Authorities weren't immediately sure how the 11 a.m. mishap at the latest phase of the Riverwalk development off River Drive occurred, Borough Administrator/Police Chief Michael Foligno said.
The victim was taken to Hackensack University Medical Center in critical but stable condition, Foligno said.
The job was shut down and OSHA responded Saturday afternoon to "investigate and determine the next step," he said.
These include when work can be resumed, what measures must be taken and what types of penalties, if any, should be imposed.
Foligno couldn't confirm a source's contention to Daily Voice that the formwork for the poured concrete elevator shaft gave way either during or shortly after the pour.
Scaffolding set up inside the shaft likely broke the 35-foot fall, another source said.
Riverwalk community currently has 158 units within two, four-story buildings built in 2012 and 2014, as well as retail space and offices. The next phase of the project is to include 240 luxury rental units -- with a business center, pool and clubhouse -- in two buildings overlooking the river.
Click here to follow Daily Voice Fort Lee and receive free news updates.