A new study on the effects of urination in chlorinated water has found that it can form two chemicals, trichloramine and cyanogen chloride, which have been associated with lung problems and can affect the heart and nervous system. In short, peeing in your pool makes negligible amounts of harmful chemicals.

The study was published in the American Chemical Society's Environmental Science and Technology journal and involved chlorinating uric acid to look at the byproducts. One of the byproducts, cyanogen chloride, can affect organs through inhalation, and the World Health Organization (WHO) recommends that its maximum concentration in drinking water should be 70 micrograms per liter or less.

Another interesting fact about cyanogen chloride: it has a military designation of CK and is considered a chemical warfare agent.

The highest concentration that the team observed was around 33 micrograms per liter at 8 milligrams per liter of chlorine—a much higher chlorine concentration than is used in the average pool—which still falls under the levels considered safe enough by the WHO. While there is no imminent threat of poisoning yourself with your own urine in the pool, the authors state that both trichloramine and cyanogen chloride are "volatile" and "have the potential to adversely affect air and water quality in chlorinated, indoor pools." They further note that since peeing in a pool is a voluntary process, "opportunities exist for significant improvement of air and water quality… via changes in swimmer hygiene practices."

The study was sponsored in part by the National Swimming Pool Foundation, which offers certifications for pool and spa technicians.

DOI: 10.1021/es405402r, Environmental Science and Technology.