BOSTON – While much of this city worried Thursday about driving through the underground highway system known as the “Big Dig,” the political fallout from Monday’s fatal ceiling collapse in a Big Dig connector tunnel escalated.

Massachusetts Gov. Mitt Romney announced he was filing emergency legislation to take control of the investigation into the accident, in which 12 tons of concrete crushed a woman to death as she rode to Logan International Airport with her husband.

State Attorney General Tom Reilly pressed forward with a criminal case that could lead to manslaughter charges and already has delivered subpoenas to the Big Dig’s major contractors.

The state’s two top legislative leaders on Thursday joined a chorus seeking the ouster of Matthew Amorello, the head of the Massachusetts Turnpike Authority, the agency that oversees the $14.6 billion project, the largest urban infrastructure effort in American history. Amorello stated again that he intends to remain on the job.

Also on Thursday, the state’s congressional delegation asked the National Transportation Safety Board to manage the inquiry into the accident, calling for “an immediate independent review.”

Amorello reiterated on Thursday that at least 60 other tunnel defects had been identified since the accident. And while Boston drivers wondered how the 40-foot ceiling panels above the eastbound lanes of the connector could have come loose and crashed to the ground, the state’s Secretary of Transportation said that the ceiling on the westbound side was in worse shape.

The tunnel connector – a crucial route to the airport – remained closed indefinitely.

In a city that lived with 15 years of noise, grime and streets clogged with heavy equipment while an old elevated highway was replaced with a sleek subterranean road and tunnel system, the construction calamity also unleashed a crisis of public confidence.

“It undermines our faith in the system,” said Michael Szykolka, a tour guide for Boston’s Freedom Trail.