The Toxic Truth About Swimming Pools

The pool is still very much open at our house all summer long. Swimming gets kids moving, gets them outside, wears them out in the best possible way, and gives families a reason to slow down together. None of that is changing.

What has changed is how I think about what we’re actually sitting in for hours at a time.

Not in a fear-based way. More in a “once you know this, you can’t unknow it” kind of way. Most of what people accept as normal around pools, the overpowering chlorine smell, burning eyes, that headache after indoor swimming, the new inflatable that smells like a tire factory, are actually signals worth paying attention to.

The good news is that making pool season meaningfully cleaner just requires a handful of small habits that make a real difference over the course of an entire summer.

That Strong Chlorine Smell Is Not a Sign of a Clean Pool

This is the biggest misconception most people have about pools, and it’s worth getting right.

Most people walk into a pool area, catch that sharp chemical odor, and assume it means the water is clean and well-maintained. In reality, that smell usually means the chlorine is already overloaded.

What you’re smelling is largely chloramines: compounds that form when chlorine binds with the contaminants people bring into the water. Sweat. Body oils. Sunscreen. Hair products. Dirt. Urine. Chlorine itself needs to be there; pools need sanitation. The problem is what happens when it has to constantly react with everything entering the water. Those reactions create irritating byproducts that linger in both the water and the air above it.

That’s why heavily chlorinated pools leave people with:

• Red, burning eyes
• Dry, itchy skin
• Coughing or a tight feeling in the chest
• Headaches after longer swims

Contrary to popular belief, red eyes are not usually caused by chlorine alone; they’re typically caused by chloramines irritating the eyes. A properly maintained pool should actually smell surprisingly mild.

Indoor pools can be especially rough because chloramines accumulate in the air directly above the water surface. Without adequate ventilation, swimmers spend hours inhaling those compounds. That heavy, stuffy feeling at some indoor pools is due to the chemistry.

The Easiest Fix Most People Skip: Shower Before Swimming

A quick rinse before getting in the pool removes sweat, lotions, oils, sunscreen, and dirt that would otherwise react with chlorine and form more chloramines.

Most people skip it. Kids especially sprint toward the water the second they arrive anywhere near a pool. But even 30 seconds under a showerhead makes a difference for everyone who shares that water.

Sunscreen: Why Mineral Matters More in Summer

Sun protection is non-negotiable. Skin damage accumulates over time, and skipping sunscreen isn’t the answer. The question is which kind?

Most conventional sunscreens use chemical UV filters, oxybenzone, avobenzone, octinoxate, and octocrylene, which absorb UV radiation and convert it into heat within the skin. What shifted the conversation was FDA-funded research showing that several of these ingredients can be absorbed through the skin and enter the bloodstream at levels exceeding the agency’s threshold for additional safety testing.

That was enough for us to switch to mineral sunscreen.

Mineral sunscreens use non-nano zinc oxide as the active ingredient. Instead of chemically absorbing UV rays, zinc oxide sits on the skin and physically reflects or scatters radiation. Non-nano matters for particle size; the goal is avoiding extremely fine particles that may behave differently in the body or environment.

A few practical advantages mineral sunscreen has over chemical formulas:

• Works immediately: no 15–30 minute wait for activation
• Gentler on sensitive skin: many people who experience stinging or irritation from chemical sunscreens do significantly better with zinc-based products
• Better for kids: especially relevant when you’re reapplying multiple times a day

The formulations have improved considerably in recent years. Mineral sunscreen used to mean a thick, obvious white cast. The newer options are far more wearable.

Pool Floats and Inflatables: That Smell Means Something

This is one of those things that didn’t occur to me until I unpacked a new inflatable one summer and the smell hit me immediately.

That “new plastic” odor coming off a fresh pool float isn’t harmless. It’s off-gassing.

Most inexpensive inflatables are made from soft PVC plastic combined with plasticizers, often phthalates, that make the plastic flexible rather than rigid. Phthalates don’t stay permanently bound to the material. Over time, they release into the surrounding air, especially in heat. That strong chemical smell from a new float is those volatile compounds escaping.

What to do:

• Look for phthalate-free inflatables: more brands offer these now, especially those focused on children’s products
• Air new inflatables out before use: leave them inflated in a garage, backyard, or porch for a day or two before kids use them; the heaviest off-gassing happens early
• Apply the same habit to water shoes, cheap goggles, vinyl toys, and foam pool accessories

Indoor Pools Deserve Extra Attention

Outdoor pools get most of the attention during summer, but indoor pools can pose a distinct set of exposure issues worth knowing about.

In an enclosed environment, chloramines and other volatile byproducts accumulate in the air directly above the water. Poor ventilation means swimmers inhale those compounds continuously for hours. Research has examined respiratory health among competitive swimmers and pool staff who experience this repeatedly over time; the findings have led to growing interest in improving aquatic facility ventilation standards.

A clean indoor pool feels noticeably different. The air doesn’t feel heavy. Eyes don’t sting upon entry, and there’s no headache after an hour. If a pool hits you with a wall of chemical air before you’ve even opened the gate, that’s information worth acting on.

For families with kids in regular swim lessons or year-round club swimming, paying attention to the specific facility’s air quality is worth the effort.

What Our Family Actually Does

None of these changes requires a major lifestyle shift. Here’s what our swim season actually looks like:

• Quick rinse before swimming: even if it’s just 30 seconds
• Bathroom break before getting in: especially for younger kids
• Mineral sunscreen, reapplied properly: non-nano zinc oxide formula
• New inflatables get aired out: before anyone uses them
• Notice how indoor pools smell and feel: and choose facilities accordingly when we have a choice
• Avoid the strongest synthetic chemical products: when cleaner alternatives exist

The pool is still one of the best parts of summer. Kids still spend entire afternoons turning pruney in the water.

Frequently Asked Questions

Why does the pool smell like chlorine if chlorine itself is odorless? The “chlorine smell” most people associate with pools is actually caused by chloramines: chemical compounds formed when chlorine reacts with organic contaminants like sweat, urine, sunscreen, and body oils brought in by swimmers. Chlorine itself has very little odor. A strong chemical smell at a pool usually indicates that the chlorine is overloaded with contaminants, not that the water is exceptionally clean. A properly maintained pool with low chloramine levels should smell relatively mild.

Does chlorine cause red eyes from swimming? Not usually. Chloramines, not chlorine itself, most commonly cause red, irritated eyes after swimming. When chlorine binds with contaminants in the water, the resulting compounds are more irritating to eye tissue than chlorine alone. This is one reason showering before swimming, which reduces contaminants entering the water, helps everyone in the pool, not just yourself.

Is mineral sunscreen better than chemical sunscreen for kids? Many health-conscious families prefer mineral sunscreen for children because zinc oxide works immediately without requiring absorption into the skin, and FDA-funded research has raised questions about the systemic absorption of several common chemical UV filters at levels that warrant further safety testing. Mineral sunscreens using non-nano zinc oxide also tend to be gentler on sensitive skin and cause less stinging and irritation than many chemical formulas. The tradeoff is typically a slightly thicker texture and possible white cast, though newer formulations have improved significantly.

Why do new pool floats and inflatables smell so strongly? The smell from new plastic pool inflatables is off-gassing; volatile compounds, often including phthalates from the PVC material, are being released into the air. Phthalates are plasticizers added to make PVC flexible, but they don’t remain permanently bound to the material and can escape as gases, particularly at high temperatures. Airing new inflatables out for one to two days before use significantly reduces early exposure, since off-gassing is heaviest when the product is new.

Are indoor swimming pools more dangerous than outdoor pools? Not necessarily more dangerous, but the exposure profile is different. In enclosed indoor spaces, chloramines and other volatile disinfection byproducts accumulate in the air directly above the water surface rather than dispersing into open air. Poor ventilation allows these compounds to build to higher concentrations. Competitive swimmers and pool staff who spend extended time in indoor pools have been studied for associated respiratory effects. For casual swimmers, the risk is lower, but paying attention to air quality and choosing well-ventilated facilities is still worthwhile.

Should you shower before or after swimming in a pool? Both, ideally. Showering before swimming removes sweat, body oils, sunscreen, and cosmetics that would otherwise react with chlorine to form chloramines, protecting both yourself and everyone else in the pool. Showering immediately after swimming rinses chlorine, chloramines, and disinfection byproducts off the skin before they can be absorbed further or cause irritation. Both habits are free, take under a minute each, and make a genuine difference in chemical exposure.

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