Philadelphia City Council members had some tough questions today for top city officials at the first of a series of hearings on demolition practices.

Council formed a special committee to investigate demolition procedures after the Market Street building collapse that killed six people earlier this month.

Deputy Mayor Everitt Gillison and Licenses and Inspections Commissioner Carlton Williams were the first to testify.

Williams told Councilman Curtis Jones that whether to evaculate occupied buildings near a demolition site is a case by case decision.

"So tell me what factors at the site would warrant you saying 'we might want to vacate this [building]'? Jones asked.

"It's very difficult to give you that answer," Gillison said. "If an imminently dangerous building is ready to collapse, then we [will] notify the residents right away to vacate the premises."

Councilman Jim Kenney asked Gillison to say specifically how city demolitions are held to a higher standard than those in the private sector.

"I think the question is that we're responsible as project manager for the ones that we do," Gillison said. "They are responsible for handling their issues."

Days after fatal incident, Mayor Michael Nutter announced higher standards for private demolitions.

The committee has announced four more hearings on June 27, July 11, Aug. 1, and August 13.