Iraq\'s biggest oil refinery, Baiji, was operating at full capacity yesterday after an explosion and fire on its main gas pipeline shut down most production units, officials said. A fire broke out at Baiji on Friday after an explosion on the primary pipeline that transports natural gas from Kirkuk\'s gas field to the refinery. The gas is used to operate some of its production units. Officials said they had switched to a backup pipeline to bring gas into the plant. \"Now the refinery is operating at full capacity, there is no problem with any of the units,\" Shakir Al Awadh, an engineer at Baiji refinery, told Reuters. \"The incident, which happened yesterday, was outside the administrative border of Baiji refinery. The incident was a result of a leak in the gas pipeline and an electrical fault.\" Officials had initially said it would take 48 hours to restore full operation at the refinery.