In the summertime, when the weather is fine, you may have swimming on your mind. A swimming pool dip can cool you off. But some other bodily functions may produce unhealthy chemical reactions. Urinating in a chlorinated pool can lead to small amounts of chemicals that might irritate your lungs, according to this new video from Breakthrough Science and the American Chemical Society.

The culprit is uric acid in urine, says chemist Ernest Blatchley of Purdue University, who admits in the video that he has peed in a pool. But he doesn't anymore, and not just because it is impolite. He and some colleagues discovered that uric acid and chlorine interact to produce small amounts of cyanogen chloride and trichloramine. When inhaled in large volumes these chemicals can damage internal organs. The amount of these chemicals that can be made by the typical amount of urine released by a swimmer--30 to 80 milliliters--is much smaller than anything that has been linked to physical harm, Blatchley hastens to say. But particularly in indoor pools, it is possible they could cause some irritation, he says. He and his colleagues originally reported these results in the journal Environmental Science & Technology.

Peeing in the ocean should be worry-free, however. That's according to some reporting by Lauren Wolf, an editor at Chemical & Engineering News. Urine, she notes, is largely water and salt--and that happens to be, largely, what seawater is made from. There isn't anything like chlorine in ocean water to trigger a bad reaction. Plus, she notes, fish and whales are doing a lot of ocean urinating on their own.