A gas pipeline in Iran\'s southwestern province of Khouzestan exploded Friday without causing any casualty, the official IRNA news agency reported. A fire broke out around the city of Dogonbadan in the Keshab region after the pipeline, which carried gas from Pazran to the oil fields in Gatchsaran, exploded in the evening, said the report. No casualty was reported due to the blast, while the emergency workers are trying to contain the fire, it said. The cause of the explosion was still unknown, it said. Another two blasts occurred in Iran Friday morning, hitting an oil field and a refinery respectively. One worker was killed and three others were injured when a blast occurred at the Bibi Hakimeh oil field in the province of Khouzestan and caused a fire. The reason for the blast was also unclear, according to local Mehr news agency. The state IRIB TV said later Friday that the fire at Bibi Hakimieh oil field was contained and two of the three wounded staff members were sent to a hospital in the southern Ghenaveh port for further treatments. The other explosion and subsequent fire occurred at the Shahzand oil refinery in central Iran\'s Markazi province. The reason for the incident is not yet known, and there is no report yet about the possible casualty or degree of damage to the refinery, Mehr reported. Since May, there have been several explosions and fire accidents in Iran\'s refineries, oil fields and gas and oil pipelines.