Parent. Researcher. Teacher.
Just when you thought it was safe to go back in the water.
A review of medical literature about
chlorinated pool water.

By: Stan Kurtz, 5.16.06

He stood anxiously with his little toes dangling over the water. Even more anxious were his parents who empathetically stopped breathing as he took his first leap in the pool. After what felt much longer than a few seconds, his head popped up and he was dog paddling. His parents quickly glanced at each other, exhaled, and began to relax -- but should they?

Most people know that swimming is a wonderful activity for children that provides aerobic exercise, sensory stimulation, social interaction, and safety skills. Lesser known is the toxic risks of swimming in chlorinated pools.

In 1986, the risks of chlorine in swimming pools began to illuminate. In the article, “Erosion of dental enamel among competitive swimmers at a gas-chlorinated swimming pool,” it was noted that improper management of pH balance in a chlorinated pool could cause, “swimmer’s erosion,” to teeth. (PMID: 3953542) We often see people put chlorine in the pool, but how about the baking soda? Many children with autism and some children with chronic illness already have a challenged pH balance.

In 1987, The Journal of Pediatrics published the article, “Chlorine inhalation toxicity from vapors generated by swimming pool chlorinator tablets.” This article documented two cases of serious respiratory injury after brief exposure to vapor from solid chlorine compounds. It suggested that physicians caring for children include warnings about these preparations in their routine counseling of parents. (PMID: 3822645)

In 1994, the Institute of Environmental Studies in The Netherlands conducted a pilot study addressing chronic exposure to chlorination products in swimming pools. Detectable levels of chloroform was found in blood samples of competitive swimmers using indoor pools, but not in outdoor pools. That said, indoor swimmers had raised beta-2-mcroglbulin, and indicator of renal damage. These signs of kidney issues were significantly raised in younger indoor swimmers. (PMID: 7911264)

In 1996, reports began to appear about the high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers according to an article published in the Medical Science Sports Exercise Journal and further investigation was suggested. (PMID: 8775165)

In Barcelona, Spain, allergy and asthma were reported in elite summer sports athletes in an article in the Journal of Allergy and Clinical Immunology in September of 2000 (PMID: 10984362). The article mentioned that competitive swimmers inhale and microaspirate large amounts of chlorine derivatives from swimming pool disinfectants and that 36-79% of Olympic swimmers showed bronchial hyperresponsiveness to methacholine or histamine. (PMID: 10984362)

In 2002, a report about was published by the Department of Respiratory Medicine in Birmingham, UK, about occupational asthma in three workers who were exposed to vapor from an indoor chlorinated swimming pool. The workers had not even entered the water. (PMID: 12030720) That same year, a report was published of a chlorine vapor accident at a recreational center in Rome. In a short exposure to high levels of chlorine products, 71.6% of children the 82 children tested had presented with acute respiratory symptoms. (PMID: 12524934)

In a swimming pool in Seattle in 2004, a previously healthy 23 year old was hospitalized after chlorine gas exposure at a fitness center swimming pool. 36 hours later he developed worsening dyspnea and cough and blood-tinged sputum. A chest radiograph demonstrated diffuse tiny nodular opacities and he was later diagnosed with diffuse bronchiolitiis. It was said to be an uncommon case, but it took 5 months for this young man to clinically recover. (PMID: 14982650)

The simple conclusion of a 2006 Canadian study published in the International Archives of Occupational and Environmental Health was, “Swimmers exposed to chlorination by-products in both the water and air of indoor swimming pools experience frequent respiratory symptoms that could potentially be reduced by limiting exposure to these products.” (PMID: 16586082)

In April of 2006 an article was published in Pediatric Emergency Care that started by saying, “Chlorine is a potential respiratory hazard in both occupational and household settings.” It went on to discuss a case where a 9 year old girl developed a pneumonia, hypoxemia, and dyspnea 12 hours after an exposure to chlorine from aerosolized swimming pool purification tablets. Her recovery took four months. (PMID: 16651917)

Summary: Swimming is a wonderful activity and it also provides important safety skills for our children, particularly special needs children due to a seemingly increased rate of drowning (McCandless, 2006). The medical literature seems to suggest that acute or chronic exposure to chlorine products and byproducts can be hazardous.

Since many of our children are already toxic in one way or another, exposure to chlorine might be additionally challenging for them.

If your child is going to be exposed to chlorine, Dr. Sidney Baker has suggested using Taurine prior to the exposure, and Dr. Jacquelyn McCandless has suggested magnesium sulfate cream (Kirkman makes it or you can have a compound pharmacy make it) and apply about a half-teaspoon after showering off the pool water.

If you have a choice between indoor or outdoor chlorinated pools, it seems while both create a chlorine and chlorine vapor exposure, that outdoor pools may be a bit safer because of better ventilation.

Chlorine is also a product of bath water, and a half-cup to a cup of Epson salts in the bathtub may help prevent toxicity. Epson salts are also a good magnesium supplement. Magnesium does many wonderful things including helping to process calcium and iron, as well as keeping your child’s bowel movements regular.

With safer, more natural methods of disinfecting pool water available today, chlorine exposure may be needless. A preferred defense is to remove chlorine from your pool system and replace it with a saline system.

Yahoo searched links to saline pool information


McCandless, Jacquelyn Dr., 2006, Several discussion emails and public posts discussing the Vargas’ autopsy brain inflammation report on a group of children, a majority of whom drowned.

Pediatr Emerg Care. 2006 Apr;22(4):254-7.

Chlorine-related inhalation injury from a swimming pool disinfectant in a 9-year-old girl. Vohra R, Clark RF. Department of Emergency Medicine, Division of Medical Toxicoloy, University of California and California Poison Control System, San Diego Division, San Diego, CA, USA. Chlorine is a potential respiratory hazard in both occupational and household settings. The clinical sequelae of inhalation are variable in severity and timing, and subacute presentation is a concern. We report the case of a 9-year-old girl who developed dyspnea, hypoxemia, and pneumonitis approximately 12 hours after exposure to chlorine released from aerosolized swimming pool purification tablets. Her course was characterized by improvement with supplemental oxygen and bronchodilator therapy. Follow-up pulmonary testing at 4 months after the episode revealed the presence of mild obstructive reactivity of the airways, but she was able to perform normal activities without requiring medications. We discuss the pathophysiology, symptoms, therapy, and long-term follow-up of chlorine inhalation injuries. PMID: 16651917 [PubMed - in process]

Int Arch Occup Environ Health. 2006 Apr 4; [Epub ahead of print]

The determinants of prevalence of health complaints among young competitive swimmers. Levesque B, Duchesne JF, Gingras S, Lavoie R, Prud'homme D, Bernard E, Boulet LP, Ernst P. Institut national de sante publique du Quebec, 945 Ave Wolfe, G1V 5B3, Sainte-Foy, Quebec, Canada. Objectives: Chloramines, which are produced by the reaction of chlorine with the organic matter present in indoor pools, are potential airway irritants in swimmers. The objective of this study was to compare the prevalence of health complaints of young swimmers and young indoor soccer players and to evaluate the relationship between chloramine concentrations and the athletes' health complaints. Methods: Health complaints were first (Part 1) documented by questionnaire in 305 competitive swimmers and 499 indoor soccer players of the Quebec City region (Canada). Then, (Part 2) health complaints were documented during five training sessions in 72 competitive swimmers in comparison to 73 soccer players. The chloramines in the swimming pool air and water were measured as well as the peak expiratory flow (PEF) before and after the training session. Results: In Part 1, the swimmers reported more lower (adjusted OR: 1.5; IC95%= 1.0-2.2) and upper respiratory symptoms (adjusted OR: 3.7; IC95%= 2.4-5.8). In Part 2, the swimmers experienced more frequent lower (adjusted OR: 3.5; IC95%= 2.0- 6.0) and upper respiratory symptoms (adjusted OR: 3.1; IC95%= 1.8-5.4). Overall, swimmers exposed to the highest levels of chloramines in the air and water had more respiratory complaints. Conclusions: Swimmers exposed to chlorination by-products in both the water and air of indoor swimming pools experience frequent respiratory symptoms that could potentially be reduced by limiting exposure to these products. PMID: 16586082 [PubMed - as supplied by publisher]

Environ Health Perspect. 2004 Dec;112(17):1768-71. Comment in: -1. Environ Health Perspect. 2004 Dec;112(17):A1010.

Pulmonary epithelial integrity in children: relationship to ambient ozone exposure and swimming pool attendance. Lagerkvist BJ, Bernard A, Blomberg A, Bergstrom E, Forsberg B, Holmstrom K, Karp K, Lundstrom NG, Segerstedt B, Svensson M, Nordberg G. Environmental and Occupational Medicine, Department of Public Health and Clinical Medicine, Umea University, Umea, Sweden. Airway irritants such as ozone are known to impair lung function and induce airway inflammation. Clara cell protein (CC16) is a small anti-inflammatory protein secreted by the nonciliated bronchiolar Clara cells. CC16 in serum has been proposed as a noninvasive and sensitive marker of lung epithelial injury. In this study, we used lung function and serum CC16 concentration to examine the pulmonary responses to ambient O3 exposure and swimming pool attendance. The measurements were made on 57 children 10-11 years of age before and after outdoor exercise for 2 hr. Individual O3 exposure was estimated as the total exposure dose between 0700 hr until the second blood sample was obtained (mean O3 concentration/m3 times symbol hours). The maximal 1-hr value was 118 microg/m3 (59 ppb), and the individual exposure dose ranged between 352 and 914 microg/m3hr. These O3 levels did not cause any significant changes in mean serum CC16 concentrations before or after outdoor exercise, nor was any decrease in lung function detected. However, children who regularly visited chlorinated indoor swimming pools had significantly lower CC16 levels in serum than did nonswimming children both before and after exercise (respectively, 57 +/- 2.4 and 53 +/- 1.7 microg/L vs. 8.2 +/- 2.8 and 8.0 +/- 2.6 microg/L; p < 0.002). These results indicate that repeated exposure to chlorination by-products in the air of indoor swimming pools has adverse effects on the Clara cell function in children. A possible relation between such damage to Clara cells and pulmonary morbidity (e.g., asthma) should be further investigated. PMID: 15579425 [PubMed - indexed for MEDLINE]

Respir Care. 2004 Mar;49(3):291-4. Acute inhalation injury with evidence of diffuse bronchiolitis following chlorine gas exposure at a swimming pool. Parimon T, Kanne JP, Pierson DJ. Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, Box 359762, 325 Ninth Avenue, Seattle, WA 98104, USA. A previously healthy 23-year-old man with nonproductive cough and sore throat presented to the hospital a few hours after chlorine gas exposure at a fitness center swimming pool. Initial physical examination and chest radiograph were normal. Thirty-six hours later he developed worsening dyspnea and cough, with development of blood-tinged sputum. Arterial blood gas analysis showed mild hypoxemia and a subsequent chest radiograph demonstrated diffuse tiny nodular opacities. Findings on a thin-section computed tomogram of the chest were consistent with diffuse bronchiolitis. Pulmonary function tests showed a mild obstructive abnormality and he demonstrated substantial bronchodilator response. The patient was treated with oral corticosteroids and an inhaled beta(2) agonist, to which he responded well, with full clinical recovery occurring over 5 months. This manifestation of chlorine gas exposure at a swimming pool is unusual. Publication Types: . Case Reports PMID: 14982650 [PubMed - indexed for MEDLINE]

Epidemiol Prev. 2002 Sep-Oct;26(5):240-7. [Respiratory effects of exposure to chlorine vapors during a swimming pool accident in a recreational center in Rome] [Article in Italian] Di Napoli A, Agabiti N, Ancona C, Forastiere F, Lo Presti E, Corbo GM, D'Orsi F, Perucci CA. Agenzia di sanita pubblica, Regione Lazio, Roma. When inhaled, chlorine is a highly irritating gas that can damage larger airways as well as distal lung structure. We examined the short-term respiratory effects of acute chlorine inhalation during a swimming pool accident. On October 22, 1998, an emission of chlorine vapours occurred in the chlorinating maintenance procedures room of a recreational center in Rome. A total of 282 subjects (134 children) inhaled hydrogen chloride and sodium hypochlorite. Most people received bronchodilators and cortisone at the emergency room; five children were hospitalised. A telephone follow-up was taken on 260 (92.2%) subjects to obtain information about duration of exposure (less than 3 minutes, 3-5 minutes, more than 5 minutes), intensity of exposure (not at all/a little, a fair amount, a lot), and acute respiratory symptoms. A total of 236 (90.7% of the target) individuals underwent clinical examinations, which took place 15-30 days after the accident. Lung function was measured in 184 people (82 children) after 15-30 days. A multiple linear regression was run to test the association between chlorine exposure and lung function, separately in adults and in children. Acute respiratory symptoms occurred among 66.7% adults and 71.6% children. The incidence rates were highest among those who had chronic respiratory disease and had a longer duration of exposure. In about 30% of the subjects, respiratory symptoms persisted 15-30 days after the accident. Lung function levels were reduced among those who reported high intensity of exposure in comparison to those who reported low exposure, both in children and in adults (forced expiratory volume in one second, FEV1, ml differences: -109 (CI 95%: -310, 93) and -275 (CI 95%: -510, -40). Given high prevalence of potential exposed people, findings from this study should alert public health authority about the possible clinical consequences. PMID: 12524934 [PubMed - indexed for MEDLINE]

Eur Respir J. 2002 May;19(5):827-32. Comment in: -1. Eur Respir J. 2002 May;19(5):790-3.

Occupational asthma caused by chloramines in indoor swimming-pool air. Thickett KM, McCoach JS, Gerber JM, Sadhra S, Burge PS. Dept of Respiratory Medicine, Heartlands Hospital, Birmingham, UK. The first series of three workers who developed occupational asthma following exposure to airborne chloramines in indoor chlorinated swimming pools is reported. Health problems of swimmers in indoor pools have traditionally been attributed to the chlorine in the water. Chlorine reacts with bodily proteins to form chloramines; the most volatile and prevalent in the air above swimming pools is nitrogen trichloride. Two lifeguards and one swimming teacher with symptoms suggestive of occupational asthma kept 2-hourly measurements of peak expiratory flow at home and at work, analysed using the occupational asthma system (OASYS) plotter, and/or had specific bronchial challenge testing to nitrogen trichloride, or a workplace challenge. Air measurement in one of the pools showed the nitrogen trichloride levels to be 0.1-0.57 mg x m(-3), which was similar to other studies. Two workers had peak expiratory flow measurements showing occupational asthma (OASYS-2 scores 2.88 and 3.8), both had a positive specific challenge to nitrogen trichloride at 0.5 mg x m(-3) with negative challenges to chlorine released from sodium hypochlorite. The third worker had a positive workplace challenge. Swimming-pool asthma due to airborne nitrogen trichloride can occur in workers who do not enter the water because of this chloramine. The air above indoor swimming pools therefore needs to be assessed and managed as carefully as the water. Publication Types: . Case Reports PMID: 12030720 [PubMed - indexed for MEDLINE]

J Allergy Clin Immunol. 2000 Sep;106(3):444-52.

Allergy and asthma in elite summer sport athletes. Helenius I, Haahtela T. Department of Allergology, Skin and Allergy Hospital, Helsinki University Central Hospital, Helsinki, Finland. Exercise may increase ventilation up to 200 L/min for short periods of time in speed and power athletes, and for longer periods in endurance athletes, such as long-distance runners and swimmers. Therefore highly trained athletes are repeatedly and strongly exposed to cold air during winter training and to many pollen allergens in spring and summer. Competitive swimmers inhale and microaspirate large amounts of air that floats above the water surface, which means exposure to chlorine derivatives from swimming pool disinfectants. In the summer Olympic Games, 4% to 15% of the athletes showed evidence of asthma or used antiasthmatic medication. Asthma is most commonly found in endurance events, such as cycling, swimming, or long-distance running. The risk of asthma is especially increased among competitive swimmers, of which 36% to 79% show bronchial hyperresponsiveness to methacholine or histamine. The risk of asthma is closely associated with atopy and its severity among athletes. A few studies have investigated occurrence of exerciseinduced bronchospasm among highly trained athletes. The occurrences of exercise-induced bronchospasm vary from 3% to 35% and depend on testing environment, type of exercise used, and athlete population tested. Mild eosinophilic airway inflammation has been shown to affect elite swimmers and cross-country skiers. This eosinophilic inflammation correlates with clinical parameters (ie, exercise-induced bronchial symptoms and bronchial hyperresponsiveness). Athletes commonly use antiasthmatic medication to treat their exercise-induced bronchial symptoms. However, controlled studies on their long-term effects on bronchial hyperresponsiveness and airway inflammation in the athletes are lacking. Follow-up studies on asthma in athletes are also lacking. What will happen to bronchial hyperresponsiveness and airway inflammation after discontinuation of competitional career is unclear. In the future, follow-up studies on bronchial responsiveness and airway inflammation, as well as controlled studies on both short- and long-term effects of antiasthmatic drugs in the athletes are needed. Publication Types: -1. Review PMID: 10984362 [PubMed - indexed for MEDLINE]

Med Sci Sports Exerc. 1996 Feb;28(2):271-4.

Assessment of chlorine exposure in swimmers during training. Drobnic F, Freixa A, Casan P, Sanchis J, Guardino X. Physiology Department, Centre D'Alt Rendiment, Instituto Nacional de Salud e Higiene en el Trabajo, Barcelona, SPAIN. The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been recently reported. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming. Measurements of the chlorine concentration at the breathing level (< 10 cm) were obtained randomly during five nonconsecutive days in four different swimming pool enclosures. The mean level in all the swimming pools was 0.42 +/- 0.24 mg.m-3, far below the threshold limited value (TLV) of 1.45 mg.m-3 for the work places for a day of work (8 h). The TLV could be reached and even exceeded if we consider the total amount of chlorine that a swimmer inhales in a daily training session of 2 h (4-6 g) compared with a worker during 8 h at the TLV (4-7 g). Low correlation was observed with the number of swimmers in the swimming pool during the measurements (0.446) and other variables as the water surface area of the pool, volume of the enclosure, and the chlorine-addition system in the swimming pool. A low turnover rate in the air with an increase of chlorine levels through the day (P < 0.05) was observed in all pools. The concentration of chlorine in the microenvironment where the swimmer is breathing is below the TLV concentration limit, but nevertheless results in a high total volume of chlorine inhaled by the swimmers in a given practice session. The possible role of chlorine in producing respiratory symptoms in swimmers needs further investigation. PMID: 8775165 [PubMed - indexed for MEDLINE]

Toxicol Lett. 1994 Jun;72(1-3):375-80.

Swimming pool chlorination: a health hazard? Aiking H, van Acker MB, Scholten RJ, Feenstra JF, Valkenburg HA. Institute for Environmental Studies, Vrije Universiteit, Amsterdam, The Netherlands. A pilot study addressed potential effects of long-term exposure to chlorination products in swimming pools. The indicator compound chloroform was detectable in blood from competitive swimmers in an indoor pool (mean = 0.89 +/- 0.34 microgram/l; n = 10), but not in outdoor pool swimmers. No hepatotoxic effect was indicated by serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) or gamma-glutamyl transpeptidase (gamma-GT) enzyme levels. beta-2-microglobulin, an indicator of renal damage, was significantly elevated in urine samples of the slightly, but significantly, younger indoor swimmers. The precise ratio between these 2 possible causes, age and chloroform exposure, as well as the mechanism of the former, remain to be elucidated. PMID: 7911264 [PubMed - indexed for MEDLINE]

Pediatrics. 1987 Mar;79(3):427-30.

Chlorine inhalation toxicity from vapors generated by swimming pool chlorinator tablets. Wood BR, Colombo JL, Benson BE. We have presented two cases of serious respiratory injury after brief exposure to vapors from solid chlorine compounds. We could find no previous reports of such accidents and, therefore, have related these cases to alert the medical community. We would recommend that physicians caring for children include warnings about these preparations in their routine counseling of parents. Publication Types: -1. Case Reports PMID: 3822645 [PubMed - indexed for MEDLINE]

Am J Epidemiol. 1986 Apr;123(4):641-7.

Erosion of dental enamel among competitive swimmers at a gas-chlorinated swimming pool. Centerwall BS, Armstrong CW, Funkhouser LS, Elzay RP. In September 1982, two Charlottesville, Virginia, residents were found by their dentists to have general erosion of dental enamel consistent with exposure to acid. Both patients were competitive swimmers at the same private club pool. No other common exposure could be determined. An epidemiologic survey was made of 747 club members. Symptoms compatible with dental enamel erosion were reported by 3% of nonswimmers (9/295), 12% of swimmers who were not members of the swim team (46/393), and 39% of swim team members (23/59). All four swimmers with clinically verified dental enamel erosion had trained regularly in the pool for competitive swimming meets, compared with one of eight matched swimmers without enamel erosion. Examination of the implicated swimming pool revealed a gas-chlorinated pool with corrosion of metal fixtures and etching of cement exposed to the pool water. A pool water sample had a pH of 2.7, i.e., an acid concentration approximately 100,000 times that recommended for swimming pools (pH 7.2-8.0). A review of pool management practices revealed inadequate monitoring of pool water pH. Acid erosion of dental enamel--"swimmer's erosion"--is a painful, costly, irreversible condition which can be caused by inadequately maintained gaschlorinated swimming pools. Publication Types: . Case Reports PMID: 3953542 [PubMed - indexed for MEDLINE]