Four workers died from a lack of oxygen Saturday at a construction site in south China's Guangxi Zhuang Autonomous Region, local authorities said.

The accident happened around 1 p.m. when four workers went into an excavation pit to rescue another worker who had fallen in at a construction site in Longlin County of Baise City, said a spokesman with the municipal public security department.

Four workers died of hypoxia while another was revived after emergency treatment at the hospital, said the spokesman.

Police have begun an investigation into the accident.