China ? At least 46 miners were killed today when an explosion ripped through a coal mine in central China, state media reported.

The blast hit a mine in Pingdingshan city in the province of Henan, the State Administration of Work Safety said. Seventy-two miners were trapped initially but 26 escaped, the official Xinhua News Agency reported.

State broadcaster CCTV reported on its website many of the deaths were caused by carbon monoxide poisoning set off by the explosion. The report said an investigation is under way into the cause of the blast.

Safety has improved sharply in recent years, but China’s mining industry is by far the world’s deadliest. Accidents and blasts killed more than 2,600 coal miners last year.