The four workers were installing glass at a construction site on Nguyen Cong Tru Street, Hai Ba Trung District when the scaffolding suddenly collapsed at around 8 p.m, said Nguyen Van Luong, deputy head of the firefighting and rescue police division under the Hai Ba Trung police department.
Duong Bao Minh, 34, who lives on Nguyen Cong Tru Street, said: "I was drinking around five meters away when I heard the sound of glass breaking and the sound of a heavy impact. I was scared and ran away. When I looked back, I saw four people, a woman and three men, lying on the street."
Police officers came around 20 minutes later. Ambulances took the workers to the hospital. The collapsed scaffolding, which was suspended in the air, was taken down at around 9 p.m.
The workers were working on an eight-story building on an area of around 200 square meters. Construction had begun late last year and was nearly complete.