Why Cave Diving is Dangerous (and How to Do it Safely)

In this statement, Chris Haslam, a well-known RAID technical diving instructor, neatly echoed the sentiments of the diving community of southern Thailand, from where several expert cave divers traveled this week to assist with the rescue of 12 boys and their coach from the Tham Luang cave system near Chiang Rai.

While storms continued to rage across the south, news of the final individuals emerging from Tham Luang cave broke via text message, word of mouth, and hesitant rumour – before it was finally confirmed by the Thai Navy SEAL’s Facebook page, uplifting the tentative optimism that took root nationwide, as the world watched the intricacies of cave diving play out across global media.

The world of cavern and cave diving poses an unusual and unique set of risks, but like any extreme sport, such risk can be managed with the correct training and experience. With this specialized training, you can be on your way to exploring a whole new world flowing right under your feet, from the magical cenotes of Mexico to the caverns of Florida, to the extensive systems of Europe or the sinkholes of south Australia.

Cave diving is considered a type of technical diving, and should never be attempted by anyone with an average open water or advanced level recreational scuba license. Technical diving covers a wide range of activities, requiring special training to mitigate the kinds of risk each specialty introduces.

While the Tham Luang rescue involved additional complexities not encountered during an average cave dive, divers are well trained to manage these threats because as readily seen over the last few weeks, conditions can change in a heartbeat, so dive plans must be flexible to accommodate for the worst. According to seasoned pros like Haslam, with the right training, cave diving can be an incredibly enjoyable and rewarding experience.

According to RAID, a top scuba training agency, the number one cause of serious injury or death in cave diving is not gear failure, getting lost, becoming trapped, or running out of air. These are simply consequences of divers exceeding the limits of their personal training and experience.

RAID continues to explain that the most common emergencies for cave divers are small equipment issues, like torches flooding, reels tangling, masks breaking, or navigational problems – all contingencies that can be managed with proper training, keeping calm, and a team ethos.

So what are the risks unique to cave diving?

Overhead environment: Perhaps the most obvious observation, cave divers must account for the fact that regardless of the situation, making an unplanned return to the surface is out of the question. Air supply is finite, and standard emergency techniques may not be feasible.

Turbidity: Cave environments are unique ecologically, and limited natural light is one risk pretty consistent across conditions. Continuous guide lines to the surface help divers to avoid getting lost, especially during times of sudden limited visibility, and impeccable buoyancy control ensures a stable environment. A simple flutter kick of a fin can upwell silt and sediment, causing visibility to drop from crystal-clear to near zero.

Air supply: A diver’s air consumption rate varies from one individual to the next, but this can be even more unpredictable in high stress environments. A sudden change in conditions or unforeseen issue can increase a diver’s stress, causing the breathing rate to accelerate and jeopardize the planned air supply.

Gas mixtures: All scuba diving is affected by what is called the partial pressure of a gas. Water is about 800 times heavier than air, and as divers descend, this increasing pressure impacts every breath taken. Too much oxygen or nitrogen – the main components of air – can lead to serious complications for divers of every level. This risk is compounded by physical stressors like cold water, heavy equipment and exhausting movement, and added depth. Psychological stressors like low visibility and enclosed environments are also a factor.

Erik Brown, one of the rescue team members who spent an exhausting 63 hours over seven missions to lead the Wild Boars team to safety, is an expert cave diving instructor now based in Koh Tao, Thailand. The experienced veteran, dubbed Thor by Thai media, has led and participated in cave dives across the globe, and said that he’d never experienced conditions like those faced by the dive team in Tham Luang. Aside from the anticipated risks of cave diving, the team had to manage constantly rising water levels from unusually heavy rains, fears of dropping oxygen levels inside the cave, outdated maps, and the enormous challenge of guiding inexperienced teenagers to safety through conditions considered unprecedented even by experts in the field.

A crucial rule lauded by experts worldwide is that divers should always stay within the limits of their own training. The foundation of today’s cave training across all diving agencies originates from Basic Cave Diving: A Blueprint for Survival, a book written by Sheck Exley, a famous early cave explorer who compiled the basic principles of safe cave diving – training, guide line, air, depth, and lights.

Brown heads up a specialized dive outlet on Koh Tao called Hydronauts, which offers all levels of RAID dive training from very basic, introductory programs, to full regimens to prepare divers for highly specialized environments like caves.

In the first level of cave training, divers are introduced to full overhead cavern-like environments, which include cave systems that receive direct natural light. Students practice skills like navigation along permanent guide lines with a “Tee” to side passages, all while managing gas and contingencies. Training and skill development emphasizes that unlike open water dives, any problem that arises while inside a cave must be managed right there and then, as access to the surface may not be feasible, introducing concepts like “time stress” and “distance stress.”

Scuba diving in general requires mental strength, and added risk and challenges only increase the need for mental resolve against these physiological challenges. This fact supports the theory that the Wild Boars’ coach guiding his team through Buddhist meditation practice while they waited for rescue, could have been very instrumental in the operation’s overall success.

Graduates of introductory cave dive programs like those Brown teaches, can confidently plan and dive in cavern-like environments up to 40m in depth, penetrating to a maximum of 300m into the cavern, or when a team member reaches one-third of their starting air supply – whichever comes first.

For those looking to delve deeper into cave systems, continued instruction builds on these basic management techniques, in-water skills, dive planning, and team dynamics. The Level 2 RAID course, for instance, prepares students to enter systems that penetrate further distances and incorporate more complex navigation, refining technical diving skills and situational awareness while simultaneously using new equipment, such as running lines and reels, developing individual ability to work comfortably and safely.

Teamwork again is emphasized, ensuring all graduates have the physical and mental endurance, as well as technical skill, to meet contingencies and be capable of self and buddy rescue at all times.

Pre-requisites for introductory cave diving courses vary by certifying agency – RAID, PADI, SSI, TDI, among others – and can include a dive log reflecting a minimum of 50 hours underwater, prior experience of diving at night or in limited visibility, certification for using Nitrox – different blends of nitrogen and oxygen – and in some cases, qualification as a rescue diver.