A fire broke out during a maintenance operation at the Aftab oil refinery in the Iranian city of Bandar Abbas, Iranian state media reported on Thursday, adding the cause of the fire was being investigated.
There were contradictory reports about casualties, with several local news agencies saying one person died and three were injured.
Earlier, Iranian state news agency IRNA said several people had been killed and injured, but it cautioned there had been no official statement.
Later, the refinery's operating company said in a statement that the facility did not sustain any major damage and that the injured had been deemed in a stable condition.