A deadly 2016 plane crash was caused by the pilot's lit cigarette in the cockpit, investigation reportedly finds

• An EgyptAir flight from Paris to Cairo crashed in 2016, killing all 66 people on board.
• Investigators have found the crash was caused by a fire in the cockpit, according to Italian newspaper Corriere della Sera.

A 2016 EgyptAir plane crash that killed all 66 people on board was caused by the pilot's lit cigarette in the cockpit, a recent investigation reportedly found.

A 134-page document submitted to the Court of Appeals in Paris last month said investigators determined that the burning cigarette combined with escaping oxygen from the co-pilot's mask and caused a fire on board Flight 804, according to a report from Italian newspaper Corriere della Sera.

The co-pilot's oxygen mask had been changed three days prior to the crash and set to "emergency mode," according to the report, and a fire was triggered after leaked oxygen was sparked by the lit cigarette.

Smoking in the cockpit was not banned by EgyptAir at the time of the crash, the Independent reported.

EgyptAir 804 was traveling from Paris to Cairo on May 19, 2016, when it crashed into the Mediterranean Sea, killing all 66 people on board.

It was not immediately known how the plane went down. A 2019 report commissioned by France's justice ministry suggested the crash was a result of lacking maintenance and said the plane should never have taken off in Paris.

The French air accident investigation agency had said previously that a cockpit fire likely caused the crash; Egyptian authorities initially claimed it was a terrorist bombing.