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Hydrogen Sulphide

Who is at risk?

Hydrogen Sulphide occurs naturally in the earth and so people involved in oil and natural gas drilling are particularly at risk.

Hydrogen Sulphide is also produced in the breakdown of human and animal waste by bacteria and can accumulate in sewers and sewage treatment plants.


Foul odour of rotten eggs


Hydrogen sulphide is extremely toxic, preventing the brain from using oxygen which can lead to dizziness, collapse and death.

Hydrogen Sulphide cases loss of smell causing people to mistakenly think that he gas has left the space.

Acute Exposure

Concentration Effect
0.01–0.03 ppm Odour detectable to the human nose
1-20 ppm Very strong odour, nausea, eye irritation headaches
20-50 ppm Irritation in the throat and lungs – supressed sense of smell and appetite
100 - 200 ppm Severe nose, throat and lung irritation
500 ppm Respiratory paralysis, heart palpitations, collapse and death
>1000 ppm Rapid collapse and death

Exposure Controls & Protection

NFPA 704 Signal

  Hazard Value Description
Health 4 Can be lethal.
Flammability 4 Burns readily. Rapidly or completely vaporizes at atmospheric pressure and normal ambient temperature.
Instability 0 Normally stable, even under fire conditions
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