The impact of the explosion was so powerful that the grinder shot up in the air and got lodged in the roof of the building, according to an eyewitness.
The unidentified 32-year-old man was busy slicing through a liquid paraffin gas cylinder when things went wrong.
The incident happened at printing company, Colpak, in Seventh Avenue, Kensington, on Wednesday afternoon.
It’s believed sparks from the grinder may have interacted with gas in the cylinder, causing it to explode.
Police spokesperson Constable Johnatan Filander says no one else was injured in the incident.
“On Wednesday at 4pm, a 32-year old male was on duty, cutting a metal drum with a grinder, at a business premises in 7th Avenue, Kensington,” Filander says.
“The drum exploded and fatally injured the man. No one else was injured during this incident and an inquest docked has been registered for further investigation,” he says.
Colpak CEO Steven Broekhuysen says the man was not busy with work at the time of his death.
“We can confirm that one of our members of staff died on 8 June 2016 while engaged in a non-work related activity at our Kensington premises. We are assisting his family and are providing counselling to affected staff,” he says.