Mechanism of action 
As the charcoal burns, the concentration of carbon monoxide gradually increases. Because of its toxicity (and not the exhaustion of oxygen as sometimes thought) CO concentrations of as little as one-tenth of one percent of the air in a confined space are fatal if inhaled over an extended period. The incomplete combustion of carbon produces carbon monoxide, which binds strongly to hemoglobin, rapidly decreasing the ability of blood to deliver oxygen to the body. This results in death due to hypoxia brought about by carbon monoxide poisoning.
The method is described as "easy and painless" compared to other suicide methods. Unlike jumping from a high-rise building or cutting with a knife, the suicidal person does not have to overcome their fear of pain. To simulate the condition of those who accidentally die from CO poisoning, one might take drugs such as alcohol to induce sleep.
Some have challenged the description of the method as painless, noting that the lack of oxygen can cause choking but as noted above this is based on a misunderstanding of the mechanism of action, it is the cumulative serum concentration of CO, not the depletion of oxygen that causes death. A survivor of this method usually needs intensive care. They may have permanent brain damage.
In November 1998, a middle-aged woman in Hong Kong committed suicide using this method inside her small, sealed bedroom. As this method is not listed in Tsurumi's Complete Manual of Suicide from 1993, she may have invented it herself; she had a chemical engineering background.
Meanwhile, Hong Kong was suffering from an economic depression at the time, and suicide in general was increasing. After the details of this suicide were highly publicised by local mass media, many others attempted and succeeded in committing suicide in this way. Within two months, charcoal-burning had become the third major suicide killer in Hong Kong. Charcoal-burning suicide accounted for 1.7% of Hong Kong suicides in 1998 and 10.1% in 1999. By 2001, it had surpassed hanging as the second most-common method of suicide in Hong Kong (second only to jumping), accounting for about 25% of all suicide deaths. The method has since spread to mainland China, Taiwan and Japan.
In order to prevent charcoal burning, the Hong Kong Government replaced the traditional countryside charcoal barbecue with an electric grill. Some non-government organizations worked with charcoal retailers to promote the message of "treasure your life" by putting "seek help" labels on the charcoal bags.
A Taiwanese woman, Claire Lin, while chatting with others using her Facebook account, committed suicide by asphyxiation while burning a charcoal fire in a sealed indoor room. She was found the next day on March 19, 2012.
- Chart of exposure vs. ppm
- Chung WS, Leung CM (June 2001). "Carbon monoxide poisoning as a new method of suicide in Hong Kong". Psychiatr Serv 52 (6): 836–7. doi:10.1176/appi.ps.52.6.836. PMID 11376237.
- Life is precious
- "Father Arsene did cut his stick; that evening, he and his old wife suffocated themselves with charcoal." Ch 3. The Carouse Full Text
- Chan KP, Yip PS, Au J, Lee DT (January 2005). "Charcoal-burning suicide in post-transition Hong Kong". Br J Psychiatry 186 (1): 67–73. doi:10.1192/bjp.186.1.67. PMID 15630126.
- Media coverage boosts 'charcoal burning' suicides — 28 February 2003 — New Scientist
- Leung CM, Chung WS, So EP (May 2002). "Burning charcoal: an indigenous method of committing suicide in Hong Kong". J Clin Psychiatry 63 (5): 447–50. doi:10.4088/JCP.v63n0512. PMID 12019670.