THIS STORY HAS BEEN FORMATTED FOR EASY PRINTING

Big Dig woes still pose threat

Corrosion caused one fixture to fall in Feb. from ceiling of O’Neill tunnel

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By Eric Moskowitz
Globe Staff / March 17, 2011

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A 110-pound light fixture crashed onto the northbound lanes of the Thomas P. “Tip’’ O’Neill Jr. tunnel in early February, striking no vehicles, but prompting state officials to launch an inspection of light fixtures throughout the Big Dig tunnel system.

State Transportation Secretary Jeffrey B. Mullan said that years of corrosion had weakened the aluminum rails by which the 8-foot-long light fixture was suspended from the ceiling, causing the steel fasteners to fail. The light fixture landed between two travel lanes in the tunnel sometime on the morning of Feb. 8.

Mullan stressed that the vast majority of the 23,000 light fixtures in the O’Neill, Ted Williams, and other Big Dig tunnels were undamaged, and that most of the corrosion was concentrated at the entrances and exits of tunnels where moisture from the outside is most prevalent. However, after the Big Dig’s troubled history that includes a fatal tunnel ceiling collapse in 2006, state officials launched a systemwide investigation of all tunnel lighting, though they did not inform the public for more than a month.

“This is a relatively isolated incident, but it’s something that we’re taking very seriously, and we won’t be able to reach any conclusions regarding causation until we complete 100 percent of the inspection,’’ Mullan said, displaying a sample light and a corroded fixture at a briefing yesterday afternoon. “There’s no question in my mind that the tunnels are robust and safe for the traveling public.’’

The light fixtures run the length of the tunnels and are mostly positioned above the lane markers. Each contains two fluorescent tubes housed in an aluminum frame that is hooked by a set of 10 stainless steel clips to another aluminum frame that, in turn, is bolted to the concrete ceiling. The light fixture that fell had corrosion that affected all 10 clips, but Mullan said such extensive damage was rare. State inspectors found one other light fixture with corrosion damage where nine of the steel clips are connected, but most frames showed no corrosion or only limited damage, according to Frank Tramontozzi, the state’s chief highway engineer and its acting highway administrator.

In all, Mullan said, about 3,000 of the 230,000 steel clips securing the lights were no longer holding onto anything because the aluminum rail had corroded. Inspectors repositioned all of those clips to make sure they were fastened to sturdy aluminum.

The Big Dig, a 7.5-mile maze of tunnels and highways, is sort of a crossroads of New England, carrying more than 250,000 vehicles daily through the O’Neill and Williams tunnels alone. The $15 billion project is credited with greatly reducing travel time to Logan Airport from west and south of Boston, and with relieving downtown congestion. But its ballooning price tag — the Big Dig was first estimated to cost $2 billion — and repeated construction and maintenance problems have made it a national lightning rod for criticism.

In July 2006, Milena Del Valle, 38, of Jamaica Plain, was killed when a concrete section of the ceiling in the Interstate 90 Connector Tunnel fell on the car in which she was riding to the airport. Her husband managed to crawl out of the crushed vehicle.

The ceiling collapse led then-Governor Mitt Romney to launch a “stem-to-stern’’ inspection of the Big Dig tunnels, requiring the temporary closure of large sections of the project. The inspection resulted in some reinforcement of sections of tunnel ceilings, but state officials said yesterday that the visual inspection was not designed to detect corrosion inside light fixtures.

The companies that oversaw the Big Dig, Bechtel and Parsons/Brinckerhoff, ultimately paid the state $400 million to settle claims of shoddy workmanship, including a 2004 episode in which a breach in the wall sent water gushing into the O’Neill tunnel. It was later revealed that the tunnel was riddled with leaks in its roof. In 2008, the Del Valle family received about $28 million in a settlement with the Massachusetts Turnpike Authority, Bechtel, Parsons/Brickerhoff and other Big Dig contractors.

In the light fixture collapse, Mullan said the state’s initial inspection suggested that the powder-based white paint on the frames caused the aluminum to corrode when it came in contact with moisture and road salt. Mullan said the state plans to aggressively pursue measures to recover damages from NuArt, the California firm that made them. NuArt officials could not be reached for comment last night.

The problem was not previously discovered because the state’s annual inspection of the tunnels included only a visual inspection of the lights. Now they are being pried open manually, Mullan said.

In places where the fixture has corroded, the clips are being moved to fasten onto a non-corroded part of the aluminum lip. Every light above the roadway and 95 percent of all lights have been inspected, with the remainder expected to be complete by next Friday, Mullan said.

Meanwhile, the state is sending failed components to an independent laboratory for analysis, and it is working on a longer-term solution that is at least a few months away.

Mullan defended the decision to hold off on disclosing the problem, saying he did not want to create panic or confusion.

“I wanted to have a better idea of what exactly we were dealing with — whether or not this was an isolated situation or more of a systemic issue. It takes a while to conduct all of the reviews. We’ve been at it quite some time. Twenty-three thousand fixtures is a very large number,’’ he said. “We feel confident now that we’re getting to the bottom of the situation and we have enough information to adequately tell the public what has happened.’’

Eric Moskowitz can be reached at emoskowitz@globe.com. Sean Murphy of the Globe staff contributed to this report.