But sometimes the chemical is in the form of a yellow-green gas that isn't flammable, but can cause serious health problems in high concentrations.
For example, on June 5, about 50 people, most of them children, became "violently ill" due to chlorine gas at a pool in Utah.
Police said a pump malfunctioned, forcing too much chlorine into the pool. When the pump restarted, it turned into gas.
Some of those affected experienced coughing, vomiting and bleeding from their noses.
If you're exposed to dangerous concentrations of chlorine, the the Centers for Disease Control and Prevention says you may experience some of the following signs or symptoms.
- Blurred vision
- Burning pain, redness, blisters on the skin. The injuries may also be similar to frostbite if exposed to liquid chlorine
-Difficulty breathing or shortness of breath
-Fluid in the lungs
- Nausea and vomiting
Long-term health complications typically develop in people who have fluid in their lungs after the initial chlorine exposure.
If you're exposed to the gas, quickly move to an area where there's fresh air.
The CDC also advises moving to the highest ground possible since chlorine is heavier than area and will sink to low-lying areas.
It also says you should wash your entire body and get medical care as quickly as possible.
There is no antidote for chlorine exposure.
The CDC has a full list of how you can protect yourself and what to do if you're exposed.
Get more information about chlorine by calling the regional poison control center at 1-800-222-1222.
You can also reach the Public Response Hotline at 800-CDC-INFO or email them.
Chlorine sickens about 50 people in 'freak accident' at Utah pool, police say