BEIJING: A blast in a tunnel has killed 20 workers at a highway construction site in central China.

The explosion Saturday in Hunan province also injured one person, said two officials from the provincial work safety bureau. They would only give their surnames, Li and Yang, a common practice among Chinese government employees.

The blast occurred when a vehicle was unloading explosives in the tunnel on a highway under construction between Yanling and Rucheng in Hunan, the official Xinhua news agency said.

Twenty workers died in the blast and one body has been recovered, Xinhua said. Four other workers escaped with injuries, and one was hospitalized in critical condition.

Accidents and explosions are common in China due to lax enforcement of safety standards.

In November, an explosion in southwestern China killed at least seven people and injured about 200. It was caused by three explosives-laden vehicles that caught fire and also destroyed a garage and a food warehouse.