunnels were safe for truckers and others to use. In the report, federal officials said the project is structurally sound and remains safe for traffic but recommends that work continue with inspections and repairs to put a stop to any and all leaks as soon as possible.”

The Federal Highway Administration began investigating the safety of the tunnels when the first leaks started popping up late last year. The recently released report was based on a three-day assessment of the tunnels’ integrity conducted in December by senior engineers, according to The Boston Globe.

The safety of the tunnels has been questioned since Jack Lemley, an independent engineer who is examining the massive set of tunnels, said in mid-March that he was no longer able to assure that the tunnels making up the Big Dig were safe.

“I am now unable to express an opinion as to the safety of the I-93 portion of the Central Artery,” Lemley wrote in a letter he reportedly sent to the Massachusetts Turnpike Authority that was delivered March 9. The Boston Globe obtained a copy of the letter. “My modified position is necessary due to a revised understanding of the magnitude of problems that we became aware of following our testimony on Nov. 30, 2004, and the recent failures reported in the local newspapers.”

His comments were widely reported in the media. But they were not the first time someone had raised concerns about the Big Dig, formally known as the Central Artery Project.

In late 2004, The Boston Globe began a series of blistering reports about a series of leaks that appeared in the tunnel system. Since the initial report, leaks have been reported in more and more tunnel sections, leading to investigations and legislative hearings.

As of March 15, The Globe reported that leaks, construction faults and damage to fireproofing can be found in roughly 40 sections of the tunnels.

The Big Dig was created to take the elevated interstates that once ran into the center of Boston and replace them with wider, higher-capacity underground highways, including new tunnels and bridges to carry traffic over and under the city’s waterways. The Big Dig carries portions of several highways, including Interstate 93 and I-90.

The $14.6 billion project – called the largest of its kind ever in the United States – included numerous, massive cost overruns, and the private concerns in charge of the work have drawn the ire of local, state and federal officials.

Federal Highway Administration officials said in a statement that they would continue to monitor the project, not only to ensure it is safe and remains open to traffic, but also to protect the multibillion-dollar investment taxpayers have made in the project.

The agency expects to issue a follow up later this year, after inspections and repairs are complete.