This is the latest in a series of fatal incidents involving Or Kim Peow Contractors, which was the firm tasked with building the structure.
The worker who died this morning is Mr Chen Yinchuan.
He is believed to have been killed instantly when the structure collapsed.
The other injured workers suffered fractures, head pain and ankle injuries.
One of those workers had his right hip impaled.
The workers were sent to Changi General Hospital for treatment.
A corbel is a structural piece of stone or metal jutting from a wall to carry a weight.
Or Kim Peow Contractors had been found guilty of breaching the Workplace Safety and Health Act 3 days ago after another construction site incident which left 1 worker dead and 3 injured.
Before that, the firm had had received 25 demerit points from the Ministry of Manpower and was blacklisted from January to April.