Authorities are still trying to ascertain what led to an explosion that left two men injured at a factory in Jeppestown on Monday morning. Two workers at the factory sustained moderate to serious burn wounds in the explosion at the building in Berg Street, ER24 paramedics said in a statement. "ER24 paramedics arrived on the scene shortly before 10:00 to find the fire department already in attendance," said ER24 spokesperson Ross Campbell."The injured were treated on the scene by our medics, before being transported to a burns unit facility for further medical care." "Upon further assessment, two workers on the first floor were found to have suffered moderate to serious burns." Johannesburg EMS spokesperson Robert Mulaudzi said the wounded men were taken to Milpark Hospital, where they were also treated for smoke inhalation. The exact cause of the explosion was currently unknown, but was being investigated, Mulaudzi added.