Avoiding caving accidents


Caving is a fascinating and exciting hobby and, for some of us, a way of life, but it is not without its dangers. Even the most experienced cavers sometimes overlook potentially hazardous situations and make mistakes, sometimes with fatal consequences. Dozens of caving mishaps and accidents happen every year around the world, many of which could have been avoided. This document is meant to inform new cavers and to remind experienced cavers of ways in which they can avoid injuries and accidents. May we all have many years of happy and safe caving ahead of us!
General Caving:

  • When possible, participate in small-party and self-rescue training courses.
  • Carry at least three independent back-up sources of light with fresh batteries and bulbs (not counting your primary light source). Good back-ups include extra headlamps, flashlights, and LEDs. Glow sticks can be helpful, but they should be back-ups of your back-ups. Each source of light should be adequate enough by itself to help you exit a cave safely.
  • Always wear your helmet.
  • It is easy to become dehydrated in a cave. Be sure you bring plenty of water.
  • Know your physical capabilities and limitations, never exceed them. Don't push yourself beyond your limits.
  • Before entering a cave, inform someone who is not entering the cave of where you are going and when you expect to return.
  • Carefully check the cave entrance for scorpions, spiders, and poisonous snakes when you enter and exit the cave.
  • When entering a cave through a gate, inspect the condition of the lock before locking the gate behind you.
  • Never cave alone. Always include at least one experienced caver in your group. It is best to cave with at least two other cavers.
  • Look behind you as you travel through the cave so you will recognize the way out.
  • Avoid going into difficult or challenging sections of a cave by yourself, and don’t leave behind an individual who has gone into such a section to check it out.
  • Avoid leaving a cave until everyone in your group is safely out of the cave, unless you are obtaining help in an emergency or escorting an injured caver out of the cave.
  • If you must leave for help in an emergency, leave flags along the trail to the accident site so you and rescuers can easily find your way back.
  • Pay attention to weather conditions if you plan on entering a cave that is known to flood during rainstorms. If rain is forecast, do not enter the cave. If you inadvertently find yourself in a rapidly flooding cave and your exit is flooded, retreat to a high area in the cave to wait for the water to recede.
  • Rock fall is one of the most common and serious sources of accidents. Always be aware of loose rock, and either remove the loose rock from its dangerous location or give it wide berth. Be aware that loose rock and unreliable holds are most common in unexplored or low-traffic caves.
  • If a hold looks like it should be tested, you should probably avoid it altogether.
  • If you are on a digging project, watch for signs of instability and risk of collapse, especially in virgin passage. Never dig in a passage with people deeper in the cave.
  • When entering a tight vertical slot, be aware that gravity will assist you in descending, and it may be more difficult to climb back out.
  • If you will be visiting a cave repeatedly over a period of several weeks or months, consider placing a cache of food, water, and other supplies in a convenient location inside the cave.
  • A 20-foot length of 1-inch webbing, carbiners, and other equipment such as chocks or removable climbing anchors are good to have along for creating make-shift harnesses, clipping into traverse lines, and performing rescues.
  • If a difficult drop or climb can be by-passed with a safer route, use the safer route.
  • If you are visiting a cave that has a substantial bat population or is a known source of histoplasmosis, follow these precautions to avoid infection: wear a face mask in dusty areas; avoid touching your face with dirty hands; wash hands thoroughly before eating; and wash hands and shower thoroughly after exiting the cave.


Wet caving

  • If you use carbide, store it in a reliable, waterproof container. Acetylene gas is generated when carbide contacts water. This gas is hazardous, flammable, and can cause chemical burns. Do not use carbide lamps if acetylene gas is present.
  • Consider wearing a full wetsuit if you will be wading or swimming.
  • Before entering deep water, whether inside or outside a cave, loosen or remove packs and equipment. These items could weigh you down and impair your ability to swim.


Vertical caving

  • Obtain appropriate and adequate vertical-caving training in a controlled environment (not in a cave) before attempting a vertical cave. Then perfect your vertical technique on short drops before attempting deep ones.
  • You should understand how your equipment works, how to increase and decrease friction during a rappel, and how to prevent or stop an out-of-control rappel.
  • You should be competent at performing changeovers on-rope and getting off rope quickly to avoid hanging on rope. If you encounter difficulty on rope, you should perform a changeover before becoming exhausted. An immobile caver hanging on rope can lose consciousness in a matter of minutes; death can follow soon after.
  • You should be adept at performing a pick-off (climb up and help a stranded caver get down).
    When designing your climbing system, build in redundancy to protect yourself against equipment failure. Know that it is not uncommon for ascenders to become disconnected from ropes. Have an extra ascender attached to your harness and/or a cow's tail to protect yourself in such situations, and to aid in negotiating difficult lips and knots in the rope.
  • When rappeling, always carry your ascender attached to your harness so you can easily attach it to the rope for backup.
  • Consider using a quick-attach safety ascender to attach yourself to the rope at the beginning of a rappel and at the end of a climb. On a rappel, do not remove it from the rope until you are safely over the lip and hanging freely, in case your rappel device gets caught while going over the lip. On ascent, after you climb over a lip, do not remove your safety ascender from the rope until you are a safe distance from the lip.
  • Never become separated from your own climbing and rapelling gear. Always carry your own equipment to avoid becoming separated from it.
  • Learn how to create a workable harness and/or a set of prusik knots from the tail end of your rope.
  • Before rigging a pit, check for and remove any loose rock around and below the lip of the pit that could fall on a caver. Be aware that tree roots can loosen rock around an otherwise stable-looking pit entrance.
  • Always tie a figure-8 loop in the end of all ropes, including those not intended for rapelling, such as safety ropes. Not only does this prevent a caver from rappeling off the end of the rope, it provides a convenient loop to stand in while adjusting equipment or performing a changeover.
  • When rigging up your harness, always remember to properly fasten all the buckles by doubling the webbing back through them.
  • Although there are many different types of harnesses, those with independent leg loops can offer additional protection from a fall if the main buckle comes undone.
  • Brand-new rope is usually slicker than used rope, and will cause a faster rappel. In such a case, be sure to rig your rappel device to accomodate a faster rappel.
  • Before attaching to a rope, inspect and understand the rigging. Identify and correct potentially dangerous situations.
  • For a rappel, check that you are attaching to the correct rope by verifying with others in your group and checking the condition of the rope below. If possible, observe that the end of the rope reaches the bottom of the drop.
  • Communicate with each other using standard climbing and rappeling signals to inform each whether someone is on-rope, and whether or not the rockfall zone is clear of other people.
  • Avoid allowing a person of unknown or lesser experience climb last or rappel first, in case they have difficulty on rope.
  • If your rappel device is a six-bar rack, be sure you use five or six bars and spread them as necessary. It is always safer to have more than an adequate amount of bars and go slowly, than to risk an uncontrollable rappel or fall if one bar gets knocked loose and leaves too few bars.
    Always avoid standing in the rockfall zone at the bottom of a pit. If necessary, take shelter under an overhang.
  • Always wait until the rope and rockfall zone is clear of other cavers before getting on-rope. Cavers at the top can inadvertently loosen rock onto cavers below.
  • If you must stop during a rappel to adjust rope pads or work with other equipment, always securely tie off your rappel device.
  • Never have more than one person on-rope at a time unless someone is performing a pick-off. Besides the obvious strain this can cause on rope and equipment, it can also be difficult during ascent for the uppermost caver to climb over the lip with the weight of other climbers on the rope below.
  • When rappeling deep pits, the weight of free-hanging rope decreases the further one rappels down the rope. This phenomenon in turn reduces the amount of friction the rack produces on the rope, and increases your speed and your chances of losing control. Therefore, you may need to use fewer bars at the top of the pit to move, but add bars as you approach the bottom to add friction.
  • If a rappel has become too fast and you cannot add a bar, you can stop the rappel by quickly wrapping the rope around your leg by spinning the ankle around the rope. You should practice this technique in a controlled setting before you might need it in an emergency situation.
  • If you are at the bottom of a pit and observe that a caver has lost control on rappel, you can give a bottom belay by pulling or hanging on the rope. Be careful not to stand in the rockfall zone, if possible.
  • Climbs that are not difficult enough to require ascending gear may require a belay.
    Ladder climbs should always be belayed.
  • If you are belaying, use a sling and carbiner, if necessary, to redirect the rope so that you can belay from a safe location (out of the rockfall zone). Also, be sure to belay in line with the climber’s route.
  • If you are self-belaying with a prusik knot or similar knot attached to your harness or leg loop, be sure you attach the knot to the rope below the rappel device, not above it. Also, the sling formed by the knot must be short enough to quickly grip the rope below the rappel device when you release it.
  • If someone has bothered to install a traverse line to help cavers around a difficult pit or crevice, you should clip into it.
  • Never assume that a fixed rope in a cave is safe. If you must use such a rope, test it by having at least two cavers hang on the bottom.
  • If you place a rope, it is your responsibility to remove it.
  • Never attempt to descend or ascend a pit or other steep drop hand-over-hand. (Experienced cavers should know this, but newbies may not.)


Bad air

Bad air can cause impairing physical symptoms, acidosis in the blood, and, in extreme cases, death. Bad air is typically created by an increase of CO2 (carbon dioxide) to 3% or above and/or a decrease of O2 (oxygen) below 21%. The effects of bad air at certain concentrations can become worse depending on the air pressure in the cave. Bad air in the form of high CO2 may be triggered by warm weather (causing reduced air convection); vegetation (washed in during a rain) decaying in a cave; and outgassing of CO2 from speleothems. Bad air can also be attributed to the presence of other gases such as nitrogen gases (methane and nitrogen oxides), hydrogen sulfide, or gases from pollution. Bad air may occur in pockets in some caves where air circulation is poor, such as in small, dead-end passages. Many bad-air gases, such as CO2 and methane, are heavier than normal air and settle in low spots in the cave, such as near the bottom of pits.

Bad air can cause the following symptoms:

  • Shortness of breath
  • Headache, dizziness, ringing in ears
  • Sweating
  • Exhaustion
  • Nausea, vomiting
  • Confusion, anxiety, panic, discomfort, claustrophobia, a strong urge to leave the area
  • Irritability
  • Loss of consciousness

Follow these guidelines to avoid bad air:

  • Be aware of how you and others in your group feel. Do not ignore or dismiss any symptoms. If you or anyone exhibits symptoms of bad air, immediately leave the area to where the air is purer or exit the cave.
  • You can test the air by attempting to light a candle (a recommended flame-test indicator), or a match, butane lighter, or carbide lamp. If the flame is small, separated, brief, or non-existent, bad air may be present. Do not test the air with a flame if you suspect bad air caused by pollution from a flammable source. This test is not entirely accurate; bad air may still be present even if you succeed in lighting a strong flame. Likewise, candles are such a sensitive indicator that they might not light in air that is only slightly bad.
  • Consider buying an air-testing kit if you will be entering caves that are known to have past bad-air problems.
  • When entering a pit or a low area in the cave that may have bad air, allow only one person to descend first to verify that the air is safe. That person should have necessary climbing gear ready to attach quickly to the rope for immediate ascent, if need be.
  • If a bad-air danger sign is installed at the cave entrance or if the cave is otherwise known to have consistent or chronic problems with bad air, do not enter it or enter it only if you are experienced to the effects of bad air.


Much of the information in this document was adapted from the following sources:

American Caving Accidents 1996-1998 issue of NSS News, April 2000, vol. 58, no. 4, part 2

Encounters with Bad Air, Warren Doc Lewis. NSS News, vol. 58, no. 11, November 2000

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