Discussion

This report is the first to summarize data from NAFIS; 15.7% of the estimated 309,000 U.S. public aquatic venues are located in the 16 reporting jurisdictions. The findings of this report underscore the need to improve the operation and maintenance of U.S. public aquatic facilities to prevent illness and injury, as more than three quarters (78.9%) of routine inspections of public aquatic venues identified at least one violation. Multiple reports have previously examined data collected during inspections of U.S. public aquatic facilities with similar results, including analyses of 1961–1963 data from DuPage County, Illinois (20), 1999–2007 data from Plano, Texas (21), and 2005–2006 data from Nebraska (22). Three additional reports examined data collected during routine inspections of public aquatic facilities conducted in 2002 and 2008 in multiple jurisdictions across the United States (Table 5) (19,23,24). All of these reports also found that violations of public health codes are identified frequently and immediate closures of public aquatic venues frequently occur.

Of note, 12.3% of routine inspections (11.8% of pools and 15.1% of hot tubs/spas) resulted in immediate closure and violations of inspection items that corresponded to the 15 critical illness and injury risk-minimizing MAHC elements were identified frequently (Table 3) (Table 4). These findings underscore the public health function that code enforcement, conducted by environmental health practitioners, plays in preventing illness and injury at public aquatic facilities. During inspections, environmental health practitioners can serve as illness-and-injury-prevention advisors to aquatic facility operators. Immediate closures and identified violations offer an opportunity to educate operators about how to properly operate and maintain aquatic facilities and why these measures are necessary, to prevent repeated violations of a given operation or maintenance standard in public aquatic facility codes. Currently, only 68% of U.S. local public health agencies regulate, inspect, or license public aquatic facilities (25).

Minimizing Risk for Aquatic Facility–Associated Outbreaks of Infectious Etiology

In aquatic facilities, halogenation (e.g., chlorination or bromination) is the primary barrier to the transmission of infectious pathogens; proper pH ensures that the more active form of the halogen is available to inactivate infectious pathogens, and the automated chemical feeder delivers the halogen and pH-adjusting chemical. ††† Outbreaks of acute gastrointestinal illness caused by halogen-susceptible pathogens do not occur unless the disinfectant concentration is inadequate; pH is improper; the automated chemical feeder is in poor condition or inoperable; or an operator error has occurred. Environmental health practitioners in the 16 reporting NAFIS jurisdictions identified disinfectant concentration, pH, and automated chemical feeder violations during 11.9%, 14.9%, and 5.2% of all inspections, respectively. These findings are corroborated by national data on outbreaks of infectious etiology; during 2003–2012, halogen-susceptible pathogens caused 15.2–20.2% of aquatic facility–associated outbreaks of acute gastrointestinal illness.§§§ Transmission of halogen-susceptible infectious pathogens (e.g., E. coli O157:H7 or Shigella spp.) can be prevented at MAHC-recommended disinfectant concentrations (1 ppm minimum free available chlorine [MAHC 5.7.3.1.1.2¶¶¶] or 3 ppm minimum free available bromine [MAHC 5.7.3.1.2.2]) at pH 7.2–7.8 (MAHC 5.7.3.4.1). To minimize the incidence of disinfectant concentration and pH violations, aquatic facility operators (MAHC 6.3.1.1) should complete a training course (MAHC 6.1.1.1) (22,26) that covers water disinfection and chemistry, mechanical systems (including automated chemical feeders), and other risk management strategies (MAHC 6.1.2).

Disinfectant concentration and pH violations were frequently documented at wading pools and interactive water play venues. Both of these aquatic venue types have features that make it more difficult to maintain halogen levels: wading pools are typically shallow, which facilitates halogen depletion by the sun’s ultraviolet light, and interactive water play venues typically aerosolize the water, which depletes halogens. Wading pools and interactive water play venues are designed and intended for young children. Young children are more likely to experience acute gastrointestinal illnesses, such as cryptosporidiosis (caused by the extremely halogen-tolerant Cryptosporidium) (27–29), and are more likely to contaminate the water because they either are incontinent or have inadequate toileting and hygiene skills. Contamination can occur via direct release of formed or diarrheal feces (30), or as much as 10 grams of fecal material can rinse off a young child’s perianal surface and into the water (31). Furthermore, swim diapers do not prevent feces, urine, or infectious pathogens from contaminating the water (32); and oxidation of organic or nitrogenous compounds (e.g., feces and urine) released or rinsed into the water deplete the halogen. In addition, young children typically ingest more recreational water than adults (33), putting them at increased risk for infection if pathogens are present. Consequently, maintaining proper disinfectant concentration and pH, combined with effective control of the automated chemical feeder, is particularly critical in these aquatic venues. The MAHC classifies wading pools and interactive water play venues as “increased-risk aquatic venues” and recommends all such newly constructed or substantially altered aquatic venues include secondary disinfection systems (e.g., ultraviolet light or ozone [MAHC 4.7.3.3]) to achieve at least 3-log 10 (99.9%) inactivation of Cryptosporidium.

Disinfectant concentration and pH violations were also frequently documented at hot tubs/spas. Maintaining adequate disinfectant concentration in hot tubs/spas can be particularly difficult, because the halogen can be depleted by both the higher water temperatures and aerosolization of water by jets. Moreover, thermophilic infectious pathogens, such as Pseudomonas aeruginosa and Legionella spp., can colonize and amplify in hot tubs/spas in which the disinfectant concentration is inadequately maintained (34,35), leading to biofilm build-up that can protect these pathogens from disinfectants, even when adequate disinfectant concentration is maintained (36). During 2003–2012, Pseudomonas aeruginosa and Legionella spp. were confirmed or suspected to have caused 77 hot tub–/spa-associated outbreaks (8,15,37–39). To increase the likelihood that adequate disinfectant concentration is maintained, facility operators should ensure that hot tubs/spas have higher minimum disinfectant concentrations (3 ppm minimum free available chlorine [MAHC 5.7.3.1.1.2.3] or 4 ppm minimum free available bromine [MAHC 5.7.3.1.2.2]) than other aquatic venues. In addition, because cyanuric acid (which prevents halogen depletion by the sun’s ultraviolet light) increases inactivation times of infectious pathogens (40–43), cyanuric acid should not be used in hot tubs/spas (MAHC 5.7.3.1.3.1). Debris and organic materials (which deplete halogens) and biofilm should be removed from the water and accessible surfaces of hot tubs/spas (MAHC 5.6.10.6.1) and there should be more frequent draining and cleaning of hot tubs/spas than other aquatic venues (MAHC 5.12.7.2). Finally, aquatic facility operators or responsible supervisors should conduct routine checks, in part to ensure biofilm has been removed from accessible surfaces, prior to facility opening (MAHC 6.4.1.3.1).

Minimizing Risk for Drowning, Pool Chemical–Associated Health Events, and Other Injuries

Maintaining enclosures (e.g., fencing, walls, and self-closing and self-latching gates and doors) (44) and safety equipment (e.g., hook or ring) at aquatic facilities minimizes the risk for drowning. Violations of these safety measures were documented by environmental health practitioners during 5.7% and 16.6%, respectively, of routine pool inspections. Enclosures should be maintained at all times (MAHC 5.6.10.5.1) and newly constructed or substantially altered aquatic facilities should have 6-foot fences (MAHC 4.8.6.2.4.2) and fencing mesh with no greater than a 1.75-inch opening to minimize scalability by young children (MAHC 4.8.6.2.1.2). Routine checks to ensure safety equipment is in place and in good repair should be conducted prior to facility opening (MAHC 6.4.1.3.1); if all required equipment is not present, the venue should be immediately closed (MAHC 6.6.3.1). Bather surveillance by trained lifeguards is another strategy to minimize the risk for drowning, but drowning can occur even in the presence of lifeguards (45). Lifeguard staffing should include clear and unobstructed zones of surveillance, and lifeguard staffing numbers should be based on the number of zones needed to have 100% unobstructed vision of the entire aquatic venue (MAHC 6.3.3.1.1, 6.3.3.1.2, and 6.3.3.1.3). To help minimize the risk for main drain–associated entrapment,**** aquatic facility operator training should include the requirements of the Virginia Graeme Baker Pool and Spa Safety Act (MAHC 6.1.2.1.4.7).

Risk for pool chemical–associated health events can be minimized through proper pool chemical labeling, storage, and security. Violations of this critical element were documented by environmental health practitioners during 18.1% and 9.9% of routine inspections of pools and hot tubs/spas, respectively. Data reported elsewhere indicate that 87% (27/31) of reported pool chemical–associated health events resulted from mixing incompatible chemicals, and 69% (25/36) of pool chemical–associated health events were caused by poor chemical storage or handling practices (14). Aquatic facility operator training should include pool chemical safety (e.g., how to read pool chemical labels required by the Occupational Safety and Health Administration or the Environmental Protection Agency [MAHC 5.9.2.1.1] to identify incompatible chemical[s] and personal protective equipment needed for safe handling) (MAHC 6.1.2.1.4.6). Safe chemical storage practices include preventing access by unauthorized persons, such as children (MAHC 5.9.1.4); safe chemical handling practices include adding a concentrated pool chemical to water when diluting and not vice versa to prevent splashing of the concentrated chemical, potentially explosive reactions, and release of toxic chlorine gas (MAHC 5.9.2.4.2.1). Exposure to chemical vapors, fumes, or gases should be minimized by ensuring there is no air movement from the chemical storage area into any other interior space of a building intended for occupation (MAHC 4.9.2.6.1). Finally, when the recirculation pump shuts down or fails to generate adequate flow but the automated chemical feeder pumps continue to inject concentrated chlorine and acid into the water, the mixing of concentrated chemicals produces toxic chlorine gas. Restarting the recirculation pump then vents the toxic chlorine gas from the venue plumbing and into the aquatic venue. To prevent this from happening, an electrical interlock should be installed between the automated chemical feeders, the recirculation pumps, and water flow meter/flow switch to shut down automated chemical feeder pumps if the recirculation pumps shut down or there is inadequate water flow in the venue plumbing (MAHC 4.7.3.2.1.3).

Violations related to water temperature were documented during 7.5% of routine inspections of hot tubs/spas. Sitting in high temperature water for a prolonged time essentially mimics fever and poses a risk for hyperthermia in vulnerable persons. For example, young children are still developing the ability to regulate body temperature, and body temperature regulation is especially difficult for infants given their small body mass relative to their body surface area. In addition, data suggest that hot tub/spa use by pregnant women, particularly in the first trimester, might be associated with birth defects (46,47). To minimize the risk for injury related to water temperature, the water temperature should not exceed 104° F (40° C) (MAHC 5.7.4.7.2). Hot tub/spa signage should include text indicating that children aged <5 years are prohibited from using hot tubs/spas, pregnant women should not use the hot tub/spa without prior consultation with a health care provider, and the water temperature should not exceed 104º F (40º C) (MAHC 6.4.2.2.3.7). Aquatic facility operators might consider providing accurate thermometers that allow bathers to easily check the hot tub/spa water temperature before entering.

Improving the Collection and Storage of Aquatic Facility Inspection Data

The process of submitting, reformatting, standardizing, and analyzing 2013 NAFIS data highlighted several areas where the collection and storage of aquatic facility inspection data could be improved. First, data on aquatic facility setting (e.g., apartment/condominium, hotel/motel, and waterpark) were not included in most submitted data sets and pool category (e.g., wading pool and interactive water play venue) for almost all inspected pools was designated as “pool” instead of a specific type of pool. This precluded the characterization of the distribution of immediate closures and violations by aquatic facility setting and limited characterization by pool category. Collecting aquatic facility setting, aquatic venue type, and pool category data enable identification of increased-risk settings, aquatic venue types, and pool categories. Second, data on quantitative results of water quality testing conducted during inspections were not collected or submitted, limiting the interpretation of disinfectant concentration and pH violation data. Quantitative results of water quality testing are particularly useful when there are different public health implications related to upper and lower limits of mandated water quality parameters. For example, as pH decreases below 7.2, disinfection effectiveness increases because more of the active form of the halogen (e.g., hypochlorous acid) is formed; however, as pH decreases below 7.2, bathers are increasingly likely to experience skin and eye irritation and the aquatic venue plumbing is more likely to corrode. Alternatively, as pH increases above 7.8, disinfection effectiveness decreases (because less of the active form of the halogen is available for disinfection), and bathers are again increasingly likely to experience skin and eye irritation. Third, data for which specific inspection items resulted in immediate closures were submitted by only one jurisdiction; these data enable more in-depth characterization of immediate closures and identification of operator training needs. The structure of inspection forms and design of the electronic databases can also be optimized to facilitate analysis. For 10 (67%) of 15 critical illness and injury risk-minimizing MAHC elements (Table 2), at least one NAFIS jurisdiction combined data on multiple inspection items. While this practice expedites data collection and entry and limits data storage needs, it precludes analysis of individual inspection items and leads to an underestimate of the total number of identified violations. Assessing and documenting findings for individual inspection items enables a more comprehensive picture of the operation and maintenance of public aquatic venues. Additionally, structuring databases to efficiently document whether each individual inspection item was in compliance, in violation, or not inspected, could allow for the inclusion of complaint and follow-up inspection data in analyses. Finally, nine (36%) NAFIS jurisdictions could not participate in this report. Not all NAFIS jurisdictions had electronic data, and among those that did have electronic data, not all could readily access or retrieve their data in time to collaborate on this report. CDC has developed two resources to help optimize the collection and analysis of aquatic facility inspection data: a draft model inspection form (http://www.cdc.gov/mahc/tools-forms.html), which includes approximately 50 MAHC illness and injury risk-minimizing elements that protect public health, and a set of recommendations to improve data collection and database construction (http://www.cdc.gov/healthywater/swimming/pools/regulation/recommendations-pool-inspection-data-collection.html).