Chlorine is intentionally introduced into swimming pool water as a powerful disinfectant to eliminate harmful pathogens, such as bacteria and viruses. However, when chlorine reacts with organic matter introduced by swimmers, like sweat, urine, and body oils, it forms chemical byproducts called chloramines. When pool chemistry is poorly managed, it is these chloramines—not the free chlorine itself—that cause the adverse health effects associated with swimming in “over-chlorinated” water. These volatile compounds irritate the body through direct contact and inhalation, and they are the actual cause of the strong, pungent “chlorine smell” often mistaken for a clean pool.
Immediate Irritation of Skin and Eyes
Direct exposure to water with high levels of irritating chloramines and an imbalanced pH causes immediate, localized discomfort. The skin’s natural protective barrier, composed of oils and moisture, is stripped away by the water’s chemical content, resulting in dryness and itching. For people with sensitive skin, this exposure can trigger a condition known as irritant contact dermatitis, presenting as a red, bumpy, or scaly rash.
The eyes are highly susceptible to this chemical irritation, which manifests as immediate burning, stinging, and noticeable redness, a condition often called chemical conjunctivitis. This irritation is largely attributed to the chloramines dissolving the thin tear film that naturally protects the eye’s surface. In severe cases, prolonged contact with highly irritating water can lead to blurry vision or persistent discomfort after exiting the pool.
Respiratory System Impact and Inhalation Risks
The most concerning health risks from swimming in poorly balanced water involve the respiratory system, as volatile chloramines are released into the air above the pool surface. The most irritating of these compounds is trichloramine (NCl3), which is highly volatile and readily becomes an airborne gas, particularly in poorly ventilated indoor facilities. When inhaled, trichloramine acts as a strong irritant, immediately affecting the mucous membranes of the nasal passages and throat.
Symptoms of this inhalation exposure include coughing, wheezing, hoarseness, and a burning sensation in the airways. Swimmers and pool staff who experience frequent or prolonged exposure may see an exacerbation of pre-existing conditions, such as asthma. In extreme, acute exposure situations, the chemical irritation can be so severe that it causes difficulty breathing or symptoms indicative of a reactive airway dysfunction syndrome (RADS). The concentration of these airborne irritants is often highest in the breathing zone directly above the water, which makes the risk greater for children and competitive swimmers.
Acute First Aid and Recovery Steps
If symptoms of irritation begin while in the pool, the immediate first step is to exit the water and move to an area with fresh air, which helps to mitigate further inhalation exposure. Any clothing that has been saturated with the chemically imbalanced water should be removed to prevent prolonged skin contact. The affected skin and hair should be thoroughly rinsed with clean, fresh water in a shower to wash away residual chloramines and free chlorine.
For irritated eyes, continuous irrigation with copious amounts of water for at least 15 minutes is recommended to flush out the irritants. Simple saline solution or over-the-counter eye drops can provide additional relief after the initial flushing is complete. If respiratory symptoms, such as persistent coughing, chest tightness, or difficulty breathing, continue after leaving the pool and moving to fresh air, professional medical attention should be sought immediately. Similarly, any pain, blistering, or signs of chemical burns on the skin require prompt medical evaluation.