The Grenfell Tower cladding companies “are little more than crooks and killers”, the public inquiry into the disaster has been told, as internal documents submitted to the inquiry appeared to reveal they knew for years their materials would burn. Lawyers for the bereaved and survivors revealed emails and slideshows from inside Arconic, Celotex and Kingspan, which they claimed showed “widespread and persistent wrongdoing” as they sold products they knew “were dangerous to life”. Adrian Williamson QC and Sam Stein QC, representing the bereaved and survivors, said firms and regulators operated in a “toxic and incestuous culture”. A total of 72 people died as a result of the fire on 14 June 2017, and the public inquiry is now starting its examination of the manufacture, marketing and testing of the materials used in the 2014-2016 refurbishment. In one email produced at the inquiry, a senior executive at Arconic, which made Grenfell’s polyethylene (PE) core cladding panels, told colleagues that a shortfall in the product’s fire performance was “something that we have to keep as VERY CONFIDENTIAL!!!!”. In another, he admitted PE panels would spread fire “over the entire height” of a tower. And Celotex, which made most of the plastic foam insulation, produced a “chilling” internal presentation in 2014 that announced it would be able to market its combustible product partly because “nobody understood the test requirements”, the inquiry heard. “These companies … knew their materials would burn with lethal speed and yet they marketed their products into an uncaring and underregulated building industry which spread them around like a disease,” said Stein. All three companies have denied wrongdoing. In statements to the inquiry last week, Arconic said the main fault lay with those responsible for the refurbishment, Celotex accused construction professionals of failing to follow building regulations and Kingspan said the outcome of the fire would have been no different if non-combustible insulation had been used. But lawyers for the bereaved and survivors hit back in the hearing on Monday accusing them of “mendacity”. “Arconic, Celotex and Kingspan were content to push hazardous products into the market place and sought to market them dishonestly,” said Williamson. “These products should have been safe and should have been tested and certified rigorously and should have been marketed in an honest and transparent fashion, but none of that happened.” “At all times they concentrated on the route to market, not the route to safety,” he said. He showed a 2009 email from Claude Wehrle, a senior Arconic executive, attaching pictures of a high-rise facade fire in Bucharest involving similar PE aluminium composite (ACM) panels it eventually sold for Grenfell. The pictures showed “how dangerous PE can be when it comes to architecture”, he said. In another email produced at the inquiry from 2013, Deborah French, Arconic’s UK sales representative, sent Wehrle a news story about another ACM cladding fire in the United Arab Emirates. She referred to an account of testing that had been done on ACM panels which concluded: “using PE is like a chimney which transports the fire … in the shortest time.” The tests were done in front of architects “who almost fainted”. In October 2015 Wehrle shared more photos of a more limited cladding fire in China which used a fire-retardant version of ACM panels. He remarked: “In PE, the fire would have spread over the entire height of the tower.” And in early 2016, he emailed colleagues about a fire close to a building that was clad in its PE panels, saying it was lucky the wind didn’t change direction. “We really need to stop proposing PE in architecture,” he said. “We are in the know and I think it is up to us to be proactive AT LAST.” But by then the same panels were going up at Grenfell. “Arconic knew internally that something was very wrong but certainly did not let that knowledge escape from their company,” said Williamson. The inquiry also heard how when Celotex started selling its combustible insulation in the UK in late 2013, its product manager asked internally: “Do we take the view that our product shouldn’t realistically be used behind most cladding panels because in the event of a fire it would burn?” They didn’t take that view, noting that its rival Kingspan had been successfully selling a similar insulation by “saying very little”. The product failed its first fire test but passed when extra materials were added. The marketing brochure didn’t mention the failed test but said that the product was class 0 throughout. This didn’t in fact mean that it was of limited combustibility, as standards required, but related to fire spread. It exploited “confusion in the industry” about the terms. It sent Grenfell’s cladding contractor, Harley, an abridged test report, which didn’t include “worrying images of extensive charring and fire damage”. Kingspan, meanwhile, was “brazen” about persuading a certification body, LABC, to approve its product, Kooltherm. “We threw every bit of fire test data we could at [the certifcator],” said Philip Heath, an executive at Kingspan in an internal email. “We probably blocked his server. In the end I think the LABC convinced themselves Kooltherm is the best thing since sliced bread. We didn’t even have to get any real ale down him.” The inquiry continues.