In June 2018, a junior football team became trapped in Tham Luang Nang Non, a cave system in Chiang Rai province, northern Thailand. Twelve members of the team, aged 11 to 16, and their 25-year-old assistant coach entered the cave on 23 June after a practice session. Shortly after they entered, heavy rainfall began and partially flooded the cave system, blocking their way out and trapping them deep within.
Efforts to locate the group were hampered by rising water levels and strong currents, and the team were out of contact with the outside world for more than a week. The cave rescue effort expanded into a massive operation amid intense worldwide public interest and involved international rescue teams. On 2 July, after advancing through narrow passages and muddy waters, British divers John Volanthen and Rick Stanton found the group alive on an elevated rock about 2 kilometres (1.2 mi) from the cave entrance.
Rescue organisers discussed various options for extracting the group, including whether to teach them basic underwater diving skills to enable the earliest possible rescue, to wait until a new entrance to the cave was found or drilled, or to wait for the floodwaters to subside by the end of the monsoon season several months later. The final strategy was for each boy to be fitted with an oxygen mask and sedated, then brought to the cave entrance by divers. After days of pumping water from the cave system and a respite from the rainfall, the rescue teams worked quickly to extract the group from the cave before the next monsoon rain, which was expected to bring additional downpours on 11 July. Between 8 and 10 July, all 12 boys and their coach were rescued from the cave by an international team.
The rescue effort involved as many as 10,000 people, including more than 100 divers, scores of rescue workers, representatives from about 100 governmental agencies, 900 police officers and 2,000 soldiers. Ten police helicopters, seven ambulances, more than 700 diving cylinders and the pumping of more than one billion liters (260,000,000 U.S. gal) of water from the caves were required.
Saman Kunan, a 37-year-old former Royal Thai Navy SEAL, died of asphyxiation on 6 July while returning to a staging base in the cave after delivering diving cylinders to the trapped group. The following year, in December 2019, rescue diver and Thai Navy SEAL Beirut Pakbara died of a blood infection contracted during the operation. Following the rescue, cave-diving was incorporated into the training regimen for Thailand's Navy SEALs to better prepare them for similar emergencies.
Background and disappearance
Tham Luang Nang Non is a karstic cave complex beneath Doi Nang Non, a mountain range on the border between Thailand and Myanmar. The cave system is 10 kilometres (6.2 mi) long and has many deep recesses, narrow passages and tunnels winding under hundreds of metres of limestone strata. Since part of the system is seasonally flooded, a sign advising against entering the caves during the rainy season (July to November) is posted at the entrance.
On Saturday 23 June 2018, a group of 12 boys aged between 11 and 16, from a local junior football team named the Wild Boars, and their 25-year-old assistant coach, Ekkaphon Kanthawong, went missing after exploring the caves. According to early news reports, they planned to have a birthday party in the cave after the football practice and spent a significant sum of money on food, but they denied this in a news conference after the rescue. The team was stranded in the tunnels by sudden and continuous rainfall after they had entered the cave system. They were forced to leave some food supplies behind when fleeing the rising water.
At around 7 pm that evening, the head coach and founder of the team, Nopparat Kanthawong (Thai: นพรัตน์ กัณฑะวงษ์), checked his phone and found about 20 missed calls from parents worried that their children had not returned. Nopparat dialled assistant coach Ekkaphon and a number of the boys, but he was unable to reach them. He eventually contacted Songpon Kanthawong, a 13-year-old member of the team who said that he had separated from the team after practice and that the rest of the boys had entered the Tham Luang caves. The coach raced to the caves, finding abandoned bicycles and bags near the entrance and water seeping from the muddy pathway. He alerted authorities to the missing group after seeing the team's unclaimed belongings.
Team members
There were 12 children and one adult trapped in the cave, as follows:
At the time of the rescue, the assistant coach and three of the boys had no nationality. Head coach Nopparat explained that they are from tribes in an area known as the "Golden Triangle", which extends across parts of Thailand, Myanmar, Laos and Southwestern China. This region has no clear borders and the people are not assigned passports. Their statelessness deprived them of basic benefits and rights, including the liberty to leave Chiang Rai province. "To get nationality is the biggest hope for the boys", head coach Nopparat said. "In the past, these boys have problems travelling to play matches outside of Chiang Rai because of their nationless status." Following the team's rescue, Thai officials promised to provide the three boys and the coach with legal assistance in obtaining Thai citizenship, a process that could take up to six months. The four were granted Thai citizenship on 26 September 2018.
Search
British caver Vernon Unsworth, who lives in Chiang Rai and has knowledge of the cave complex, was scheduled to make a solo venture into the cave on 24 June when he received a call about the missing boys. Unsworth advised the Thai government to request assistance from the British Cave Rescue Council (BCRC). On 25 June, Thai Navy SEALs divers arrived and began searching the cave. A Thai Navy SEAL said the water was so murky that even with lights they could not see where they were going underwater. After continuous rain, which further flooded the entrance, the search had to be temporarily interrupted. On 27 June, three BCRC cave divers arrived with specialist equipment including HeyPhone radios, followed by separate teams of open-water divers. On 28 June, a United States Air Force team—reportedly United States Air Force Pararescuemen from the 320th Special Tactics Squadron, the 31st Rescue Squadron, and the 353rd Special Operations Group—joined them. By 29 June, an Australian Federal Police team of Specialist Response Group divers had arrived, followed by a Chinese team of divers from the Beijing Peaceland Foundation on Sunday, 1 July.
Meanwhile, policemen with sniffer dogs searched the surface above for shaft openings that could provide alternative entrances to the cave system below. Drones and robots were also used in the search, but no technology existed to scan for people deep underground.
BCRC divers Richard Stanton and John Volanthen advanced through the cave complex placing diving guidelines, supported by Thailand-based Belgian cave diver Ben Reymenants and French diver Maksym Polejaka. The search had to be suspended due to the weather, as rainfall increased the flow of water in the cave where the divers were battling strong currents and poor visibility. The search resumed on 2 July after the weather improved. The twelve boys and the coach were discovered at approximately 22:00 by Stanton and Volanthen, whose efforts were overseen from outside by BCRC diver Robert Harper. The boys and coach were on a narrow rock shelf about 400 metres (1,300 ft) beyond the "Pattaya Beach" chamber, named after an above-ground beach in Thailand. Volanthen had been placing guidelines in the cave to assist others in navigation when he ran out of line. He then swam to the surface and soon found the missing group, smelling them before hearing or seeing them. A video of the encounter, showing the boys and their interactions with the divers, was posted on Facebook by the Thai Navy SEALs. Former Chiang Rai provincial governor Narongsak Osatanakorn, who was in charge of rescue work, said, "We found them safe. But the operation isn't over." The Thai, US, Australian and Chinese diving teams supported by the BCRC divers began transporting diving bottles into the cave system and established an air supply storage area in Chamber 3.
On 3 July, the trapped group was joined by three Thai Navy SEALs who supported them until the rescue. The SEALs included Thai Army doctor Lt. Col. Pak Loharachun of the 3rd Medical Battalion, who had completed the Navy SEALs course. Thai officials told reporters that rescuers were providing health checks and treatment and keeping the boys entertained and that none of those trapped were in serious condition. "They have been fed with easy-to-digest, high-energy food with vitamins and minerals, under the supervision of a doctor", Rear Admiral Apagorn Youkonggaew, head of the Thai Navy's Special Forces, told reporters. A video made by the rescuers, and shared a few hours later by the Thai Navy SEALs, showed all twelve boys and their coach introducing themselves and stating their age. Wrapped in emergency blankets and appearing frail, they all said hello to the outside world. "Sawatdi khrap", each boy said with his palms together in wai, the traditional Thai greeting. A second video shows a medic treating them. It was believed that some of the group could not swim, complicating what would already be a difficult rescue. The Army doctor discovered that they had attempted to dig their way out of the cave. The team members had used rock fragments to dig every day, creating a hole five metres deep.
BCRC diver Jason Mallinson offered the boys and coach an opportunity to send messages to relatives by using his wet notes pad. Many of the notes said they were safe, reassured family members that everything was fine, and included words of love, reassurance and encouragement.
Planning and preparation
A logistics camp was established at the cave entrance, which accommodated hundreds of volunteers and journalists in addition to the rescue workers. The site was divided into several zones: restricted areas for the Thai Navy SEALs, other military personnel, and civilian rescuers; an area for the relatives to give them privacy; and areas for the press and the general public.
An estimated 10,000 people contributed to the rescue effort, including more than 100 divers, representatives from about 100 government agencies, 900 police officers, 2,000 soldiers and numerous volunteers. Equipment included ten police helicopters, seven police ambulances, and more than 700 diving cylinders, of which more than 500 were in the cave at any time while another 200 were in the queue to be refilled. More than a billion litres of water (the equivalent of 400 Olympic-size swimming pools) were removed.
Challenges
The place where the boys became stranded was about 2 kilometres (1.2 mi) from the entrance and 800–1,000 metres (2,600–3,300 ft) below the top of the mountain. The route to their location was blocked by several flooded sections, some with strong currents and zero visibility, and there were some extremely narrow parts, the smallest measuring only 38 by 72 centimetres (15 in × 28 in). The journey through the cave to reach the boys took six hours against the current and five hours to exit with the current, even for experienced divers.
The rescue workers battled rising water levels from the outset. In an effort to drain the cave, a stone diversion dam was built upstream, and systems were installed to pump water out of the cave and divert flows that were entering it. On 4 July, it was estimated that the pumps were removing 1,600,000 L/h (420,000 US gal/h) from the cave, ruining nearby farm fields in the process. For a time, well-meaning volunteers were inadvertently pumping water back into the groundwater supply. Helped by a spell of unseasonably dry weather, these efforts reduced water levels by 1.5 centimetres (0.6 in) per hour on 5 July, enabling the rescue teams to walk 1.5 kilometres (0.93 mi) into the cave. However, heavy rains forecast for 8 July were expected to halt or reverse the process and could even flood the position where the boys and their coach were trapped.
On 6 July, the oxygen level in the cave was detected to have dropped, raising fears that the boys might develop hypoxia if they remained there for a prolonged time. By 8 July, the oxygen level was measured to be 15%; the level needed to maintain normal function for humans is between 19.5% and 23.5%. Thai military engineers attempted to install an air supply line to the boys, but the effort was abandoned as impractical.
Options
As the crisis unfolded, rescuers planned several different methods to save the team and coach. The principal options were to:
- Wait until the end of the monsoon season; with divers providing food and water.
- Teach the group basic diving skills.
- Find an alternative entrance to the cave which could allow for an easier escape; one shaft was discovered that went down 900 metres.
- Drill a rescue shaft; more than 100 shafts were bored into the limestone, but no suitable location was found.
The diving option
Multiple dangers—the threat of more heavy rain, dropping oxygen levels, and the difficulty or impossibility of finding or drilling an escape passage—forced rescuers to make the decision to bring out the team and coach with experienced divers. The Thai Navy SEALs and US Air Force rescue experts met with the Thai Minister of the Interior who approved the plan. 90 divers worked in the cave system, 40 from Thailand and 50 from other countries. The media initially reported that the Thai military had said rescuers would teach the boys basic diving skills to enable them to make the journey. However this was quietly deemed too risky and instead the boys were fully sedated and were unconscious for the journey. Organisers built a mock-up of a tight passage with chairs, and divers practised with local boys in a school swimming pool. Thai SEALs and US Air Force experts then refined the plan to use teams of divers to bring out the weakened boys.
Rescue diver fatalities
On 5 July, at 8:37 pm, Saman Kunan (Thai: สมาน กุนัน; born 23 December 1980), a 37-year-old former Thai Navy SEAL, made a dive from Chamber 3 to the T-junction close to Pattaya Beach to deliver three air tanks. During his return dive, he lost consciousness underwater. His dive buddy attempted CPR without success. Kunan was brought to Chamber 3 where CPR was attempted again, but he could not be resuscitated and was pronounced dead at about 1 am on 6 July.