TEHRAN, Iran (AP) — The death toll from an explosion at a coal mine in eastern Iran rose to 50 on Wednesday after one of the miners who was injured in the weekend blast died in hospital, the Iranian state television reported.

A methane gas leak sparked an explosion on Saturday at the mine in Tabas, about 540 kilometers (335 miles) southeast of the capital, Tehran. Such gases are common in mining, though modern safety measures call for ventilation and other measures to protect workers.

It wasn’t immediately clear what safety procedures were in place at the privately owned Tabas Parvadeh 5 mine, operated by Mandanjoo Co. The firm could not be reached for comment.

Iranian state TV said out of the 17 injured miners, nine were hospitalized, one of whom died on Wednesday.

The bodies of 49 workers who were killed in the blast have been recovered and the operation concluded on Wednesday morning, leaving no one unaccounted for. There were 66 miners at work at the time of the explosion.

Iran’s mining industry has been struck by disasters before. In 2017, a coal mine explosion killed at least 42 people. In 2013, 11 workers were killed in two separate mining incidents. In 2009, several incidents killed a total of 20 workers.

Lax safety standards and inadequate emergency services in mining areas were often blamed for the fatalities.