LONDON — Emiliano Sala, the Argentine soccer player who died in a plane crash in the English Channel in January, had been exposed to “potentially fatal” levels of carbon monoxide, the British authorities revealed on Wednesday.
Mr. Sala, 28, who was on a flight from France to Wales on Jan. 21 when the aircraft went down, sustained carbon monoxide poisoning in the cockpit of the plane, according to a report released by Britain’s Air Accidents Investigation Branch as part of its inquiry into the crash.
Toxicology tests on Mr. Sala’s blood revealed that he had been exposed to the odorless, colorless gas at a high level that “in an otherwise healthy individual is generally considered to be potentially fatal,” according to the interim report, or special bulletin.
Mr. Sala’s body was not recovered until February. The body of the plane’s pilot, David Ibbotson, has not been found, but investigators concluded that he would most likely have been affected by carbon monoxide exposure.
Exposure to carbon monoxide, or CO, can damage the brain, heart and nervous system, with symptoms including blurred vision, loss of coordination, seizures, heart attack and unconsciousness.
“It is clear from the symptoms that exposure to CO can reduce or inhibit a pilot’s ability to fly an aircraft depending on the level of that exposure,” the report said.
Days before the crash, Mr. Sala had transferred from Nantes in the top French league to Cardiff City of the English Premier League. He was traveling to Cardiff in a single-engine, propeller-driven Piper Malibu aircraft when it vanished over the English Channel near Guernsey.
Mr. Sala had sent concerned messages about the condition of the plane before taking off, warning that the aircraft “seems like it’s falling to pieces,” a WhatsApp audio message to a group of friends revealed.
“If, in an hour and a half, you have no news from me, I don’t know if they are going to send someone to look for me, because they are not going to find me,” he said in the message.
The Air Accidents Investigation Branch, which is part of the British government’s Department for Transport, is exploring the source of the carbon monoxide.
“The investigation continues to look into a wide range of areas in relation to this accident, but in particular we are looking at the potential ways in which carbon monoxide can enter the cabin in this type of aircraft,” said Geraint Herbert, the principal inspector of air accidents at the investigation branch, in a video posted on Twitter.
Although the discovery of carbon monoxide poisoning sheds light on the crash, officials cautioned against speculation over the cause until their full report is issued.
The special bulletin said that investigators were still looking into “pertinent operational, technical, organizational and human factors which might have contributed to the accident.”
Mr. Sala’s funeral was held in the village of Progreso, Argentina, in February, and he was to be cremated, officials said.
In April, a photograph circulated online of what was believed to be Mr. Sala’s body in the mortuary, prompting a police investigation. This month, two Britons appeared in court and acknowledged accessing CCTV footage of Mr. Sala’s post-mortem examination.
The two were released on bail and will appear before the same court next month.