The explosion happened after a tanker carrying gas got stuck under a low-lying bridge, sparking flames. As firefighters tried to extinguish the flames the tanker exploded, approximately 40 minutes after it got stuck under the bridge.

A "fire bomb" from the explosion substantially damaged Tambo Memorial Hospital, located about 100m away.

Several health workers were in the hospital's parking lot, some about to leave after their shifts and others trying to move their cars away from the fire.

In addition to the loss of life, the hospital’s emergency unit and X-ray department were badly damaged, Minister of Health Joe Phaahla said.

ALSO READ: Death toll in Boksburg explosion now stands at 34

According to a report by AP News, other fatalities were residents who had gathered to see the burning truck. At least 321 injured people were taken to various hospitals in Johannesburg.

Several houses and vehicles were also damaged by the explosion, according to officials.

The 32-year-old driver was taken into police custody but was released pending further investigations. 

The tanker truck transporting liquefied petroleum gas was en route to Botswana from South Africa’s Indian Ocean port of Richards Bay, said officials.

The company that had hired the driver, Innovative Staff Solutions, has said that he was not negligent. He had taken a wrong turn and was following directions to get back onto the highway. The clearance for the bridge was not visible, but he stopped and estimated that the truck would get under the bridge. But he did not calculate that as the front of the truck went lower in a dip, the back end would go higher.

When the rear of the truck got stuck, the driver called the fire department and tried to keep motorists and pedestrians away from the site. He collapsed from inhaling the gas fumes and was taken away by an ambulance shortly before the explosion.

eNCA