The incident on Wednesday evening also left 15 people in hospital, four of them critical and 11 in a serious condition, according to Ekurhuleni Disaster and Emergency Management Services spokesperson William Ntladi.  

A police statement said: “It is alleged that nitrate oxide leaked from the cylinder and poisoned the community of Angelo informal settlement in Boksburg. As per information on site, illegal mining activities were ongoing using nitrate oxide to extrapolate what is said to be gold from the soil within the informal settlement.”

However, Business Maverick journalist Ed Stoddard reports that two security sources with knowledge of illegal mining said they doubted that nitrate oxide would have been the source of the tragedy if it was linked to illegal mining.

“It might be mercury poisoning. If it is not used correctly it can produce a poisonous gas,” said one source, who suspected this was more likely, and noted that the informal settlement is next to a slimes dam or mine dump.

Another security source familiar with mercury and cyanide being used said he had not heard of nitrate oxide being used in South Africa.

People gather near the scene of a suspected gas leak thought to be linked to illegal mining, in the Angelo shack settlement near Boksburg on 6 July 2023. (Photo: Reuters / Siphiwe Sibeko)

Ntladi said the incident had been handed over to the SAPS and forensic investigators were conducting a preliminary investigation on the scene.  

The death toll was initially reported as 16, but Gauteng premier Panyaza Lesufi has since confirmed another death at Tambo Memorial Hospital.   

Read more in Daily Maverick: Trauma counselling for OR Tambo Hospital staff as Boksburg tanker blast death toll rises to 37

Ekurhuleni mayor Sivuyile Ngodwana, speaking to SAfm, said the city would treat the incident as a priority. He also called on residents to report illegal mining.   

“We are pleading with the communities to report these illegal operations that are happening in their communities because we have now witnessed the danger of this thing. They must report them to the police because we don’t want any other incident like this to happen.”

Onlookers gather at the scene following a suspected gas leak thought to be linked to illegal mining in the Angelo informal settlement on 6 July 2023. (Photo: Reuters / Siphiwe Sibeko)

Asked about the magnitude of illegal mining, Ngodwana said: “We knew there were (illegal activities) but we didn’t know they were operating like this. It is a serious challenge that we are fighting [and] that we must fight on.”  

‘Lazy response’

The EFF criticised the police for their allegedly delayed response after residents reportedly complained about a foul smell hours before the tragedy.  “The EFF slams the lazy response by the South African Police Service after being informed of the issue as soon as it occurred. State emergency services should, at all times, be the first to respond in such situations,” said EFF provincial chairperson Nkululeko Dunga. 

The Angelo informal settlement in Boksburg – the scene of the suspected gas leak that claimed 17 lives on 5 July 2023. (Photo: Felix Dlangamandla)

Dunga conveyed the party’s condolences to the deceased.“This catastrophic event should bring to question the role of the companies that have for years plundered both the mineral and human resources without any commitment to the economic reparation and environmental rehabilitation of the people and the land on this continent,” he added.  

The ANC caucus in Ekurhuleni said it had sent “sincere words of heartfelt condolences to the affected families, hoping that they find strength during this difficult moment”.

The incident comes seven months after 37 people died as a result of a gas tanker explosion in Boksburg on 24 December 2022. Twelve were healthcare workers from Tambo Memorial Hospital. DM