The Nutter administration has invoked a provision of the controversial DROP retirement program to delay the departures of a dozen city managers and top officials who had planned on retiring next year.

The administration cited the September 2015 World Meeting of Families, which includes a visit by Pope Francis, as a reason to extend the retirement dates for five managers, including the deputy commissioner for parks and recreation, Susan Slawson, and her chief of staff, Cynthia D. Douglas.

The remaining seven, including three information technology specialists, saw their retirement dates extended because the city did not have suitable replacements. Under DROP rules, participants give notice four years in advance of their scheduled retirement date so the city can prepare for their leaving.

The city also plans to offer retirement extensions for upward of 100 police officers to ensure adequate security for the papal visit, which is expected to draw more than a million people to a Mass on the Benjamin Franklin Parkway.

"The city has a number of major events next year, and I am trying to make sure we have sufficient expertise and experience to deal with them," Everett Gillison, Mayor Nutter's chief of staff, said Wednesday. "I want to ensure that things happen with the smoothness I've experienced over the last seven years. I don't want to shoot myself in the foot during the last year of the administration."

Mark McDonald, spokesman for the mayor, said the costs associated with the extensions were negligible.

"It is not an added cost to the general fund," he said. "There is a small cost to the pension fund, but a manageable one."

The DROP program had been a target of the mayor, particularly after a 2010 report that said it would increase pension costs by $258 million over a decade. City Council declined to take measures to kill the program.

The program allows a city employee to pick a retirement date four years in the future and begin immediately accumulating pension benefits while working. The benefits are kept in an interest-bearing account and paid as a lump sum when employees retire.

Under DROP, the mayor has the discretion to extend an employee's retirement date by a year if an "extraordinary circumstance exists which threatens public health, safety, and welfare" of citizens.

Gillison said it was determined that such circumstances existed in the cases of each of the 12 managers who had their retirement date extended.

"I don't take what I'm about to go into next year lightly," he said. "I asked the deputy mayors to identify key folks who might want to stay. We did this on a case-by-case basis."

As for the police officers being offered extensions, Gillison said they would be needed for a variety of reasons.

"I think we are going to have to deal with people sleeping in the parks a lot more, and be sensitive to the crowds we are going to get starting in July and extending through September," he said, referring to tourism in general. "I need people who know how to talk to people in a respectful manner but also can motivate the groups to keep things going in a positive way."

The Committee of Seventy, the civic watchdog group, has been a critic of DROP. Its new chief executive, David Thornburgh, did not, however, see a conflict in the administration's opposition to the program and its use of its procedures in this instance.

"The question is, 'Are these people extraordinary and couldn't be replaced?' " Thornburgh said. "As long as DROP is a policy that is on the books, it becomes a management question. This is the last year of your term and you have a big event that is important to the city and you have to make a call as to who you need on deck to pull it off. I guess I feel, as a citizen, I want us to put our best foot forward."

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