Big dig blunders
By Herald staff
Wednesday, July 12, 2006 - Updated: 07:19 AM EST

1987: Federal money approved for the Central Artery/Third Harbor Tunnel project, aka the Big Dig, at an estimated cost of $2.5 billion

     1991: Work begins on the Big Dig, which now has a $5 billion price tag

     December 1995: Grand opening of the Ted Williams Tunnel

     Jan. 12, 1996: Toll collectors in the Ted Williams Tunnel forced to wear respirators because of sickening fumes

     January 1996: Officials pump 400,000 gallons of water out of Ted Williams Tunnel air ducts because of persistent leaks

     May 1997: Big Dig price tag now $7.78 billion

     June 1998: Internal memo circulated by managers at Bechtel/Parsons Brinckerhoff raises concern about potential leaks. Memo made public in 2004. Dig now estimated at $10.4 billion

     April 11, 2000: Federal audit reveals that Big Dig managers deliberately misled federal officials about cost overruns for the now-$13 billion project

     September 2001: Leaks discovered in I-93 tunnel, pushing back the project’s completion date

     March 2003: I-93 northbound Big Dig tunnel opens to traffic

     December 2003: I-93 southbound Big Dig tunnel and Zakim Bridge open to traffic

     Jan. 11, 2004: Ice buildup in I-93 tunnel causes lane shutdown, resulting in sparodic traffic jams

     November 2004: The Herald reports that despite explicit warnings by top Big Dig officials in 1997, contractors failed to correct ineffective waterproofing practices that threatened to undermine construction in some of the most sensitive areas of the project

     Sept. 15, 2004: Gusher bursts in the I-93 tunnel

     March 2005: Inspections reveal 189 wall panels are defective and there are more than 2,000 leaks in the I-93 tunnels

     March 13, 2005: Chunks of ice fall from the Zakim Bridge and land on at least one car, forcing closure of all but two lanes on the bridge

     April 4, 2005: Federal Highway Administration deems Big Dig tunnels structurally sound

     April 5, 2005: Three cars and an ambulance transporting a patient are badly damaged by falling debris in the I-93 tunnel

     May 2005: Attorney General Tom Reilly learns that Big Dig contractors had been secretly patching a leak in the Fort Point Channel tunnel that was spewing 20 gallons of water per minute through cracks.

     2005: Estimated cost of the Big Dig $14.6 billion and counting

     January 2006:Final Big Dig ramp completed

     July 10, 2006: Large concrete slab in an I-90 Seaport connector tunnel crashes down on a car, killing one person and shutting down the tunnel in both directions