There has been an explosion at the ethylene plant of Sasol Polymers in Secunda.

Sasol spokesperson Johann van Rheede said on Wednesday that there may have been fatalities but it was not yet clear.

"There are injuries and there may be fatalities. Emergency support services are securing the safety of people and the site," he said.

The blast happened at 9.40am on Wednesday.

Rheede said information would be released as it became available. - Sapa