Rebreather divers Vincent Hong and Tim Saville died just days apart during an HMHS Britannic wreck expedition off the Greek island of Kea in 2019 – but the truth about their causes of death might never be known because of shortcomings on the part of local investigators, an inquest has concluded.
No blood samples had been taken at the initial post mortem examinations, nor had the contents of the divers’ tanks been checked at the time.
High levels of carbon monoxide (CO) were later found in the tissues of both divers, neither of whom was a smoker, and family-members have expressed their belief that this was not a coincidence. However, none of the other expedition divers had shown any symptoms of CO poisoning, as might be expected with a contaminated filling system.
An inquest in Hull considered these questions in April this year, as reported on Divernet, but was adjourned to give East Riding of Yorkshire senior coroner Prof Paul Marks time to consider the “highly technical” evidence further. The proceedings resumed on 30 August, and were reported by the Hull Daily Mail and Yorkshire Post.
Hong, 53, an anaesthetist and hyperbaric physician from Anlaby, Yorkshire, died on 27 September on a work-up dive to the 76m-deep wreck of the Burdigala, and two days later Saville, 61, a businessman from Honley, also in Yorkshire, died following a dive to the Britannic.
Carbon monoxide levels
The coroner had indicated in April that he was inclined to dismiss CO poisoning as a contributing factor in either death, but toxicologist Dr Stephen Morley stated that in the absence of blood samples it was not possible to either confirm nor rule out this explanation.
A second post mortem had later been carried out on both divers at the coroner’s request by UK pathologist Dr Lisa Barker. This had been challenging because the bodies had already been examined before being embalmed, but she had succeeded in obtaining tissue samples.
These had indicated Saville’s CO levels to be at 15% and Hong’s 11%. Dr Barker said that these levels were abnormally high – as non-smokers less than 1% might be expected – but would not usually prove fatal. She also found significant evidence of heart disease in Saville and some evidence of heart lesions in Dr Hong, but could not ascertain the exact cause of death.
Expedition leader Simon Townsend stated that the men had trained for two years for the challenging technical dives to the 120m-deep Britannic, and that preparations and safety briefings had been comprehensive.
Hong was ascending from a 63m dive to the Burdigala but about halfway up became entangled in the line, tried to use his DPV to facilitate his ascent and lost his rebreather mouthpiece before becoming unresponsive.
Conditions were said to have been ideal two days later, according to evidence provided by diver Clare Fitzsimmons. The team were again using DPVs, but while heading for the wreck about 12 minutes into the dive she had turned to see Saville kneeling with his rebreather mouthpiece out.
He was non-responsive when put onto his bail-out, and had been allowed to drift to the surface while the other divers completed their two-hour decompression.
CPR had been carried out on both divers at the surface, but both had later been pronounced dead at a nearby health centre.
The coroner called cardiologist Dr Mark Turner, a Royal Navy diving medic and chair of the UK Diving Medical Committee, as an expert witness. Largely ruling out CO as a factor, he said that on a stressful deep dive heart disease could have been significant, particularly in Saville’s case, making him more susceptible to immersion pulmonary oedema (IPO).
Dr Turner had also stated in April that problems appeared to have been flagged with Saville’s rebreather, and his lagging behind could suggest that he had been overcome by CO2, with subsequent narcosis affecting his judgment and causing him to lose his mouthpiece.
Prof Marks returned an open verdict on both deaths, stating only that they were related to scuba diving and with hypertension a contributory factor in Saville’s case. “We have been let down by Greek authorities who did not take blood samples at the time to test for carboxyheamoglobin levels and did not examine the gas cylinders,” he pointed out.
“I appreciate how difficult this has been for both families losing loved ones to activities they loved and were excellent at. The fact that there were two deaths in three days is not lost on me. Whether this was coincidence or something else I cannot determine.”
Prof Marks has agreed to relatives’ requests that he contact UK governing body the British Sub-Aqua Club about equipping all UK dive-boats with defibrillators and its need to stress the danger bad fills can present to divers.
“It is important for us that carbon monoxide poisoning has not been dismissed, which was a concern following the previous hearing,” Saville’s wife Liz told press after the inquest. “At some level we believe that played a part in what happened.”
She said that the families had battled to obtain a “wholly inadequate” police report. “They had not analysed the tanks, nor inspected the equipment properly. At that point we asked the solicitor if he could help us get the investigation done again.
“I am honestly not sure whether we will get answers over actually what killed them, but hopefully we will get some concessions over what we want done better.”
Of the hearing she said: “It has been a thoughtful and detailed inquest and we are thankful for that, even if we still don’t know exactly what happened.”
A criminal court case in Greece is set for January 2024, with Kea Divers, which arranged the diving, accused of negligent manslaughter. Liz Saville and Hong’s widow Lily are both required to attend as witnesses.