Hydrogen Sulfide is bad stuff. Friend did work for a tannery. One night the concrete lined cesspool they stored waste from leather manufacturing blurbled and tu

Hydrogen Sulfide is bad stuff. Friend did work for a tannery. One night the concrete lined cesspool they stored waste from leather manufacturing blurbled and turned over releasing CO2, Methane and Hydrogen sulfide. Killed two security guards in their guard shack 100 yards away. I think like cyanide you lose your sense of smell as the concentration approaches lethal levels. That leads people to assume concentrations are falling instead of increasing.