Following an explosion, Khark petrochemical complex caught on fire on Saturday evening, IRNA reported.
A provincial official confirmed explosion in the complex.
Gholamreza Keshtkar said that cause of explosion was high pressure in a central boiler.
He added that fire is under control and relief workers are helping injured persons.
Keshtkar said four people have been killed in this incident. Three bodies have been recognized but the fourth has not been found yet, said Keshtkar.
He also said that the complex provided part of provincial electricity supply, so there would be some problems in the electricity network.
More than 400 employees work in Khark petrochemical complex.
Khark is an island in the Persian Gulf and is part of Bushehr province.