Officials are doubting that a deadly gas leakage may have been a cause behind the death of 17 people including children that occurred in an illegal mine at a South African shantytown at an informal settlement in Boksburg, east of Johannesburg.

Gauteng Province Premier Panyaza Lesufi, visiting the site of the disaster near Boksburg, east of Johannesburg, said investigations were underway to determine how the cylinder in which the unidentified toxic gas was stored had sprung a leak.

Police and forensic investigators advised people to clear the area as the scene is still active with toxic gas.