(KTVI)-It’s a hidden danger most parents have probably never heard of: kids drowning hours after they’ve left the swimming pool. It’s called “secondary drowning” or dry drowning and can lead to serious complications and even death.

It starts with someone taking water into their lungs. You might notice coughing when they come up for air, but when they come out of the water they seem to be fine, so most parents ignore it. But sometimes water fills the lungs and chemicals from pools or hot tubs cause damage.

Doctors say after your kids leave the pool, take notice if they are coughing , having difficulty breathing, acting tired, experiencing headaches, or vomiting.

If you notice any secondary drowning symptoms, have them checked out immediately.