Joburg gas blast source still unknown

The City of Johannesburg says methane gas was the cause of Bree Street explosion but officials still don’t know what was the source of the gas. 

City manager, Floyd Brink, told the media on Wednesday afternoon that their investigation discovered that methane gas was the cause of the blast three weeks. The gas is regarded as lighter than air and it travelled up along the services tunnel, from an unknown source to the crest of the tunnel near Von Brandis Street.  

The explosion left 48 people injured, one person dead and 34 cars damaged.

Brink ruled out negligence, terrorist action, illegal mining, cable theft, foul play by anybody as the cause of explosion. He further explained that they had already spent R4m in the project on professional experts’ services, cordoning off the area, technology used and the provision of temporary relief services in a form of water tankers as well as temporary ablution services. 

“The delivery of this report marks the end of the immediate response work we reported on previous and paves that way to our medium interventions which will include the restoration and repair work. Our rough estimate for repairs currently sits at R178m. This estimate might change once we receive the detailed designs for the entire project. A lot of lessons were learned following this unfortunate incident,” said Brink.

He further explained that they have beefed up their team adding fire specialist with experience in industrial explosions and gas systems, international fire dynamics and explosion simulation specialist engineer, specialists in explosion, gas and fire dynamics at universities and international network of fire engineers, structural engineer, geotechnical engineer, electrical engineer, civil engineer and forensic specialist among others. 

To avoid future similar recurrences, Brink said the tunnel design would be upgraded based on current international codes for tunnels to reduce the risk and severity of explosions.  

He said: “We will also introduce continuous gas detection and alarms and gas detector sensor monitors for all staff working the tunnels regularly. Our tunnels design will be based on international relevant standards. Tunnel roof and sidewalls will be designed to withstand and depressurise with deflagration vents a 9.5% methane explosion.

“Suitable materials for the tunnel would be reinforced, concrete side walls and roofs designed for this over-pressure and release. At this stage, we remain confident that we are on the right path in our efforts to respond and recover from the incident and will once more implore the public to bear with us and to give us space to do all we must for the successful recovery of the site and services.” 

Joburg mayor Kabelo Gwamanda said: “As the executive mayor, I established a technical team led by the city manager to lead a detailed and advanced investigation into the explosion and the responses required from the city.

“We have also had positive engagements with a variety of affected stakeholders including property owners along Lillian Ngoyi Street [Bree Street]. Our intention is to ensure that as we push to rehabilitate and rebuild, we do so in a transparent and inclusive manner.”