A 24-year-old lifeguard developed a persistent cough, chest tightness, progressive shortness of breath, eye irritation and headaches that would worsen toward the end of his workday. In December 1998, the American Journal of Public Health published a study that found the lifeguard and 32 of his peers had developed granulomatous lung disease, known as “Lifeguard Lung,” from working in an indoor swimming pool.
The facility closed the pool and installed a new air ventilation system in hopes of fixing the air quality issue that was causing the lung disease. Yet, when the pool re-opened, the lifeguards’ symptoms returned. It turned out that the problem wasn’t coming only from the air quality, but also from toxins in the pool water itself.
The Problem: Over Chlorination and Disinfection By-Products
After conducting additional research, closing and re-opening the pool twice and surveying all pool employees, researchers concluded that the disease came from “a pathogenic bioaerosol amplified in and disseminated from pool water features”: bacteria in the spray-feature water were sprayed into the air as a fine mist that lifeguards breathed. They also found that more ventilation alone did not prevent new cases after the pool reopened. The fix that worked was source control: the facility rebuilt the water-feature circuits, and the pool reopened “without apparent disease recurrence” (Rose et al., American Journal of Public Health, 1998).
Disinfection by-products, or DBPs, form when outside pollutants such as sweat, urine, dirt, oils and lotions are brought into pool water and react to the chlorine in the water. These contaminants combine with chlorine already present in the pool to create combined chlorines, or chloramines, which are a common DBP found in pools and spas. Chloramines are not effective at sanitizing the pool, and chloramines that escape into the air can cause “respiratory, eye, or skin irritation in swimmers and staff,” according to CDC (2025).
Lifeguard Lung is a different problem from chloramine irritation, though both can affect the same indoor pool staff. It is also known as granulomatous pneumonitis. Lifeguard Lung is a disease that’s caused by the immune system in the lungs “turning on” in reaction to an inhalant. In the 1998 study, the likely cause was breathing bacteria and bacterial endotoxin suspended in water droplets small enough to be inhaled by the lungs.
What Can Your Aquatics Facility Do About It?
If you want to protect your swimmers, staff and patrons from the risk of lung diseases and other pool-related ailments, there are a few steps you can take to improve your facility’s air and water quality and provide a safe and healthy environment.
To proactively care for your facility’s pool and prevent DBPs from forming, here are a few steps you can take:
- Making sure that your pool is being shocked on a regular basis and the proper chlorine levels are being maintained.
- Prevent over chlorination in your pool by adding a supplemental sanitation system, such as hydroxyl-based AOP.
- Ensure all patrons shower before getting in the pool to reduce contaminants added into the water.
- Move fresh air across the water surface and exhaust chloramine-laden air to the outside, as CDC (2025) recommends.
- Make sure your filter is working properly and being regularly cleaned and replaced as needed.
What does research show about chloramine exposure in pool staff?
Lifeguards and pool staff breathe indoor pool air for whole shifts, so airborne chloramines, the most irritating being trichloramine, affect them more than swimmers who visit for an hour. In 20 indoor pools in Italy, staff exposed to more than 0.5 mg/m³ of trichloramine had higher odds of red eyes (odds ratio 3.16) and voice loss (odds ratio 3.56) (Fantuzzi et al., Journal of Exposure Science and Environmental Epidemiology, 2013).
A Quebec study of 41 public indoor pools measured chloramines in the air at an average of 0.23 mg/m³, up to 0.56 mg/m³, and found the levels “generally relatively high compared to current guidelines or reference values from several countries” (Tardif et al., Environmental Research, 2016). A 2024 follow-up in six Quebec pools found average worker exposure above the 0.35 mg/m³ limit the authors used, and 38% of workers reported cough (Ahmadpour and Debia, Annals of Work Exposures and Health, 2024).
At an Ohio indoor waterpark, NIOSH found that “lifeguards had significantly more work-related respiratory symptoms, eye and nose irritation,” and that cough and eye irritation rose on busy days, with air supply and return vents 30 to 80 feet above the deck (NIOSH Health Hazard Evaluation 2007-0163-3062, 2008). NIOSH’s follow-up guidance tells facilities to keep combined chlorine as low as possible, place supply and return ducts so air moves at deck level, drain spray features when they are not in use, and train staff to report symptoms (NIOSH Workplace Solutions, 2010). The 2024 Model Aquatic Health Code calls for combined chlorine below 0.4 ppm (CDC, 2024). For a full facility plan, see Clearing the Air: how to improve indoor pool air quality and what chloramines are and how to reduce them.
An Advanced Solution: AOP Pool Treatment
Hydroxyl-based AOP pool systems are a supplemental, low-maintenance way to improve your aquatics facility’s air and water quality and reduce the chloramines behind eye and lung irritation while reducing chemical consumption. In Clear Comfort’s commercial case studies, AOP reduced chloramines and other disinfection by-products by 50% to 90% (results vary by facility) while oxidizing pool water to give your facility the best water that feels softer, smells better and looks clearer.
AOP pool water treatment does not replace the spray-feature upkeep that stopped Lifeguard Lung in the 1998 study, but it oxidizes organic contaminants in the water, and in a 2014 University of Colorado Boulder lab study it inactivated up to 99.99% (4-log) of chlorine-resistant Cryptosporidium. Advanced oxidation systems also help limit the formation of chloramines and other DBPs, helping create a healthier environment for aquatics facilities.
The system works by injecting hydroxyl radicals, strong and short-lived oxidizers, into the pool plumbing. These hydroxyls break down contaminants in the pool water, alongside a low chlorine residual, which can help facilities lower chlorine and other chemical costs by 30% to 50% (a result range from Clear Comfort’s commercial case studies, not a guarantee). AOP systems are one part of protecting aquatics facility patrons and staff, along with good ventilation, pre-swim showers and spray-feature upkeep.
Frequently asked questions
What is lifeguard lung?
Lifeguard lung, also called granulomatous pneumonitis, is an inflammation of the lungs reported in lifeguards at an indoor pool. A 1998 study in the American Journal of Public Health described 33 affected lifeguards, with symptoms such as cough, chest tightness and shortness of breath.
What causes lifeguard lung?
The 1998 study traced it to bacteria in the pool’s water spray features that were sprayed into the air as a fine mist and inhaled. More ventilation did not stop new cases, but rebuilding the water-feature circuits did.
Is lifeguard lung caused by chlorine?
The 1998 study did not find chlorine to be the cause; it pointed to a bacterial mist from water features. Chloramines are a separate hazard for indoor pool staff, linked by CDC to eye, skin and respiratory irritation.
What combined chlorine level should an indoor pool keep?
The 2024 CDC Model Aquatic Health Code calls for combined chlorine below 0.4 ppm, and CDC says most health departments set a limit of 0.4 ppm or less. Test it regularly and superchlorinate when it rises.
How do you get rid of chloramines and chlorine smell at an indoor pool?
CDC recommends requiring swimmers and staff to rinse off and use the toilet before swimming, moving fresh air across the water surface and exhausting chloramine-laden air outside. Keeping combined chlorine low and adding supplemental treatment, such as UV, ozone or hydroxyl-based AOP, helps break down chloramines in the water.
For more information about how your aquatics facility can benefit from AOP pool water treatment, check out some of our testimonial reviews from customers that have improved their facilities with Clear Comfort AOP.
