A British music producer’s alcoholism likely made him more susceptible to a medical event that caused him to die while scuba diving off Byron Bay in New South Wales, a court has heard.

Karl Bareham was found lying on the ocean floor 2.5km off the coast, without his breathing equipment in his mouth, during a dive tour of Nguthungulli/Julian Rocks on 24 September 2019.

The 37-year-old had arrived in Australia the day before to tour with City and Colour musician Dallas Green.

The NSW deputy coroner on Wednesday heard from three medical experts who weighed up what could have caused Bareham’s death.

Under questioning from counsel assisting the coroner, Rob Ranken, the experts agreed that Bareham’s chronic alcoholism may have triggered a medical event while he was underwater.

However, they disagreed on what they thought the ultimate cause of death was.

Dr Ian Millar, a specialist in diving and hyperbaric medicine, and Dr Alison Ward, a forensic pathologist, agreed in their evidence before the court that Bareham ultimately drowned after a sudden cardiac event or seizure.

They said his alcoholism and lung disease made him more susceptible to such a medical event.

The pair said it was most likely he suffered from cardiac arrest or a seizure because it appeared it took just seconds for Bareham to become incapacitated.

The court heard that a scuba diving instructor had found Bareham with his regulator out of his mouth and attempted to put it back in his mouth.

The three experts agreed that he may have voluntarily or involuntarily taken out his breathing equipment due to the medical episode.

“It’s a dying last-gasp panic reaction,” Millar told the inquest.

Dr Glen Hawkins agreed with the two other medical experts it was possible Bareham suffered cardiac arrest or a seizure.

But he told the court Bareham’s ultimate cause of death was not drowning but immersion pulmonary edema – a condition caused by too much fluid in the lungs.

“[Drowning as the cause of death] is like saying everyone in a plane crash dies of blunt force trauma, not what is the cause of the plane crashing,” Hawkins said.

Hawkins told the court that excessive drinking impacts the organs and, in Bareham’s case, that had caused liver disease. He may also have suffered from cardiomyopathy – a heart muscle disease.

Hawkins said these pre-existing medical conditions made him more susceptible to pulmonary edema.

Hawkins told the court that the pulmonary edema likely led Bareham to suffer from hypoxia – which can cause confusion and euphoria – and he then became unconscious.

The court heard that Bareham had a low alcohol blood level while scuba diving – likely equating to two drinks – and that was potentially from the night before.

Asked if that might reduce the chance of Bareham suffering an alcohol withdrawal-related seizure, Hawkins said on Wednesday: “It doesn’t preclude it but he’s less likely to.”

On Tuesday, on the second day of the inquest, the court heard evidence from a NSW police diver that the pressure of Bareham’s breathing apparatus was above usual parameters.

Millar and Hawkins agreed that while the effort to suck air from the regulator may have been slightly more difficult than usual, it still would have been tolerable for most people.

If it wasn’t, they said, Bareham would likely have made an effort to get to the surface.

“If you felt that way, you would have gone to the surface,” Hawkins said.

The inquest continues and is expected to end on Friday.