It happened on Driggs Avenue near South 4th Street just after 8:30 a.m. Thursday.
The city's Department of Buildings said the workers fell one story when the parapet wall of the sidewalk shed gave way while they were working to erect a suspended scaffold.
Video from Citizen App shows emergency responders on the scene and a victim being carried away on a stretcher.
The workers were taken to the hospital with non-life threatening injuries.
The DOB has issued a partial Stop Work Order along with two violations to the contractor: One for failure to safeguard, and the other because the sidewalk shed was not constructed according to code specifications.
The scaffold was not damaged.
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