City Council on Thursday night reached a compromise on legislation critical to moving the $700 million Convention Center expansion forward, but may have violated Pennsylvania's open-meetings law in the process.

Discussion of how to break a weeklong 8-8 deadlock regarding whether nonunion contractors could work on the project, and how much work would go to minorities, went on for hours behind closed doors.

Most meetings were held inside the office of Council President Anna C. Verna.

In efforts to reach a resolution before a prescheduled meeting Monday with Gov. Rendell, Verna called for a recess during Thursday's final Council session of the year when the Convention Center bill came up on the calendar.

That was before noon. Council did not reconvene publicly for a vote until after 9 p.m.

In between, some Council members attended holiday parties. Some attended fund-raisers. Some milled around in Council chambers.

And some worked on related legislation.

By early evening, nearly every Council member had strolled into Verna's office - Mayor Street was there, too - to weigh in or be advised of compromise language that was reached by blending two amendments together. Both amendments surfaced during the recess hours.

It appeared that members walked in and out of Verna's office at varying times, with some gathering in small groups in separate rooms within the office.

But no Council member interviewed yesterday could say with certainty that there wasn't at least a quorum - in this case nine or more members - gathered at one time together.

"Depends on when you were in there," Councilwoman Marian Tasco said.

"There may have been a time when there may have been more people in there than the Sunshine Law permits, but I don't think we were talking about pending legislation at the time," Councilman Frank Rizzo said.

"They could have been there, I don't know," Councilwoman Carol Ann Campbell said. "I don't know how long anyone was there before I got there."

The state's Sunshine Law prohibits a quorum from meeting privately to discuss public policy or take official action.

"The Sunshine Act doesn't require only that the final vote occur in public. It requires much more - that in most cases the discussions leading up to the decision be open," said Teri Henning, general counsel of the Pennsylvania Newspaper Association.

Verna's spokesman, Anthony Radwonski, said the Council president could not be reached yesterday.

The goal of permitting the public to witness decisions and deliberations is to boost public confidence in government.

Council members, with one exception, said they support that goal, and don't support breaking the law, but are frustrated nonetheless.

Unlike Council, "the state [legislature] has the ability to caucus," Tasco said. "There are times you have to be able to caucus to have an in-depth discussion where people are more open about their positions than in a public forum. It helps you come to a more honest resolution."

But Councilman W. Wilson Goode Jr. said, "To me, most of the discussion yesterday was about a discussion for how you break a stalemate in a situation like this. And at some point, what you get to is people agreeing on how they are going to agree, not necessarily what they are agreeing on."

That said, he added: "I don't care about the Sunshine Law. I don't know who cares about the Sunshine Law, and I'm not sure whether it was broken or not."

Contact staff writer Marcia Gelbart at 215-854-2338 or mgelbart@phillynews.com.