By Jacob Oreshan
Chemical suicides have plagued the United States since 2008 and continue to be on the rise. This method of suicide originated in Japan in 2007, where authorities have seen more than 2000 such cases. Chemical suicide, sometimes called detergent suicide, involves mixing common household chemicals to create deadly hydrogen sulfide (H2S) gas, which can quickly reach lethal concentrations in confined spaces. In 2008, first responders in the United States responded to three incidents; in 2009, there were nine incidents, in 2010, there were more than 30 incidents; in 2011, there were 44 incidents; and in 2012, there were more than 45 incidents. It is important to realize that analysts believe these cases are drastically underreported in the United States at this time.
Hydrogen sulfide, H2S, is a colorless gas that has a strong odor of rotten eggs or sulfur associated with it. It is extremely toxic by inhalation, posing a large risk to first responders who do not wear proper respiratory protection when dealing with it or who are unaware of its presence. H2S is an olfactory nerve paralyzer, meaning it will rapidly fatigue the sense of smell, even when present in low concentrations. Overall, 25% of the deaths associated with hydrogen sulfide gas occur in rescuers, first responders, bystanders, or professionals who deal with it on a regular or routine basis. However, when discussing chemical suicides, there have been no deaths to first responders to date.
Hydrogen sulfide has a vapor density of 1.19, making it heavier than air. As first responders monitor the atmosphere when they approach the space where a suspected chemical suicide has occurred, they can expect to find vapors lower to the ground. However, once they enter the space or begin air monitoring within the space, it can be expected that diffusion will have occurred and they will find the space completely filled with vapors. Vapors may be knocked down with a water spray if it is felt that that is the best course of action for the incident; however, all runoff created should be contained and disposed of properly as it will be toxic and corrosive.
Hydrogen sulfide is made by mixing hydrochloric acid with a sulfur-containing compound (in a high enough concentration to react with the hydrochloric acid). In many cases, the two chemicals mixed have been hydrochloric acid and lime sulfur. Lime sulfur (Bonide) is a 28% solution of calcium polysulfide. Both products are easy to obtain and can be purchased at a local hardware, grocery, or big box store. Approximately ½ cup of each product will produce about 1,000 ppm H2S inside the passenger compartment of a vehicle or other small confined space (approximately 3,500 cubic feet). The individuals who have mixed these chemicals have been mixing several containers of each product, not increasing the concentration of gas produced but increasing the volume of gas produced. As one of the chemicals being mixed is an acid and the other a base, a mildly exothermic, somewhat violent reaction can be expected. Because of this, evidence that the reaction has occurred may be visible from outside of the confined space.
Personal protective equipment used for dealing with chemical suicide incidents involving hydrogen sulfide should be adequate and appropriate for the degree and type of contamination encountered. Each incident will be slightly different and PPE needed will vary according to the incident. As the IDLH threshold for hydrogen sulfide is 100 ppm, self-contained breathing apparatus must be used. Chemical protective clothing is not necessary and is not generally recommended for dealing with hydrogen sulfide gas. Hydrogen sulfide poses a minimal risk through cutaneous absorption and also a minimal risk of secondary contamination by first responders. Structural firefighting turnout gear or Tyvek suits will provide adequate skin protection for dealing with hydrogen sulfide gas.
By DOT definition, hydrogen sulfide meets the criteria to be considered a flammable gas, as the flammable range is 4.3 % – 45%. The autoignition temperature is 500 degrees Fahrenheit. However, in these particular situations, the flammability risk is fairly low. To ensure first responder safety, all ignition sources should be eliminated to reduce the flammability risk. A charged handline should be made ready in case a source of ignition is found. The vapors in the space should be ventilated properly once all precautions have been taken to safely do so.
Decontamination for first responders should be set up appropriately for the degree of contamination encountered at the scene. A full technical decontamination setup may not be necessary, or appropriate, for the incident. At minimum, skin should be washed with water for three to five minutes. If eyes or skin appear to be irritated, continue to flush with water during medical observation and transport to a nearby medical facility.
Contamination for victims of chemical suicides will be more acute and decontamination will require more time and attention. All clothing should be removed and double bagged. Decontaminate the body as dictated per normal standard operating procedures or guidelines. Victims may off-gas from their lungs after they have been deceased for a significant period of time. This may pose a risk for those transporting victims and those performing autopsies. Body bags are recommended for transporting victims only if they must be transported in an enclosed vehicle in which they will be occupying the same space as the driver. The best option for moving a victim of chemical suicide would be to wrap them in sheets and tarps, then transport in an “open” vehicle such as an official pickup truck (i.e., one belonging to the local police/sheriff’s department, fire department vehicle, etc.). Protocols should be established in a preplan prior to an incident occurring. These protocols should be written with the involvement of the county coroner’s office, local hospital in which a contaminated victim may be transported to, and local transporting agencies.
Hydrogen sulfide will act as a mucous membrane and respiratory tract irritant. In extremely high concentrations, it may also act as a skin irritant. Low concentrations would be considered anything below 50 ppm. Symptomatology associated with exposure to low concentrations would be irritation of the eyes, nose, and throat. Symptomatology associated with higher concentrations is much more severe and will target different body systems. Central nervous systems stimulation (excitation, rapid breathing, and headache) will precede central nervous system depression (impaired gait, dizziness, respiratory paralysis, and death). Exposure to high concentrations of H2S may also cause an accumulation of fluid in the lungs. This may be an immediate symptom or delayed up to 72 hours.
Treatment for those exposed to hydrogen sulfide mainly involves supporting cardiovascular and respiratory functions. Nitrite therapy has been recommended as a therapy for hydrogen sulfide exposure. Amyl nitrite should be given by inhalation for 30 seconds every minute until an intravenous line can be established. This should be followed by administration of intravenous sodium nitrite. This may aid recovery by forming sulfmethemoglobin, thus removing sulfide from combination in tissue. This treatment is only recommended if it can be started shortly after exposure and if it can be started without interfering with the establishment of adequate ventilation and oxygenation procedures.
Hydrogen sulfide has a rate of decay that ranges from 12-37 hours. This will be dependent on ambient air temperature. The colder the ambient air temperature, the longer the rate of decay will be. The warmer the ambient air temperature, the shorter the rate of decay.
Hydrogen cyanide, HCN, is a colorless gas or a bluish-white liquid that may have an odor associated with bitter or burnt almonds. Approximately 20-40% of the population cannot make the odor association due to a genetic trait. HCN will rapidly fatigue the olfactory senses for those that can detect the odor. It is extremely toxic by inhalation, skin absorption, and ingestion. HCN is considered a blood agent when used as a chemical weapon.
Cyanide poisoning is marked by abrupt onset of profound and dramatic symptoms. Symptomatology associated with exposure to lower concentrations (25-50 ppm) of hydrogen cyanide may be eye irritation, headache, nausea, and vomiting. Symptomatology associated with exposure to higher concentrations may include syncope, seizures, coma, gasping respirations, and cardiovascular collapse. Central nervous systems symptoms may vary and include but are not limited to excitement, dizziness, nausea, vomiting, headache, weakness, drowsiness, lockjaw, convulsions, hallucinations, loss of consciousness, and death. Respiratory symptoms are progressive and include but are not limited to shortness of breath, chest tightness, rapid breathing, increased depth of respirations, slowing of respirations, gasping, and respiratory arrest. In cases involving cyanide, NEVER attempt resuscitation without a barrier in place.
Treatment involves providing patients with 100% oxygen with the administration of specific antidote kits. The Cyanide Antidote Kit contains amyl nitrate, sodium nitrate, and sodium thiosulfate. The sodium nitrate followed by the sodium thiosulfate, injected intravenously, is capable of detoxifying one lethal dose of sodium cyanide and may be effective after respiration has stopped, as long as the heart is still beating. The Cyanokit is another cyanide antidote treatment available. The active ingredient in this kit is hydroxocobalamin. This forms a strong bond with the cyanide, forming a nontoxic cyanocobalamin, another form of B12, which is then safely excreted in the urine. No medications should be administered without direct orders from a doctor who has been notified of the victim’s current status.
Instructions for chemical suicides are readily available on the Internet. Most sites encourage anyone planning to use this method to provide appropriate warnings about the presence of the deadly gas to people who might respond to the suicide. Newer versions of Internet instructions provide very explicit information on how to make and generate hydrogen sulfide gas. Premade signs continue to be available as well. The easily recognizable incidents will have signs posted in the vehicle windows or inside the structure, as is the case 90% of the time. There are, however, the not so easily recognizable incidents where there are no signs and little in the way of clues. This is why we need to have a heightened sense of awareness.
In several incidents, individuals manufactured hydrogen cyanide (HCN) instead of hydrogen sulfide. These instances of hydrogen cyanide are rare because the chemicals needed for the reaction are not as readily available as chemicals used to make hydrogen sulfide.
Responders must do a thorough scene safety check before attempting to enter/open a vehicle with unresponsive patients. It is recommended that the responders observe a “10 seconds to save your life” rule. Responders should take an extra 10 seconds during size-up to peer into the vehicle and look for pails, buckets, or other mixing vessels in the front or rear seats; containers of acids and pesticides; a yellow or green residue in the vehicle; and vents that may be taped off. If the incident occurs in a structure, such as an outbuilding or other contained area, there may not be any written warnings present. Responders need to be extremely cautious when investigating suspicious odor calls inside a structure.
Currently, in the United States, the use of hydrogen sulfide or hydrogen cyanide has been limited to individual suicides. Approximately a half a cup of an acid-containing product and a half cup of a sulfur-containing product will generate enough gas to fill a standard four-door sedan with more than 1,000 ppm hydrogen sulfide gas. Most individuals are mixing several gallons inside their vehicles, generating an incredibly lethal atmosphere in a matter of seconds that will linger for several hours.
There is the potential for chemical suicide incidents to occur at middle and high schools. Intelligence obtained from Internet chat sites indicates a shift to younger and younger individuals interested in information on this method for committing suicide. There is concern that there will be a shift to the “suicide pact” method, as has been seen in the United Kingdom. It is possible that two or three students may make their way to the school parking lot and commit suicide using the hydrogen sulfide method.
The National HazMat Fusion Center has established best practice guidelines for a response to a chemical suicide incident. The information is available in a flowchart and may be downloaded from the Web site www.hazmatfc.com. It is recommended the flowchart be laminated and placed in all response vehicles.
BIO:
Jacob Oreshan III is a deputy chief with the New York State Office of Fire Prevention and Control, Special Operations Branch. He is a National Certified Firefighter and Hazardous Materials Technician. He has been a firefighter for 26 years, the past 11 with New York State Fire.
