Elena Chong, Khushwant Singh, Straits Times 8 Nov 08;
A TRAINEE diver, just one dive away from qualifying as an open-water diver in February last year, never finished his quest.
A scuba tank filled with an exceptionally high level of carbon monoxide ended it for Mr Sue Qing Wen off Pulau Hantu. The 20-year-old sank out of the dive crew's sight and drowned; his body was found three days later, the tank still strapped on.
Lab tests found the tank to contain 785 parts per million (ppm) of carbon monoxide and 12.3 ppm of hydrogen sulphide - both toxic. The compressed air in a normal scuba tank should contain 80 per cent nitrogen and 20 per cent oxygen.
Nobody at the inquiry into his death could explain how so much of these poisonous gases got into his tank; neither could it be determined how inhaling them could have affected him.
State Coroner Victor Yeo thus recorded an open verdict.
The Health Sciences Authority's forensic scientist Chia Poh Ling said the high level of carbon monoxide in the tank could have come either from a contaminated air supply or the tank having been filled where there was a high level of the gas. Another tank taken off the boat was found filled with the expected 20.7 per cent of oxygen, 55 ppm of carbon monoxide and 1.7 ppm of hydrogen sulphide.
The manager of Dolphin Dive & Adventures Francis Yeo, 29, testified that when he filled up the 24 tanks a day before the dive, he did it by the book. He said he also turned off the boat's engine and placed the air-intake valve upwind of the compressor engine so exhaust would not be sucked into the tank.
Associate Professor Philip Eng of the Department of Respiratory Medicine at the Singapore General Hospital said too much carbon monoxide causes dizziness and nausea; fits set in within 45 minutes, and unconsciousness, in two hours.
Exposure should not exceed more than 35 ppm of the gas over eight hours.
On Feb 17, Mr Sue and five other dive students headed out to Pulau Hantu with several others for their final dive assessment following theory lessons and a practice session in a pool.
The first two dives were uneventful. Before the third and final dive, the trainees changed tanks.
Mr Sue was paired with fellow trainee Mohamed Fairus Jumali, 35. They entered the water with divemaster Gerald Chew Tiau Chin, 27, descending vertically by holding onto a line tethered to the seabed.
When they had gone down 8m, the trio paused to make way for another trainee going up. This was when Mr Chew and Mr Fairus lost sight of Mr Sue. Mr Chew looked for him on the sea bed to no avail.
He resurfaced and alerted Dolphin Dive employee Joanne Sim Hui Jun, 28. It was she who saw Mr Sue surface a distance away, waving and without his breathing apparatus.
She signalled to him to put it back on and inflate his buoyancy compensator device, a vest worn by divers which can be inflated or deflated to control buoyancy.
A lifebuoy thrown towards Mr Sue fell short of him. Ms Sim said Mr Sue, then conscious, sank into the water amid strong currents.
The family's lawyer Simon Tan, said Mr Sue's parents felt that the circumstances of his death are no clearer now and want to see justice done. They are considering commencing legal action against the relevant parties.
Mr Tan said that on the day of the incident, the family waited for Mr Sue to join them for their Chinese New Year reunion dinner.
Instead, they got a visit from the police after 8pm bearing the news that he had gone missing.
