Video report by ITV News Correspondent Sejal Karia
The second phase of the inquiry into the blaze began on Monday with the inquiry's chief lawyer accusing companies of passing the blame on to each other rather than accept any responsibility.
Richard Millett QC said: "Each core participant who played a material part in the refurbishment of Grenfell Tower has laid out a detailed case for how it relied on the work of others and how in no way was the work it did either substandard or non-compliant."
"In every case what happened was, as each of them would have it, someone else's fault," he said.
The second phase of the public inquiry will examine how the 24-storey residential block came to be wrapped in flammable cladding, which phase one of the inquiry found was the "principal" reason for the rapid spread of the flames.
Richard Millett QC during the second phase of the inquiry's opening remarks.
Lead refurbishment architects Studio E said it had no knowledge the materials were "unsafe", cladding subcontractor Harley Facades said it did not choose the materials, and main contractor Rydon said its cladding and insulation providers, Arconic and Celotex, had mislead buyers into believing their product was safe for use in high-rises despite appearing to be aware of the dangers.
An internal report from an Arconic director in 2011 noted the material Reynobond PE was “dangerous on facades and everything should be transferred to (FR) fire resistant as a matter of urgency”, according to counsel for Rydon Marcus Taverner QC.
The email, sent by official Claude Wehrle, added: “This opinion is technical and anti-commercial it seems.”
Mr Taverner also read out an internal Celotex email from November 2013 which showed officials knew using the insulation CelotexRS500 alongside aluminium composite material (ACM) cladding could be dangerous.
The email said: “We cannot seem to find or design a suitable barrier in which we have enough confidence that it can be used behind a standard ACM panel which we know will melt and allow fire into the cavity… Or do we take the view that our product realistically shouldn’t be used behind most cladding panels because in the event of a fire it would burn?”
The inquiry will hear from Exova, which gave fire safety advice, Arconic and Celotex on Tuesday.
She was the immediate past president of the Women's Engineering Society which received funding last year from Arconic, the supplier of Grenfell's cladding.
Grenfell United, a group representing survivors of the fire and relatives of those killed, said they hoped the inquiry would "expose" those who authorised the "devastating refurbishment" of the building's cladding between 2012 and 2016.
"Those responsible continue to deflect blame and we have to suffer their persistent refusal to accept accountability for the preventable loss of life," the group said.
"At the end of this process it will be clear that criminal charges must be brought for the deaths of our loved ones."
A small group of protesters gathered outside the inquiry's venue on Monday morning, chanting: "Justice for Grenfell - we want the truth."
Grenfell was built in 1974 but was significantly altered between 2012 and 2016 when combustible aluminium composite material (ACM) cladding was added to the concrete exterior.
The first phase of the inquiry found the cladding did not comply with building regulations and was the "principal" reason for the rapid and "profoundly shocking" spread of the fire, which killed 72 people.
The second phase of the inquiry will examine how the cladding products were tested, and how the residents' complaints to the tower's management were dealt with.
It is due to run until June 2021, and more than 93,000 documents have so far been disclosed, the inquiry said.