Almost Urban Myth
It took some time, but I finally tracked down the "recipe" for producing toxic H2S gas in these incidents.
Basically, laundry detergent is NOT implicated. Nor is dishwashing detergent.
I was interested in finding out the ingredients from an academic point of view (I have a degree in biochemistry) as well as accidentally avoiding a similar combination.
KIDS DON'T TRY THIS AT HOME
The recipe involves combining a Japanese bath salt (Mottouhappu) that contains calcium sulfide (unusual if not absent here) with a Japanese toilet cleaner (Sunpole) that is 9.5% hydrochloric acid. The acid supplies the energy needed to generate the toxic H2S (hydrogen sulfide) gas.
It should be common knowledge that acidic toilet cleaners should not be mixed with any other chemicals. Toxic chlorine gas can be released, for example, if ordinary chlorine bleach is mixed with an acidic (HCl) toilet cleaner. Most toilet cleaners sold these days contain HCl - probably as a substitute for more effective phosphoric acid.
I don't know if common Epsom salts, which contain magnesium sulfate, would produce the same reaction as the Japanese Motouhappu bath salt that contains calcium sulfide, but it would probably be best not to combine epsom salts and toilet cleaner as well. I suspect that epsom salts plus toilet cleaner would not produce the toxic gas, but it can't hurt to be on the safe side.
I attribute the confusion about "detergent" with something lost in translation from the Japanese language web sites that originally published the "recipe". The "detergent" in this case being the toilet cleaner. What is described as "bath lotion" is the calcium sulfide containing bath salt solution.
By the way, H2S is produced from a number of natural processes, and in minute amounts is thought to be a part of the body's natural systems. Most commonly it's encountered with well water, and it's also the odiferous component of flatus. So in tiny amounts it's ok, but it can be quite deadly in larger amounts.
news.yahoo.com
