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Injuries at a Water Slide -- Washington

On July 12, 1983, a new outdoor water slide consisting of two fiberglass tubes 4 feet in diameter and 360 feet in length opened in Washington State. Sliders climbed 55 vertical feet to the entrance, where they jumped into a current of water and rode it through either tube, negotiating two 360-degree turns and two 45-degree drops before exiting into a splash pool.

From July 13 to August 31, 65 persons injured at this amusement ride sought medical care in local physicians' offices and emergency rooms and were reported to the County Emergency Medical Service. The slide operators reported that 178 patrons sought first aid at their facility, of whom 10 (6%) were transported to a hospital. The rate of injury recorded by the slide operators was 8.1 per 10,000 rides sold, and the rate of medically treated injuries was 3.0/10,000.

The 65 medically treated sliders ranged in age from 8 years to 45 years. Age was unknown in one case. About equal numbers were aged 5-14 years, 15-24 years, and 25 years or older (Table 1); 42 (65%) were female. Injuries included fractures, concussions, bruises and abrasions, and sprains and strains (Table 1). Most concussions, skull and spinal fractures, lacerations, and "other injuries" occurred among females, while most sprains, strains, and "other fractures" affected males. For all injuries except concussions, the majority of persons were aged 15 years or older. All fractures occurred among persons 15 years of age or older. Of the nine spinal fractures, eight were lumbar compression fractures and one was a fracture of the coccyx. The "other fractures" were of the ribs in one case and of the humerus in the other. The sprains and strains were primarily back injuries. Of the 18 lacerations, 12 (67%) required sutures.

Interviews with 46 (71%) of the injured persons identified two primary locations at which injuries occurred--the 45-degree drops and the final outlets. Of the 46, 32 (70%) reported being injured while going over the drops or shortly thereafter, either by landing on the buttocks or lower back or by being knocked off balance and thrown against the sides of the tube; 11 (24%) were upended by the current at the outlet, striking their heads on the sharp-edged lip of the tube. The injuries occurred on the first or second ride in two-thirds of the 46 cases.

The slide operators instituted several changes to reduce the number of injuries, including removing a curve from one tube on July 23, requiring every slider to wear a helmet on the first two rides after August 1, rounding the edge of the outlet lip on August 12, and placing extra warning and instruction signs on August 31. Rates of injury declined during July and early August, but rose again in the latter half of August (Figure 1). Improvements in rates were not closely related in time to the specific corrective measures taken. No slide-related injuries were reported by medical-care sources after August 31. Reported by S Marks, MD, C Hyatt, MD, Snohomish County, S Milham, MD, Epidemiology Section, Div of Health, Washington Dept of Social and Health Svcs; Div of Field Svcs, Epidemiology Program Office, Special Studies Br, Chronic Diseases Div, Center for Environmental Health, CDC.

Editorial Note

Editorial Note: Water slides are "recreational devices designed to provide a descending ride into a splash-down pool at the base of the slide . . . by providing a flowing water film" (1). An estimated 600 are in operation in the United States, and operators of large slides may sell an estimated 500,000 tickets per year (2). In 1983, according to the National Electronic Injury Surveillance System of the Consumer Products Safety Commission, water slides accounted for the largest single share, 30% (2,941 cases), of injuries that occurred at amusement rides and were treated in emergency rooms in the United States. Several water slide-associated fatalities have also been reported (3).

Guidelines based largely on theoretical, engineering considerations have been published for the structure and operation of water slides (1). There is yet no experience or empirical knowledge relating risks of injury to specific design features. The relative severity of the injuries reported in this investigation--fractures and cerebral concussions in 25 (38%) of 65 cases--suggests that excessive speed and loss of body control occurred during the ride. These factors and the association of injuries with two specific sections of the slide in 94% of cases interviewed suggest that design considerations were important in this episode. Whether the rates or severity of injury at this slide are unusually high cannot be determined without comparable studies at other sites.

There is no obvious explanation for the observed changes in injury rates over the summer. No alterations were made in the 45-degree drop sections of the course, and the curve that was removed was not determined in patient interviews to be a high-risk location. The use of helmets and the rounding of the outlet lip are likely to have reduced head injuries, lacerations, and abrasions, and the proportion of "repeaters" in the slider population, who had already successfully avoided injury and would be somewhat familiar with the course, may have increased substantially during the season. These protective considerations could have caused the early decline, but they were still applicable when rates rose again in late August.

Whether the larger number of cases among females indicates a higher injury rate for that sex is uncertain. Studies of swimming pool and other aquatic injuries have found higher risks among males (4) attributed to greater risk-taking behavior by males (5). The prominence of older persons among fracture victims suggests that larger body size and/or mass may be significant risk factors for severe injury. To minimize risk, it may be necessary to make special considerations for sliders of greater size, weight, and age in the design and/or admission guidelines for water slide rides.


  1. Department of Health and Human Services. Suggested health and safety guidelines for recreational water slide flumes. Atlanta, Georgia: Centers for Disease Control, 1981.

  2. Weiner RI. Large water slide safety problems and implications, past--present--future. Paper presented at American Water Slide Association meeting, Kansas City, Mo., Nov. 21, 1982.

  3. National Injury Information Clearinghouse, U.S. Consumer Product Safety Commission, Washington, D.C., 1982. Unpublished data.

  4. CDC. Aquatic deaths and injuries--United States. MMWR 1982;31:417-9.

  5. Davis HF, et al. The 1990 objectives for the nation for injury prevention: a progress review. Public Health Reports 1984;99:9-24.

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