BEIJING (AP) — A highway tunnel under construction in southwestern China has collapsed, killing four people and leaving another eight missing, authorities said Wednesday.

Water and mud burst from the tunnel as work was underway Tuesday evening in the Yunnan province city of Lincang, trapping 13 workers inside.

The news office of the Lincang city government said five were pulled from the rubble, but only one survived and was hospitalized in stable condition.

Waterlogged and unstable conditions were complicating rescue work. Sniffer dogs and life detection machines were deployed and a medical team was on standby at the site.

China suffers frequent industrial accidents despite efforts to improve safety training and inspections.

Last month, an underground parking garage under construction in southwest China collapsed, killing eight people. In March, a massive chemical blast left nearly 80 people dead in one of China’s worst industrial accidents in recent years.