Another focus is on foam-like padding on the bar’s ceiling and whether it was compliant with safety standards.
Two fire safety experts told BBC Verify that the materials visible in photos and videos of Le Constellation appeared to show “egg box foam”, a type of sound-absorbing material made from polyurethane (PU).
In the photo of the bottles being held up, flames are visible on a part of the ceiling with a foam-like covering.
PU foam is often treated with fire-retardant before being installed as a noise dampener in factories and entertainment venues.
But untreated, it can be highly flammable.
“Once ignited, polyurethane acoustic foam can exhibit rapid flame spread across its high-surface-area profile and produce dense, toxic smoke, significantly accelerating fire growth and reducing available escape time,” said Dr Peter Wilkinson of Loughborough University.
Professor Edwin Galea, from the University of Greenwich, said the effectiveness of retardant treatment on PU foam can wear off over time.
The Swiss authorities say they cannot confirm what type of foam-padding was used in the bar and whether or not it complied with safety standards.
In Friday’s press conference, officials talked about a “flashover” happening in the bar.
Professor Galea explained this is what happens when hot gases rise to the ceiling, reach a critical temperature and then ignite the room near instantaneously.
According to Michael Klippel, a fire safety expert at ETH Zurich University, “survival after flashover is very unlikely”.
The authority responsible for overseeing fire safety inspections in Crans-Montana is the Office Cantonal du Feu (OCF) of the Canton of Valais. The inspections are carried out by local officials.
Swiss authorities said in a press conference that inspections on a building the size of Le Constellation should have been carried out each year.
BBC Verify has contacted the OCF to request access to previous inspection documents.