A diver drowned in Da Nang Thursday while fixing a broken drill tip at a bridge construction site.
Nguyen Van Dau, 33, was paid VND10 million (US$513) to bring up a drill tip 32 meters below the surface of the Han River.
Dau was supposed to do two dives. The first dive was successful; Dau surfaced after 15 minutes with part of the tip. He descended once again and didn't resurface.
Another worker from the Tran Thi Ly bridge construction site dived to check on Dau and found his dead body.
Some of the workers said the tube supplying oxygen to Dau was narrow and might have twisted, diminishing Dau's air supply.
Workers also said the cold water might have weakened him.
Rescuers managed to bring his body to the surface on Thursday evening, seven hours after the event.
First investigation showed that Dau had been stuck in a pipe, which is part of the bridge construction.
The state-owned Cienco No.1 is the contractor of the bridge.
Police are investigating the case further.