The 6000-km long pipeline network belongs to Products and Pipelines Marketing Co, a full subsidiary of the NNPC, which is responsible for domestic marketing of petroleum products. Mr Ajuonuma said NNPC was in the process of determining the scope of the project, pointing out the replacement would take about a year to complete. He spoke against a background of recurring pipeline vandalism in Nigeria, often leading to high tolls of human casualty though explosions and fires, and the disruption of domestic supply of gasoline. The pipelines were laid mostly in the 1980s, as Nigeria sought then to link its refineries and depots for product storage. As part of the replacement exercise, the government wants the pipes buried deeper than they are now, to reduce vandals' access to them. The latest pipeline explosion occurred in a Lagos suburb, killing hundreds of people. Ajuonuma said the damage to the pipeline caused by the blast would take up to three days to repair before normal pumping resumes. Shortage of gasoline in Nigeria over the Christmas period forced the price to rise by more than 300 % in some places, causing many Nigerians to cancel trips. Vandals had caused a similar damage on 8 December to another segment of the pipeline which transports imported products from Atlas Cove Jetty, where it's discharged from tankers, into storage tanks located at Moisimi, in Lagos. Mr Ajuonuma said pipeline vandalism was the greatest recurring cause of gasoline shortage in Nigeria, as it disrupts distribution of imported products and forces local refineries to shut down. Two of Nigeria's refineries – at Kaduna in the north, and Warri in the Niger Delta – have been shut down since the beginning of this year, following the vandalism of a "strategic" pipeline that supplies crude oil to them from fields in the Niger Delta, he said. The other two refineries are located in Port Harcourt, but are operating at a fraction of their installed capacity. Consequently, Nigeria imports about 90% of its domestic requirements of gasoline and other refined products. "Imports will stay with us if we don't cure this problem of vandalism," Mr Ajuonuma said. "If we cut it, we can reduce imports by 70%, and when the new refineries come on stream, we will remove the remaining 20%," he added.