ArcelorMittal's plant in Vanderbijlpack, South Africa, is currently searching for three employees who went missing after the accident. Largest steel producer in Africa reported that on Wednesday morning, part of the chimney of one of the coke oven batteries fell into the control room, where people who have not yet been found were working.
The company states that the cause of the incident is not yet known, but search and rescue teams are working at the scene of the accident.
"A full investigation will then be carried out to understand what happened and to avoid similar situations in the future," said Cobus Verster, CEO of ArcelorMittal South Africa.
The National Metalworkers' Union (NUMSA) has expressed concern about workers trapped in the rubble.
The company said the coke oven battery was damaged as a result of the incident and will likely be sent for repairs once the extent of the damage is determined.