Table 1.

Effects of H₂S at various concentrations

Concentration of H2S, ppm	Symptoms of exposure
0.05	Pungent smell mimicking "rotten egg"
0.1	Anosmia
50-150	Becoming paralyzed in a few minutes
250	Photophobia, lacrimation, rhinorrhea, cyanosis, pulmonary edema
250-500	Headache, nausea, vomiting, diarrhea, dizziness, palpitation, tachycardia, hypotension, muscle fasciculation, muscle weakness, apnea, disorientation, coma
500-750	Respiratory arrest within 30 to 60 min
750-1000	Collapsing momentarily or knocked down
>1000	Dying immediately within a breath