Danger lurks in shallow water; the hidden risks of diving.

The U.S. Consumer Product Safety Commission found that in 1989 about 7,700 people were injured after striking the bottom of a pool and about 7,900 more were hurt by possibly hitting either a pool's bottom or sides.(1) About 60 percent of these injuries resulted from a headfirst dive into shallow water.(2) Common sense suggests that these divers were just plain careless.

As the Michigan Supreme Court held in 1990, "[T]here is nothing deceiving about [a pool's] appearance, nothing enigmatic about [its] properties. [Pools have] no mechanical devices, but rather [are] uncomplicated ... product[s] with universally known characteristics."(3) The court thereby reversed an appellate ruling that "nothing in the appearance of the pool itself gives a warning of the very serious consequences to which a mundane dive can lead."(4)

Which is the better view? If the dangers are as "open and obvious" as the pool industry contends and case law generally supports, why are hundreds of people annually rendered paraplegic or quadriplegic as a result of shallow-water dives?

In this simple question lies the recognition that the dangers of shallow-water dives(5) are not "open and obvious."(6) Once this is recognized, pool designers, manufacturers, sellers, and maintainers will have a legal duty to effectively warn potential divers about these dangers.

Legal Argument

The legal community generally supports the following contention: "No one can mistake [pools] for other than what they are, i.e., large containers of water that sit on the ground, all characteristics and features of which are readily apparent or easily discernible upon casual inspection."(7) If a danger is readily apparent, then no duty to warn exists.(8) This misconception pervades most defense arguments supporting the "open and obvious" nature of the risks involved with shallow-water diving.

Unfortunately, to the average person acting reasonably and prudently, water's deceptive qualities may combine with the diver's inability to accurately perceive depth. This creates the illusion of a safe, inviting environment that, in reality, is extremely dangerous.

To dive safely, a person must accurately judge the water's depth, calculate the diving angle needed to safely enter the water, and complete the trajectory of the dive under water without striking the bottom. Presumably, once informed that the depth of a body of water is four feet, a diver could calculate the angle necessary to safely enter the water.

This assumption is inaccurate because

* the intellectual and cognitive estimation of water depth differs substantially from the optical estimation;

* the average diver does not understand the hydrodynamic and biomechanical forces acting on the body; and

* unless explicitly warned about specific risks, a diver may unknowingly take risks he or she does not understand.(9)

Most people do not understand the complex and often subtle factors involved in diving and, therefore, have a false sense of security when they are diving into shallow water.

It can be argued that this misunderstanding is learned at very early ages and recalled later in life. Small children almost never get hurt by striking the bottom when diving into shallow water. They weigh too little and are too short to hit the bottom at threatening speeds. Indeed, in a major Nova University study of 360 shallow-water diving accidents, not a single victim was under the age of 10.(10)

After children undergo growth spurts during adolescence, they weigh substantially more and are much taller. So they will strike bottom more readily when diving into shallow water. Still, they remember diving safely into shallow water from their childhood experiences and expect to do so as they get older.

Medical literature indicates that most people have impaired depth perception, or "disabled stereopsis."(11) The brain calculates the angle and trajectory of a dive based on the perceived depth of a body of water. A diver who perceives the water to be deeper than it is will adjust the angle and trajectory of the dive not to the actual depth, but to the perceived depth. This misjudgment, which is made by most divers, is not a conscious act, but an automatic consequence of their inability to accurately determine the depth of water.

Medical research supports this thesis. Studies have shown that disabled stereopsis contributes to disorientation and illusory depth cues that may, in turn, lead to injuries.(12) Also, research shows that the ability to judge depth perception is imperfect.(13)

Also, several factors can interfere with accurate aquatic depth perception. These are waves and ripples on the water's surface, the fact that water is not perfectly transparent, the color of the pool, and the diver's impaired eyesight. As a simple example, most people have stepped into shallow water and been surprised to find the bottom deeper than they thought.

A common belief is that everyone knows that diving into shallow water is dangerous. But when beginning lifeguard students were asked how shallow pool water could be to safely execute a dive, the most common response was four feet. Others answered five feet, and a few even suggested three feet.(14) Most swimmers will admit that they have dived into water less than five feet deep. They would also probably agree that they did not consider that action particularly reckless, dangerous, or foolish.

Need for Warnings

The average diver does not understand the hydrodynamics of diving and often believes that he or she can make a safe shallow dive. Divers do not realize that the forces working on their bodies will not be what they expect. When the water is not deep enough for a safe dive, the diver will not have time to change the underwater trajectory, even when aware of the water depth. Not only is the ability to judge depth inaccurate, but the diver will have a mere fraction of a second to act before hitting the bottom of the pool.

Most people do not appreciate the forces created by the act of diving. They perceive water as a soft, inviting cushion that will absorb the impact of the dive. On the contrary, for adults shallow water will not effectively slow the body before the head strikes the bottom of the pool.

According to one study, "[H]ydrodynamic drag generally does not start to slow the diver's in-water speed to values less than at water entry until a significant portion of the diver's body is immersed."(15) In other words, the diver's head accelerates until most of the body is in the water. For someone five to six feet tall, that is a dangerous fact. The notion that three to five feet of water will absorb the impact of a diver is erroneous.

Further, the average recreational diver does not appreciate how slight a force can injure the cervical spine and render someone paraplegic or quadriplegic. Studies reveal that divers can compress their vertebrae at extremely low speeds.(16)

For example, a mere 10.2-feet-per-second dive can compress a diver's third and fourth cervical vertebrae, causing a potentially catastrophic injury.(17) Most adults performing a clean-entry dive from pool-side travel at a dangerous speed until they are four and a half feet under the water. If a diver weighs more than 160 pounds, has a dive angle steeper than 45 degrees, or dives from a height greater than eight inches above the water, the head speed will be even higher, and the diver will need an even greater distance under water to slow the descent.

Defense attorneys and pool industry experts often assert that the victim was a knowledgeable, intelligent, and reasonable person who should have appreciated the risk of diving into shallow water. Although an objective standard is applied to defendants for failure to warn of unreasonably dangerous conditions, the test for determining whether a plaintiff has assumed the risk of an act is largely subjective.(18)

Defense experts assert, and victims usually acknowledge, that diving into shallow water is dangerous. But generalized knowledge that such diving involves some danger should not result in assuming the real risks involved.

For example, operating a farm combine is dangerous. Yet specific warnings are placed on hot, moving, or otherwise dangerous parts because the average person does not understand or appreciate the hidden dangers and risks of operating the machinery. In the same way, the average diver does not appreciate the magnitude of risks taken when diving into shallow water.(19)

If diving injuries simply resulted from reckless behavior, experience at a particular pool or the existence of warning signs would not have a significant statistical correlation to the number of diving injuries. But in the survey of 360 shallow-water diving accidents noted previously, it was found that 62.2 percent of those hurt were injured on their first dive, and 67.8 percent of diving-injury victims were visiting the pools for the first time.(20) The victims were unaware of the dangers discussed previously and, as a result, had no reason to believe that they were engaging in dangerous activity.

Most disturbing of all, 331 of the 360 sites, or 91.2 percent, had no signs warning pool users not to dive into the water where their injury occurred.(21) Most diving-injury victims are not victims because they are foolish--they are victims because they are not warned.

The fact that 91.2 percent of pools investigated in the study lacked warning signs indicates a strong correlation between injuries and absence of signs. Once the complex combination of factors acting on the diver are explained, the risks of diving into shallow water appear unreasonable in light of the foreseeable injuries. The previously discussed biomechanical and hydrodynamic forces are not consistent with the "consumer's expectation." Apartment owners, hotel and motel owners, country club owners, and municipal owners of pools should owe a duty to warn. A pool designer, manufacturer, and builder should have a duty to warn potential divers. A lifeguard should be liable for failure to warn a diver of the potential hazards of a shallow-water dive (with the usual vicarious responsibility of the lifeguard's employer).

Policy Considerations

Often, in products liability and negligence discussions, a risk/benefit or economic analysis is applied to the question of duty. Obviously, the costs associated with the care and treatment of a paraplegic or quadriplegic are enormous. The immediate costs of medical care do not include additional damages like loss of earnings, loss of consortium, and emotional pain and suffering. In comparison, the average cost of a commercial "Danger--No Diving" sign is less than $10, a minor expense compared to the alternative medical and legal costs of an injury. Ironically, the additional expense of requiring mandatory "No Diving" signs will have no adverse effect on the use, enjoyment, or marketability of swimming pools.

The comprehensive study of diving injuries conducted at Nova University poses the question: "Who is responsible? Some say the diver did a stupid thing or ... was horsing around and showing off.... Responsibility involves anyone associated with the planning, design, and operation of the facility where the injury occurred, and the regulatory agencies charged with the responsibility to govern these facilities."(22)

Consistent with a minimum shallow-water standard depth of five feet, standard "Danger--No Diving" signs with appropriate graphics depicting a diver hitting the bottom of the pool should be mandatory. The profiles and characteristics of diving victims showing that they are not reckless, coupled with the statistical correlation to a lack of warning signs at the pool locations, indicate that the responsibility for the injury is not solely that of the diver. Aquatic experts maintain that the responsibility for warnings should rest with the designers, manufacturers, builders, sellers, owners, operators, and managers of swimming pools, who are well aware of the damning medical and statistical information and yet insist they have no duty to warn potential divers.(23)

The authors are not the first to propose that warning signs displayed at pools could prevent accidents.(24) Swimming pools should be required to display signs to warn prospective divers about the hidden dangers of diving into shallow water.

Pool manufacturers should include warning signs with the pools they sell. The signs need to be eye-catching, clearly visible, and obvious in meaning. A warning is often ineffective unless it informs people what will happen if they ignore it. A faded picture of a diver showing a circle with a line drawn through it carries little impact. A colorful graphic showing a diver hitting the bottom of the pool and a caption reading "Danger! Shallow Water. Do Not Dive! Diving Can Cause Permanent Injury or Death" is much more effective.(25)

Lifeguards should be held to a legal duty to warn potential divers as part of their employment responsibilities. If a lifeguard allows diving into shallow pool water without attempting to warn divers, the lifeguard tacitly approves of the behavior and thus contributes to any resulting injury. Lifeguards must accept some responsibility for injury prevention through enforcement of the no-diving rules. In turn, employers of lifeguards guilty of misconduct, whether negligent or intentional, would be accountable under the doctrine of respondeat superior.(26)

A decade ago, one judge commented, "The danger of diving headfirst into shallow water may seem at first glance to be a matter of common knowledge and understanding.... However, closer examination of the evidence indicates that the nature and extent of the danger... is not commonly understood, even by many adults of considerable experience."(27) Judicial reflections like this one indicate that the issues raised by diving injuries should be subject to full hearings before factfinders. Diving injuries must not be attributed only to the divers' reckless conduct.

In these days of heightened concern about the influence of "junk science" in our courtrooms, theories of accountability based on scientific data and opinion must be used with caution and with insistence on competent, credible, and reasoned assessments of relevant circumstances involved in each case.(28)

And the evidence on the hidden dangers of shallow-water diving is clear. Medical evidence indicates that the neurological process for judging depth perception involves a risk of misjudgment and that disabled stereopsis will occur in familiar environments.

Kinesiological evidence shows that the diving motion is significantly influenced by the initial visual determination of depth and remains relatively unchanged throughout the course of motion. The aquatic evidence establishes that the diver's misjudgment results in catastrophic injury to many young adult victims who were not adequately warned on their first pool visits and on their very first dives.

To prevent further devastating injuries to young people and to prevent unnecessary costs, the legal community must shed the all-too-easy characterization that the dangers of diving into shallow water are open and obvious and must recognize swimming pools for what they are, products that have hidden and deceptive qualities.

The best way to prevent injuries is to warn divers of these qualities. Without warnings, people will continue to unknowingly play a game of Russian roulette whenever they dive into shallow water.

Notes

(1)PAULA PRESENT, U.S. CONSUMER PROD. SAFETY COMM'N, DIVING STUDY: REPORT ON INJURIES TREATED IN HOSPITAL EMERGENCY ROOMS AS RESULT OF DIVING INTO SWIMMING POOLS ii (Sept. 1989).

(2)Id.

(3)Glittenberg v. Doughboy Recreational Indus., 462 N.W.2d 348, 358 (Mich. 1990).

(4)Glittenberg v. Wilcenski, 435 N.W.2d 480, 482 (Mich. Ct. App. 1989).

(5)"Shallow water" has been defined as "the portions of the pool or spa with water depth less than five feet (5')." AMERICAN NAT'L STANDARDS INST., STANDARDS FOR RECREATIONAL SWIMMING POOLS 42 (1992).

(6)"'Open and obvious' is defined as conditions that create a risk of harm that is 'visible' ... is a well-known danger, or ... is discernible by casual inspection. Thus, one cannot be heard to say that he did not know of a dangerous condition that was so obvious that it was apparent to those of ordinary intelligence." Glittenberg v. Doughboy Recreational Indus., 491 N.W. 208, 214 (Mich. 1992) (quoting 3 Am. L. Prod. Liab. 3d (Callaghan) [section]33.26 at 56).

(7)491 N.W.2d 208, 217.

(8)Christman v. Senyk, 293 N.E.2d 126 (Ohio Misc. 1972) (noting duty to warn of any concealed or hidden danger).

(9)Erickson v. Muskin Corp., 535 N.E.2d 475, 482 (Ill. App. 1989).

(10)MILTON GABRIELSEN & MICHAEL SPIVEY, DIVING INJURIES: THE ETIOLOGY OF 486 CASE STUDIES WITH RECOMMENDATIONS FOR NEEDED ACTION, ch. 4, at 1 (1990).

(11)A recent study of optometry students revealed that only 2 of the 43 students showed no sign of disability. The prevalence of disabled stereopsis in this group was no less than 34 percent and might have been as great as 95 percent. William L. Larson, Prevalence of Disabled Stereopsis in a Class of Optometry Students, 69 OPTOMETRY & VISION SCI. 923 (1992). See also Paul Slaton, Prevalence of Disabled Stereopsis, 70 OPTOMETRY & VISION SCI. 433 (1993) (letter to the editor).

(12)"Incongruous and illusory depth cues, arising from 'interference patterns' produced by overlapping linear grids at the edges of escalator treads, may contribute to the disorientation experienced by some escalator users, which in turn may contribute to the causes of some of the many escalator accidents which occur." Roger C. Munck-Fairwood, Depth Perception of Interfering Periodic Patterns: A Possible Contribution to Disorientation on Escalators, 21 PERCEPTION 747 (1992).

(13)See Larson; Slaton, supra note 11.

(14)Elliot S. Weissbluth, Unpublished Survey of 250 Students in American Red Cross Lifeguard Training Classes, Univ. of Texas, Sept. 1989-June 1992 (on file with author).

(15)GABRIELSEN & SPIVEY, supra note 10, ch. 13, at 14.

(16)JAMES MCELHANEY ET AL., BIOMECHANICAL ANALYSIS OF SWIMMING POOL NECK INJURIES (1979).

(17)Id.

(18)Williams v. Brown Mfg. Co., 261 N.E.2d 305, 312 (Ill. 1970).

(19)Ward v. Kmart Corp., 554 N.E.2d 223, 230 (Ill. 1990) (observing that "a plaintiff's awareness of a condition is not always an adequate warning of the consequences of encountering it").

(20)GABRIELSEN & SPIVEY, supra note 10, ch. 4, at 6-7.

(21)Id. ch. 4, at 8.

(22)GABRIELSEN & SPIVEY, supra note 10, ch. 1, at 4.

(23)McCormick v. Custom Pools, Inc., 376 N.W.2d 471, 474 (Minn. Ct. App. 1985). See also King v. National Spa and Pool Inst., 570 So. 2d 612 (Ala. 1990) (holding that a swimming pool trade association had a duty to exercise due care in promulgating minimum design and construction standards).

(24)OFFICE OF INFO. & PUB. AFFAIRS, U.S. CONSUMER PROD. SAFETY COMM'N, RELEASE NO. 90, 116, WARNING SIGNS AT POOLS COULD PREVENT ACCIDENTS (June 27, 1990).

(25)For an excellent discussion of warnings, see Robert J. Cunitz, Warnings: A Human Factors Perspective, in HANDLING PRODUCT WARNING LITIGATION (John Wiley & Sons, Inc., forthcoming).

(26)See generally MICHAEL L. CLOSEN & GARY ROZIN, AGENCY AND PARTNERSHIP 161-214 (1992).

(27)Leonard v. Pitstick Dairy Lake & Park, Inc., 464 N.E.2d 644, 649 (Ill. App. Ct. 1984).

(28)See Daubert v. Merrell Dow Pharmaceuticals, Inc., 113 S. Ct. 2786 (1993); Sharon Begley, The Meaning of Junk Science, NEWSWEEK, Mar. 22, 1993, at 62.