Hundreds of cracked or deteriorating nuts holding up Big Dig tunnel light fixtures must be replaced, but state highway officials say they have no idea how much it will cost taxpayers to fix the defective hardware.
Inspectors are still checking tunnel light systems with fiber optic cameras, but so far the probe has found 878 damaged nuts in the Ted Williams Tunnel and 49 nuts that need to be replaced in the I-90 Connector and the I-93 tunnels, according to MassDOT Highway Administrator Thomas Tinlin.
The highway chief insists the roads are safe for drivers, but the Big Dig tunnels have come under scrutiny before when a light fixture fell four years ago. In the past month, about 70 percent of fixtures in the Williams Tunnel have been checked, while only about 14 percent have been tested in the Connector and I-93 tunnels, said Tinlin, who expects to complete all light inspections by the end of November.
Revelations of the faulty fasteners come after the Herald reported last week that taxpayers have been stuck with the plumbing bill for up to $7 million a year to fix Big Dig tunnel leaks that have deluged the underground highway system.
More than 16 million gallons of water were pumped from the Big Dig tunnels in the first six months of this year — nearly the same amount that was removed from all the tunnels in each of the last two years.
Tinlin said replacing the fasteners could take six months and the work is expected to be paid for with state tunnel maintenance funds. But Tinlin told the Herald his team has yet to determine what the project will cost.
“We will be out there every night doing the work. Some of the reports I got back is this could take six months,” said Tinlin, who stressed drivers are safe because the nut-and-bolt system is one of three separate structures securing the lights in place. “We know the lighting system in the tunnels is safe. There is no danger of this falling.”
The Big Dig tunnels have a tragic history. Milena Del Valle died in 2006 after a 3-ton ceiling tile fell on her car while she was riding through an I-90 tunnel. Only later did the public learn the tunnel ceiling had gone years without inspection.
And just four years ago, state crews had to repair tunnel light fixtures when it was learned the Patrick administration had kept the public in the dark for weeks after a corroded 110-pound light fixture fell in the Tip O’Neill Tunnel. This time, inspectors don’t think corrosion is responsible for the deficient hardware, which is undergoing lab analysis, according to Tinlin.
Tinlin said he ordered a system-wide tunnel inspection of lights after a state-contracted engineering firm found a cracked nut on a light fixture in the Ted Williams Tunnel on Sept. 15.
“The working theory is they may have been over-torqued and became damaged when somebody thought they needed to over-tighten them,” said Tinlin.
“All of these could have been cracked since the day they were installed. Once we get the analysis from the lab back, then we can talk to our friends at Federal Highway and see if it’s covered by the trust fund,” he said.
Tinlin said the move to replace light-fixture hardware could be funded with money in a $303 million trust fund — set up to hold settlement money from shoddy Big Dig work — if lab results show the damaged hardware resulted from poor installation during the original tunnel construction.
State officials have expressed frustration that federal authorities won’t let MassDOT use trust fund money to repair tunnel leaks, which meet federal safety standards and are considered routine maintenance — the type of work not covered by the trust fund.
