Effects of Hydrogen Sulfide on Humans and its Toxicity | Pioneer of a gas alarm gas detector / alarm - Riken Keiki Co., Ltd.

Effects of Hydrogen Sulfide (H2S) on Human Body

Concentration (ppm) Effects and Toxicity
0.025 Smell vaguely. (It varies according to the individual.)
0.3 Smell clearly.
3`5 Smell moderate degree of objectionable odor.
10 Lower-level to irritate eyes' mucus membranes. 
20`40 A strong odor. Lower-level to irritate lungs' mucous membranes.
100 Sense of smell is impaired in 2 ~ 15 minutes. Eyes and respiratory tract are irritated in 1 hour.  8 ~ 48 hours continuous exposure can lead to death.
170`300 1 hour exposure is the limit for not causing serious health problems.
400`700 Life-threatening exposure in 0.5 ~ 1 hour.
800`900 Bring on loss of consciousness, cessation of breathing and death.
1000 Bring on immediate loss of consciousness and death.