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Blister Agent

What are blister agents and where are they found?
Blister agents, also known as "vesicants," are chemicals which can burn and blister any part of the body they come in contact with. They are man-made chemical warfare agents and are not found naturally in the environment. The federal government strictly regulates the production, sale and possession of blister agents. Common blister agents are mustard (HD), nitrogen mustard (HN), lewisite (L), and phosgene oxime (CX). Links to specific information on these agents can be found below.

Blister agents are mostly found as liquids, but they may give off vapors. These vapors are usually heavier than the air and stay low to the ground , or can sink into spaces below ground such as basements or subway tunnels when released.

Some blister agents are odorless, while others may give off odors that smell similar to garlic, onions, fruits or geranium flowers. .

How can I be exposed to a blister agent?
Blister agents are not commonly found in everyday environments. You are exposed to a blister agent only when you come into contact with it. Exposure could occur when they are used by terrorists as a weapon; however, accidental releases can happen but are very rare. If blister agents are released, exposure mostly occurs when people breathe in the vapors or come into direct contact with the liquid. The liquid and vapors are also harmful when they touch the skin and eyes. Most clothing does not protect the skin from blister agents.

Person-to-person contamination is possible by touching the clothing or skin of exposed people if they are covered with a large amount of vapor or any amount of liquid .

How can exposure to blister agents affect my health?
Injury caused by blister agents depends on the type of blistering agent, the amount, the length of time and how a person was exposed. Health effects may occur right away or can take up to 24 hours to appear. Symptoms may include:
  • Skin redness, itching, painful blistering, or second- and third-degree burns
  • Eye irritation, burning, tearing, blurry vision, temporary or permanent blindness
  • Bloody and/or runny nose, sinus pain, sore throat, cough, shortness of breath, and/or other breathing problems
  • Nausea, vomiting, abdominal pain, or diarrhea
  • Death may occur directly from the exposure or as a result of complications related to the injuries.

Long term and on-going exposure to blistering agents may cause cancer in the airways, lungs, skin and other parts of the body years after exposure.

People with existing health problems, children, and the elderly are generally more vulnerable to the effects of blister agents.



Showing these signs and symptoms does not necessarily mean that a person has been exposed to a blister agent. These health effects can also be caused by other conditions.

How are the effects of blister agent exposure on pets and what do I need to do?
Pets exposed to blister agents are likely to have the same reaction as people. If your pet is exposed to blister agent, wear gloves and protective clothing to wash your pet. Wash your pet with soap and tap water. After washing your pet and cleaning the area, put clothing, gloves, towels and sponges in a double plastic bag. Disposal sites will be set up for these bags.

For more information on how to care for an exposed pet, contact your veterinarian or the ASPCA Animal Poison Control Center (888-426-4435).

What should I do if I have been exposed to a blister agent? How can I protect myself?
Leave the area where the blister agent was released IMMEDIATELY and get to fresh air as quickly as possible to prevent further contamination. Keep in mind that blister agents are heavier than air, so they will sink to the ground or to lower building levels. If possible move to higher ground.
  • If the blister agent was released indoors, get out of the building.
  • If the blister agent was released outdoors, leave the area.

Call 911 if you have serious injuries or symptoms and be sure to explain what occurred as information may be helpful in identifying the chemical and determining appropriate treatment.

Self-decontaminate: get the blister agent off your body as quickly as possible.
  • Carefully remove contaminated clothing and avoid contact with your skin. Place clothes in a double plastic bag. Disposal sites will be set up for these bags.
  • Wash your skin with soap and tap water. Rinse your eyes with plenty of tap water for 5-10 minutes.
DO NOT make yourself vomit if you have swallowed a blister agent. This may cause more injury than having the chemical settle in your stomach. Drink a small cup of water or milk to dilute any remaining chemicals.

If a child or an elderly or disabled person needs help with decontamination, help them decontaminate by following the steps above. Protect yourself from exposure before assisting others by wearing gloves and protective clothing if available.

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

Is there a test for exposure to blister agents?
There is no standard test to determine exposure to a blister agent. Diagnosis is usually based on the specific symptoms experienced and circumstances of an event. Information you observe about the release of an agent may be important for diagnosis, so please share all information about your exposure with your health care provider.

Is there a specific treatment for exposure to blister agents?
Decontamination is extremely important for exposure to a blister agent. The most important thing to do is to remove any remaining blister agent from your body. Follow the steps above if you have been exposed.

There is no specific antidote for blister agents. Treatment is aimed at further decontamination and relief of signs and symptoms .

What happens if a blister agent is released in New York City?
The city has emergency response plans to minimize harm to residents, workers and visitors. During any emergency, City health officials will provide instructions through TV, radio and online on how best to protect yourself and your loved ones. Information will also be available on the city’s website, and by calling the city’s information line 311.

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’).

Go to Notify NYC online to sign up for updates from city officials about emergencies.

Go to Ready New York online for more information about preparing for an emergency.

How Will I Cope?
An event involving the release of a blister agent 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 blister agent release that affects the city and you feel overwhelmed and unable to cope, or if 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 blister agents, visit:

Centers for Disease Control and Prevention (CDC)

Agency for Toxic Substances and Disease Registry (ATSDR)
Lewisite (L), Mustard-Lewisite Mixture (HL): atsdr.cdc.gov/tfacts163.html
Sulfur Mustards: - Additional Link
Nitrogen Mustard
Phosgene Oxime