Your teenager wants to work as a lifeguard at the fitness center, and you’ve signed up your youngest for swim lessons there. So you check out the indoor pool and take in the overpowering smell of chlorine. Can that be healthy?

Healthy is a relative term. Chlorine is a sanitizing agent. Given all the bodies—and the accompanying germs, dirt and body fluids—that share the water in a public pool in a day, you can’t knock sanitation. The problem is that when chlorine mixes with organic matter, such as the leaves that might fall into a backyard pool, or the urine from a kid who thinks it’s OK to use a pool as a potty, it produces chloramines, including nitrogen trichloride.

Such chemical compounds are to blame for skin and eye irritation and according to a 2003 Occupational and Environmental Medicine study, they increase the risk of asthma (the same chemical reaction that causes eye inflammation also inflames the lung tissue). Some, such as chloroform, are considered carcinogens. So precautions are in order.

The chlorine-produced gases are strongest right above the water level, so a competitive swimmer would be inhaling more of them than, say, a lifeguard high up on a chair or a child taking a 30-minute lesson. However, keep in mind that children breathe more air relative to their body size than adults do. Good ventilation is key; opt for an outdoor pool if possible, especially if your child is prone to asthma or if the indoor pool you’re considering is in a room without a high ceiling or with poor ventilation.

And please, make sure your child uses the potty, not the pool. If you think it’s OK as long as your child is the only one doing it, keep in mind that that toxic reaction of organic matter and chlorine is happening closest to the source: Your precious little one. And the more that stuff happens, the more chlorine is needed to combat it.

We’re not trying to scare you out of the pool. We all want our children to know how to swim for safety reasons if nothing else, and if your kid enjoys swimming, the risk of inhaling a bit of chlorine over a lifetime shouldn’t outweigh the health benefits of such physical activity. Use common sense: If the smell is overpowering or if your child comes out of the pool with a cough or irritated eyes, mention it to the people in charge so they can check the chlorine levels. You’ll be doing everyone a favor.