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A mountain of rock sits above them, and muddy, flooded passages are their only way out

Expert cave diver and RCGS Explorer-in-Residence Jill Heinerth explains the risks and challenges of rescuing a boys’ soccer team trapped in a flooded cave in Thailand

  • Jul 05, 2018
  • 1,558 words
  • 7 minutes
Two divers scuba diving in a cave in the Bahamas Expand Image

Update – July 10

The world breathed a sigh of relief this morning with the news that the 12 soccer players and their coach were successfully rescued from Tham Luang Nang Non in northern Thailand. As an expeditionary cave diver with decades long friendships with the members of the rescue team, I understand how challenging this extrication has been. Although we cannot forget the loss of a brave Thai Navy diver, we can celebrate what has been the most ambitious cave rescue in history. Anyone watching the news these past two weeks will have thought about whether they could have kept calm in the blackness of an underwater cave, wearing a full face mask and trusting rescuers as they push you through body-contorting squeezes. The survival of the boys came down to some critical and important decisions. First, British divers Rick Stanton, John Volanthen and a support team, discovered the boys on July 2, while running crucial safety guidelines to the chamber where they were trapped. Second, the coach of the team not only safeguarded the group, reportedly giving up his own food, but also kept their spirits up. He taught them to meditate and stay positive. Third, Dr. Richard Harris, an Australian expeditionary cave diver who specializes in remote wilderness medicine, assessed and maintained everyone’s health and made the right decisions about who to send through the cave first. In the face of low oxygen supplies, high carbon dioxide, pathogens such as histoplasmosis-inducing bat guano, Harris was the last man out. His decision to send the strong children first proved the concept and buoyed everyone’s spirits in the face of terrible odds.

What lessons will the world take away from this rescue? I’m amazed at how remarkable humanity can be when we work together, without regard for geography, creed or colour. When terrible things happen, the best of humanity can show up. From the locals providing meals for cold rescuers to the tech gurus offering support to the cave divers dropping their jobs and traveling halfway around the world to veteran Thai Navy diver who gave the ultimate sacrifice, more than 1,000 people reminded us that we are capable of great things. In the face of fear and uncertainty, we held hands, shed tears and made the world a better place. Twelve boys and their coach will soon be able to hug their families and pay it forward.

Update – July 6 

Today I awoke to the news that a member of the Thai Navy Team has lost his life while supporting rescue efforts for the boys’ soccer team trapped in a flooded cave in Thailand. I wish I could say that I was surprised by the news, but unfortunately the incident highlights the significant risks that are faced by both the trapped team and their rescuers.

Although details are sketchy, it appears that the diver ran out of breathing gas while ferrying an oxygen tank to the chamber. 

For the first nine days, 12 small boys and their adult coach were stuck in the small space without adequate ventilation. As the traffic into the space has increased, atmospheric conditions are deteriorating. More people in the small space, delivering food and supplies, results in lower oxygen and higher carbon dioxide levels. Humans normally breathe roughly 21 percent oxygen in each inhaled breath. Levels of 16 per cent or lower are associated with lower levels of consciousness and what we call hypoxia. Some experienced mountaineers operate at even lower levels of oxygen, but they are highly trained and acclimatized to those hypoxic levels. That said, anything below 16 per cent is a literal death zone. The rising carbon dioxide is also worrying. That alone can lead to muscle twitching, difficult breathing, headaches and eventual unconsciousness. 

The risks of sheltering in place are numerous. Besides the low oxygen levels, sanitation in a small space will be difficult at best. Resupply of food and water will be critical to survival. Psychological health and the need to exercise to prevent muscle atrophy should not be underestimated. Living in a damp underground space can also lead to strange bacterial skin infections and other maladies. Perhaps the greatest issue of all is that the monsoon season is only beginning and is forecast to bring above normal rainfall to the area. If rain falls too quickly before the cave can drain, then the chamber can flood to the ceiling.

There are still no easy solutions at hand. Training the kids to swim and dive should begin in earnest in case they get to the point where fast evacuation is the only option. But in the interim, cavers and climbers will continue to search for other potential leads that might get them closer to the chamber. Precise radio-location of the enclosed space using ultra low frequency radio beacons might help pinpoint the precise places where an air well shaft could be drilled. Even a Herculean digging operation might occur if the precise location is determined. In this video from a recent National Geographic project, you can see the radio location “cave pinger” at work. 

In any case, I wish the team the best possible health and safety as they do everything possible to bring the children out of the cave. The world needs some good news right now.

While I’m filming icebergs in Greenland, the world has been watching the drama unfold in Tham Luang Nang Non cave in Thailand, where a team of 12 soccer players aged 11 to 16 and their coach became trapped during a flash flood on June 23. Nine days after the children and their coach were trapped, my friend and fellow cave explorer Rick Stanton and his diving partner John Volanthen surfaced in the muddy sump to find the team in generally good condition.

My eyes welled up when I saw the blurry YouTube video of the boy’s soccer team taken by their rescuers on July 2, and heard Rick’s voice ask how many people were in the chamber. When the answer came back “13,” I could hear a little crackle in his usually level voice. Rick, a retired fireman, is one of the best cave explorers in the world. As a survivor of many close calls himself, he has the steely nerves and pragmatism needed for one of the most dangerous human activities — cave diving. The world is celebrating, but the team and their rescuers aren’t out of the dark yet. A mountain of rock sits above the boys, and muddy, flooded passages are their only way out. For the world’s best divers, the return trip takes eleven hours, multiple scuba tanks and body-contorting squeezes. Most of these boys can’t swim.


There are a few options ahead, but time is not on their side. The survivors in the cave are weak and traumatized, while the team of exhausted cave-diving volunteers, which now exceed 40, are in a race against monsoon rains threatening to dump a new deluge by the weekend. Cavers are working in the mountains above to find a route to access the sealed chamber, and cave divers, including the Thai Navy SEALS, are ferrying food and medical supplies through the flooded passageways to the trapped group. Efforts are underway to pump water out of the cave before the next downpour, while diving equipment is being gathered in case the boys need to be trained to swim and scuba dive out.

Each of these solutions has extreme risks. The public seems to be weighing in favor of diving out of the cave, but as a cave explorer myself, I have to caution that this is extremely risky. This very solution was employed by Rick Stanton in a cave in Mexico when he rescued a team of British soldiers trapped by flooding in 2004, so he knows how difficult it can be. Add to this the fact that he would be responsible for carrying a child through lengthy, zero-visibility passages surging with high velocity floodwater while clutching a guideline for navigation. If a child panics or inhales water, there is no way to surface. Drowning in the arms of the rescuer is a very real risk. The best cave divers in the world can make the exit in four hours, but with a child in their arms, it will take considerably longer.

The other option is for the team to stay put until the monsoon rains stop and the water recedes, a prospect that could take months (Thailand’s rainy season usually ends in October). However, this option is only viable if the chamber stays dry in the worst of the coming rains, and a nearly continuous stream of cave divers resupplies the group, while working blindly in treacherous underwater cave conditions. This too will require incredible teamwork and tenacity. The psychological welfare, physical comfort and medical needs of everyone involved will need to be considered. Leadership, physical activity, hygiene and a sense of normalcy would need to be established at the camp.

I don’t envy the decision-makers in Thailand. I wish all the best for the health and welfare of both the trapped team and their volunteer rescuers. This is not going to end quickly, but let’s hope it ends safely.


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