Rep. Lynch Renews Calls For Big Dig Investigation

BOSTON (CBS) - State leaders insist the Big Dig tunnels are safe, but Congressman Stephen Lynch is renewing calls for an investigation into potentially dangerous problems first exposed by WBZ.

Lynch says he's very concerned about the safety of the tunnel and the area around it and he's calling on the Feds to come in and take a look.

Lynch says because of the high volume of car and train traffic in that area, he's especially concerned about the structural integrity.

WBZ-TV's Kathy Curran reports

A common ground freezing technique was used when the tunnel was built, but as it has thawed it has created a massive sinkhole. We reviewed documents dating back to 1997 about the freezing process.

There were questions raised about the stability of the soil, possible seepage and how to monitor any movement underground back then, now with the sinkhole Lynch doesn't feel it's safe.

Mass Highway Administrator Frank DiPaola tells WBZ there's evidence of a sink hole because the ground underneath has settled. The tunnels haven't moved and engineers believe it is safe. He says in about a month they'll drill down on both sides of the tunnel to get soil samples and a better picture of what's going on.