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Chlorine Gas

What is chlorine gas?
Chlorine is one of the most common elements in nature. At room temperature, chlorine is a poisonous yellow-green gas with strong bleach-like odor. The gas can be pressurized and cooled to change into a liquid so that it can be shipped and stored. When liquid chlorine is released, it quickly turns into a gas that stays close to the ground and spreads rapidly. It can be dangerous if humans come into contact with it, as it can irritate and damage tissues. It can even cause death.

How is chlorine used?
Chlorine is most commonly used to bleach paper and textiles, to make insecticides and plastic. It is also used to disinfect drinking water, swimming pools and to treat sewage. During World War I, chlorine was used as a chemical warfare agent.

How might I be exposed to chlorine gas?
People can become exposed to chlorine liquid and gas during industrial (chemical) accidents, during accidental leak from a truck or train carrying chlorine or at home when household chlorine bleach is mixed with other cleaning agents and releases chlorine gas. Terrorists can also use chlorine gas as a weapon to cause injury.

If chlorine gas is released into the air, people may be exposed through skin or eye contact. They may also be exposed by breathing air that contains chlorine. If chlorine liquid is released into water, people may be exposed by touching or drinking water that contains chlorine.

If chlorine liquid comes into contact with food, people may be exposed by eating the contaminated food.

How can chlorine affect my health?
Injury caused by chlorine exposure depends on the amount, length of time and how a person was exposed. When chlorine gas comes into contact with moist parts of the body such as the eyes, throat and lungs, it produces an acid that can irritate and damage the tissues.

The immediate symptoms of chlorine exposure include:
  • Coughing and chest tightness
  • Burning sensation in the nose, throat and eyes
  • Watery eyes and blurred vision
  • Nausea and vomiting
  • Burning pain, redness and blisters on the skin if exposed to gas; skin injury similar to frostbite if exposed to liquid chlorine
  • Difficulty breathing or shortness of breath may appear immediately if high concentrations of chlorine gas are inhaled, or may be delayed if low concentrations of chlorine gas are inhaled.

Death may occur with large or prolonged exposures. People with existing health problems such as asthma or other chronic respiratory diseases are generally more susceptible to the effects of chlorine gas .

What are the long-term health effects of chlorine exposure?
Unless there are complications during therapy such as pneumonia, long-term complications in are unlikely.

What should I do if I am exposed to chlorine in a chemical emergency?
Avoid further exposure. Leave the area where the chlorine was released and get fresh air immediately.
  • If the chlorine was released outdoors, leave the area. Chlorine is heavier than air, so it will sink to the ground or to lower building floors. Go to higher grounds or to upper floors.
  • If the chlorine was released indoors, leave the building.
Decontaminate. Get the chlorine off your body as quickly as possible.
  • Remove clothing contaminated with chlorine immediately. Be careful to avoid touching other parts of your body with contaminated clothes. Place clothes in a double plastic bag and seal the bag. Disposal sites will be set up for the bags.
  • Rinse your eyes with plenty of tap water for 5-10 minutes and wash contaminated skin with soap and water.

What should I do if I have been injured from exposure to chlorine?
Call the Poison Control Center [(212) POISONS (764-7667) or 1-800-222-1222 if you experience symptoms of chlorine exposure. If your symptoms are serious or persistent, call 911.

Are there any medical tests for exposure to chlorine?
There are no specific medical tests to determine whether you have been exposed to chlorine. Diagnosis is usually based on the specific symptoms and circumstances surrounding the release of an agent. Information you observe about release of an agent may be important for diagnosis, so share all information about your exposure with medical providers.

What are the effects of chlorine exposure on pets and what do I need to do?
The effect of chlorine on people and animals is very similar. If your pet was exposed to chlorine liquid or gas, wash your pet with soap and water. Wear gloves and protective clothing to prevent the chlorine covering your pet from contaminating you. After washing, put clothing and gloves in a double plastic bag. Disposal sites will be set up for the bags.

Contact a veterinarian or the ASPCA Animal Poison Control Center (1-888-426-4435).

What are the effects of chlorine exposure on pets and what do I need to do?
City agencies have emergency response plans to minimize the harm to NYC residents, workers and visitors.
During any emergency involving the release of chlorine, health officials will provide instructions through TV and radio news on how best to protect yourself and your loved ones. The City’s website, nyc.gov and 311 also will provide instructions and information.

How can I prepare for an emergency?
Being as prepared as possible before an emergency happens is the best way to stay safe. Tools that can help in any emergency include a household disaster plan, an emergency supply kit and a bag of supplies you can grab on the go (a go-bag).

Visit Notify NYC to sign up to receive updates about emergencies from City officials.

Visit Ready New York for more information about preparing for an emergency.

How Will I Cope?
An event involving a chlorine gas release can be very stressful, especially if it is large scale event. It can disrupt your everyday life and make you and those around you feel less safe. You may experience fear and uncertainty. Learning about stress and strategies to manage it can help you cope.

Prepare Today, Cope Better Tomorrow - Stress during Disasters provides basic information and practical advice on dealing with the stress and anxiety caused by disasters. It is available in seven languages.

If there is a chlorine gas release in the city and you feel overwhelmed and unable to cope, or if you are concerned about someone else, you can find help by calling 1-800 LIFENET. LIFENET is a free, confidential helpline for New York City residents, available 24/7, with trained staff ready to take your calls and offer advice: 1-800-LifeNet 1-800-543-3638 (English), 1-877-Ayudese 1-877-298-3373 (Spanish), 1-877-990-8585 (Chinese), 1-212-982-5284 (TTY).

Where can I get more information?
For more information about chlorine gas, visit:

Centers for Disease Control and Prevention (CDC)

Agency for Toxic Substances and Disease Registry (ATSDR)

New York State Department of Health (NYC DOH)