When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an industrial accident. They could also be planned, as in the case of a terrorist attack with a chemical weapon.

Some hazardous chemicals have been developed by military organizations for use in warfare. Examples are nerve agents such as sarin and VX. Many hazardous chemicals are used in industry - for example, chlorine, ammonia, and benzene. Some can be made from everyday items such as household cleaners.

Although there are no guarantees of safety during a chemical emergency, you can take actions to protect yourself. You should have a disaster plan. Being prepared can help reduce fear, anxiety, and losses. If you do experience a disaster, it is normal to feel stressed. You may need help in finding ways to cope.

What are chemical emergencies?

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.

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 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.

In-depth information on chemical emergencies

Chemical emergency information designed for groups such as first responders, clinicians, laboratorians, and public health practitioners can be found in the case definitions, toxic syndrome descriptions, toxicological profiles, medical management guidelines, emergency response cards, First Responders page, and Laboratory Information page.

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

Some kinds of chemical accidents or attacks, such as a train derailment or a terrorist incident, may make staying put dangerous. In such cases, it may be safer for you to evacuate, or leave the immediate area. You may need to go to an emergency shelter after you leave the immediate area.

How to know if you need to evacuate

You will hear from the local police, emergency coordinators, or government on the radio and/or television emergency broadcast system if you need to evacuate.

If there is a “code red” or “severe” terror alert, you should pay attention to radio and/or television broadcasts so you will know right away if an evacuation order is made for your area.

Every emergency is different and during any emergency people may have to evacuate or to shelter in place depending on where they live.

What to do

Act quickly and follow the instructions of local emergency coordinators, such as law enforcement personnel, fire departments, or local elected leaders. Every situation can be different, so local coordinators could give you special instructions to follow for a particular situation.

Local emergency coordinators may direct people to evacuate homes or offices and go to an emergency shelter. If so, emergency coordinators will tell you how to get to the shelter. If you have children in school, they may be sheltered at the school. You should not try to get to the school if the children are being sheltered there. Transporting them from the school will put them, and you, at increased risk.

The emergency shelter will have most supplies that people need. The emergency coordinators will tell you which supplies to bring with you, but you may also want to prepare a portable supply kit. Be sure to bring any medications you are taking.

If you have time, call a friend or relative in another state to tell them where you are going and that you are safe. Local telephone lines may be jammed in an emergency, so you should plan ahead to have an out-of-state contact with whom to leave messages. If you do not have private transportation, make plans in advance of an emergency to identify people who can give you a ride.

Evacuating and sheltering in this way should keep you safer than if you stayed at home or at your workplace. You will most likely not be in the shelter for more than a few hours. Emergency coordinators will let you know when it is safe to leave the shelter and anything you may need to do to make sure it is safe to re-enter your home.

Some kinds of chemical accidents or attacks may cause you to come in contact with dangerous chemicals. Coming in contact with a dangerous chemical may make it necessary for you to remove and dispose of your clothing right away and then wash yourself. Removing your clothing and washing your body will reduce or remove the chemical so that it is no longer a hazard. This process is called decontamination.

People are decontaminated for two primary reasons:

1. to prevent the chemical from being further absorbed by their body or from spreading on their body, and
2. to prevent the chemical from spreading to other people, including medical personnel, who must handle or who might come in contact with the person who is contaminated with the chemical.

Most chemical agents can penetrate clothing and are absorbed rapidly through the skin. Therefore, the most important and most effective decontamination for any chemical exposure is decontamination done within the first minute or two after exposure.

How to know if you need to wash yourself and dispose of your clothing

In most cases, emergency coordinators will let you know if a dangerous chemical has been released and will tell you what to do.

In general, contact exposure to a chemical in its liquid or solid form may require you to remove your clothing and then thoroughly wash your exposed skin. Exposure to a chemical in its vapor (gas) form generally requires you only to remove your clothing and the source of the toxic vapor.

If you think you have been exposed to a chemical release, but you have not heard from emergency coordinators, you can follow the washing and clothing disposal advice in the next section.

What to do

Act quickly and follow the instructions of local emergency coordinators. Every situation can be different, so local emergency coordinators might have special instructions for you to follow. The three most important things to do if you think you may have been exposed to a dangerous chemical are to (1) quickly remove your clothing, (2) wash yourself, and (3) dispose of your clothing. Here’s how:

• Removing your clothing:
  • Quickly take off clothing that has a chemical on it. Any clothing that has to be pulled over your head should be cut off instead of being pulled over your head.
  • If you are helping other people remove their clothing, try to avoid touching any contaminated areas of clothing, and remove the clothing as quickly as possible.
• Washing yourself:
  • As quickly as possible, wash any chemicals from your skin with large amounts of soap and water. Washing with soap and water will help protect you from any chemicals on your body.
  • If your eyes are burning or your vision is blurred, rinse your eyes with plain water for 10 to 15 minutes. If you wear contacts, remove them and put them with the contaminated clothing. Do not put the contacts back in your eyes (even if they are not disposable contacts). If you wear eyeglasses, wash them with soap and water. You can put your eyeglasses back on after you wash them.
• Disposing of your clothes:
  • After you have washed yourself, place your clothing inside a plastic bag. Avoid touching contaminated areas of the clothing. If you can’t avoid touching contaminated areas, or you aren’t sure where the contaminated areas are, wear rubber gloves or put the clothing in the bag using tongs, tool handles, sticks, or similar objects. Anything that touches the contaminated clothing should also be placed in the bag. If you wear contacts, put them in the plastic bag, too.
  • Seal the bag, and then seal that bag inside another plastic bag. Disposing of your clothing in this way will help protect you and other people from any chemicals that might be on your clothes.
  • When the local or state health department or emergency personnel arrive, tell them what you did with your clothes. The health department or emergency personnel will arrange for further disposal. Do not handle the plastic bags yourself.

After you have removed your clothing, washed yourself, and disposed of your clothing, you should dress in clothing that is not contaminated. Clothing that has been stored in drawers or closets is unlikely to be contaminated, so it would be a good choice for you to wear.

You should avoid coming in contact with other people who may have been exposed but who have not yet changed their clothes or washed. Move away from the area where the chemical was released when emergency coordinators tell you to do so.

What “sheltering in place” means

Some kinds of chemical accidents or attacks may make going outdoors dangerous. Leaving the area might take too long or put you in harm’s way. In such a case it may be safer for you to stay indoors than to go outside.

“Shelter in place” means to make a shelter out of the place you are in. It is a way for you to make the building as safe as possible to protect yourself until help arrives. You should not try to shelter in a vehicle unless you have no other choice. Vehicles are not airtight enough to give you adequate protection from chemicals.

Every emergency is different and during any emergency people may have to evacuate or to shelter in place depending on where they live.

How to prepare to shelter in place

Choose a room in your house or apartment for the shelter. The best room to use for the shelter is a room with as few windows and doors as possible. A large room with a water supply is best—something like a master bedroom that is connected to a bathroom. For most chemical events, this room should be as high in the structure as possible to avoid vapors (gases) that sink. This guideline is different from the sheltering-in-place technique used in tornadoes and other severe weather and for nuclear or radiological events, when the shelter should be low in the home.

You might not be at home if the need to shelter in place ever arises, but if you are at home, the following items, many of which you may already have, would be good to have in your shelter room:

• First aid kit
• Flashlight, battery-powered radio, and extra batteries for both
• A working telephone
• Food and bottled water. Store 1 gallon of water per person in plastic bottles as well as ready-to-eat foods that will keep without refrigeration in the shelter-in-place room. If you do not have bottled water, or if you run out, you can drink water from a toilet tank (not from a toilet bowl). Do not drink water from the tap.
• Duct tape and scissors.
• Towels and plastic sheeting. You may wish to cut your plastic sheeting to fit your windows and doors before any emergency occurs.

How to know if you need to shelter in place

Most likely you will only need to shelter for a few hours.

• If there is a “code red” or “severe” terror alert, you should pay attention to radio and television broadcasts to know right away whether a shelter-in-place alert is announced for your area.
• You will hear from the local police, emergency coordinators, or government on the radio and on television emergency broadcast system if you need to shelter in place.

What to do

Act quickly and follow the instructions of your local emergency coordinators such as law enforcement personnel, fire departments, or local elected leaders. Every situation can be different, so local emergency coordinators might have special instructions for you to follow. In general, do the following:

• Go inside as quickly as possible. Bring any outdoor pets indoors.
• If there is time, shut and lock all outside doors and windows. Locking them may pull the door or window tighter and make a better seal against the chemical. Turn off the air conditioner or heater. Turn off all fans, too. Close the fireplace damper and any other place that air can come in from outside.
• Go in the shelter-in-place room and shut the door.
• Turn on the radio. Keep a telephone close at hand, but don’t use it unless there is a serious emergency.
• Sink and toilet drain traps should have water in them (you can use the sink and toilet as you normally would). If it is necessary to drink water, drink stored water, not water from the tap.
• Tape plastic over any windows in the room. Use duct tape around the windows and doors and make an unbroken seal. Use the tape over any vents into the room and seal any electrical outlets or other openings.
• If you are away from your shelter-in-place location when a chemical event occurs, follow the instructions of emergency coordinators to find the nearest shelter. If your children are at school, they will be sheltered there. Unless you are instructed to do so, do not try to get to the school to bring your children home. Transporting them from the school will put them, and you, at increased risk.
• Listen to the radio for an announcement indicating that it is safe to leave the shelter.
• When you leave the shelter, follow instructions from local emergency coordinators to avoid any contaminants outside. After you come out of the shelter, emergency coordinators may have additional instructions on how to make the rest of the building safe again.

Arsine is the gaseous and the most toxic form of the element, arsenic. It is a nonirritating gas with a mild odor (odorless at low doses) that is used in the semiconductor and metals refining industries. Stibine is a toxic gas that has effects similar to those of arsine, but stibine is not encountered as frequently as arsine. The most likely route of exposure to arsine and stibine is inhalation.

Arsine toxicity is different from arsenic toxicity. Arsine causes massive hemolysis and results in anemia, jaundice, and hemoglobinuric renal failure. The intensity and length of arsine exposure, and the premorbid condition of the person exposed, will contribute to the time of onset and the severity of illness. For example, exposure of a person with underlying coronary artery disease is likely to result in greater morbidity than exposure of a healthy person at the same dose.

The following is a more comprehensive list of signs and symptoms that may be encountered in a person exposed to arsine. Symptoms are not listed in order of presentation or specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

1. General
   • Weakness
   • Malaise
   • Fatigue
   • Fever
2. Gastrointestinal signs and symptoms
   • Nausea
   • Vomiting
   • Abdominal pain
   • Liver injury
3. Central nervous system signs and symptoms
   • Headache
   • Lethargy
   • Convulsions
   • Coma
   • Peripheral neuropathy (1–3 weeks after acute exposure)
   • Neuropsychological symptoms (several days after exposure): memory loss, restlessness, confusion
4. Cardiovascular signs
   • Tachycardia
   • Hypotension
   • ECG changes (repolarization, S-T segment, and T-wave changes)
5. Respiratory signs and symptoms
   • Tachypnea
   • Dyspnea
   • Pulmonary edema
6. Genitourinary signs
   • Hemoglobinuria
   • Oligouria
   • Renal failure
7. Laboratory findings
   • Anemia
   • Elevated bilirubin (indirect)
   • Hyperkalemia
   • Damaged red blood cells (basophilic stippling, anisocytosis, Heinz-Ehrlich bodies)
   • Low haptoglobin
   • Elevated plasma-free hemoglobin levels
   • Elevated urinary hemoglobin
   • Elevated BUN and creatinine
   • Abnormal liver function tests
   • Thrombocytopenia
   • Elevated blood or spot urine arsenic level

Note: The actual clinical manifestations of arsine exposure may be more variable than the syndrome described above.

Differential diagnosis

• Colchicine
• Copper sulfate
• Envenomations (snake or spider)
• Dinitrophenols
• Lead
• Naphthalene
• Phosphine
• Thallium

Vesicants, also referred to as “blister agents,” were the most commonly used chemical warfare agents during World War I. The most likely routes of exposure are inhalation, dermal contact, and ocular contact. Vesicants are highly reactive chemicals that combine with proteins, DNA, and other cellular components to result in cellular changes immediately after exposure.

Depending on the vesicant, clinical effects may occur immediately (as with phosgene oxime or lewisite) or may be delayed for 2 to 24 hours (as with mustards). Following exposure, the most commonly encountered clinical effects include dermal (skin erythema and blistering), respiratory (pharyngitis, cough, dyspnea), ocular (conjunctivitis and burns), and gastrointestinal (nausea and vomiting).

The amount and route of exposure to the vesicant, the type of vesicant, and the premorbid condition of the person exposed will contribute to the time of onset and the severity of illness. For example, ingestion of a vesicant leads to gastrointestinal symptoms more prominent than those that would result from inhalation exposure to the same dose and type of vesicant.

Signs and symptoms

The following is a more comprehensive list of signs and symptoms that may be encountered in a person exposed to a vesicant. Signs and symptoms are not listed in order of presentation or specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

Respiratory signs and symptoms

• Chest tightness
• Clear rhinorrhea
• Cough
• Dyspnea (shortness of breath)
• Hemoptysis
• Nasal irritation/pain
• Sore throat
• Tachypnea

Dermal signs and symptoms

• Blisters (within 1 hour with phosgene oxime, delayed for 2 to 12 hours with lewisite, delayed for 2 to 24 hours with mustards)
• Erythema (immediate with lewisite and phosgene oxime, may be delayed for 2 to 24 hours with mustards)
• Immediate blanching (phosgene oxime)
• Itching
• Necrosis and eschar (over a period of 7 to 10 days)

Ocular signs and symptoms

• Blindness
• Blurred vision
• Corneal ulceration
• Conjunctivitis
• Eyelid edema
• Eye pain/burning
• Lacrimation
• Photophobia

Cardiovascular signs

• Atrioventricular block and cardiac arrest (with high-dose exposure)
• Hypotension (with high-dose exposure to lewisite)

Gastrointestinal signs and symptoms (prominent if ingestion is a route of exposure)

• Abdominal pain
• Diarrhea (sometimes bloody)
• Hematemesis
• Nausea and vomiting

Central nervous system signs and symptoms (with exposure to high doses)

• Ataxia
• Coma
• Convulsions
• Tremors

Hematological signs and symptoms

• Anemia
• Bleeding/hemorrhage
• Bone marrow supression
• Increased susceptibility to infection
• Leukocytopenia
• Thrombocytopenia

Laboratory findings suggestive of vesicant exposure

Although it is a nonspecific finding, leukopenia can indicate vesicant exposure. It usually begins 3 to 5 days after exposure. With a white blood cell count 500, the prognosis is poor.

Differential diagnosis

• Barbiturates
• Bullous pemphigoid
• Chemotherapeutic agents
• Carbon monoxide
• Other chemical burns (such as with strong acids, bases, or corrosives)
• Pemphigus vulgaris
• Stevens-Johnson syndrome
• Staphylococcus scalded skin syndrome
• Toxic epidermal necrolysis

Note: The actual clinical manifestations of a vesicant exposure may be more variable than the syndrome described above.

Nerve agents are chemical warfare agents that have the same mechanism of action as OP organophosphate pesticides insecticides. They are potent inhibitors of acetylcholinesterase . Inhibition of acetylcholinesterase leads , thereby leading to an accumulation of acetylcholine in the central and peripheral nervous system. Excess acetylcholine produces a predictable cholinergic syndrome consisting of copious respiratory and oral secretions, diarrhea and vomiting, sweating, altered mental status, autonomic instability, and generalized weakness that can progress to paralysis and respiratory arrest.

The amount and route of exposure to the nerve agent or OP pesticide, the type of nerve agent or pesticide, and the premorbid condition of the person exposed person will contribute to the time of onset and the severity of illness. For example, inhalation of a nerve agent or an OP pesticide leads to a quicker onset of poisoning with more severe symptoms when compared to with dermal exposure s, given the same amount of agent.

Signs and symptoms

The following is a more comprehensive list of signs and symptoms that may be encountered in a person exposed to a nerve agent or OP pesticide. Signs and symptoms are not listed in order of presentation or specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

Central nervous system signs and symptoms

• Miosis (unilateral or bilateral)
• Headache
• Restlessness
• Convulsions
• Loss of consciousness
• Coma

Respiratory signs and symptoms

• Rhinorrhea (perfuse watery runny nose)
• Bronchorrhea (excessive bronchial secretions)
• Wheezing
• Dyspnea (shortness of breath)
• Chest tightness
• Hyperpnea (increased respiratory rate/depth) – early (increased respiratory rate/depth)
• Bradypnea (decreased respiratory rate) – late (decreased respiratory rate)

Cardiovascular signs resulting from blood loss

• Tachycardia (increased heart rate) – early (increased heart rate)
• Hypertension (high blood pressure) – early (high blood pressure)
• Bradycardia (decreased heart rate) – late (decreased heart rate)
• Hypotension (low blood pressure) – late (low blood pressure)
• Arrhythmias Dysrhythmias (prolonged QT on EKG, ventricular tachycardia)

Gastrointestinal signs and symptoms

• Abdominal pain
• Nausea & and vomiting
• Diarrhea
• Urinary incontinence, frequency

Musculoskeletal signs and symptoms

• Weakness (may progress to paralysis)
• Fasciculations (local or generalized)

Skin and mucous membrane signs and symptoms

• Profuse sweating (local or generalized)
• Lacrimation (tear formation)
• Conjunctival injection

Laboratory finding suggestive of nerve agent poisoning

• Decreased plasma or red blood cell (RBC) cholinesterase activity.

Limitations

• Wide normal range for enzyme activity makes interpretation difficult without a baseline measurement.
• Cholinesterase activity correlates poorly with severity of local effects after vapor exposures.
• Plasma or RBC cholinesterase may be disproportionately inhibited depending on the particular nerve agent, amount of exposure and time interval since exposure.

Interpreting cholinesterase activity

• Plasma cholinesterase
  • usually declines faster than RBC cholinesterase ;
  • is easier to assay than RBC cholinesterase ;
  • regenerates faster than RBC cholinesterase ;
  • may have a day-to-day variation in enzyme activity may be as high as 20% ;
  • is less specific than RBC cholinesterase ; and
  • can show false depression from liver disease, malnutrition, pregnancy, genetic deficiency, or drugs ( e.g., codeine, morphine, cocaine, succinylcholine) .
• Red blood cell cholinesterase
  • is a better reflection of CNS cholinesterase activity ;
  • is more specific test than plasma cholinesterase ;
  • may have a day-to-day variation in enzyme activity may be as high as 10% ; and
  • can show false depression from antimalarial therapy , or pernicious anemia

Differential diagnosis

• Carbamate insecticides
• Medicinal carbamates (eg, pyridostigmine, neostigmine, physostigmine)
• Cholinomimetic compounds (eg, pilocarpine, methacholine, bethanechol)
• Nicotine alkaloids (eg, nicotine, coniine)
• Muscarine-containing mushrooms
• Neuromuscular blocking drugs (eg, atracurim, vecuronium)

Note: The actual clinical manifestations of an exposure to a nerve agent or an organophosphate pesticide may be more variable than the syndrome described in this document.

This toxic syndrome description is based on CDC’s best current information.
It may be updated as new information becomes available.

Ricin and abrin are potent biological toxins that are derived from plant sources (castor beans and rosary peas, respectively). More is known about ricin toxicity; however, abrin toxicity is similar in its mechanism of action. In the body, these toxins inhibit protein synthesis leading to cell death. Clinical manifestations are dependent on the route of exposure. Ingestion typically leads to profuse vomiting and diarrhea followed by multisystem organ failure and possibly death within 36 to 72 hours of exposure. Inhalation typically leads to respiratory distress, fever, and cough followed by the development of pulmonary edema, hypotension, respiratory failure, and possibly death within 36 to 72 hours.

The amount and route of the exposure to ricin or abrin and the premorbid condition of the person exposed will contribute to the time of onset and the severity of illness. For example, the inhalation of ricin or abrin would be expected to lead to a quicker onset of poisoning and to cause a more rapid progression of poisoning compared with the ingestion of either of these toxins, given the same exposure amount.

Signs and symptoms of exposure

The following is a more comprehensive list of signs and symptoms that may be encountered in a person exposed to ricin or abrin. The list does not convey prioritization or indicate specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

Gastrointestinal

• Abdominal pain
• Abnormal liver function tests
• Diarrhea (non-bloody or bloody)
• Multiple ulcerations and hemorrhages of gastric and small-intestinal mucosa on endoscopy
• Vomiting

Respiratory

• Cough
• Chest tightness
• Dyspnea
• Hypoxemia
• Non-cardiogenic pulmonary edema

Skin and mucous membranes

• Redness and pain of eyes and skin

General

• Dehydration
• Fever
• Fatigue
• Muscle pain
• Weakness

Other organs

• Cardiovascular collapse due to hypovolemia
• Convulsions or seizures (uncommon)

Laboratory Findings (non-specific)

• Hematuria
• Increased liver function tests
• Increased renal function tests
• Leukocytosis or increased white blood cell count
• Metabolic acidosis

Note: The actual clinical manifestations of a ricin or abrin exposure may be more variable than the syndrome described above.

Differential diagnosis

Inhalation:

• Exposure to pyrolysis byproducts of organofluorines (Teflon, Kevlar)
• Oxides of nitrogen
• Ozone
• Phosgene
• Staphylococcal enterotoxin B

Ingestion:

• Amatoxin containing mushrooms
• Arsenic
• Caustics
• Colchicine
• Enteric pathogens
• Iron

TOXIC SYNDROME DESCRIPTION

Chloroacetophenone (CN), chlorobenzylidenemalononitrile (CS), chloropicrin (PS), bromobenzylcyanide (CA), dibenzoxazepine (CR), and combinations of these chemicals are irritant agents that belong to a class of agents collectively known as riot control agents or “tear gas”. Of the many tear gas agents used worldwide, CN and CS are the most common. Most exposures are inhalational, ocular, or dermal and typically lead to complaints of eye, nose, and throat irritation; hacking cough; suffocation or choking sensation; and dyspnea. High-dose exposures in an enclosed space which likely occurs only rarely, may lead to the development of airway edema, non-cardiogenic pulmonary edema, and possibly respiratory arrest.

The amount and route of the exposure to tear gas and the premorbid condition of the person exposed will contribute to the time of onset and the severity of illness. For example, given a similar route of exposure, clinical effects may vary from mild to severe, depending on the concentration of tear gas to which a person has been exposed.

The following is a more comprehensive list of signs and symptoms that may be encountered in a person exposed to tear gas. Symptoms are not listed in order of presentation or specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

1. Respiratory signs and symptoms
   • Chest tightness
   • Cough
   • Cyanosis
   • Dyspnea
   • Hoarseness
   • Hypoxemia
   • Non-cardiogenic pulmonary edema
   • Sensation of suffocation
   • Tachypnea
   • Wheezing or rales
2. Skin and mucous membranes
   • Skin: redness, pain, blistering, and burns
   • Ocular: lacrimation, ocular irritation and redness, blurred vision, corneal burns
   • Nasal: rhinorrhea, burning, irritation, edema
   • Oropharynx: oral burns and irritation, sore throat, hoarseness, dysphagia, salivation

Note: The actual clinical manifestations of tear gas exposure may be more variable than the syndrome described above.

Differential diagnosis

• Ammonia
• Chlorine
• Hydrogen chloride
• Hydrogen sulfide
• Nickel carbonyl
• Phosgene
• Sodium azide
• Sulfuric acid