The accident occurred on May 20 in Bong Son Ward, where a concrete pump truck had been operating on Bien Cuong Street to pour concrete for a house renovation project.
Officials said the pump boom suddenly cracked and collapsed during operation, striking workers at the construction site.
The injured workers were rushed to Bong Son General Hospital for emergency treatment, but one 46-year-old victim from Bong Son Ward, later died from severe injuries.
Local authorities confirmed that two other workers were being treated for injuries.
Police and relevant agencies are examining the scene and investigating the cause of the accident.
