HANOI (Reuters) - Rescue teams in Vietnam struggled on Tuesday to save 11 laborers trapped and running low on oxygen after a tunnel collapsed earlier in the day during construction of a hydropower plant.
Rescuers braved heavy winds and rain to remove rocks and sand after a section of the tunnel caved in 500 meters from its entrance at the site in the Central Highlands province of Lam Dong, trapping a third of its workers and crushing tubes supplying oxygen to them.
"It's very worrying now as the oxygen is limited, the space is too narrow, the air is humid and there's water too," Dang Quang Dat, director of Song Da 505, the trapped workers' firm, told Vietnam Television (VTV).
"This morning we were able to send compressed air for them to breathe, but this afternoon there's no compressed air anymore because all the tubes were blocked," he said late on Tuesday, 12 hours after the accident.
It was unclear what caused the tunnel to collapse but a preliminary probe suggested it was triggered by heavy rain. The government asked ministries to coordinate and police, military and firefighters were deployed to boost the rescue effort.
"We're trying our best to provide oxygen ... we've drilled holes in several spots but there's a large amount of rocks and dirt falling and the geological structure is complicated," said Doan Van Viet, chairman of the provincial people's committee, the local administration.
"The rescue conditions are very difficult with the rain, heavy winds, narrow tunnel and rising water," he said.
The hydropower plant, one of dozens planned or under construction in energy-hungry Vietnam, is expected to produce about 110 million kWh annually, with total investment of 475 billion dong($22.24 million)
(Reporting by Mai Nguyen; Editing by Martin Petty and Tom Heneghan)