what are the items needed for gaz in Japan please? do you mean with bbq carbon monoxide?
According to nlm.nih.gov:
Fatal intentional exposures in the United States (U.S.) have not been described in the medical literature; however, suicides using H2S have been described in Japan since 2007.
8 These suicides have been dubbed "detergent suicides" by the media because they are carried out by mixing household chemicals (often an acidic toilet bowl cleaner as a proton donor and insecticides or bath salts as a sulfur source) to produce toxic concentrations of H2S gas.
9 The specifics of this technique became available on Japanese websites in late 2007. It is thought that availability of this information contributed to a dramatic increase in the number of these cases reported.
A bit vague, but if your curious:
To assess the frequency of hydrogen sulfide (H[2] S) suicides and describe the characteristics of victims in the United States (U.S.) since the technique became common in Japan in 2007.To ascertain the frequency of intentional H[2] S related deaths in ...
www.ncbi.nlm.nih.gov