*** Trigger Warning: This article discusses the topic of Chemical Assisted Suicide. We acknowledge the content in this article may be difficult or triggering for some. If you or someone you know is suicidal, please, contact your physician, go to your local ER, or call the suicide prevention hotline at 800-273-TALK (8255), or message the Crisis Text Line at 741741. Both programs provide free, confidential support 24/7.***


Chemical Assisted Suicide: Responder Information for our field personnel

Problem: There is no longer a routine call. Recognize that every response is unique and should be treated as such. Always wear proper PPE and SCBA.

Mixing household chemicals to create toxic vapors:

  • Look for and recognize containers that may indicate presence of common household chemicals

In most cases, two (or more) chemicals will be mixed to produce vapors.

Analyze the Problem

Recognition/ID and Warning Signs:

  • Open containers or a ‘mixing container’. Chemicals may not be properly marked/labeled
  • Do NOT rely on suicide notes or placards near the entry pathway for first responders which warn of danger
  • Open containers or household chemicals where they would not normally be found (vehicles, bedrooms, etc.)
  • Taping of doors, windows, dash vents, openings or other attempts to seal the enclosure
  • Locations: Vehicles and Structures:
  • If this is a chemical suicide remember it is a crime scene and needs to be treated as such
  • Look for indicators in the surrounding area and question occupants. After analysis, vehicles and structures can be ventilated. Do NOT rely on presence or lack of chemical/unusual odors. Be aware of contact with liquids or powders and provide decontamination for occupants and responders.

Plan the Response

Take time to look into the vehicle for signs of a suicide (mixing vessels, residue, containers)

Response Options:

  • Rescue/Recovery
  • Evacuation/Isolation
  • Protective handline
  • Decontamination
  • Preserve evidence

Selection of PPE:

  • Follow FCE FOG for proper PPE and respiratory protection selection

Obtain control of air monitoring equipment

Selection of Decontamination

  • Technical decontamination should be established for entry teams conducting control tasks

Plan of Action

  • Use a Risk Based Response control plan
  • Vehicle vs. Structure
  • Compartment size will/can play a role in the levels of concentration, resulting in varying levels
  • The smaller the compartment the higher the concentration -> higher toxic levels and potential to reach LEL levels
  • Ventilate all occupancies to change the concentration levels of the environment
  • Open the doors to vent

Implement the Plan

Fire Department Handline (vapor disbursement or extinguishment)

  • Vapor Disbursement – Use water spray to reduce vapors or divert vapor cloud drift. Make sure to control and isolate runoff
  • Extinguishment – May form explosive mixtures with air. May be ignited by heat, sparks or flames

Ventilation/Change the Environment – Properly trained and equipped first responders should ventilate after a thorough analysis of potential hazards

Air monitoring – Should be conducted throughout the incident and until evidence has been collected

Decontamination – All entry team members should undergo a technical decon. Beware of potential for occupants and clothing to ‘off-gas’ trapped vapors. EMS and the hospital must be notified in advance in order to avoid contamination of personnel/equipment

Crime scene considerations – Minimize responder exposure while preserving evidence


  • Maintain Situational Awareness – Don’t count on warning signs. Be aware of secondary contamination

Hydrogen Sulfide

Description Colorless gas Odor threshold 0.77 ppm
Molecular formula H₂S Odor description Rotten egg
Molecular weight 34.08 Exposure route Inhalation
Density 1.19 (≈ 20% heavier than air) Signs & symptoms Irritation of respiratory system
& eyes, apnea, coma
Auto ignition temperature 260°C (500°F) LEL/UEL 4%, 44%
Vapor pressure 15, 600 mm Hg @ 25°C (77°F) IDLH 100 ppm
Solubility Soluble in water, hydrocarbon
solvents, ether and ethanol
Detection PID with 10.6 eV lamp
Notes Death by inhalation can occur
quickly at low levels


Hydrogen Cyanide

Description Bluish-white liquid/colorless gas Odor threshold 0.58 ppm
Molecular formula HCN Odor description Bitter almond (odor may not be
detected by smell)
Molecular weight 27.03 Exposure route Inhalation, absorption
Density 0.94 (lighter than air) Signs & symptoms Respiration/depth change,
confusion, asphyxia
Auto ignition temperature 538°C (1000°F) LEL/UEL 5.6%, 40%
Vapor pressure 630 mm Hg @ 20°C (68°F) IDLH 50 ppm
Solubility Miscible in water, alcohol,
slightly soluble in ether
Detection PID with 13.6 eV lamp
Notes Death by inhalation can occur
quickly at low levels