BOSTON -- Turnpike board members, angered at the Big Dig's ongoing cost hikes, are actively exploring the possibility of replacing the firm managing the massive highway project.

Bechtel/Parsons Brinckerhoff, one of the largest engineering and construction firms in the world, has overseen construction of the Central Artery project since the project broke ground in 1991.

While finding a replacement for Bechtel would be difficult, it's not impossible, according to Jordan Levy, a board member of the Massachusetts Turnpike Authority.

"There is no company in the world that is indispensible," Levy said. "Nobody should ever feel that they have us. That's when the numbers start going up like a slot machine."

The $14.4 billion Big Dig has been plagued with cost increases throughout its history. In the past two months, officials announced two more hikes totaling $300 million.

The overruns prompted Levy to ask for a public meeting with Bechtel. That meeting is scheduled for Sept. 6.

Levy says he wants Bechtel to explain the overruns. He said he is also prepared to ask the three-member board to take action in response to Bechtel's answers.

He would not say what kind of action he might recommend.

The fact that few companies have Bechtel's vast engineering resources puts the state in a difficult position.

"We're really talking about brain surgery here," said board member Christy Mihos. "There's not many (companies) who can do this, so that puts more pressure on all of us."

Bechtel spokesman Howard Menaker said he's looking forward to the meeting.

"We hear their concerns and we want to give them concrete answers," he said. "We want to see this project all the way to the end."

The Big Dig, officially known as the Central Artery/Third Harbor Tunnel Project, will bury three miles of Interstate 93 beneath downtown Boston.