Eight workers were swept away by water while working at an under-construction hydropower dam in the northwestern province of Son La on Saturday, the Voice of Vietnam (VOV) reported.
The accident happened at around 8 a.m. at the construction site of Suoi Sap 1 Hydropower Plant in Bac Yen District.
Eleven workers were reportedly installing turbines for the dam when a valve used to close the reservoir broke due to a technical error.
Water from the reservoir flowed into a water inlet sluice. Three workers managed to run away; the eight others were swept away into the sluice and drowned.
As of 10 a.m. on Sunday, rescuers had recovered the bodies of five workers. They are searching for the three missing bodies.
Work on the Suoi Sap 1 Hydropower Plant, built by a private company, the Xuan Thien Ninh Binh Ltd. Co, began in 2009. The dam is located in a mountainous area, some 70 kilometers away from Son La City.