Scuba diving

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Recreational scuba diver.
Scuba diving in a cave
Diver taking photos of a shark







Aqualung scuba set.



Further information: Rebreather and Rebreather diving


Sir Robert Davis, head of Siebe Gorman, improved the oxygen rebreather in 1910[4][5] with his invention of the Davis Submerged Escape Apparatus, the first practical rebreather to be made in quantity.[6]


Open-circuit scuba[edit]

Further information: Scuba set


The single hose two stage scuba regulators trace their origins to Australia, where Ted Eldred developed the first example of this type of regulator, known as Porpoise scuba gear. This was developed because patents protected the Aqualung's twin hose design. The single hose regulator separates the demand valve from the cylinder, giving the diver air at the ambient pressure at the mouth, rather than ambient pressure at the cylinder valve.[8]




Applications of scuba diving[edit]

Shooting underwater video on scuba





Lastly, there are professional divers involved with underwater environment, such as underwater photographers or underwater videographers, who document the underwater world, or scientific diving, including marine biology, geology, hydrology, oceanography and underwater archaeology.[12][13]


Diving activities commonly associated with scuba include:

Type of diving activity Classification
Aquarium maintenance in large public aquariums commercial, scientific[13][14]
Boat and ship inspection, cleaning and maintenance commercial,[13][14] naval[1]
Cave diving technical, recreational, scientific
Diver training professional[13]
Fish farm maintenance (aquaculture) commercial[13][14]
Fishing, e.g. for abalones, crabs, lobsters, scallops, sea crayfish commercial,[13] recreational
Combat diver, Stealthy infiltration military[1]
Media diving: making television programmes, etc. professional[13][14]
Mine clearance and bomb disposal, disposing of unexploded ordnance military, naval[1]
Pleasure, leisure, sport recreational
Policing/security: diving to investigate or arrest unauthorised divers police diving, military, naval[1]
Search and recovery diving public safety, police, scientific, commercial[13][14]
Search and rescue diving police, naval, public service[13][14]
Spear fishing recreational
Surveys and mapping scientific, commercial,[13][14] recreational
Scientific diving (marine biology, oceanography, hydrology, geology, palaeontology, diving physiology and medicine) scientific[14]
Underwater archaeology (shipwrecks, harbours, buildings, artefacts and remains) scientific,[13][14] recreational
Underwater inspections and surveys commercial,[13] military[1]
Underwater photography and videography professional,[13][14] recreational
Underwater tour guiding professional, recreational
Underwater tourism recreational

Depth range[edit]

See also: Deep diving

The depth range applicable to scuba diving depends on the application and training, but most recreational dives are 30 metres (100 ft) deep or less.[citation needed] Recreational certification agencies generally recommend limiting recreational diving to no-stop dives or relatively short planned decompression stops to minimise risk of decompression sickness.[citation needed] and recommend limiting depths to not exceed the depth specified in the diver's certification, which is usually about 42 metres (140 ft) (by US-based agencies such as PADI and NAUI)[citation needed] or 50 metres (160 ft) (by UK-based agencies such as BSAC and SAA).[citation needed]


Technical diving may involve exploring the logistical and physiological limits of scuba diving, and in these cases a higher risk is accepted by the diver, and considerable effort may be made to reduce this risk by careful planning and contingency procedures. Depths are limited by physiological and logistical aspects - the amount of gas that can be carried, gas mixture, decompression requirements, narcosis and oxygen toxicity at high pressure, and work of breathing constraints. In many countries there is no legal limitation to the depth a recreational diver may attempt, but safe return from greater depths depends on complex logistics, good planning, considerable skill, a high level of fitness, and to some extent, luck.


Breathing apparatus[edit]

Main article: Scuba set
Scuba diver on reef
Recreational diver putting on his scuba set before diving.





Main article: Diving regulator
Aqualung Legend second stage (demand valve) regulator
Aqualung 1st stage regulator
Gekko dive computer with attached pressure gauge and compass
Suunto submersible pressure gauge display






An Inspiration electronic fully closed circuit rebreather
Main article: Rebreather

Less common are closed circuit (CCR) and semi-closed (SCR) rebreathers which unlike open-circuit sets that vent off all exhaled gases, process all or part of each exhaled breath for re-use by removing the carbon dioxide and replacing the oxygen used by the diver.,[17]




Gas mixtures[edit]

A cylinder decal to indicate that the contents are a Nitrox mixture
Main article: Breathing gas




Diver mobility[edit]


Diver propulsion[edit]



Occasionally a diver may be towed using a "sled", an unpowered device towed behind a surface vessel which conserves the diver's energy and allows more distance to be covered for a given air consumption and bottom time. The depth is usually controlled by the diver by using diving planes or by tilting the whole sled.[22] Some sleds are faired to reduce drag on the diver.[23]

Buoyancy control[edit]

Diver under the Salt Pier in Bonaire.








Underwater vision[edit]

Main article: Underwater vision
A diver wearing an Ocean Reef full face mask


Diving masks[edit]

Main article: Diving mask








Dive lights[edit]

Main article: Dive light

Water attenuates light by selective absorption.[26][27] Pure water preferentially absorbs red light, and to a lesser extent, yellow and green, so the colour that is least absorbed is blue light.[28] Dissolved materials may also selectively absorb colour in addition to the absorption by the water itself. In other words, as a diver goes deeper on a dive, more colour is absorbed by the water, and in clean water the colour becomes blue with depth. Colour vision is also affected by turbidity of the water which tends to reduce contrast. Artificial light is useful to provide light in the darkness, and to restore natural colour lost to absorption.

Environmental protection[edit]


"Shorty" style wetsuit


Main article: Wetsuit




Dry suits[edit]

Main article: Dry suit
Scientific divers wearing dry suits



Monitoring and navigation[edit]

A scuba dive computer
A scuba dive computer





Safety equipment[edit]






Further information: Scuba skills


Preparation for the dive[edit]

The purpose of dive planning is to ensure that divers do not exceed their comfort zone or skill level, or the safe capacity of their equipment, and includes scuba gas planning to ensure that the amount of breathing gas to be carried is sufficient to allow for any reasonably foreseeable contingencies. Before starting a dive both the diver and their buddy do equipment checks to ensure everything is in good working order and available. Recreational divers are responsible for planning their own dives, unless in training, when the instructor is responsible.[citation needed] Divemasters may provide useful information and suggestions to assist the divers, but are generally not responsible for the details unless specifically employed to do so. In professional diving teams all team members are usually expected to contribute to planning and to check the equipment they will use, but the overall responsibility for the safety of the team lies with the supervisor.[33][14] [15][34]

Standard diving procedures[edit]


Use of repetitive dive tables[edit]

Many repetitive dive tables, such as those based on the Bühlmann decompression algorithm and similar, use a Letter Group designation to model the amount of residual nitrogen in the diver's body after a dive. For example, in NAUI dive tables the letters range from A to L, where the letter A represents a small amount of nitrogen and the amount of nitrogen increases as the letters progress to L. At the end of a dive, a Letter Group read from the tables designates the net amount of excess nitrogen absorbed during the dive. As a diver spends time on the surface between dives, excess nitrogen is eliminated (known as "off-gassing"), and the residual nitrogen is assigned to a lower Letter Group.

At the start of a subsequent dive to a given depth, the current Letter Group determines a time penalty representing the residual nitrogen in the diver's body. This residual nitrogen time is subtracted from the time limit indicated by the tables for a dive that carried no penalty. This results in a shorter time limit for the repetitive dive. At the end of the repetitive dive, the residual nitrogen time is added to the actual dive time to determine the total equivalent nitrogen time, which is used to determine the new end-of-dive Letter Group.[35]

Post-dive procedures[edit]


Buddy, team or solo diving[edit]

Further information: Buddy diving and Solo diving




Underwater communication[edit]

Main article: Diver communications


Emergency procedures[edit]


Emergency ascents[edit]


Emergency air sharing[edit]


Rescue of an unresponsive diver[edit]

Main article: Diver rescue




Emergency procedures for specific scuba applications[edit]


Hazards of scuba diving[edit]

Divers face specific physical and health risks when they go underwater with scuba equipment.


Injuries due to changes in pressure[edit]





Effects of breathing high-pressure gas[edit]

Decompression sickness[edit]

Exterior of a deck decompression chamber




Divers inside a recompression chamber



Nitrogen narcosis[edit]

Main article: Nitrogen narcosis

Nitrogen narcosis or inert gas narcosis is a reversible alteration in consciousness producing a state similar to alcohol intoxication in divers who breathe high-pressure gas at depth.[2] The mechanism is similar to that of nitrous oxide, or "laughing gas," administered as anaesthesia. Being "narced" can impair judgement and make diving very dangerous. Narcosis starts to affect some divers at 66 feet (20 m). At this depth, narcosis manifests itself as a slight giddiness. The effects increase drastically with the increase in depth. Almost all divers are able to notice the effects by 132 feet (40 metres). At these depths divers may feel euphoria, anxiety, loss of coordination and lack of concentration. At extreme depths, hallucinogenic reaction and tunnel vision can occur. Jacques Cousteau famously described it as the "rapture of the deep".[7] Nitrogen narcosis occurs quickly and the symptoms typically disappear during the ascent, so that divers often fail to realise they were ever affected. It affects individual divers at varying depths and conditions, and can even vary from dive to dive under identical conditions. However, diving with trimix or heliox dramatically reduces the effects of inert gas narcosis.

Oxygen toxicity[edit]

Main article: Oxygen toxicity

Oxygen toxicity occurs when oxygen in the body exceeds a safe partial pressure (PPO2).[2] In extreme cases it affects the central nervous system and causes a seizure, which can result in the diver spitting out their regulator and drowning. While the exact limit is idiomatic, it is generally recognised that Oxygen toxicity is preventable if one never exceeds an oxygen partial pressure of 1.4 bar.[44] For deep dives—generally past 180 feet (55 m), divers use "hypoxic blends" containing a lower percentage of oxygen than atmospheric air. For more information, see oxygen toxicity.

Hazards due to failure of diving equipment[edit]


Hazards of the diving environment[edit]

Loss of body heat[edit]

Dry suit for reducing exposure
Main article: Diving suit

Water conducts heat from the diver 25 times[45] better than air, which can lead to hypothermia even in mild water temperatures.[2] Symptoms of hypothermia include impaired judgment and dexterity,[46] which can quickly become deadly in an aquatic environment. In all but the warmest waters, divers need the thermal insulation provided by wetsuits or drysuits.[1]

In the case of a wetsuit, the suit is designed to minimise heat loss. Wetsuits are usually made of foamed neoprene that has small closed bubbles, generally containing nitrogen, trapped in it during the manufacturing process. The poor thermal conductivity of this expanded cell neoprene means that wetsuits reduce loss of body heat by conduction to the surrounding water. The neoprene, and to a larger extent the nitrogen gas, function as an insulator. The effectiveness of the insulation is reduced when the suit is compressed due to depth, as the nitrogen filled bubbles are then smaller and the compressed gas conducts heat better. The second way in which wetsuits can reduce heat loss is to trap the water which leaks into the suit. Body heat then heats the trapped water, and provided the suit is reasonably well-sealed at all openings (neck, wrists, ankles, zippers and overlaps with other suit components), this water remains inside the suit and is not replaced by more cold water, which would also take up body heat, and this helps reduce the rate of heat loss. This principle is applied in the "Semi-Dry" wetsuit.


A dry suit functions by keeping the diver dry. The suit is waterproof and sealed so that water cannot penetrate the suit. Special purpose undergarments are usually worn under a dry suit to keep a layer of air between the diver and the suit for thermal insulation. Some divers carry an extra gas bottle dedicated to filling the dry suit, which may contain argon gas, because it is a better insulator than air.[47] Dry suits should not be inflated with gases containing helium as it is a good thermal conductor.

Drysuits fall into two main categories:

  • Membrane or Shell dry suits are usually a trilaminate or coated textile construction. The material is thin and not a very good insulator, so the insulation is provided by the air trapped in the undersuit.[citation needed]
  • Neoprene drysuits have a similar construction to wetsuits; these are often considerably thicker (7–8 mm) and have sufficient inherent insulation to allow a lighter-weight undersuit (or none at all); however on deeper dives the neoprene can compress to as little as 2 mm, losing some of its insulation. Compressed or crushed neoprene may also be used (where the neoprene is pre-compressed to 2–3 mm) which avoids the variation of insulating properties with depth. These drysuits function more like a membrane suit.[citation needed]

Injuries due to contact with the solid surroundings[edit]


Hazards of marine animals[edit]

Some marine animals can be hazardous to divers. In most cases this is a defensive reaction to contact with, or molestation by the diver.

  • Sharp hard coral skeleton edges can lacerate or abrade exposed skin, and contaminate the wound with coral tissue and pathogenic microorganisms.
  • Stinging hydroids can cause skin rash, local swelling and inflammation by contact with bare skin.
  • Stinging jellyfish can cause skin rash, local swelling and inflammation, sometimes extremely painful, occasionally dangerous or even fatal
  • Stingrays have a sharp spine near the base of the tail which can produce a deep puncture or laceration that leaves venom in the wound as a result of a defensive reaction when disturbed or threatened.
  • Some fish and invertebrates such as Lionfish, stonefish, crown of thorns starfish, and some sea urchins have spines which can produce puncture wounds with venom injection. These are often extremely painful and may be fatal in rare cases. Usually caused by impact with the stationary animal.
  • The venomous Blue ringed octopus may on rare occasions bite a diver.
  • Lacerations by shark teeth can involve deep wounds, loss of tissue and amputation, with major blood loss. In extreme cases death may result.This may result from attack or investigation by a shark with bites. The risk depends on location, conditions, and species. Most sharks do not have suitable teeth for predation on large animals, but may bite in defence when startled or molested.
  • Crocodiles can injure by lacerations and punctures by teeth, brute force tearing of tissues. and the possibility of drowning.
  • The tropical Indo-Pacific Titan triggerfish is very territorial during breeding season and will attack and bite divers.
  • Very large groupers have been known to bite divers, resulting in bite wounds, bruising and crushing injuries. This has been linked to divers feeding fish.[48][49][50][51]
  • Electric shock is the defence mechanism of Electric rays, in some tropical to warm temperate seas.

Hazards inherent in the diver[edit]



Diver behaviour and competence[edit]

Safety of underwater diving operations can be improved by reducing the frequency of human error and the consequences when it does occur.[52] Human error can be defined as an individual's deviation from acceptable or desirable practice which culminates in undesirable or unexpected results.[53] Human error is inevitable and everyone makes mistakes at some time. The consequences of these errors are varied and depend on many factors. Most errors are minor and do not cause significant harm, but others can have catastrophic consequences. Human error and panic are considered to be the leading causes of dive accidents and fatalities.[52]


Hazards of the dive task and special equipment[edit]


Risk in scuba diving[edit]


Equipment failure is rare in open circuit scuba, and while the cause of death is commonly recorded as drowning, this is mainly the consequence of an uncontrollable series of events taking place in water. Air embolism is also frequently cited as a cause of death, and it, too is the consequence of other factors leading to an uncontrolled and badly managed ascent, possibly aggravated by medical conditions. About a quarter of diving fatalities are associated with cardiac events, mostly in older divers. There is a fairly large body of data on diving fatalities, but in many cases the data is poor due to the standard of investigation and reporting. This hinders research which could improve diver safety.[55]

According to death certificates, over 80% of the deaths were ultimately attributed to drowning, but other factors usually combined to incapacitate the diver in a sequence of events culminating in drowning, which is more a consequence of the medium in which the accidents occurred than the actual accident. Often the drowning obscures the real cause of death. Scuba divers should not drown unless there are other contributory factors as they carry a supply of breathing gas and equipment designed to provide the gas on demand. Drowning occurs as a consequence of preceding problems, such as cardiac disease, pulmonary barotrauma, unmanageable stress, unconsciousness from any cause, water aspiration, trauma, equipment difficulties, environmental hazards, inappropriate response to an emergency or failure to manage the gas supply.[56]



Several plausible opinions have been put forward but have not yet been empirically validated. Suggested contributing factors included inexperience, infrequent diving, inadequate supervision, insufficient predive briefings, buddy separation and dive conditions beyond the diver’s training, experience or physical capacity.[57]

Based on actual exposure time, according to a 1970 North American study, diving was 96 times more dangerous than driving an automobile.[58] and according to a 2000 Japanese study, 36 to 62 times riskier than driving.[59] A difference between the risks of driving and diving is that the diver is less at risk from fellow divers than the driver is from other drivers.

Decompression sickness and arterial gas embolism in recreational diving are associated with certain demographic, environmental, and dive style factors. A statistical study published in 2005 tested potential risk factors: age, gender, body mass index, smoking, asthma, diabetes, cardiovascular disease, previous decompression illness, years since certification, dives in last year, number of diving days, number of dives in a repetitive series, last dive depth, nitrox use, and drysuit use. No significant associations with decompression sickness or arterial gas embolism were found for asthma, diabetes, cardiovascular disease, smoking, or body mass index. Increased depth, previous DCI, days diving, and being male were associated with higher risk for decompression sickness and arterial gas embolism. Nitrox and drysuit use, greater frequency of diving in the past year, increasing age, and years since certification were associated with lower risk, possibly as indicators of more extensive training and experience.[60]

Scuba diver training and certification[edit]

Diving lessons in shallow open water

Recreational scuba diving does not have a centralised certifying or regulatory agency, and is mostly self regulated. There are, however, several large diving organisations that train and certify divers and dive instructors, and many diving related sales and rental outlets require proof of diver certification from one of these organisations prior to selling or renting certain diving products or services.





  • Preparing and dressing in the diving suit
  • Assembly and pre-dive testing of the scuba set.
  • Breathing from the demand valve
  • Recovering and clearing the demand valve.
  • Buoyancy control using weights and buoyancy compensator.
  • Finning techniques, underwater mobility and maneuvering.
  • Making safe and controlled descents and ascents.
  • Equalisation of the ears and other air spaces.
  • Use of bailout systems (professional divers).
  • Buddy diving procedures.




Endurance records[edit]


See also[edit]


Scuba diving, grouped
  1. ^ a b c d e f g h i j k l m n o US Navy Diving Manual, 6th revision. United States: US Naval Sea Systems Command. 2006. Retrieved 24 April 2008. 
  3. ^ Henry Albert Fleuss.
  8. ^ Byron, Tom (2014-04-08). "Ted Eldred Life membership of HDS SEAP". History of Spearfishing and Scuba Diving in Australia: The First 80 Years 1917 to 1997. Xlibris Corporation. p. 320. ISBN 9781493136704. Retrieved 20 September 2016. 
  12. ^ a b c NOAA Diving Manual, 4th Edition, Best Publishing, 2001
  13. ^ a b c d e f g h i j k l m n o p Statutory Instruments 1997 No. 2776 Heatth and Safety, The Diving at Work Regulations 1997,
  14. ^ a b c d e f g h i j k l m Diving Regulations 2009 of the South African Occupational Health and Safety Act, 1993. Government notice R41, Government Gazette #32907 of 29 January 2010, Government Printer, Pretoria
  15. ^ a b c d Statutory Instruments 1997 No. 2776, Health and Safety, The Diving at Work Regulations 1997.
  16. ^ Fred M. Roberts, 1963, Basic Scuba. Self Contained Underwater Breathing Apparatus: Its Operation, Maintenance and Use. Enlarged 2nd ed. Van Nostrand Reinhold Co. New York.
  17. ^ a b Richardson, D; Menduno, M; Shreeves, K., eds. (1996). "Proceedings of Rebreather Forum 2.0.". Diving Science and Technology Workshop.: 286. Retrieved 20 August 2008. 
  22. ^ Sigl, Walter; Ulrich Von Rad; Hansjörg Oeltzschner; Karl Braune; Frank Fabricius (August 1969). "Diving sled: A tool to increase the efficiency of underwater mapping by scuba divers". Marine Geology, Volume 7, Issue 4. Elsevier. pp. 357–363. Retrieved 27 March 2016. 
  26. ^ Adolfson J & Berghage, T (1974). Perception and Performance Under Water. John Wiley & Sons. ISBN 0-471-00900-8. 
  33. ^ Staff (2002). Paul Williams, ed. The Diving Supervisor’s Manual (IMCA D 022 May 2000, incorporating the May 2002 erratum ed.). Carlyle House, 235 Vauxhall Bridge Road, London SW1V 1EJ, UK: International Marine Contractors' Association. ISBN 1-903513-00-6. 
  34. ^ Staff (April 2009). NORSOK Standard U-100 : Manned underwater operations (PDF) (3 ed.). Lysaker , Norway: Standards Norway. 
  35. ^ Powell, Mark (2008). Deco for Divers. Southend-on-Sea: Aquapress. p. 75. ISBN 1-905492-07-3. 
  36. ^ Hanna, Nick (2008). The Art Of Diving - An Adventure in the Underwater World. 8 Grange Road, Barnes London SW13 9RE, United Kingdom: Ultimate Sports Publications Limited. p. 109. ISBN 1599212277. 
  37. ^ Self Reliant Diver - Distinctive Specialty Course Instructor Guide. 30151 Tomas, Rancho Santa Margarita, CA 92688-2125 USA: Professional Association of Diving Instructors (PADI). 2014. pp. Page 2, Course Overview and Standards. 
  38. ^ "SDI - Solo Diver - Requirements" (PDF). Scuba Diving International. 1 January 2016. Retrieved 9 February 2016. 
  39. ^ Douglas, Eric (24 August 2014). "Ask An Expert: Solo diving, OK Or No Way?". Scuba Diving Magazine. Retrieved 9 February 2016. 
  40. ^ Global Underwater Explorers - GUE Standards and Procedures, v7.4 section 1.4.4 (Team Diving).
  41. ^ "SDI - Solo diver". SDITDI. 2016. Retrieved February 19, 2016. 
  42. ^ "PADI - Distinctive Specialty Diver". PADI - Distinctive Specialty Diver Courses - Self Reliant Diver Course. PADI. 2016. Retrieved February 19, 2016. 
  45. ^ "Thermal Conductivity", Georgia State University, Retrieved 15 February 2008
  46. ^ Weinberg, R. P.; E. D. Thalmann (1990). "Effects of Hand and Foot Heating on Diver Thermal Balance". Naval Medical Research Institute Report. 90–52. Retrieved 3 May 2008. 
  47. ^ Nuckols ML; Giblo J; Wood-Putnam JL. (15–18 September 2008). "Thermal Characteristics of Diving Garments When Using Argon as a Suit Inflation Gas.". Proceedings of the Oceans 08 MTS/IEEE Quebec, Canada Meeting. MTS/IEEE. Retrieved 17 April 2009. 
  48. ^ Alevizon, Bill (July 2000). "A Case for Regulation of the Feeding of Fishes and Other Marine Wildlife by Divers and Snorkelers". Reef Relief. Archived from the original on February 7, 2009. Retrieved 2009-08-08. 
  49. ^ Allard, Evan T (2002-01-04). "Did fish feeding cause recent shark, grouper attacks?". Cyber Diver News Network. Retrieved 2009-08-08. 
  50. ^ "Goliath grouper attacks". Florida Times-Union. 2005-06-19. Retrieved 2009-08-08. 
  51. ^ Sargent, Bill (2005-06-26). "Big Grouper Grabs Diver On Keys Reef". Florida Museum of Natural History. Retrieved 2009-08-08. 
  52. ^ a b Michael A. Blumenberg, 1996, Human Factors in Diving, Marine Technology & Management Group, University of California, Berkeley.
  53. ^ Bea, R.G. (1994). The Role of Human Error in Design, Construction, and Reliability of Marine Structures (SSC-378). Ship Structures Committee, Washington, DC.
  54. ^ Sheldrake, Sean, Pollock, Neal W. Steller D, Lobel L, eds. "Alcohol and Diving". In: Diving for Science 2012. Proceedings of the American Academy of Underwater Sciences 31st Symposium. Dauphin Island, AL: AAUS; 2012. Retrieved 2013-03-06. 
  55. ^ a b Concannon, David G. (2011). Vann, RD and Lang, MA, eds. "Legal Issues Associated with Diving Fatalities: Panel Discussion" (PDF). Proceedings of the Divers Alert Network 2010 April 8–10 Workshop. Durham, N.C.: Divers Alert Network. ISBN 978-0-615-54812-8. Retrieved 24 May 2016. 
  56. ^ Edmonds, Carl; Thomas, Bob; McKenzie, Bart; Pennefather, John (2015). "Why divers die" (PDF). Diving Medicine for Scuba Divers. pp. Chapter 34. Retrieved 23 May 2016. 
  57. ^ a b c Vann, RD; Lang, MA, eds. (2011). "Recreational Diving Fatalities." (PDF). Proceedings of the Divers Alert Network 2010 April 8–10 Workshop. Durham, N.C.: Divers Alert Network. ISBN 978-0-615-54812-8. Retrieved 24 May 2016. 
  58. ^ Lansche, James, M (1972). "Deaths During Skin and Scuba Diving in California in 1970". California Medicine. PubMed Central. Retrieved 26 August 2016. 
  59. ^ Ikeda, T; Ashidafirst2=H (2000). "Is recreational diving safe?". Undersea and Hyperbaric Medical Society, Inc. Retrieved 26 August 2016. 
  60. ^ DeNoble, PJ; Vann, RD; Pollock, NW; Uguccioni, DM; Freiberger, JJ; Pieper, CF (2005). "A case-control study of decompression sickness (DCS) and arterial gas embolism (AGE).". Undersea and Hyperbaric Medical Society, Inc. Retrieved 29 February 2016. 

Further reading[edit]

External links[edit]