Saman Kunan volunteered for the operation when he died in the cave system.
Saman Kunan volunteered for the operation when he died in the cave system.
A former Thai Navy SEAL has died during the rescue operation to save 12 boys and their soccer coach trapped inside a flooded cave.
Authorities have confirmed the diver's death was caused by lack of oxygen, and the man died while making his way out of the cave complex where the group is trapped.
The man has been identified as retired Navy Petty Officer 1st Class Saman Kunan who volunteered for the operation after having left his post.
Saman Kunan volunteered for the operation when he died in the cave system.
The rescuer lost consciousness after placing oxygen tanks in the cave and could not be revived despite first-aid attempts by his dive partner.
Authorities say the cave system, Mae Sai, northern Thailand, is losing oxygen as they continue to try and deliver air supplies to the kids and coach through a pipe.
They say the ventilation pipe must reach them today.
And there is now a "limited amount of time" left to get the boys out.
The level of oxygen in the cave where the boys are trapped has dropped to 15 per cent, authorities have confirmed. The usual level is around 21 per cent.
Asked how long that would last the boys, deputy commander Chalongchai Chaiyakham replied: "I'm not a medical person, I can't answer that."
At a news conference Thai SEAL commander Arpakorn Yookongkaew acknowledged time is running out.
"We can no longer wait for all conditions (to be ready) because the circumstance is pressuring us," Arpakorn said.
"At first we thought that we could sustain the kids' lives for a long time where they are now, but now, many things have changed. We have a limited amount of time." He did not elaborate.
'SAD NEWS'
Meanwhile Chiang Rai deputy governor Passakorn Boonyaluck told reporters "it was sad news, a former SEAL who volunteered to help died last night about 2am."
"His job was to deliver oxygen (in the cave). He did not have enough on his way back."
International rescuers team prepare to enter the cave where a young football team and their coach are trapped. Photo / AP
SEAL commander Yookongkaew said Mr Kunan, who was working in a volunteer capacity, was coming back from the spot inside the Thuam Luang cave where the group had been located when his supplies ran short.
"On his way back he lost consciousness," Mr Yookongkaew said, adding that a friend had tried to help bring him out.
"But even though we have lost one man, we still have faith to carry out our work."
RESCUERS TO TAKE 'MORE PRECAUTIONS'
His death raises doubts over the safety of attempting to bring the group out the same way, through cramped passageways deep inside the waterlogged cave.
Many of the boys, aged between 11 to 16, are unable to swim and none has diving experience.
Asked how the boys could make it out safely if an experienced diver could not, Mr Yookongkaew said the rescue team would take more precautions with children.
"We lost one man, but we still have faith to carry out our work," he said.
The diver's mission was to bring oxygen tanks and carry lines along the passageways between a forward operating base and the muddy embankment where the children and coach are sheltering.
Even for expert divers the journey is an exhausting 7-hour round trip.
"It's very risky (diving out). Think about it, a Navy Seal just passed away last night, so how about a 12-year-old kid," said Rafael Aroush, an Israeli diver helping the rescue bid.
Officials vowed to investigate the death, and have sent his body to a local hospital for an autopsy.
The incident marks the first major setback for the rescue effort.
Rescuers continue to work to save the Thai boys and their 25-year-old coach from the flooded cave, but some say they may be too weak to complete the terrifying mission.
It is believed 1.5km of the cave is still full of water. The rescue mission will go on despite the death.
The distance between a rescue base camp in side "chamber three" of the cave complex and where the team is stranded is 1.7km. In order to reach the boys from the base, a diver has to carry at least three oxygen tanks to reach them before replacing the tanks again on the way out.
Two of the boys and the coach are suffering from exhaustion through malnutrition, which could make it almost impossible for them to attempt the perilous journey, a Navy source told CNN.
Skilled cave divers are painstakingly teaching them to swim in preparation for a perilous escape, which involves pairing them with trained frogmen and leading them to safety through pitch-black water and narrow passageways.
Officials confirmed some parts of the journey will be walkable.
Rescuers expect the mission to be completed in stages, with the boys who are well enough removed first and those that are too sick left behind.
It takes even experienced divers six to seven hours to complete the round-trip from forward command in the third cave chamber to the boys huddled on a ledge deep inside the complex at Noem Nom Sao. This could mean a fatal delay if anything was to go wrong during the audacious rescue plan.
Engineers are working to install a cable to allow the children to speak to rescuers and their families to improve their morale.
A Thai Navy SEAL medic helps an injured child inside a cave in Mae Sai, northern Thailand. Photo / AP
Rescuers have also been transporting food, supplies and first aid into the caves, along with diving equipment to be used by the boys and oxygen "stage" tanks that will be set up every 25 to 50 metres along their route for extra air.
The coach, a former monk who is reported to be struggling after selflessly sacrificing his share of food, could still be charged over the crisis.
Approaching torrential rains also threaten to derail the risky plan to move the boys through the cave system of linked chambers.
The boys' frightened families are waiting at the cave entrance to be reunited with them.
It is believed the group may have entered as part of an initiation rite, although two mothers came forward to say they did not blame coach Ekkapol Chantawong for their boys' desperate circumstances.
48 HOURS
Rescuers said on Friday morning the rescue mission needed to be completed within 48 hours.
An anonymous navy source told the ABC three factors were driving the urgency — the water level inside the cave, the amount of oxygen available, and the health of the boys and their coach.
He said rescue co-ordinators faced "tough choices" and differences of opinion were emerging.
Australian Defence Force and Australian Federal Police have been tight-lipped about whether to attempt an extraction or wait, even until the end of the rainy season around October.
Thai rescue workers practise medical training on an entrance of Tham Luang Nang Non cave. Photo / Getty Images
The Navy source said boys' biggest challenge would be a 200m stretch of completely flooded cave that made up part of the 600m section between "Pattaya Beach" and chamber three.
A firefighter who has been working on draining the water said levels in parts of the passage leading to the chamber were still flooded all the way to the ceiling, making diving the only way out.
Volunteers' dangerous water error
Out in the open air, teams from across the world are working frantically with Thai authorities to overcome potentially deadly challenges and save the boys' lives.
Time is not on their side, with torrential monsoon rains forecast to hit Chiang Rai province this weekend, which could cut off the boys from the outside world for months.
Volunteers have been helping Thai Navy SEALs to pump water out of the caves, but some unregistered helpers made the situation worse by accidentally pumping water back into the cave, officials told the Bangkok Post.
How the rescue operation will unfold.
Operation commander Narongsak Osotthanakorn said the volunteers directed the flow of extracted water into the ground, creating a stream that fed back into Tham Luang cave.
"We are racing against water," said Narongsak, former governor of Chiang Rai province. "Water is flowing into the cave although we have plugged its channels."
Belgian cave diver Ben Reymenants, who owns a business in Phuket, was reportedly exploring a new, wider channel with air pockets that could offer a safer route out for the boys.
If one of them was to panic while following a rope through water like "black coffee", they could kill themselves or their rescuers.
Potentialy fatal delay
The distraught families of the young boys are waiting and praying at the cave mouth for news of their children. The youngsters, aged 11 to 16, were believed dead after they went missing on June 23. They were finally found alive almost 10 days later by divers on Monday, starving yet overjoyed to be discovered.
But their relatives have learnt the rescue operation could take weeks or even months if the storms arrive, and there is no easy way to extract the trapped boys from their subterranean prison.
Royal Thai Navy SEALs, Australian Federal Police divers and rescuers from countries including the UK, US and China have converged on the scene to help but they are concerned at the slowness of communication.
An image of the boys taken when they were first discovered by divers. Photo / AP
It takes even experienced divers six to seven hours to complete the round-trip from forward command in the third cave chamber to the boys huddled on a ledge deep inside the complex at Noem Nom Sao. This could mean a fatal delay if anything was to go wrong during the audacious rescue plan.
Engineers are working to install a cable to allow the children to speak to rescuers and their families to improve their morale. Media at the scene reported seeing officials taking old-fashioned military communication devices into the cave system, but one phone reportedly fell into the water and had to be replaced.
Rescuers have also been transporting food, supplies and first aid into the caves, along with diving equipment to be used by the boys and oxygen "stage" tanks that will be set up every 25 to 50 metres along their route for extra air.
The boys have been practising wearing scuba masks, and will be kitted out with wetsuits, aqua boots and a helmet as they attempt to escape.
They will share oxygen from a navy rescue diver's air supply as they follow a guide rope through the murky water.
The divers will have to remove their scuba kits to squeeze through certain narrow points along the route, with volunteers holding the guideline submerged up to 10 metres at various points in the freezing, muddy water.
A happy family member shows the latest pictures of the missing boys taken by rescue divers. Photo / AP
British cave expert Vern Unsworth, who lives in Thailand, said conditions were getting worse and there was now a narrow window in which the group could escape.
"I think we'll know in the next 24 hours … We'll keep our fingers crossed, everybody needs to pray and hope for a good outcome," Unsworth told the BBC.
Hidden passage or death-defying journey
Around 30 teams of jungle-trekking rescuers were scouring above ground for a possible "secret passage" to safety, after the boys told divers they heard dogs barking, a rooster crowing and children playing.
If they weren't hallucinating, this may mean the trapped boys are close to a shaft that rescuers could climb down for a far easier evacuation method.
Thai police stand in front of the entrance to the cave complex. Photo / AP
The current plan involves an arduous, four-hour journey for the young boys, and could last for two days of continuous individual trips.
A certified cave diver from the US said the boys would have to undergo "intensive training" if they were to stand any chance of exiting the cave alive. "Normal cave diving requires skills that go beyond what 99 per cent of the world's divers have ever seen, which is why it is so very hard to become certified to dive in caves," John Adsit wrote in an educational journal.
"The greatest enemy to a diver is panic. Students who are accustomed to the normal mishaps of swimming, like accidentally getting water in the mouth or eyes, will usually have no trouble, but for people with little swimming experience, such a minor event can lead to irrational panic.
"Most of the Thai team members are non-swimmers, and the culture there has a common belief that swimming is extremely dangerous. That starts any training in a serious deficit."
Classmates of the boys joined their families in the forest at the entrance to the cave, the BBC reported, where they sang: "Believe in God. Only belief can move a mountain."
Soldiers were controlling the crowds as heavy machinery was brought to the cave entrance and medics rehearsed carrying empty stretchers to ambulances for when the boys emerge.
It is suspected that the group entered the cave to write their names on the wall as part of an initiation ritual. But Thai police refused to comment on whether the 25-year-old coach should be charged for leading the children into the cave.
Video shot by divers showed the boys looking thin but apparently in good spirits, asking what day it was and whether they could have something to eat.
Chilean miner Mario Sepulveda, who was trapped underground for 69 days in 2010, sent a heartfelt video message to the boys, telling them they should not be afraid to cry.
They will need to show even more bravery in the days to come.
