Rescuers are pumping out water to try to find 14 construction workers trapped by a flood in a tunnel being built in southern China

The rescuers have not been able to contact the workers, Zhuhai city emergency management department said.

“Rescue work is proceeding in an intense and orderly way,” it said.

More than 1,000 workers, 22 fire engines and five pumping vehicles were taking part in the effort, with search and rescue teams dispatched from surrounding cities in Guangdong province.

The cause of the flood is under investigation.

In March, two workers died in another part of the tunnel when a protective wall collapsed and they were hit by falling stones, according to a notice from the emergency management department.

Zhuhai is a coastal city near Macao at the mouth of the Pearl River delta. It was one of China’s early special economic zones when the ruling Communist Party started opening up the nation’s economy about 40 years ago.