The Hazmat Suicides

When you see a person down in a car, not breathing, your first instinct is to get him or her out of there. That instinct can prove deadly if followed, especially by someone who doesn't know how to protect himself.

No, this isn't the name of the new Agatha Christie murder mystery. It's the phenomenon that has firefighters, police departments, and paramedics all on their toes. The culprits? Common bath chemicals and salts that can be found in any hardware store. The murder weapon? Hydrogen sulfide.

All over the country, hydrogen sulfide is replacing carbon monoxide as the silent killer of choice in suicide. It began in Japan in 2008 as a dangerous trend that swept the country. More than 500 men and women took their own lives by mixing an acid with a sulfide -- we won't mention exactly which chemicals in this article -- in their sealed cars. Had the trend been confined to that island country, it would be of less concern here. But in this Internet day and age, the trend spread to the United States, as well, as instruction manuals online shared all of the grisly details.

Suicide websites and newsgroups are all over the Internet, where those contemplating taking their own lives exchange tips and information on different methods of doing so. Hydrogen sulfide, a gas previously relegated to conversations involving sewers and refineries, is becoming popular.

Unsafe Levels of H2S

Hydrogen sulfide is a colorless gas with a distinct smell of rotten eggs at the low ppm range. According to Dennis Patrick, CIH, CHMM, CSP, the lowest detectable range by the human nose is 5 to 15 ppb. (Yes, that's a B for billion, so remember you can probably smell it before your gas detector will pick it up, because portable detectors usually operate in the ppm range.) However, the olfactory fatigue rate is so quick that in many cases, a person might think the gas is gone, when in reality it increased in concentration.

Around 40 ppm, you're looking at headaches and fatigue in the short term and memory loss and balance trouble with longer exposures. At 50 to 400 ppm, permanent damage is almost assured. The list includes coughing, vertigo, nausea and vomiting, cardiac arrhythmias, and loss of consciousness. Above 700 ppm, a single breath or two is all that is needed to take you down permanently. Needless to say, H2S is not my favorite gas with which to work.

Whereas in most cases of suicide the victim takes no one with him or her, hydrogen sulfide suicide is dangerous to others, especially first responder teams. A number of the suicides in Japan involved people using their bathroom showers as gas chambers. Unfortunately, bathrooms aren't air-tight, and a number of people in those apartment complexes had to be rushed to the hospital.

When mixed in a car, the chemicals keep mixing and producing poison gas even after the death of the person involved. This gas stays in the car, lying in wait for the first unfortunate person who pulls the door open or breaks a window. Levels as high as three times the lethal limit have been reported by hazmat teams responding to such calls.

Precautions for Emergency Responders
How can you know an unconscious person in a car is not a danger to a good Samaritan? The Joint Regional Intelligence Center issued a bulletin ( in March 2010 about the problem. Titled "Hazards Posed to First Responders by Hydrogen Sulfide Suicides," the bulletin goes over recent suicides and gives a look at the chemicals found inside a suicide vehicle.

These items are commonalities cited:

1. A note. For the most part, at least at this time, many committing suicide have been concerned enough about those around them that they post warnings. These may read, "HAZMAT TEAM NEEDED" or "DANGER: HYDROGEN SULFIDE." While a note is certainly a good first clue on approach, the lack of a note obviously does not declare the situation safe.

2. Buckets. The chemicals need a place to mix and aerate, and they want the most possible surface-to-volume ratio to do so. Large plastic buckets are usually a good sign that something untoward has occurred within the car.

3. The smell. Hydrogen sulfide has a rotten eggs smell that will pervade the area. If you notice a smell while approaching the car, keep back because the closer to the car you come, the more hydrogen sulfide gas to which you will be exposed.

4. Taped windows. Knowing that air can escape through the window cracks, the suicide cases in many cases have come with duct tape over the windows to ensure ventilation is at a minimum. This keeps the gas from escaping and results in extremely high levels of hydrogen sulfide in the air.

5. Fogged windows. Foggy windows are a sign for more than teenage activity. Making hydrogen sulfide uses wet chemistry, and this leaves filmy traces of fog on the windows. If you see someone unconscious alone with the windows fogged, be careful.

The problem is one of education and overcoming your natural instincts. When you see a person down in a car, not breathing, your first instinct is to get him or her out of there. That instinct can prove deadly if followed, especially by someone who doesn't know how to protect himself.

But how can you protect yourself from this dangerous gas? The first and best way is to just get out of there and call in the hazmat team. Don't try to help in any direct fashion except by calling 911 and explaining what you're seeing and that it may be a hazmat situation. Hydrogen sulfide is a dangerous gas, and unless you have a level A suit lying around next to an SCBA and a gas detector, it’s a bad idea to go anywhere near that car.

Some things in life are better left to the professionals. Leave murders to Nero Wolfe, leave fighting injustice to the Shadow, and leave a hydrogen sulfide suicide to the local hazmat team.

This article originally appeared in the July 2010 issue of Occupational Health & Safety.

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