Mozambique officials in South Africa say at least 10 of their nationals may be among the 17 fatalities after Wednesday night’s gas leak in an informal settlement in Boksburg, east of Johannesburg.
At least four of those being treated in hospital after the incident in the densely populated Angelo shanty town are also thought to be from Mozambique.
Toxic gases are often used by illegal gold miners – known locally as zama zamas – to extract gold from soil stolen from abandoned mine shafts.
It is thought that this could be the source of the leak.
A large number of Mozambican migrants live in South Africa having gone there for work – both in the formal and informal sector, including mining.
On Thursday, a Mozambican woman living in South Africa told the BBC that her husband had died in the gas leak.
Speaking through tears, she added that she was concerned about how she would get her husband’s body home to Mozambique as she was unemployed and he worked part-time jobs as a handyman.