TEHRAN, Iran — Iran’s official news agency says an explosion at a petrochemical factory on Iran’s largest oil terminal has killed four people. The Sunday report said high pressure in the central boiler of the factory led to an explosion and fire at the facility on Khark island in the Persian Gulf. So far the bodies of three of the victims have been found and the blaze is under control. Several other workers were injured. Khark Island, some 750 miles (1200 kilometers) south of Tehran, hosts Iran’s biggest oil terminal in the Persian Gulf. Iran is OPEC’s second largest oil exporter, producing around 4.2 million barrels of oil per day.