A year ago we wrote about a death of a San Jose teenager from poisoning by hydrogen sulfide gas, or H2S. At the time, I had hypothesized that the death might have been from an attempt at synthesizing methamphetamine gone awry.
But while one can mistakenly generate hydrogen sulfide gas from improper meth synthesis, I soon learned that intentional suicides with H2S is an increasing US trend imported from Japan. One can easily mix commonly-available consumer products to generate the gas and high enough concentrations can cause death. The gas acts in a manner similar to cyanide by binding to the heme in cytochrome c oxidase and inhibiting electron transport and ATP production by oxidative phosphorylation in the mitochondria. (Interestingly, small amounts of H2S are made in the body and is being investigated as a neurotransmitter and biological modulator.)
So deadly is hydrogen sulfide that it is considered a major occupational safety hazard for workers in municipal sewage services, industrial manure management on factory farms, and the growing aquaculture industry - the US National Oceanographic and Atmospheric administration provides detailed background and training videos here.
Now we can add first-responders like EMTs to that list. Pulitzer Prize-winning author Deborah Blum alerted me to an article in The Tampa Tribune about hazards to emergency personnel responding to "detergent suicide" attempts. (By the way, Blum just released her new book, "The Poisoner's Handbook: Murder and the Birth of Forensic Medicine in Jazz Age New York," and writes the beautifully-designed Speakeasy Science blog about culture and chemistry.)
This past Monday a 30-year-old Cary, NC, man committed suicide with hydrogen sulfide by mixing chemicals in a 5-gallon bucket inside his Toyota Camry. The gentleman was well-aware of the risk he posed to those who would find him there. As detailed in the WTVD-TV report embedded below, the man was found slumped over the wheel of his car in his apartment complex parking lot but had left warning signs on the dashboard and seats that read, "HAZMAT TEAM NEEDED" and "DO NOT OPEN!!! POISON GAS!!! Hydrogen sulfide."
I went back and re-read The Tampa Tribune article and learned that the 23-year-old man who committed suicide similarly in St. Petersburg, FL, over Valentine's Day weekend had also left similar warning notes in his car.
But in the event readers and emergency personnel see unconscious people inside parked vehicles without warning notes, be aware of the telltale smell of hydrogen sulfide: intense, rotten eggs. In the Cary case, authorities measure hydrogen sulfide gas in the car at three times the lethal concentration and a police officer responding in the St. Petersburg case had to be treated at the hospital after inhaling some of the gas.
I am deeply saddened by these stories because these people felt so badly about themselves so as to end their lives, yet they were compassionate enough to think about the welfare of those who would face risks finding them there.
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They might not have felt so badly about themselves. They may just have felt that badly about their lives.
Or actually, in the case of clinical depression, they may have just felt that badly full stop. It was that one day when they didn't decide to go on living when they got up.
Interesting indeed!
What does "biological modulator" mean?
"When you can smell HCN, it's almost too late. H2S is only dangerous when you can't smell it anymore."
-- highschool chemistry teacher
The warning notes were also a hallmark of the detergent suicide wave here in Japan. Sadly, most people chose to kill themselves in their apartment bathrooms - not really the most airtight of places. Lots of these tragedies ended up hurting, and even killing their families and neighbors.
There is some evidence that H2S signaling might be even more important than NO signaling. The research on this is very incomplete, but proteins have a great many thiol groups and virtually every transition metal is held in proteins by thiols. Iron in heme is the only exception I can think of, and there are plenty of proteins where iron is held by thiols.
A survival class I took many years ago included the lesson: "when you see a man down, first try to figure out what got him before rushing in." The instructor said to look for power lines, or the possibility of gas or sniper fire.
In regards to the rotten egg smell, if the smell goes away that doesn't mean the gas has all of a sudden dissipated, it's the first sign of hydrogen sulfide poisoning - loss off smell.
H2S can also be problematic in some natural gas exploration / exploitation.
I second Mu's comment. I had to take H2S Alive certification before doing bioinventory around gas pipelines in northern British Columbia in 2008. The trainer emphasized just because you no longer smell the rotten eggs does not mean you are safe--it may mean that it has knocked out your sense of smell. Then, of course, we got all the gory details of what happened to people who didn't follow protocol when the gas alarms sounded.
As an aside, we arrived at one of our sites to do a survey at 4:00 a.m. but we had to wait till it stopped raining so we just napped in our trucks. About 6 a.m. the pumping station alarm up the road went off. We looked back, saw the windsock was indicating slight wind in our direction, we were sitting in bit of a dip in the road----and we were wide awake and accelerating down the road within seconds. No idea if it was a test, a false alarm or a real leak, but after the training we weren't waiting around to sniff the air (no-one appeared to be at the station--no trucks, no people running for their lives, just an alarm going off).
Strange stuff.. I wonder why they chose H2S? Is it a less painful way to die?
BTW, your embed code isn't working in my FireFox browser.
I just had a thought on self-injury. Oxyhemoglobin is the sink for NO, and when there is acute anemia from blood loss, NO levels go up. At steady state the NO production rate equals the destruction rate and the reaction is first order in both NO and oxyhemoglobin, so it is their product that remains constant.
Donating blood is a good way to reduce one's hemoglobin level and produce a temporary increase in NO levels. That might be something that someone who has an urge to hurt themselves might try first, donating blood.
That's pretty dangerous stuff to end a life. Especially if you find the chemicals still floating around. Makes me think if they're trying to cheat death. If they survived that would be interesting.
How sickeningly pathetic that the writer of this article, a supposed person of advanced education, would immediately "hypothesize that {and H2S suicide} might have been from an attempt at synthesizing methamphetamine gone awry."
All I can say is WHAT AN UNEDUCATED MORON!