A 2016 EgyptAir crash that killed 66 humans within the Mediterranean became probably a result of a heart that started from a leaky oxygen mask within the cockpit, in line with the conclusions of French experts seen with the aid of AFP Thursday.

The flight crew fled the hearth and seem to were not able to find a fire extinguisher — main to the deadly crash a couple of minutes later.

“Oxygen leaking from the co-pilot’s emergency oxygen mask is seen as the decisive element in causing the fire,” the five experts wrote in their 134-page report, delivered to the Paris court of appeal in March and revealed Wednesday by Italian newspaper Corriere della Sera.

EgyptAir flight MS804 suddenly disappeared from radar screens on May 19, 2016, on its way to Cairo from Paris. Everybody on board died.

Egypt’s aviation minister had initially said a terrorist attack, rather than lack of maintenance, was more likely to have brought down the plane.

France’s aviation safety agency, however, said the aircraft transmitted automated messages indicating smoke in the cabin and a fault in the flight control unit minutes before losing contact.

The latest report does not determine with certainty what could have ignited the leaking oxygen.

An earlier expert report in June last year had suggested three possible causes for the fire — “a blanket charged with static electricity that had been requested by the pilot” to sleep, “fatty elements in the meal served to the pilot and finally a high probability of a lit cigarette or a burning cigarette butt in an ashtray”.

The crew was smoking regularly in the cockpit, the report found, while pointing to a pattern of “unprofessional activity” including listening to music, repeated comings and goings in the cockpit and “lack of attention to the progress of the flight”.

A June 2018 expert report had also highlighted the replacement, three days before the crash, of the box containing the co-pilot’s oxygen mask, for unknown reasons.

“The replacement of this equipment requires very careful verification…, oxygen leaks being particularly dangerous”, they had said.

“There was a failure of maintenance, a string of negligent behavior and serious irregularities,” two representatives of an association for the families of the MS804 victims told AFP, calling for EgyptAir to face criminal charges.