Have you ever gone swimming in a pool and gotten out with reddish, bloodshot eyes? Of course you have. Everyone has. And we all assume it's because of chlorine.
Nope, it's pee pee.
"The nitrogen in the urine combines with with the chlorine and it forms what's known as chloramine and it's actually chloramine that causes the red eyes," said Michele Hlavsa, chief of the CDC's healthy swimming program, in an interview on the Today Show. "It's not the chlorine itself. It's chlorine mixed with poop and sweat and a lot of other things we bring into the water with us."
The traditional chlorine smell we all associate with pools isn't even pure chlorine. The report reads: "What you smell are actually chemicals that form when chlorine mixes with pee, poop, sweat and dirt from swimmers bodies... These chemicals -- not chlorine -- can cause your eyes to get red and sting, make your nose run, and make you cough."
Now close your eyes and think about how many times you've opened your mouth while underwater.