LONDON (NYTIMES) - The doorbell woke Yassin Adam just before 1 am. A neighbour was frantically alerting others on the fourth floor of Grenfell Tower about a fire in his apartment.
"My fridge blew up," the man shouted.
Residents of Grenfell Tower had complained for years that the 24-storey public housing block invited catastrophe. It lacked fire alarms, sprinklers and a fire escape. It had only a single staircase. And there were concerns about a new aluminum facade that was supposed to improve the building - but was now whisking the flames skyward.
The facade, Adam said, "burned like a fire that you pour petrol on."
The incineration of Grenfell Tower on June 14, the deadliest fire in Britain in more than a century, is now a national tragedy. The London police Friday blamed flammable materials used in the facade for the spread of the blaze and said the investigation could bring charges of manslaughter.
Hundreds of families were evacuated from five high-rises that posed similar risks.
Flames consumed the tower so quickly that arriving firefighters wondered if they could even get inside. People trapped on the higher floors screamed for their lives through broken windows. At least 79 people died, a toll that is expected to rise as more bodies are recovered.
Survivors have charged that the facade was installed to beautify their housing project for the benefit of wealthy neighbours.
A formal government inquiry into the fire has just begun. But interviews with tenants, industry executives and fire safety engineers point to a gross failure of government oversight, a refusal to heed warnings from inside Britain and around the world and a drive by successive governments from both major political parties to free businesses from the burden of safety regulations.
Promising to cut "red tape," business-friendly politicians evidently judged that cost concerns outweighed the risks of allowing flammable materials to be used in facades. Builders in Britain were allowed to wrap residential apartment towers - perhaps several hundred of them - from top to bottom in highly flammable materials, a practice forbidden in the United States and many European countries.
And companies did not hesitate to supply the British market.
The facade, installed last year at Grenfell Tower, in panels known as cladding and sold as Reynobond PE, consisted of two sheets of aluminum that sandwich a combustible core of polyethylene. It was produced by the US manufacturing giant Alcoa, which was renamed Arconic after a reorganisation last year.
Arconic has marketed the flammable facades in Britain for years, even as it has adjusted its pitch elsewhere. In other European countries, Arconic's sales materials explicitly instructed that "as soon as the building is higher than the firefighters' ladders, it has to be conceived with an incombustible material."
An Arconic website for British customers said only that such use "depends on local building codes."
For years, members of Parliament had written letters requesting new restrictions on cladding, especially as the same flammable facades were blamed for fires in Britain, France, the United Arab Emirates, Australia and elsewhere. Yet British authorities resisted new rules.
A top building regulator explained to a coroner in 2013 that requiring only noncombustible exteriors in residential towers "limits your choice of materials quite significantly."
Fire safety experts said the blaze at Grenfell Tower was a catastrophe that could have been avoided, if warnings had been heeded.
"How could that happen in our country at this time?" asked Dennis Davis, a former firefighter who is vice chairman of the nonprofit Fire Sector Federation.
Adam, 44, had seen posters hung by the management company telling tenants to shut their doors and stay inside in the event of a fire. But Adam, his wife, his daughter and his pregnant sister ignored the instructions and ran.
"Anyone who listened to the fire brigade and stayed where they are," Adam said in an interview the next day, "they lost their lives."
'How Is That Possible?'
The first call to the London Fire Brigade came at 12:45 am, according to an official statement. Six minutes later, as the first firefighters reached the scene, brigade veterans struggled to fathom the speed of the blaze.
"That is not a real block with people in it!" one firefighter exclaimed, his astonishment captured in a video that was shown on the BBC and Sky News and was shot inside his vehicle as it sped toward the building.
Other firefighters in the vehicle were heard gasping in horror.
"There are kids in there," one said.
"How is that possible?"
"It has jumped all the way along the flats - look!"
How "are we going to get into that?" asked another, using an expletive.
Flames in an ordinary fire burst out of windows, moving from the inside out. Grenfell Tower burned in reverse, moving inward from the building's exterior. The flames quickly tore upward in streaks through the facade, filling apartments with toxic black smoke. Torrents of orange and red branched out of the first streaks and shot upward. The flames encased the building in a cylinder of fire.
"I have never seen such a phenomenal fire, a building engulfed top to bottom in flames," Dany Cotton, the London fire commissioner, said later that day. More than 200 firefighters battled the blaze. They brought 40 fire engines and other vehicles.
"Committing hundreds of my firefighters into a building that at points looked like it couldn't possibly stand up due to the level of fire - I actually felt physically sick with anxiety about what was happening," Cotton added.
But the firefighters went in.
The building they entered was built in 1974 in an architectural style known as Brutalism, and the original concrete structure, built without cladding, was designed to contain a fire in one apartment long enough for firefighters to prevent it from spreading very far. But the building's floor plan gives a picture of what happened.
Refrigerators in most apartments appear to have been positioned against an exterior wall, next to a window and just a few inches from the cladding installed in the renovation.
When the refrigerator on the fourth floor burst into flames, the fire ignited the flammable cladding and shot up the side of the building. The London police confirmed that Friday and identified the refrigerator brand as Hotpoint.
But experts who saw footage of the blaze had known the culprit at once. "You can tell immediately it's the cladding," said Glenn Corbett, an associate professor of fire science at John Jay College of Criminal Justice in New York.
The first well-known use of aluminum cladding on a high-rise was on the Alcoa Building, in Pittsburgh, erected as the manufacturer's headquarters. Makers of cladding promoted it as both aesthetically striking and energy-efficient, because the aluminum surface reflects back heat and light.
Demand for cladding surged with rising fuel costs and concerns about global warming, and over time, producers began selling it in a thin "sandwich" design: Two sheets of aluminum around a core made of flammable plastics like polyethylene.
The cladding is typically paired with a much thicker layer of foam insulation against the building's exterior wall, as was the case at Grenfell Tower. Then the cladding may be affixed to the wall with metal studs, leaving a narrow gap between the cladding and the insulation.
But by 1998, regulators in the United States - where deaths from fires are historically more common than in Britain or Western Europe - began requiring real-world simulations to test any materials to be used in buildings taller than a firefighter's two-storey ladder.
"The US codes say you have to test your assembly exactly the way you install it in a building," said Robert Solomon, an engineer at the National Fire Protection Association, which is funded in part by insurance companies and drafts model codes followed in the United States and around the world.
No aluminum cladding made with pure polyethylene - the type used at Grenfell Tower - has ever passed the test, experts in the United States say. The aluminum sandwiching always failed in the heat of a fire, exposing the flammable filling. And the air gap between the cladding and the insulation could act as a chimney, intensifying the fire and sucking flames up the side of a building. Attempts to install nonflammable barriers at vertical and horizontal intervals were ineffective in practice.
As a result, US building codes have effectively banned flammable cladding in high-rises for nearly two decades. The codes also require many additional safeguards, especially in new buildings or major renovations: automatic sprinkler systems, fire alarms, loudspeakers to provide emergency instructions, pressurised stairways designed to keep smoke out and multiple stairways or fire escapes.
And partly because of the influence of US architects, many territories around the world follow the US example. But not Britain.
Safety vs. Cost
British schoolchildren study the Great Fire of London, in 1666, the way US pupils might learn about the Boston Tea Party or the first Thanksgiving. But the legacy of the fire is also still felt in Britain's building codes, experts say.
London's original great fire leapt across wooden buildings. And since then, British building codes have focused primarily on the principle of stopping the spread of flames between buildings or, within larger structures, between units.
With fire prevention in Britain, "you put all your eggs in one basket," said Edwin Galea, director of the Fire Safety Engineering Group at the University of Greenwich. And for decades, this was fairly effective. Britain has long reported far fewer deaths from fires relative to population than the United States, and typically, fewer than 350 residents die each year in fires (compared with more than 3,000 in the United States).
But as early as 1999, after a fire in Irvine, Scotland, British fire safety engineers warned Parliament that the advent of flammable cladding had opened a dangerous loophole in the regulations. The Irvine fire saw flames leap up panels at Garnock Court, a 14-storey public housing block.
One resident died, four others were injured and a parliamentary committee investigated the causes.
"To a certain extent, we are hoisted by the petard of what happened here in 1666, the Great Fire of London, and we look at fire as a horizontal problem, with a fire in one building affecting the exterior of another building," Glynton Evans, a fire safety adviser to the firefighters union, said to Parliament.
"The problem with cladding is that it will, if it is able, spread fire, and it will spread it vertically."
The firefighters and engineers warned Parliament that British codes required only that the aluminum used in cladding resist ignition, even though the heat of a fire would breach the surface and expose the flammable material inside. Nor did the British rules require a test to evaluate risks in real-world conditions.
"If the cladding cannot resist the spread of flame across the surface, then it will vertically envelop the building," Evans warned, in testimony that now seems prophetic.
"In other words, the fire will spread to the outside of the building, and it will go vertically." Many other fire safety experts would repeat those concerns in the following years.
But manufacturers argued against new tests or rules. Using fire-resistant materials was more expensive, a cost that industry advocates opposed.
"Any changes to the facade to satisfy a single requirement such as fire performance will impinge on all other aspects of the wall's performance as well as its cost," Stephen Ledbetter, director of the Centre for Window and Cladding Technology, an industry group, wrote in testimony to Parliament.
"Fire resistant walls," he added, "are not economically viable for the prevention of fire spread from floor to floor of a building," and "we run the risk of using a test method because it exists, not because it delivers real benefits to building owners or users."
(In an interview last week, Ledbetter said his group had updated its position this year to warn against the type of cladding used at Grenfell Tower.)
Business-friendly governments in Britain - first under Labour and then under the Conservatives - campaigned to pare back regulations. A 2005 law known as the Regulatory Reform (Fire Safety) Order ended a requirement for government inspectors to certify that buildings had met fire codes, and shifted instead to a system of self-policing.
Governments adopted slogans calling for the elimination of at least one regulation for each new one that was imposed, and the authorities in charge of fire safety took this to heart.
"If you think more fire protection would be good for UK business, then you should be making the case to the business community, not the government," Brian Martin, the top civil servant in charge of drafting building-safety guidelines, told an industry conference in 2011, quoting the fire minister then, Bob Neill.
Martin, a former surveyor for large-scale commercial projects like the Canary Wharf, told his audience to expect few new regulations because the prime minister at the time, David Cameron, wanted to greatly reduce the burden on industry, according to a report by the conference organisers.
Two years later, in 2013, a coroner questioned Martin about the application of building regulations in the case of another London fire, which killed six people and injured 15 others at a public housing complex called Lakanal House.
Martin defended the existing regulations, including the lack of a requirement for meaningful fire resistance in the panelling on the outside of an apartment tower.
A questioner told him that the public might be "horrified" to learn that the rules permitted the use of panelling that could spread flames up the side of a building in as little as 4½ minutes.
"I can't predict what the public would think," Martin replied, "but that is the situation." Moving to a requirement that the exterior of a building be "noncombustible," Martin said, "limits your choice of materials quite significantly."
After the coroner's report, a cross-party coalition of members of Parliament petitioned government ministers to reform the regulations, including adding automatic sprinklers and revisiting the standards for cladding.
"Today's buildings have a much higher content of readily available combustible material," the group wrote in a letter sent in December 2015 that specifically cited the risk of chemicals in "cladding."
"This fire hazard results in many fires because adequate recommendations to developers simply do not exist. There is little or no requirement to mitigate external fire spread," added the letter, which was first reported last week by the BBC.
In 2014, the Fire Protection Research Foundation, an organisation in the United States, counted 20 major high-rise fires involving cladding. In at least a half-dozen - in France, Dubai, South Korea, the United States and elsewhere - the same type of panels installed at Grenfell Tower caught fire.
A 2014 fire in Melbourne, Australia, resulted in multiple investigations into the dangers of combustible cladding. Another fire broke out in Dubai, around a 60-storey skyscraper, on New Year's Eve of 2015, and yet another, around a 70-storey skyscraper there, this April.
But in Britain, still no changes were made.
"The construction industry appears to be stronger and more powerful than the safety lobby," said Ronnie King, a former fire chief who advises the parliamentary fire safety group. "Their voice is louder."
'Pray for Us'
As recently as March, a tenant blogger, writing on behalf of what he called the Grenfell Action Group, predicted a "serious and catastrophic incident," adding, "The phrase 'an accident waiting to happen' springs readily to mind."
For many tenants, an object of scorn was Grenfell Tower's quasi-governmental owner, the Kensington and Chelsea Tenant Management Organisation. It was created under legislation seeking to give public housing residents more say in running their buildings, and its board is made up of a mix of tenants, representatives of local government and independent directors.
But Kensington and Chelsea is the largest tenant management organisation in England, a sprawling anomaly supervising roughly 10,000 properties, more than 30 times the average for such entities. Tenants came to see it as just another landlord.
The organisation had promised residents of Grenfell Tower that the renovation last year would improve both insulation and fire safety. Board minutes indicate that it worked closely with the London Fire Brigade throughout the process, and local firefighters attended a briefing afterwards "where the contractor demonstrated the fire safety features."
During a board meeting last year, the organisation even said it would "extend fire safety approach adopted at Grenfell Tower to all major works projects."
But the principal contractor, the Rydon Group, based in East Sussex, England, assigned the facade work to a specialist firm that was struggling financially during the project. The firm, Harley Curtain Wall, went out of business in 2015 and transferred its assets to a successor, Harley Facades.
Another subcontractor, Omnis Exteriors, said Friday that it had not been told that the flammable Reynobond cladding was going to be combined with flammable interior insulation.
That was a problem, the firm said in a statement, adding that the cladding "should only be used in conjunction with a noncombustible material."
The cladding itself was produced by Arconic, an industry titan whose chief executive recently stepped down after an unusual public battle with an activist shareholder. Arconic sells a flammable polyethylene version of its Reynobond cladding and a more expensive, fire-resistant version.
In a brochure aimed at customers in other European countries, the company cautions that the polyethylene Reynobond should not be used in buildings taller than 10 metres, consistent with regulations in the United States and elsewhere.
"Fire is a key issue when it comes to buildings," the brochure explains. "Especially when it comes to facades and roofs, the fire can spread extremely rapidly."
A diagram shows flames leaping up the side of a building. "As soon as the building is higher than the firefighters' ladders, it has to be conceived with an incombustible material," a caption says.
But the marketing materials on Arconic's British website are opaque on the issue.
"Q: When do I need Fire Retardant (FR) versus Polyethylene (PR) Reynobond? The answer to this, in part, depends on local building codes. Please contact your area sales manager for more information," reads a question-and-answer section.
For more than a week after the fire, Arconic declined repeated requests for comment. Then, Thursday, the company confirmed that its flammable polyethylene panels had been used on the building.
"The loss of lives, injuries and destruction following the Grenfell Tower fire are devastating, and we would like to express our deepest sympathies," the company said.
Asked about its varying product guidelines, the company added, "While we publish general usage guidelines, regulations and codes vary by country and need to be determined by the local building code experts."
Hassan Ibrahim, who lived in an apartment on the 23rd floor of Grenfell Tower, was travelling outside England the day of the fire. His wife, Rania, and their two small children were not so lucky.
As the smoke and flames drifted upward, Rania Ibrahim debated with a neighbor whether to risk opening her door.
"Don't open the front door," her neighbour told her. "You are not going to be able to breathe - you are just going to bring the smoke in. You have your children. Standing near the door with all the smoke is not going to help you."
"Maybe someone outside?" Ibrahim asked plaintively.
For a moment, she threw the door open. "Hello! Hello! Come here," she shouted into the blackened hallway. Then she gave up and retreated. "OK, OK, I closed it," she said. "I am not going to go."
Ibrahim recorded a video as she fretted over what to do - and then posted it online as the fire was still raging.
The fire service said it received 600 calls from the building that night, some lasting an hour. Speaking in Arabic over a telephone, Ibrahim said: "We are on the last floor. The last floor is the one that has not caught fire yet."
Then, a few moments later, she said: "It's over. It is here." "Pray for us," she added.
Her husband arrived at the charred hulk of the building the next day. His wife and children are still among the missing.