City officials ordered on Tuesday a partial construction shutdown for another office tower in Midtown Manhattan that is being converted to apartments, following the city's ramped-up investigations of such projects.

Some construction is now paused at 750 Third Avenue, according to city records. Developer SL Green is converting the 35-story office building into about 600 new apartments with a party room, sun deck and screening room.

That stoppage marks the third office-to-residential conversion where work is currently halted since the old Pfizer headquarters neared partial collapse earlier this month. City officials also issued a partial stop-work order for another conversion project at 77 Water Street in Manhattan's Financial District this month, though that one was lifted days later.

The Department of Buildings ordered construction to pause after inspectors discovered several steel columns at the site that had been reinforced in ways not previously included in the design plans approved by the city. Upon identifying this discrepancy, a city inspector asked for updated documentation on the steel columns and that wasn't provided, the Buildings Department said.

SL Green said it had previously identified the inconsistency with the steel columns and was working on updating its design plans to later file with the city.

"There are no structural issues with the building, and we are already working with the licensed professional engineer of record to address this condition," a spokeswoman for SL Green said.

Dozens of these conversion projects are in various stages of planning or construction in New York City.

The Buildings Departments is sweeping project sites across the city as part of its investigation into what went wrong to put the former Pfizer headquarters on the brink of partial collapse earlier this month. That project was put on hold after two steel columns buckled, forcing an evacuation of nine surrounding buildings.

Inspectors are now working their way through a number of construction sites, including those involving MetroLoft, the developer of the Pfizer building conversion, and inspection firm Domani Inspection Services, which also worked on the Pfizer project.

At 750 Third Avenue, the Buildings Department didn't find any "damage, cracking or other structural distress" related to this issue. Still, it imposed the partial stop-work order to give the city more time to review the project plans. Inspectors are now requesting more records related to these steel columns.

SL Green expects this project to be completed in 2029, and doesn't forecast this stop-work order to interfere with that timeline.

Stop-work orders are fairly common for New York City construction projects. The Buildings Department issued more than 7,000 of them last year.

Last week, the city shut down construction at 222 Broadway, another Manhattan office-to-residential conversion. The New York Times previously reported the partial shutdown at 750 Third Avenue.