Joburg CBD explosion explained: Methane gas identified as cause

On Wednesday, City Manager Floyd Brink said the investigation in the inner-city Joburg explosion had been completed, with methane gas identified as the cause.

The investigation into the Lilian Ngoyi and Bree Streets explosion was conducted by a specialised team consisting of fire specialists, international engineers, structural experts, and professionals in occupational health and safety.

Joburg explosion explained

Brink addressed concerns over the City’s internal capacity to handle such disasters, saying the level of expertise required to deal with the aftermath cannot be maintained in-house.

While the City’s existing technical skills are deemed competent, specialised skills are also required in this case, hence leveraging private sector knowledge and international expertise.

The city manager expressed confidence in the ongoing response and recovery efforts and requested public patience and space for the successful recovery of the site and services.

Methane gas cause of explosion

The cause of the explosion was found to be methane gas, which traveled up along the services tunnel from an unknown source.

The City of Joburg’s priority now that response work has drawn to a close is to restore and repair the tunnels underneath the city, estimated to cost R178 million.

Brink said the City already spent approximately R4 million on professional experts’ services, site cording, technology, and temporary relief services.

Moreover, Egoli Gas wasn’t to blame since a pipeline explosion or pipe rupture was ruled out, as was a large leak.

No negligence or sabotage

The report ruled out terrorist action, foul play, negligence, or intentional release of gas into the tunnel.

The response from emergency services were deemed effective and compliant, and no shortcomings were identified from EMS or the JMPD.

The teams also did not find any evidence of people living in the tunnels, or any recent incidents of cable theft.

Planned upgrades after Joburg explosion

The 90-year-old tunnels underneath inner-city Johannesburg will now be upgraded according to the relevant international codes and South African standards.

New safety measures will include continuous gas detection and alarms, while the tunnel’s structure will be reinforced to withstand a 9.5% methane explosion.

Going forward, the focus will be on explosion prevention, with accidental combustible gas release in tunnels and/or cavities, Brink said.

READ: Tunnel, inner city upgrade estimated at R178 million