Public Intelligence

Daily Intelligence Notes

• 1 page
• For Official Use Only
• March 31, 2010

Officer Safety Alert: Hydrogen Sulfide Suicide Method

(U/FOUO) The Statewide Terrorism & Intelligence Center (STIC) has previously reported on an emerging suicide method in which two chemicals are mixed, producing Hydrogen sulfide (H2S), a colorless, flammable gas with a distinct odor similar to rotten eggs. This method is increasing in popularity and is not geographically isolated.

(U/FOUO) Typically, the victim will mix the two chemicals in a container while sitting in a closed automobile, parked in a public place. Most suicides using this method have warned responders to the dangers of H2S by posting signs in the interior of the automobile.1 In one recent case in North Carolina, however, the signs were not posted.

(U/FOUO) The method is believed to have originated in Japan3, where more than 800 suicides using this method were committed in 2009. In the U. S., the method is not as widely used, with fewer than 20 cases
reported in the last 12 months, but it is increasing in popularity. Most H2S suicides have occurred on the East and West Coasts, however, a recent case near Kansas City, Missouri, illustrates it is spreading to the center of the country.

(U/FOUO) There is no set formula for this method. The general “recipe” calls for some type of strong acid to be mixed with a product containing calcium polysulfide. Many internet sources cite brand names for either agent necessary for the method. One source states that if two liters of each agent are rapidly mixed in an enclosed space, a lethal concentration of 1000 parts per million will quickly be generated. H2S is covered in the 2008 edition of the Emergency Response Guidebook under Guide Number 117 and ID Number 1053.

(U/FOUO) Analyst Note: Members of law enforcement, first responders and private sector security should exercise caution when approaching a vehicle or a building where the potential for hazardous materials could reside. When in doubt, contact your local HazMat Team for assistance. Members of the private sector are asked to contact local law enforcement to report suspicious activity. Members of law enforcement are encouraged to contact STIC at 877-455-7842 or STIC@isp.state.il.us, to report suspicious activity.