Nutter announced the choices at a news conference.
"Our objective is to bring the mayor a plan to make this the best L&I department in the United States," said Vaira, 76, who is volunteering his time.
Vaira said he was familiar with construction practices and the building trades after serving 10 years as the national hearing officer for the Laborers International Union of North America, conducting hundreds of hearings on issues, including workplace safety, construction procedures, and government oversight.
Corbett, 53, was unable to attend the announcement because of a scheduling conflict.
Nutter said the group would evaluate all aspects of L&I's operations, including organization, staffing levels, budget, and use of technology, comparing it with similar regulatory agencies around the country.
The panel has no specified budget, but the mayor said the city would provide whatever resources it needed to complete its work.
L&I Commissioner Carlton Williams vowed his department's full cooperation. Citing some changes already made, such as requiring safety plans for every demolition application, he said, "We fully understand that we can and will continue to improve, for the benefit of public safety."
The creation of such a panel was initially suggested publicly by City Treasurer Nancy Winkler and her husband, Jay Bryan, whose daughter Anne Bryan was among the victims of the June 6 collapse. Anne Bryan and a friend, Mary Simpson, were visiting the Salvation Army thrift shop at 22d and Market Streets to donate clothes that day.
They and four other people were crushed to death, and 14 others were injured, when a four-story brick wall fell onto the shop from a demolition site next door.
The demolition project had been underway for three weeks without a visit from a city inspector, according to officials. Procedures at the time did not call for an inspection until demolition was completed.
Nutter said he had been considering some kind of independent review of L&I operations since the day of the accident. The Bryans had been helpful in shaping the mission and membership of the panel, he said.
Along with Vaira and Corbett, the panel members are:
Emily Bittenbender, managing partner, Bittenbender Construction.
Ryan Boyer, business manager, Laborers' District Council of Philadelphia and Vicinity.
Robert Brehm, associate professor, Drexel University.
Lorraine H. Brown, chairman and CEO, Temple Group Inc.
Jim Dollard, safety director, Local 98 of the International Brotherhood of Electrical Workers.
Anne Fadullon, incoming president, Building Industry Association of Philadelphia.
Scott Knowles, director, Great Works Symposium, and associate professor, Drexel University.
Steven S. Lakin, executive managing director, General Building Contractors Association.
Angelo Perryman, Perryman Building & Construction Services.
City Councilwoman Maria Quiñones Sánchez, chair of Council's L&I Committee.
Gregory C. Stewart, vice president, Gilbane Building Co.
Francis Vargas, project manager, Allied Construction Services.
The panel also includes three city officials: John Elfrey, director of operations for Nutter's Office of Transportation and Utilities; Streets Commissioner David Perri; and Barry Scott, risk manager in the Office of Risk Management.
Vaira, now in private practice, was U.S. attorney during a period that included prosecutions tied to the FBI's Abscam corruption investigation as well as the mob warfare that followed the 1980 murder of crime boss Angelo Bruno. Originally appointed by Democratic President Jimmy Carter, Vaira was later tapped by Republican President Ronald Reagan to head a presidential commission on organized crime.
The Bryans issued a statement Thursday calling the panel's creation "a genuinely sincere and immensely encouraging effort by the Nutter administration to make sure such a disaster can never happen again."