Pool safety isn’t something to be taken lightly. Water recreation provides a lot of fun, but it also holds hazards.
Pool chemicals, including chlorine and acid, are unstable substances that can be lethal when not handled properly. Chlorine is necessary to keep water clean and sanitary. There needs to be at least 1 ppm of chlorine in pools and 3 ppm in hot tubs to maintain a safe environment. Acid serves to balance pH levels.
Just as lifeguards and flotation devices help protect swimmers, precautions and proper equipment can reduce the risk of severely dangerous chemical reactions.
In general, the chemicals used to treat pool water are added to moving water in the pool’s circulation system, which allows the chemicals to mix at an appropriately diluted concentration. Unfortunately, if the circulation system fails, the two chemicals can be exposed to one another at high concentrations, creating a substance very similar to mustard gas. Since mustard gas is 2.5 times heavier than air, it sits on the surface of the water, directly exposing swimmers.
On June 4, 2019, that is exactly what happened at Pleasant Grove Veterans Memorial Pool in Utah, USA. A safety system malfunctioned, and too much chlorine and acid were released into the pool. Nearly 50 individuals, including some small children, were hospitalized due to prolonged exposure to the gas.
Also in the summer of 2019, 14 children were exposed to an overdose of chlorine at the La Salle Park public pool in Burlington, ON. Eight ambulances arrived at the scene and swimmers had to be evacuated. The pool was closed for the remainder of the day.
A similar accident occured in San Jose, California, USA in 2018. Here, 35 people were sent to the hospital after breathing in chlorine gas that had settled at the top of the pool.
Dozens of such incidents happen in public pools across North America every year, injuring hundreds of individuals, sometimes even causing long-term respiratory complications. The injuries are terrible on their own, and for-profit pools can also lose income and public trust as a result.
The good news is that this suffering is generally preventable. Electrical failures and operator error are the most common causes of chemical accidents. So, with proper training and some procedural adjustments, the risk can be reduced to almost nothing.
In the United States, a pool operator training course is required by law in many areas. There are two accepted courses: the CPO program, which is sponsored by the National Swimming Pool Foundation, and the AFO program, sponsored by the National Recreation and Parks Association. In Canada, certified pool operator (CPO) certification is required by health departments in most provinces. Check with your local health department for specific options and regulations.
Pool operator training classes are invaluable in helping operators maintain a safe environment for swimmers. Certification ensures that employees know the current regulations and guidelines, how to test and balance water chemicals, the disinfection processes, facility safety procedures, how to react in an emergency, and more. Certification classes can range from a 16-hour, in-person course to home study options that might take up to six months to complete. Hybrid courses, with at-home study followed by limited, socially distanced in-person instruction, have emerged over the last year to accommodate restrictions due to COVID-19.
Complex concepts such as geometry, chemistry, hydraulics and electricity are part of pool operations, and need to be explained in a way that users will both understand and remember. Luckily, training by a certified instructor ensures that public and private pool operators are familiar with the chemicals, procedures, and potential hazards associated with operating a swimming pool, and have been taught how to handle any malfunctions in the circulation and chemical equipment.
As aquatics technology has become increasingly sophisticated, sanitation and safety have improved. But more complex technology means that local operators need increased training to learn how to safely handle each component. Anyone who has not been trained on the use of equipment, chemicals and processes should not have access to the machinery. This is a liability as well as a safety concern–just as technicians aren’t expected to know CPR and shouldn’t be left in charge of swimmers, lifeguards don’t know the protocols for chemical safety, and shouldn’t be in the vicinity of potentially dangerous equipment.
In addition to training, proper equipment plays a vital role in keeping swimmers safe. Failures happen most often when the circulation pump fails, whether due to mechanical or operator error. The water stops flowing but the chemical pump continues operating, leaving the chlorine and hydrochloric acid to mix at a high concentration and combine into a dangerous compound. Traditionally, an alarm called a flow sensor is installed in the circulation system so that the operator is alerted to a malfunction. This is the primary safety system, but it is by no means perfect.
The surprisingly straightforward solution is to tie the chemical pump directly to the electrical system. This type of setup ensures that during an electrical failure, both the chemical and circulation pumps stop operating. The two systems are now both flow locked and electrically locked. In this way, the chlorine and hydrochloric acid never mix while the water is stagnant. A simple mechanical device can merge the electrical systems, creating the desperately needed secondary safety system.
After multiple accidents in Utah, including the one mentioned above, the state health authority updated the health codes to require public pools to update their equipment to fit this model. Redundant systems have existed for years for automated heating, electrical and chemistry equipment. Unfortunately, up until recently, backup systems for the chemical feed system were non-existent. It took the tragedies of hundreds of injuries to bring this issue to the forefront.
In 2018, there were around 5,000 publicly-owned pools and splash pads in Canada. All of these pools would benefit from a redundant chemical pump safety device. Other public-use pools not owned by the government should also consider a safety upgrade. This includes hotel pools and spas, school swimming pools, homeowner’s association pools, and any other water feature used by crowds of people.
Where the safety of others, particularly of children, is concerned, the pool industry needs to be driving the innovations and changes that solve problems instead of waiting on government regulations to do so. While it is not always a legal requirement, the World Health Organization also recommends that dosing pumps be designed to shut down if the circulation system fails.
Canadian law does require that pool owners “take such care as in all circumstances of the case is reasonable to see that persons entering the premises, and the property brought on the premises by those persons are reasonably safe while on the premises.” (Occupiers’ Liability Act) This means that pool owners can be held liable for chemical accidents that might have been reasonably prevented.
The primary safety system, the flow interlock device, works in most cases to prevent chemical incidents in public-use pools. But the possibility of a malfunction means that every swimmer is not safe. A secondary, electrical interlock device is inexpensive and protects individuals from injuries and public facilities from liability.
In the event of a chemical accident at a publicly used pool, call 911 or your local emergency number immediately. Remove anyone who has been exposed from the area. If it is safe to do so, turn off the chemical and circulation pumps. Have an emergency response plan ready that all employees are familiar with. Only allow properly trained people to work with the chlorine/pH control feed and recirculation systems. And of course, practice regular maintenance for all chemical equipment to prevent failures.
Not only should an emergency response plan be at the ready, it’s important to periodically test equipment and staff. Natural disasters don’t always give advanced warning, so in the event of an earthquake, tornado, flood, fire or routine power outage, it’s crucial to know that the equipment will shut down as it should.
All public pool operators should explore the nominal cost and time it takes to install a secondary chemical dosing safety device. Just as other sensitive systems need redundancy, the chemical pumps should be carefully monitored and regulated using more than one process. The lives and safety of swimmers are worth more than any short-term cost or inconvenience.
Kory Parker is the Aquatic Division Manager at Stratton and Brätt, as well as one of only two national instructors for the National Recreation and Park Association Aquatics Facilities Operations in the region he serves. He has worked in the aquatics industry for decades, and oversees hundreds of pools each year, including major aquatic centers and waterparks. Kory holds a bachelor’s degree from Utah State University.