BOSTON (AP) – The state spent at least an additional $35 million trying to repair leaks in the Big Dig highway project that carries Interstate 93 under downtown Boston, according to a new report.

State Inspector General Gregory Sullivan said Wednesday a preliminary review by his found contractors filed about 150 leak-related changes to original contracts that added $35 million to the project’s $14.6 billion price tag.

The contracts include the portion of the project where an 8-inch leak in September water pouring onto the roadway, causing massive traffic backups.

“These changes orders are only the tip of the iceberg,” Sullivan wrote in a letter to Matthew Amorello, chairman of the Massachusetts Turnpike Chairman, the agency that oversees the project. “First, they cover just two of the tunnel’s eight contracts and less than a quarter of the roadway that runs through downtown Boston. Second, the problem if far from fixed.”

Sullivan’s letter pointed a finger at the project’s private manager Bechtel/Parsons Brinckerhoff, which failed to refer a single waterproofing or tunnel leak to the project’s cost recovery team.

“(Bechtel) has failed in its professional and contractual duty to ensure quality construction,” he wrote. “Rather than admitting to this failure, (Bechtel) has tried to obscure the issue by seeking to blame others.”

Bechtel officials rejected the criticism.

They said there haven’t been $35 million worth of changes related to leaks for that section of the tunnel.

“(Sullivan) is flat out wrong and has been on technical issues on this project in the past,” said Bechtel spokesman Andy Paven.

“We take these issues very seriously.”

Earlier this year, state Auditor Joseph DeNucci’s identified what he said was an additional $10 million in cost increases due to damage caused by water leaks and seepage in the tunnels.

Turnpike Chief of Staff Marie Hayman said all contractors will be held accountable for fulfilling the requirements of their contracts.

William Horne, a member of the Turnpike’s cost recovery team, said it will review Sullivan’s letter and send demand notices to contractors when appropriate.

Sullivan’s letter came as Turnpike officials struggled to counter public worries about the leaks.

The tunnel is still under construction and that a certain number of smaller leaks are expected in a project the size of the Big Dig, Amorello said.

“Not only is the roof of the tunnel not yet fully installed, but there are also a number of locations where the underpinnings for the old elevated artery need to be removed,” he said. “Until that is done, it’s impossible to know the exact origin of all this water infiltration.”

He said the tunnel is safe for motorists.

Project Manager Michael Lewis said there were about 10,000 locations in the tunnel where roof girders connect to wall panels. He said there was some water seepage in about 1,000 of those connections, and about half of them have been fixed.

“Our contract requires a dry tunnel, but dry doesn’t mean bone dry,” he said. “All tunnels leak. All tunnels take on water.”

Leaks in the Big Dig tunnel system are more widespread than state officials have acknowledged, and top construction managers warned as far back as 1998 about problems that could cause failures in tunnel waterproofing efforts, records show.

Documents obtained by The Boston Globe show project managers collectively signed off on at least $10 million in cost overruns to repair the leaks and water damage since early 2001.

The documents show the Massachusetts Turnpike Authority and Bechtel established a Leak Task Force early in 2001.

Worries about the leaks are being felt in Washington.

Sen. John Kerry, D-Mass., released a statement Wednesday calling for improved oversight at the project.

“It’s incredible that year after year, in spite of all the warning signs and near death experiences for this critical project, no one has figured out where the buck stops,” he said.

The Senate Commerce Committee, chaired by Sen. John McCain, R-Ariz., could hold a hearing on the Big Dig on Tuesday if the Senate is still in session next week. The committee has been contacting potential witnesses.

Among the likely witnesses are representatives from the Turnpike Authority, the inspector general for the federal Department of Transportation, and retired judge Edward M. Ginsburg, who was appointed last year to lead the team reviewing the project for overcharges by contractors.

If the Senate adjourns before Tuesday, McCain’s tenure as chairman ends and it is uncertain when or if a hearing would be scheduled.

AP-ES-11-17-04 1942EST