US Highway Administration releases interim report on Boston's Big Dig: press release claims tunnel safe, but report does not

April 6, 2005

On April 4, the Federal Highway Administration released an interim report on leaks in the Central Artery Tunnel, part of Boston's Big Dig. The press release about the report claims that the report "concludes that the project is structurally sound and remains safe for traffic." However, the report does not reach those conclusions.

The report does not evaluate the current safety level of the tunnel; and on the subject of safety, it notes that ensuring the safety of the tunnel will require speedy implementation of a permanent repair of last September's major leak. The safety claim is repeated and touted as a "rare bit of good news" about the Big Dig in an Associated Press story by Steve Leblanc.

The Central Artery Tunnel, which allows Interstate 93 to pass beneath downtown Boston, experienced a 300 gallon-per-minute leak of water into the tunnel in September of 2004, according to the recent report. Mac Daniel of the Boston Globe notes in a recent article that the September leak caused "a 10-mile traffic jam".

In response to the leak, the Federal Highway Administration formed the Tunnel Leak Assessment Team to provide an independent assessment of the leaking in the tunnel and the efficacy of the repairs underway.

The report reaches three main conclusions:
 * "Chronic low level leaks" continue, but sealing work is expected to seal them "in the summer of 2005".
 * A temporary repair of the major leak which occurred in mid-September, 2004, has been completed, and permanent repairs are "under review".
 * Regarding permanent repairs, it adds, "Whichever option is selected must be implemented quickly to ensure the safe and uninterrupted passage of the traveling public."
 * "Additional defects" have been discovered in the slurry wall panels where September's major leak occurred.
 * In response to these discoveries, the report recommends, "The Project is encouraged to quickly complete the inspection of all panels and develop a standardized inspection process and related documentation."

According to the New York Times, Matthew Amorello, chairman of the Massachusetts Turnpike Authority, praised the report, stating that, "This independent affirmation that the I-93 tunnels are safe and structurally sound will allow drivers to use them with confidence."