Table 2.

Dose-related effects of hydrogen sulfide inhalation exposure.

3–5 ppm	Offensive “rotten egg” smell
10–20 ppm	Eye irritation
50–100 ppm	Conjunctivitis, severe eye injury
100–150 ppm	Olfactory fatigue. Can no longer smell hydrogen sulfide odor
150–250 ppm	Irritation of nose, lungs, nausea, headache, vomiting, dizziness
250–500 ppm	Severe respiratory irritation, pulmonary edema
500–1000 ppm	CNS stimulation, seizures, hyperpnoea, apnea, coma, death
1000 ppm and above	Immediate knockdown, death from respiratory paralysis