What Is Chlorine?
Chlorine is a common element in household cleaning and pesticide products. You’re probably most familiar with its use in pools to keep them free from bacteria and algae. It is naturally a gas but can be processed through pressurization and cooling to turn it into a liquid. Whether in gas or liquid form, chlorine has a yellow or green tint.
Chlorine itself is not flammable, but when mixed with other chemicals such as ammonia or turpentine, it can have an explosive reaction to fire or extreme heat. In some cases, these reactions can cause chlorine to turn back into its gaseous form and release into the air.
Chlorine is used in drinking water in very small doses to kill bacteria. With proper use and handling, it is safe to be around. Still, you should always keep it and other chemicals away from children.
Chlorine poses a danger in your home when you mix a chlorine-based cleaner with another cleaner. The different chemicals may react and release chlorine gas into the air of your home. This exposes your skin, eyes, and lungs to potential damage. You can also be exposed if you eat something that's been contaminated if chlorine gets into a water or food source.
Chlorine Uses
The main use for chlorine is as a disinfectant, to sanitize water and industrial wastes. It’s also an ingredient in many cleaning products you use at home.
Disinfecting water
Chlorination is the process of adding chlorine to drinking water. It’s been part of the water treatment process for over 100 years.
Chlorine kills the germs that cause diseases such as hepatitis and salmonella. Public water systems add it to their water supply to remove germs, prevent odor, and improve the taste of the water. It is also used to disinfect sewage and waste from manufacturing plants.
Disinfecting pools
Adding chlorine to pools and hot tubs kills germs such as E. coli and cryptosporidium that can spread from person to person through the water. When used correctly, chlorine kills most germs within a minute. The chlorine smell you may notice at public pools doesn’t come from the chlorine itself. It happens when chemical compounds called chloramines in chlorine combine with sweat, pee, and cosmetics on your skin.
In household cleaning products
Chlorine bleach is one of the most commonly used disinfectants. It contains sodium hypochlorite dissolved in water. Chlorine is good at removing stains from fabrics, disinfecting surfaces, and removing mold and mildew.
Other uses
Manufacturers also use chlorine to:
- Make pesticides, artificial rubber, and water coolants
- Whiten paper and cloth
- Produce polymers and synthetic rubber
- Wash meat and produce
Chlorine Allergy
Chlorine doesn’t cause allergies, but it can trigger a reaction by irritating your skin. People who are sensitive to chlorine may develop itching, redness, or a rash when their skin comes into contact with it. Chlorine can also trigger or worsen asthma or allergies by irritating the lungs.
Chlorine rash
If you’re sensitive to chlorine, you may get a rash on your skin after you swim in chlorinated water. A chlorine rash can be:
- Red
- Bumpy
- Itchy
- Scaly
- Crusty
How Can You Be Exposed to Chlorine?
You’re most likely to come into contact with chlorine if you use bleach cleaners or if you work with this chemical. When chlorine reacts with water in your body, it forms acids that can damage your cells. Here are some ways you might get exposed to chlorine:
Mixing household cleaners
You could be exposed to chlorine gas if you mix chlorine bleach with acid-based household cleaning products such as window cleaners, dishwasher detergents and rinses, toilet bowl cleaners, or drain cleaners.
Exposure to this gas irritates your eyes, nose, throat, and lungs and can cause symptoms such as:
- Burning and watery eyes
- Burning in the nose
- Breathing problems
- Coughing
- Skin swelling and blisters
Exposure to large amounts of chlorine mixed with household chemicals can be life-threatening.
Occupational exposure
Working with chlorine on the job also increases your risk for exposure. When chlorine gets released into the air, it can irritate your nose, throat, and lungs if you breathe it in. It can also cause burns if you accidentally spill it on your skin.
Accidents at companies that work with chlorine put both employees and nearby residents at risk for exposure. In 2024, a fire broke out at BioLab, a chemical plant in Conyers, Georgia, releasing chlorine into the air. Nearby residents reported symptoms such as shortness of breath, blurry vision, headaches, and throat irritation after the incident.
Ingestion of chlorine
Another way you may get exposed to chlorine is if you eat food or drink water contaminated with this chemical, or if you accidentally swallow a cleaning product that contains chlorine. During the COVID-19 pandemic, there were reports of people drinking diluted chlorine bleach to treat their symptoms. This dangerous practice could lead to life-threatening liver failure, abnormal heart rhythms, and severe vomiting.
Chlorine Exposure Limits
Health and safety organizations measure chlorine exposure in parts of gas per million parts of air (ppm). Each organization has set a slightly different limit for chlorine exposure on the job:
The Occupational Safety Administration (OSHA): No more than 1 ppm for any amount of time
The National Institute for Occupational Safety and Health (NIOSH): No more than 0.5 ppm during any 15-minute work period
The American Conference of Government Industrial Hygienists (ACGIH): 0.5 ppm average over an eight-hour work shift
These numbers are for chlorine gas limits in the air. You can get too much exposure if chlorine touches your skin, even if the amount in the air is lower than the recommended limit.
What Is Chlorine Poisoning?
Chlorine poisoning involves symptoms such as trouble breathing and burning of the eyes and nose after you’re exposed to chlorine gas. It’s most likely to happen if you mix chlorine bleach with an acidic household cleaner.
The chlorine gas reacts with water in your body to form harsh acids that damage cells. Chlorine poisoning can affect many different parts of your body, including your eyes, nose, throat, lungs, and digestive tract.
Signs of Chlorine Poisoning
The severity of symptoms from chlorine poisoning depends on the amount of chlorine you were exposed to. Minor exposure to chlorine may mean fewer or less severe symptoms. Significant exposure can lead to serious health consequences and even death.
Factors that affect the severity of chlorine exposure include:
- Amount of chlorine
- Length of time you were exposed
- How you were exposed
- Where the gas or liquid came in contact with your body (eyes, skin, mouth, lungs)
You may have symptoms immediately, or they may appear a while after exposure.
Some symptoms to look out for include:
- Blurry vision
- Red, irritated, watery eyes
- Pain, irritation, redness, and blisters where chlorine touched your skin
- Burning in your nose, throat, chest, and eyes
- Coughing or wheezing
- Tightness in your chest
- Not being able to breathe normally
- Feeling nauseous
- Vomiting
Keep in mind that these symptoms may also appear if you are exposed to other chemicals. If you know what brand of cleaner or pesticide you were exposed to, share that with your doctor when you seek medical attention.
If your chlorine exposure symptoms aren’t treated, you may have long-term side effects. If you have severe effects such as fluid in your lungs, you’re more likely to develop long-term health conditions.
Diagnosing Chlorine Poisoning
Your doctor will ask about your symptoms and exposure to chlorine gas. During the exam, the doctor will look for signs of chlorine poisoning, including:
- Shortness of breath
- Bubbling, clicking, rattling, or high-pitched sounds when you breathe
- Blue color to your skin from a lack of oxygen
- Wheezing
- Widening of your nostrils when you breathe
Tests like these can help your doctor diagnose chlorine poisoning:
- Pulse oximetry, a device that attaches to your finger to measure the amount of oxygen in your blood
- Chest X-ray
- Blood tests
- Arterial blood gas, which measures levels of oxygen, carbon dioxide, and acid in your blood
- Electrocardiogram (ECG), which checks the electrical activity in your heart
- Lung function tests
- Bronchoscopy or endoscopy, which places a camera down your throat to look for burns in your esophagus, lungs, and stomach
Treating Chlorine Poisoning
Follow these steps to minimize the effects of exposure:
Move away. If it happened indoors, go outside. If it happened outside, walk away from the area. Your goal is to get fresh air into your lungs and lessen the amount of chlorine in your system.
Don’t attempt to clean up the chlorine because this increases your exposure time. Instead, warn medical personnel or local authorities so it can be cleaned properly. If others are nearby, warn them about the chlorine so no one else is harmed.
Take off your clothes. If there's a chance chlorine is on your clothes, take them off immediately. If possible, pull them down your body or cut them off to avoid further skin or soft-tissue exposure. Avoid touching contaminated areas, including surfaces you or your clothes touched.
Wash your body. You also want to wash your body as quickly as possible to remove any chlorine from your skin. You don’t need anything special to remove chlorine — soap and warm water work well. If your eyes are burning or your vision is blurry, rinse your eyes with clean, running water for at least 10 minutes. If you wear glasses or contacts, remove them and set them aside with your clothes.
Seek medical attention. If you ingest chlorine orally, don’t attempt to flush your system. Instead, seek immediate medical attention. There is no antidote that your doctor can give you, but there are ways to remove chlorine from your system. Your doctor will also treat your symptoms to lessen pain and allow your body to heal from the damage.
Is Chlorine in Pools Safe?
Adding chlorine to pools helps protect you from bacteria and other germs that could make you sick. The amount of chlorine in pools and hot tubs is usually small — between 1 and 3 ppm. At this level, there’s enough chlorine to kill germs, but not enough to irritate your skin, eyes, and lungs.
Breathing in chloramine for long periods may cause problems, especially for people who have lung disease. You’re more likely to breathe in large amounts of this chemical in an indoor pool because it has less ventilation than an outdoor pool.
The pH measures how acidic or basic pool water is. The CDC recommends keeping pools at a pH of 7.0 to 7.8.
If the chlorine concentration is higher than recommended, it could irritate your eyes and skin. Accidentally swallowing a mouthful of pool water shouldn’t hurt you, but drinking large amounts could cause burning in your mouth and throat, along with vomiting and diarrhea.
Takeaways
Chlorine is a chemical element that’s used in disinfectants, cleaning products, and manufacturing processes. While it’s safe in small amounts, exposure to too much chlorine can cause symptoms such as trouble breathing, vomiting, and burning in your eyes and nose. If you’re accidentally exposed to chlorine, wash the exposed areas of your body and get medical help right away.
Chlorine FAQs
How is chlorine made?
Chlorine gas occurs naturally. But manufacturers also make chlorine by passing an electrical current through a mixture of salt and water (saline). This procedure, called electrolysis, produces chlorine gas.
Is chlorine harmful to humans?
Chlorine is safe when used in recommended amounts. Exposure to large amounts of chlorine gas can cause symptoms such as eye and skin irritation, breathing difficulty, and vomiting.
Does chlorine kill lice?
The amount of chlorine in public pools and hot tubs won’t kill head lice, but lice don’t usually spread through water. They pass from person to person by direct contact, or through sharing brushes and other items that have touched the hair of an infected person.
How to lower chlorine in pools
You can reduce the amount of chlorine in your pool by adding more fresh water, or by adding sodium thiosulfate to the water. This chemical will help neutralize the excess chlorine.
Can we drink chlorinated water?
The amount of chlorine in drinking water is safe to drink. Swallowing small amounts of pool water shouldn’t harm you, but drinking large amounts could lead to chlorine poisoning.
