Chemical Emergencies Overview

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The CDC has a key role in protecting the public's health in an emergency involving the release of a chemical that could harm people's health. This page provides information to help people be prepared to protect themselves during and after such an event.

On this page:

What chemical emergencies are
Where hazardous chemicals come from
Types & categories of hazardous chemicals
Hazardous chemicals by name (A-Z list)
Protecting yourself if you don't know what the chemical is
Basic information on chemical emergencies
In-depth information on chemical emergencies
For more information…

What chemical emergencies are

A chemical emergency occurs when a hazardous chemical has been released and the release has the potential for harming people's health. Chemical releases can be unintentional, as in the case of an industrial accident, or intentional, as in the case of a terrorist attack.

Where hazardous chemicals come from

Some chemicals that are hazardous have been developed by military organizations for use in warfare. Examples are nerve agents such as sarin and VX, mustards such as sulfur mustards and nitrogen mustards, and choking agents such as phosgene. It might be possible for terrorists to get these chemical warfare agents and use them to harm people.

Many hazardous chemicals are used in industry (for example, chlorine, ammonia, and benzene). Others are found in nature (for example, poisonous plants). Some could be made from everyday items such as household cleaners. These types of hazardous chemicals also could be obtained and used to harm people, or they could be accidentally released.

Types and categories of hazardous chemicals

Scientists often categorize hazardous chemicals by the type of chemical or by the effects a chemical would have on people exposed to it. The categories/types used by the Centers for Disease Control and Prevention are as follows:

Biotoxins—poisons that come from plants or animals
Blister agents/vesicants—chemicals that severely blister the eyes, respiratory tract, and skin on contact
Blood agents—poisons that affect the body by being absorbed into the blood
Caustics (acids)—chemicals that burn or corrode people’s skin, eyes, and mucus membranes (lining of the nose, mouth, throat, and lungs) on contact
Choking/lung/pulmonary agents—chemicals that cause severe irritation or swelling of the respiratory tract (lining of the nose and throat, lungs)
Incapacitating agents—drugs that make people unable to think clearly or that cause an altered state of consciousness (possibly unconsciousness)
Long-acting anticoagulants—poisons that prevent blood from clotting properly, which can lead to uncontrolled bleeding
Metals—agents that consist of metallic poisons
Nerve agents—highly poisonous chemicals that work by preventing the nervous system from working properly
Organic solvents—agents that damage the tissues of living things by dissolving fats and oils
Riot control agents/tear gas—highly irritating agents normally used by law enforcement for crowd control or by individuals for protection (for example, mace)
Toxic alcohols—poisonous alcohols that can damage the heart, kidneys, and nervous system
Vomiting agents—chemicals that cause nausea and vomiting

Hazardous chemicals by name (A-Z list)

If you know the name of a chemical but aren’t sure what category it would be in, you can look for the chemical by name on the A–Z List of Chemical Agents.

Protecting yourself if you don't know what the chemical is

You could protect yourself during a chemical emergency, even if you didn't know yet what chemical had been released. For general information on protecting yourself, read this Web site's fact sheets on evacuation, sheltering in place, and personal cleaning and disposal of contaminated clothing.

Basic information on chemical emergencies

Basic chemical emergency information designed for the public can be found in the general and chemical-specific fact sheets and in the toxicology FAQs on this Web site.