With whispers of summers reaching into our Vitamin D deprived souls, many will soon head to the pool to cool off after soaking up the rays. But taking off a wet bathing suit to go to the bathroom is an undeniable pain. Many swimmers, especially those who spend long hours in the pool, don’t bother getting out for a bathroom break.

“I think there’s just something about getting into chlorine water that you just automatically [urinate],” Olympic swimmer Ryan Lochte admitted in a 2012 radio interview.

Lochte’s confession understandably raised a few eyebrows, but fellow Olympian Michael Phelps backed him up in an interview with the Wall Street Journal.

“It’s kind of a normal thing to do for swimmers,” Phelps explained. “When we’re in the water for two hours, we don’t really get out to pee; chlorine kills it so it’s not bad.”

Like Phelps, many rationalize pool urination because they believe that chlorine, a bacterial disinfectant, will neutralize the urine. However, a study published last year out of the American Chemical Society’s Environmental Science & Technology Journal stakes out an entirely different claim.

One of the authors of the study, Purdue University Professor Ernest R. Blatchley III, explained the danger behind public figures making unfounded pool-peeing assumptions.

“[There are] a lot of people in the swimming community who look up to these people and listen to what they have to say,” Blatchley told The Atlantic. “[Phelps and Lochte] are not chemists and should [not] be making statements that are false.”

Instead of chlorine neutralizing urine, the uric acid in urine actually binds with the chlorine creating chlorine by-products that carry human health risks. In their research, Blatchley and the other authors mixed pure chlorine and uric acid. Within an hour, both trichloramine (NCl3) and cyanogen chloride (CNCl) had formed. According to the Centers for Disease Control and Prevention (CDC), cyanogen chloride is a known toxin that can harm the lungs, heart, and central nervous system, while trichloramine has been linked to adverse affects on the respiratory system, in addition to skin and eye irritation. In extremely high doses, Blatchley notes, cyanogen chloride has been used as a chemical warfare agent.

In a Wall Street Journal poll, 63 per cent of poll participants admitted to peeing in the pool, and by most metrics, that percentage is likely understated. Though not everyone pees in the pool, on average 30 to 80 mL of urine is left in the pool per person, which is equivalent to a small shot glass of pee per person. In the summer, when pools fill up, so does the amount of uric acid.

While it is true that the levels of chlorine by-products often remain relatively low, therefore posing a low risk especially for those without preexisting respiratory problems, the veritable formation of chlorine by-products is asking for trouble.

In addition to increasing respiratory risk, chlorine by-products also mean a lowered capacity for chlorine to do its sterilizing job.

“If chlorine is combining chemically with contaminants like urine, then it is not available to destroy germs in the pool that can make swimmers sick with diarrhea, swimmer’s ear, and various skin infections,” Dr. Chris Wiant explained to the Water Quality and Health Council.

Therefore, not only is this form of athlete-approved public urination foul, it also unnecessarily increases poolside health risks.