These 2 used h2s
http://www.dailymail.co.uk/news/art...b-Joanne-Lee-planned-deaths-online-hours.html
You need 2 things, a source of acid and a source of lime suphur that contains approx 28% calcium polysulfides.
The japs invented the method. They used a litre of toilet cleaner called sunpole that contained 9.5% hydrochloric acid. Then dumped that into a bucket that had sulphur bath salts in.
It briefly became a method in USA
https://sherrypikesuicide.wordpress.com
In the US the source of lime sulphur used was made by bonide, it was a brush on rose bush insecticide. So many h2s deaths there had an empty bottle at the scene that bonide stopped making it.
Lime sulphur now is hard to find. The only places are online bonsai tree supply sites. Search for Jin Seal.
You'll need a litre and the acid source which is easy to get.
As it became more popular in the US they started training hazmat how to cope with an incident.
This guy used a tent.
http://www.dailymail.co.uk/news/art...hal-mix-poison-kill-inside-tent-end-term.html
It's a very deadly gas at 1000 parts per million.
Smells of rotten eggs and can kill in 3 breaths.
Dangerous to rescuers. The whole street will get evacuated for at least half a day if you did it in a house.