Legends of Diving Articles


Historical Perspective
and Risk Management
by Dr. Glen Egstrom
© 2010 Presentation by
Glen H. Egstrom Ph.D., Professor Emeritus
All Rights Reserved.

Ben Franklin Wisdom

In the year 1787 he observed, " having lived long, I have experienced many instances of being obliged, by better information and for consideration, to change opinions even on important subjects which I once thought right but found to be otherwise?.


Before 1535 A.D. - Diving non-events. A montage of diagrams of Vegetius Hood (1511), an Assyrian Frieze (900 B.C.) and Alexander the Great submerged in a Diving Bell (3rd Century B.C.)


Milestones for U/W Workers

  • 1850 Green ?Diving Armor" used air to 158?

  • 1880 Fleuss Rebreather used by Lambert in flooded tunnel at 60?

  • 1905 USN Manual for
    divers air to 200"

  • 1915 USN working air dives 304?

  • 1918 Ogushi respirator to 324" on air

  • 1927 USN EDU HeO2 capability

  • 1935 Behnke USN studies
    1-4 ata Oxygen

  • 1937 Nohl supported by
    Dr. End dives to 420" on HeO2 in Lake Michigan

  • 1944 Surface supplied Science diver

  • 1948 Aqualung marketed in U.S. Rene's in Westwood, Ca.
    gets 10 units

  • 1949 Limbaugh and Rechnitzer
    using Aqualungs at UCLA for scientific diving

  • 1950 Limbaugh and
    Rechnitzer move to Scripps

  • 1951 First Scientific Diving
    Course at Scripps

  • 1954 Scripps diving program lists
    4 of 60 Science divers certified to
    250" depth, tables to 300?

  • 1955 L.A. County U/W
    Instructors course

  • 1956 Royal Navy dives HeO2 to 600?

  • 1957 Sea Hunt begins

  • 1961 Sea Lab I 11 days at 192?

  • 1963 USN Extreme exposure air tables to 300?

  • 1968 Gruener and
    Watson to 437" on air

  • 1969 Sea Lab III at 600" Fatality on bottom

  • 1973 USN PO2 1.6 ata 30 min. Emergency 2.0 -30

  • 1976 USNLight weight
    HeO2 gear to 300"

  • 1982 Scientific Diver exemption from OSHA Regs.

  • 1983 The Edge electronic
    dive computer

  • 1985 OSHA Guidelines for
    Scientific Diving

  • 1989 Exley dives to 881" on
    trimix in cave

  • 1990 NOAA PO2 1.6 ata for
    45 min. emergency 120 min. or 2 ata for 30 min.

  • 1997 Pyle making closed circuit
    dives >300" dive time of 4:12 at 400?

  • 1999 Andrews air dive to 513?

  • 2001 Hall makes film with dives to 325?-400" using closed circuit, mixed gas. 179 day project

Denayrouze/Rouquayrol Aerophore

1918 - Ogushi Peerless Respirator (Air to 282?-324)


Statistical Probability

  • Statistical Probability is based upon an evaluation of the incidents (numerator) versus the exposure (denominator).

  • Without a numerator and a denominator it is not possible to quantify risk.

Poul Anderson

I have never encountered a problem, however complicated, which, when viewed in the proper perspective did not become more complicated.

Risk Analysis

  • The identification of hazards should be based upon existing scientific evidence that can show a direct relationship between cause and effect.

  • Provide a description of the risk based upon an objective evaluation of the likelihood of occurrence of undesirable side effects for a given dose of exposure.

  • Describe the analysis of potential public exposure and the nature of the calculated risk.

The Goals

  • To develop a state of the art appreciation for for the complexity of the issues involved in Scientific Diving.

  • To develop perspective with regard to risks vs. benefits of Scientific Diving.

  • To provide objective data with regard to current issues in the field.

The Calculated Risk

  • The description of the risk is then based upon the objective evaluation of the likelihood of the occurrence of undesirable side effects following a given ?dose" of aquatic exposure.

  • We will never be without risk in diving but we must use reasonable care in determining the degree of risk we are prepared to accept.

Acceptable Risk

  • There is no guarantee of diving safety and all risks are relative to the specific conditions of each project.

  • All participants must make a personal decision regarding the degree of relative risk that is acceptable to them.

  • Diving safety programs require implementation at the operational level.

Comparison of Risks

  • The rate and intensity of accidental injury and fatality is more under the control of behavior (and misbehavior), than it is under the control of product design or a government regulation.

  • One effective way to manage a risk is to concentrate on public awareness of the risks vs. benefits of Scientific Diving.

Thoughts for the day

  • A 190" limit for air diving may be overly conservative

  • 1914 air was being used to 300?

  • Ohgushi self contained air used at 324" in 1918

  • Surface supplied air used to 300" in 1915

  • Using mixed gas technology is common in 1900?s

  • Currently mixed gas open and closed circuit Used to 1000+ feet.

  • Light weight mixed gas apparatus used over 30 years

  • Scientific diving has been slow in taking advantage of new technology advances.


Original Presentation (Large .mht File Size)
Historical Perspective and Risk Management


Glen H. Egstrom,
 Ph.D B.S. UND 1950
Professor (Emeritus)

Teaching responsibilities at UCLA and during Diving Medical courses in the past 50 years have included courses and graduate seminars in applied anatomy, exercise physiology, underwater physiology, environmental physiology, aquatic kinesiology, biomechanical analysis and conditioning for optimal performances. As campus Diving Officer between 1964 and 1992 he also operated a major recreational and scientific scuba diving training program at UCLA and is currently a member of the UCLA Diving Control Board. As Director of the Underwater Kinesiology Laboratory he continues as the Principal Investigator for the Diving Safety Research Project and other aquatic safety studies. Biography


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© 2010 Dr. Glen Egstrom
All Rights Reserved.

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