Soundproofing foam in focus in probe of deadly Swiss bar fire

By AFP
January 3, 2026


The question of whether safety standards were respected has been debated since a bar fire in Crans-Montana, Switzerland, killed 40 people - Copyright AFP MAXIME SCHMID

The soundproofing foam covering the ceiling of a Swiss ski resort bar that went up in flames on New Year’s Eve, killing 40 people, is being closely scrutinised by investigators.

The question of whether safety standards were respected has been debated since the fire broke out at Le Constellation bar in Switzerland’s glitzy resort town Crans-Montana at around 1:30 am (0030 GMT) on Thursday, as the venue was crammed with young partygoers.

Beatrice Pilloud, the lead prosecutor in Switzerland’s southwestern Wallis canton, told reporters Friday that the leading hypothesis was that “sparklers or Bengal candles attached to champagne bottles and lifted too close to the ceiling” of the bar’s basement had ignited the deadly blaze.

One video shared on social media showed the low ceiling — covered with soundproofing foam — catching alight and the flames spreading quickly, as revellers continued to dance, unaware of the death trap they were in.

Once they realised, panic set in.

“The investigation is indeed focusing on the installation of this foam”, and it will have to determine whether this soundproofing material “is compliant” and whether it “caused the fire or not”, Pilloud said.



– ‘Very easily flammable’ –



For Freddy Rigaux, a former professional firefighter in France and a court-appointed expert, the material visible in videos shared online corresponds to products that are “easily, even very easily, flammable”.

It clearly did not meet the so-called M1 fire-resistance standards required for ceilings in public buildings in France, he said, explaining that M1-rated materials are combustible, but not flammable.

“They will degrade under the effect of heat, but will not produce flames, particularly flaming droplets as seen in the video,” he said.

When soundproofing foam is not treated with flame retardants, fire can spread very rapidly, the expert explained.



– ‘Inconceivable’ –



According to Romain Amisse, another court-appointed fire expert, the fumes emitted when such material burns are toxic, especially in very confined spaces, as is the case in the Le Constellation’s packed basement.

He said the Swiss tragedy was reminiscent of the Cuba Libre bar fire, which killed 14 people in Rouen, northern France, in 2016.

In Crans-Montana, “you have pretty much the same situation, with highly flammable foam on the ceiling that produces a lot of smoke”, he said.

David Zenouda, the vice-president of the Union of Trades and Industries in the Hotel and Catering Sector in Paris, said using the type of foam seen in the Crans-Montana images for soundproofing a venue was “inconceivable”.

“For soundproofing, we have specific materials for covering ceilings and walls, creating a kind of box within a box,” he told AFP.

What you want, he said, was to create a “box with a plasterboard panel… on which you place tar paper panels with rock wool, and then another panel”.

“It is very complex and requires significant investment,” he acknowledged.

By contrast, he said, the method that appears to have been used at the Le Constellation bar is equivalent to “soundproofing material for media booths or recording studios”, not for establishments open to the public.

The danger posed was “exactly the same” as if the bar managers had decided to cover their venue with nylon sheets, he said.

“Combined with the sparklers… the effects would have been the same.”

Criminal case opened against managers of Swiss bar after deadly fire

The blaze on New Year’s Day at Le Constellation bar in Crans-Montana left at least 40 people dead.

Mourners pay tribute to the victims of the fire at the Le Constellation venue, Crans-Montana, Switzerland. | Jean-Christophe Bott/EPA

January 4, 2026 

By Jones Hayden

POLITICO. EU

Swiss prosecutors have opened a criminal investigation into the two managers of a bar where a fire on New Year’s Day killed at least 40 people and injured more than 100.

The investigation includes the suspected offenses of negligent homicide, causing bodily harm by negligence and arson by negligence, the prosecutors’ office in the canton of Valais said in a statement on Saturday.

The likely cause of the fire at Le Constellation bar in Crans-Montana was sparklers on bottles being carried too close to the ceiling, a preliminary investigation found. The blaze began about 1:30 a.m. local time on Thursday, according to the reports.

Stephane Ganzer, head of security in Valais, told Reuters news agency that the investigation would determine if the bar had undergone its annual building inspections, but that the town had not raised concerns or reported problems to the canton. The bar is owned by a French couple, according to media reports. 

Swiss Justice Minister Beat Jans told a press conference in Crans Montana on Saturday that the first priority is providing the best possible medical care and identifying the deceased. Eight Swiss nationals among those killed were the first to be identified on Saturday, according to media reports.