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Chemical Suicides: The Risk to Emergency Responders


A relatively new approach to suicide - using toxic gases generated by the combination of consumer products or common household chemicals - has become more prevalent in recent years. The vapors, especially when trapped in an enclosed space, may exist in concentrations that can be hazardous to first responders and others.

This page describes:

  • The most common approaches and types of consumer products and chemicals used

  • The signs to look for at the event scene and the hazards emergency responders may encounter

  • Response considerations that first responders must be aware of

New overview:

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Common Approaches and Chemicals

Chemical suicides, also called detergent suicides, involve self-inflicted exposure to toxic gases in a confined space (for example, cars, bathrooms, or closets), gases created by mixing consumer products or common household chemicals. This technique appears to have originated in Japan and has since become an increasingly popular method for suicide in the United States and elsewhere after instructions became available online. The two most common toxic gases produced are hydrogen sulfide and hydrogen cyanide.

Hydrogen Sulfide

Hydrogen sulfide is the most common toxic gas used in chemical suicides, because it can be easily created using some readily available consumer products. Cleaning products that contain acids (such as muriatic or hydrochloric acid) can be mixed with compounds that contain sulfur (such as pesticides and insecticides) to generate hydrogen sulfide.

Hydrogen sulfide gas is an asphyxiant that suffocates victims at the cellular level, rendering cells in the body unable to use oxygen:

  • At 100 parts per million (ppm), it is Immediately Dangerous to Life or Health (IDLH).

  • As little as 400 ppm can cause unconsciousness.

  • At 1,000 ppm, victims immediately suffer cardiopulmonary arrest.

For incidents involving the release of hydrogen sulfide gas, the 2016 Emergency Response Guidebook (ERG) suggests an initial isolation distance of 100 feet for a small spill or release of gas and a protective action distance of 0.1 miles (during the day) and 0.3 miles (at night).

The effects and symptoms begin to show almost immediately after exposure begins. At low concentrations, hydrogen sulfide can be easily detected because of its unusual, rotten egg odor. At higher concentrations, the odor might not be detected at all, because hydrogen sulfide paralyzes the olfactory nerve and deadens the sense of smell.

Symptoms can include:

  • Respiratory irritation

  • Coughing

  • Nausea

  • Vomiting

  • Headaches

  • Disorientation

  • Tremors

  • Suffocation

  • Coma

  • Death

Once the toxicant reaches the brain, successful rescue is unlikely because breathing is rapidly and severely affected.

Hydrogen Cyanide

Another toxic gas used in chemical suicides is hydrogen cyanide, though it is not as common because the consumer products needed for the reaction are less readily available. Hydrogen cyanide gas is created using an acid source and cyanide salts such as sodium cyanide or potassium cyanide.

Hydrogen cyanide is more easily absorbed through contact with mucous membranes, eyes, and skin. The effects and symptoms of hydrogen cyanide poisoning are similar to those caused by hydrogen sulfide:

  • The IDLH for hydrogen cyanide gas is 50 ppm.

  • Inhalation of 135 ppm for 30 minutes is fatal.

  • Inhalation of 270 ppm is immediately fatal.

For incidents involving the release of hydrogen cyanide gas, the ERG suggests an initial isolation distance of 200 feet for a small spill or release of gas and a protective action distance of 0.1 miles (during the day) and 0.4 miles (at night).

Hydrogen cyanide has a distinctive bitter almond odor. Like hydrogen sulfide, stronger concentrations of hydrogen cyanide deaden the sense of smell.

Early symptoms of exposure associated with lower doses include:

  • Restlessness

  • Increased respiratory rate

  • Giddiness

  • Headache

  • Palpitation

  • Difficulty breathing

Symptoms that may develop later with lower doses or acutely with higher doses include:

  • Vomiting

  • Convulsions

  • Respiratory failure

  • Arrhythmias

  • Unconsciousness

  • Death

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Recognizing Chemical Suicides

Care should always be taken at the scene of a chemical suicide because of the possibility of residual airborne material.

Indicators of a chemical suicide include:

  • A confined space (e.g., a car or room with closed doors and windows)

  • Tape or plastic covering the vents and windows

  • A victim showing no signs of trauma

  • Signs or placards posted by the victim warning of toxic gas

  • A suicide note

  • Empty cleaning supply, pesticide, or paint containers

  • Odors such as rotten eggs or bitter almonds

  • Other victims near the area complaining of symptoms such as difficulty breathing

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Responding to Chemical Suicides

Chemical suicides can pose a great danger to responders and bystanders because a cloud of toxic gas may remain at the scene (confined space), waiting to be released as a door or window is opened. The materials used in the suicide may continue to off-gas for an extended period of time after initial generation, and toxic gases may remain in the victim's lungs, clothing, or in the confined space. These gases are lethal at low concentrations and often can't be easily detected.

If a chemical suicide is suspected, first responders should follow local response guidelines, take precautions, and wear proper personal protective equipment (PPE) and self-contained breathing apparatus (SCBA). The event should be treated as:

  • A HAZMAT event, with assistance requested from a HAZMAT team

  • A crime, with assistance requested from law enforcement to preserve the crime scene

When responding to chemical suicides, you should:

  • Size up the event scene

  • Secure the area

  • Ventilate the confined space

  • Monitor the air for toxic gases

  • Decontaminate those who have been exposed

  • Initiate rescue and recovery operations

  • Protect evidence and prepare for a criminal investigation

  • Consider additional risks

Sizing Up the Event Scene

During the initial on-scene size-up, look for indicators of chemical suicide (listed above) to determine if a hazardous material might be involved.

Securing the Area

Consider securing the area by evacuating or sheltering everyone nearby. The decision to evacuate or shelter in place can be based on local protocol and factors such as:

  • Chemical concentration

  • Population size

  • Whether the contamination occurred indoors or outdoors

  • The structure, size, and characteristics of the confined space

  • Wind speed and direction

Remember to stay upwind of HAZMAT releases.

Ventilating the Confined Space

Once the area is secure and a thorough analysis of potential hazards has been conducted, ventilation can occur. Only properly trained and equipped first responders should manage ventilation activities.

Monitoring the Air

Use air monitoring equipment to determine if toxic gases are present at the scene. Monitor the air throughout the event until the scene is safe.

Decontaminating Those Who Have Been Exposed

Ensure that all entry team members and others who were potentially contaminated undergo decontamination in accordance with local protocols. Contaminated clothing should be removed and double bagged before people who have been exposed are transported to the hospital. Notify emergency medical service personnel and the hospital in advance of the HAZMAT situation to avoid further contamination.

Initiating Rescue and Recovery

Determine if the victim is responsive (conscious or unconscious). If victims are breathing, remove them from the confined space and get them to fresh air.

Remember that the victim and items inside the confined space may be contaminated and off-gassing, so wear appropriate PPE before attempting to intervene. Avoid mouth-to-mouth resuscitation because the victim's exhalations may contain toxic gases. Decontaminate the victim before leaving the scene. Make sure transport vehicles are well vented to prevent additional contamination of rescuers and bystanders.

Protecting Evidence and Preparing for a Criminal Investigation

Chemical suicides are considered crimes. Once life safety considerations have been addressed, treat the event scene as a crime scene.

Considering Additional Risks

Remember that you are dealing with a crime scene - a malevolent act rather than an accident - and that things may not be as they seem. Be alert for additional risks that may not be immediately apparent:

  • There may be untriggered devices that could explode or release additional hazardous substances if disturbed.

  • The event may be a homicide rather than a suicide and a perpetrator may still be in the area. The perpetrator may represent a threat to responders or may be prepared to trigger additional devices - for instance, to prevent access to the victim.

  • The event may have been staged to lure responders into a hazard zone where they can be attacked, either with additional chemical releases (booby traps) or through other means.

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Additional Resources

Video Training

Example of Scenes, Container, Placards, and Signs

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Other References

  1. Chemical Assisted Suicide: Responder Information (PDF - 198 KB) (HAZMAT FC)

  2. Chemical Suicides: A New Threat for Responders (Firefighters Support Foundation)

  3. Chemical Suicides in Automobiles (CDC)

  4. Chemical Suicides: Identification Guide for 911 Communications (PDF - 1094 KB) (Central Florida Intelligence Exchange)

  5. Hydrogen Cyanide (Organisation for the Prohibition of Chemical Weapons)

  6. Hydrogen Sulfide Suicide Trend: Firsft Responder Safety Update (PDF - 1114 KB) (Central Florida Intelligence Exchange)

  7. Chemical Assisted Suicide (PDF - 503 KB) (Homeland Security Digital Library)

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