Three workers died from suffocation in a pulp tank at a paper company in the south central province of Binh Dinh Tuesday.
The accident happened at around 8 a.m. at Hiep Phat Company in Phu Tai Industrial Zone, Quy Nhon City.
Huynh Chi, 45, Ho Minh Trieu, 25, and Nguyen Van Nhan, 21, reportedly entered the tank, which contained pulp mill, for cleanup.
After they did not come out after a while, a worker named Dao Van Du, 48, entered the tank to check and found the trio unconscious.
Du had to climb out of the tank as he had difficulty breathing and passed out as soon as he exited the tank.
Rescuers managed to pull the three workers out but they were already dead. Du was rushed to hospital.
He is now in stable condition.
Police said the workers may have died because of poisonous chemicals inside the tank.
Authorities are investigating the accident further.