Mario Garcia, a Miami attorney for Raquel Ibarra Mora, who lives in Costa Rica, said Mora applauded the attorney general's efforts to hold the people accountable for the accident that killed her mother.

"She hopes that this is just the beginning of many more who would hopefully be held responsible," Garcia said.

Jeffrey Denner, an attorney for Angel Del Valle, said he believes the grand jury would continue to consider criminal charges against others involved but that it was appropriate to charge Powers.

"They are certainly as culpable as it gets. They are the people who supplied the epoxy," he said.

In the report released last month, federal investigators spread blame for the collapse among the many corporations, consultants and engineers involved in the Big Dig project. The agency also faulted the Massachusetts Turnpike Authority for failing to conduct a timely tunnel inspection program.

The NTSB singled out Powers for providing "inadequate and misleading" information about its Power-Fast epoxy. Tests had shown the epoxy's "Fast Set" formulation to be "subject to creep under sustained tension loading," the report said.

Officials from Powers Fasteners issued a statement after the report was issued saying it would be "an absurd conclusion if the federal investigators were to consider Powers Fasteners in any way responsible, since the overwhelming evidence is that the fault lies elsewhere."

On Aug. 3, the NTSB sent Powers Fasteners a letter recommending they "revise the packaging, for all distributors, of your Power-Fast Epoxy Injection Gel Fast Set formulation to state explicitly that this formulation is approved for short-term loads only."

Del Valle's death prompted tunnel and road closures and sparked a public furor over the Big Dig project, the most expensive highway project in U.S. history.

The $14.79 billion Big Dig, which had an initial price tag of $2.6 billion, has been plagued by problems and cost overruns throughout the two decades it took to design and build. The construction buried the old elevated Central Artery that ran through the heart of Boston with a series of tunnels, ramps and bridges.