Critics of Boston’s Big Dig interstate construction project ripped a $458 million settlement with contractors as “chump change” that provides meager compensation to taxpayers who were left with thousands of leaks, billions of dollars in cost overruns and a tunnel ceiling that collapsed and killed a woman, according to the Boston Herald.

“The lesson learned is, (you) can pay your way out of anything,” said Christy Mihos, a former Turnpike Authority board member and gubernatorial candidate. “We’ve learned nothing, because the taxpayers are going to have to pick up the cost going forward.”

The settlement, which follows years of investigation, forces Bechtel/Parsons Brinckerhoff, a consortium that oversaw design and construction of the project, to pay $407 million for “gross failures” in multiple areas of the $15 billion project. It also requires 24 design firms to pay $51 million for errors on various contracts.

Bechtel/Parsons Brinckerhoff will escape criminal charges and will only be held liable in case of a “catastrophic” incident within the next ten years. Even then, the firm’s liability would be capped between $50 million and $100 million. The deal also does not bar the consortium from receiving future government contracts.

Attorney General Martha Coakley said the state of Massachusetts had enough evidence to indict, but realized it could exact more meaningful punishment through a settlement. The maximum penalty for a manslaughter charge against a company is $1,000 in Massachusetts.

State and federal prosecutors forced Bechtel/Parsons Brinckerhoff to admit errors and neglectful conduct, including:

• The joint-venture firm admitted it observed epoxy bolts were slipping out of the ceiling that eventually collapsed and killed Milena Del Valle, 39, who was driving with her husband to Logan International Airport, but the firm did not conduct adequate follow-up inspections to ensure the problem was resolved. The firm also acknowledged documents certifying the tunnel’s safety were not accurate.

• The firm admitted to knowingly permitting the construction of defective slurry walls in the Tip O’Neill Tunnel. The tunnel was later found to be riddled with thousands of leaks.

• The firms acknowledged poor oversight of Aggregate Industries, a concrete firm that supplied the project with loads of faulty concrete used throughout the Tip O’Neill Tunnel.

• Finally, B/PB admitted to poor oversight of contract modifications and work records that inflated the cost of the project.