A warehouse containing flammable chemicals at Imperial Motors in Wadeville, Germiston was gutted by a fire on Friday, police and the Ekurhuleni emergency services said.
Damage worth millions of rand was caused by the blaze that followed an explosion shortly after noon at the Commercial Road premises.
A Germiston emergency services official said despite the blaze's intensity - five-metre flames were reported - it was quickly contained but could not be immediately extinguished.
Firefighters were still on the scene by nightfall damping down the fire. A watch would continue through the night.
The official expressed concern at the environmental contamination caused by water run-off from the blaze.
He also said no one was killed in the blast or fire and only one firefighter required treatment for smoke inhalation.
The cause of the explosion was unknown. - Sapa