One of the most senior US executives at Arconic was probably told that the company’s cladding panels were unsafe for buildings above 12 metres in height two years before the Grenfell Tower disaster, a public inquiry has heard. The $7bn-a-year-turnover aluminium specialist sold the plastic-filled panels for use on the apartment block in west London, which was 67 metres tall and went up in flames in June 2017, killing 72 people. In June 2015 the company’s French subsidiary produced an assessment of the safety of the cladding panels at the request of Diana Perreiah, president of Arconic’s global building and construction systems business. It said the polyethylene-filled (PE) aluminium panels were “flammable”, had limitations “given by the smoke production and flaming droplets” and could only be used on buildings up to 12 metres. The inquiry has already concluded that Arconic’s Reynobond 55 PE panels were the main cause of the spread of the fire. Perreiah sought the assessment from Claude Schmidt, the president of Arconic’s French subsidiary, who told the inquiry he was “practically sure” it was sent to her. Arconic was selling the panels in the UK on the basis that they were safe for buildings over 18 metres. It had failed to update UK safety certificates after fire tests of the same panels used at Grenfell went so badly they had to be stopped, meaning the material could only be rated E for fire performance. The certificate that was consulted by the Grenfell builders claimed they reached a B classification for fire. The revelation brings the US headquarters of Arconic into the spotlight of the public inquiry, which has so far focused largely on its French subsidiary that operated in the UK market. Last year a US court rejected a product liability claim for damages against Arconic brought by survivors and the bereaved, on the basis that it should be heard in the UK. Arconic said: “It is not appropriate for us to comment while the inquiry is ongoing and before all evidence has been presented in phase two [of the inquiry].” The inquiry also heard that shortly after the request from the US parent company, Claude Wehrle, the French technical director, emailed colleagues that “PE is DANGEROUS on facades, and everything should be transferred to FR [fire retardant] as a matter of urgency.” That didn’t happen until after the disaster. Richard Millett QC, counsel to the inquiry, asked Schmidt: “If it was dangerous, why were you still selling it? Millett then asked: “Did the management of Arconic choose simply [to] ignore Mr Wehrle’s warning that PE was dangerous in facades and substitute his view for something more commercial?” The French subsidiary president replied: “No.” Schmidt is the most senior Arconic executive to give evidence to the inquiry. Three other key current and former staff, including Wehrle, are refusing to face cross-examination, citing an arcane French law that the country’s government has said does not apply. Schmidt also told the inquiry how Arconic did nothing to stop the sale of the cladding despite two high-rise infernos in the Middle East involving similar materials sparking internal concerns. The firm kept selling the plastic-filled panels after a 2012 fire at the Tamweel Tower in Dubai wrapped in similar material sent “fireballs” to the ground, and did not warn customers of possible risks. The executive said he read a BBC report in November 2012 that detailed how the Tamweel Tower’s “cladding may have been the culprit behind the blaze’s fire spread”. It was circulated internally in an email titled “Cladding blamed in skyscraper fire – sounds like something our customers make”. Wehrle also emailed colleagues to say that although the Tamweel Tower used a rival’s version of the panels, “all PE composites react in the same way”. One of Arconic’s competitors, Alucobond, told clients to say it was no longer selling PE panels after another tower in the United Arab Emirates went up in flames in 2013. Alucobond said “the perils of using cheap ACM alternatives have been exposed” and that it would only sell fire-retardant panels. Schmidt said he did not believe that Alucobond had actually stopped sales. Millett asked why Arconic did not attach a health warning to its own panels. “I can’t answer,” said Schmidt. “I don’t believe our competitors did it. Ten years later it is a legitimate question to raise, but at the time it wasn’t so obvious.” Millett asked why the fact that the material had only achieved an E rating in tests did not make the need for a health warning obvious. “I don’t have an answer,” said Schmidt, who stressed the fire in Dubai had not spread to the interior of the building. The inquiry continues.