Rescuers in northern China searched on Sunday for two people still missing after a gas explosion killed 82 in a mine that authorities said was beset by serious safety violations.

The blast at the Liushenyu shaft in Shanxi province on Friday was the country’s worst mining disaster in nearly two decades, with 247 workers underground at the time, authorities said.

AFP journalists saw relatives anxiously waiting by a checkpoint blocking the road leading to the mine on Sunday, hoping for news of their loved ones.

One man, smoking nervously on a curb, told AFP that calls to his brother — a father of three — “wouldn’t go through” since the blast.

He said he had “no idea how the accident actually happened” and that their parents were still unaware their older son was missing.

“I don’t dare tell them,” he said, asking not to be named.

Authorities launched an investigation into the blast, saying preliminary findings showed the Tongzhou Group operating the mine had committed “serious illegal violations”.

“Those found responsible will be severely punished in accordance with laws and regulations,” officials told a news conference broadcast on state-run CCTV.

More than half of the workers in the shaft on Friday had gone down without being properly registered, state media said.

The miners are normally required to undergo facial recognition checks or take location-tracking cards before their descent.

A person “responsible for” the company had been “placed under control in accordance with the law”, Xinhua news agency reported earlier.

Miners working at the Liushenyu shaft accused their employer of a lack of care, telling AFP they had to buy their safety helmets with their own money.