by Carlos E. Castañeda

(CBS SF) — Health experts and the swimming pool industry have a message for pool swimmers with irritated eyes who blame it on the chlorine: blame it instead on the urine.

It turns out red eyes following a swim are the result of chlorine binding with urine and sweat to form chloramine, which is the actual irritant.

“Peeing in a pool depletes chlorine and actually produces an irritant that makes people’s eyes turn red,” said Michele Hlavsa, chief of CDC’s Healthy Swimming Program in a press release.

The Centers for Disease Control and Prevention is teaming up with the Water Quality and Health Council and the National Swimming Pool Foundation in a campaign to educate Americans about what’s in the water and how to stay healthy while swimming.

A survey by San Francisco-based research firm Survata found that three out of every four Americans surveyed incorrectly believe it’s the chlorine causing swimmer’s eyes to turn red.

In addition, the campaign also seeks to bust other myths, such as the belief a dye can be added to pools to detect the presence of urine, or that pools have a normal chlorine smell.

“That ‘chlorine’ smell at the pool isn’t actually chlorine. What you smell are chemicals that form when chlorine mixes with pee, sweat and dirt from swimmers’ bodies,” said Chris Wiant, Chair of the Water Quality and Health Council. “These chemicals – not chlorine – can cause your eyes to become red and sting, make your nose run and make you cough.”

The CDC and pool industry urge swimmers to use common courtesy, rinse off before going into a swimming pool and don’t swim in a pool if you are sick or have open wounds.

“Swimmers should use the pool to swim, the restroom to pee and the showers to wash up before getting in the pool,” said Hlavsa. “It’s that simple.”