Hydrogen sulphide gas is produced naturally from decaying organic matter and industrial processes, and can be lethal in high concentrations. Following are some of its potential sources:
During volcanic activity, volcanoes naturally release H2S gas through their vents and cracks.
H2S gas may be present in natural gas wells and could be released during production and drilling.
It may be present in natural gas reservoirs, and can be discharged during processing and extraction.
As sulfur-containing minerals react with water to produce H2S gas, natural springs can be a source of H2S gas.
Crude petroleum may produce H2S gas during extraction and processing, posing health and safety issues.
From the decomposition of the organic content in wastewater, sewage treatment plants might emit H2S gas.
Refineries can generate H2S gas by the processing of sulphur-containing crude oil. The gas can pose threat to ones health and safety.
In the pulping process, kraft paper mills use chemicals based on sulphur, which produces H2S gas as a byproduct
Food processing units that utilize sulphurs and sulphuric acid emit H2S gas into the surrounding environment.
Wastewater treatment plants produce H2S gas during the breakdown of organic matter.
*As per BUREAU OF INDIAN STANDARDS
| H₂S levels (PPM) | Duration of exposure | |||
|---|---|---|---|---|
| 15 min | >15 min | >1h-4h | >4-8ht | |
| 10 | - | - | Eye irritation | Maximum tolerable concentration for prolonged exposure |
| 50-100 | Loss of olfactory perception | Eye irritation | Eye and bronchial irritation | Serious respiratory distress and asthenia |
| 150-250 | Eye and skin irritation | Eye and bronchial irritation | Serious respiratory distress and asthenia | Danger in case of continuous exposure |
| 300-400 | Loss of olfactory perception eye | Severe respiratory distress acute asthenia | Pulmonary edema & risk of death | Pulmonary edema & risk of death |
| 500-1,000 | Loss of consciousness respiratory distress | Risk of pulmonary edema and death | - | - |
| >1,000 | Immediate loss of consciousness and respiratory distress | |||
15 min
-
>15 min
-
>1h-4h
Eye irritation
>4-8ht
Maximum tolerable concentration for prolonged exposure
15 min
Loss of olfactory perception
>15 min
Eye irritation
>1h-4h
Eye and bronchial irritation
>4-8ht
Serious respiratory distress and asthenia
15 min
Eye and skin irritation
>15 min
Eye and bronchial irritation
>1h-4h
Serious respiratory distress and asthenia
>4-8ht
Danger in case of continuous exposure
15 min
Loss of olfactory perception eye
>15 min
Severe respiratory distress acute asthenia
>1h-4h
Pulmonary edema & risk of death
>4-8ht
Pulmonary edema & risk of death
15 min
Loss of consciousness respiratory distress
>15 min
Risk of pulmonary edema and death
>1h-4h
-
>4-8ht
-
All durations:
Immediate loss of consciousness and respiratory distress
*As per BUREAU OF INDIAN STANDARDS
