The three companies involved in the accident - BP, Transocean and Halliburton – were all accused of having cut corners in order to complete the well. At the time of the blow-out, this job was five weeks behind schedule. Five survivors talked to CNN about a corporate culture in which safety warnings were routinely ignored. "Major accidents such as the Deepwater Horizon disaster in the Gulf of Mexico could also happen in the North Sea," says Preben Lindøe, professor of societal safety and security at the University of Stavanger, Norway. "But strong, organizational barriers between the oil industry, trade unions and the Petroleum Safety Authority Norway reduce the risk," he adds. Together with his colleague, associate professor Ole Andreas Engen, he is part of the Robust Regulation in the Petroleum Sector team.