An explosion rocked Middle East’s oldest oil refinery in southwestern city of Abadan in the oil-rich Khuzestan province overnight, state media reported on Friday. According to the government’s official news website, the blast was caused by the bursting of one of the furnaces of the sulphur production unit of phase three of Abadan Oil Refinery during the start-up operation, causing a huge explosion. The blast apparently had no casualties claims that production at the refinery continues as usual. This is the second incident at the Abadan refinery, which supplies around 25 percent of the country’s fuel needs, this year. In April, a section of the refinery caught fire but the blaze was contained with no fatalities or injuries.