I just learned that this is a thing. “Detergent Suicides” was first written about in 2009 by Wired, when the Asian technique came to the US.
hydrogen sulfide gas can be produced by mixing household chemicals, such as Toilet bowl cleaner and and something sulfur based. this has led to a number of suicides by mixing the chemicals in vehicles.
A presentation on the subject is found at http://www.ilpi.com/safety/downloads/hazmat_suicide.pdf
In short, If you see an unresponsive person in a vehicle, look for the presence of chemicles, buckets, etc. If you see them, invoke a hazmat response.
