QUETTA, Pakistan (AP) — An explosion inside a coal mine in southwest Pakistan killed 12 miners while eight were rescued, an official said Wednesday.

The bodies of the dead were all recovered after the overnight collapse in Harnai, a district in the Baluchistan province, a mine inspector Abdul Rashid said.

He said investigators were still working to determine the cause of the blast.

Pakistani Prime Minister Shehbaz Sharif in a statement expressed his sorrow over the deaths.

Safety standards are commonly ignored in the coal mining industry in Pakistan, leading to accidents and explosions that kill dozens of mine workers every year. Miners often complain that owners fail to install safety equipment.

Despite the danger and low wages, hundreds of miners work in Baluchistan, where unemployment is higher than other parts of the country. Harnai is about 200 kilometers (120 miles) east of Quetta, Baluchistan’s capital city.