Palliser Airshed Society

Hydrogen Sulphide (H₂S)

Hydrogen sulphide is a colourless gas consisting of atoms of sulphur and hydrogen. H₂S has an odour of rotten eggs.

How Is It Generated?

Hydrogen sulphide is generated both naturally and anthropogenically (man-made). Sources include: swamps, sewers, sour gas wells, volcanic eruptions.

What Are The Health Effects?

• Olfactory Nerve Paralysis;
• Pulmonary Edema;
• Central Nervous System Stimulation;
• Loss of Breath; and
• Eventually Death.

Provincial Guidelines:

• The 1-hour Average Alberta Ambient Air Quality Guideline is 10 parts per billion (ppb)
• The 24-hour Average Alberta Ambient Air Quality Guideline is 3 ppb

What Can We Do?

You must take the necessary precautions when dealing with H₂S.

1. H₂S Alive: This training course deals with the proper ways of ensuring your safety when working around H₂S. No individual should be on a site where H₂S is present without this training.
2. Personal Protective Equipment (PPE): When working around H₂S it is important to be wearing the correct PPE and ensure you know how to use it effectively.
3. Monitoring: This is an important step for public safety. It provides assurance that the ambient levels of H₂S are within safe limits.

Table of Human Symptoms and Other Effects

Occupational Health and Safety Act (Alberta – AR 393/88 Chemical Hazards Regulation)

Concentration (ppb)	Exposure Time	Human Symptoms and Other Effects
0.0047	-	50% of the population can detect (smell) H2S.
3	24 hours	Alberta ambient air quality guideline for 24 hours.
<10	8 hours	Daily workday exposure limit.
10	1 hour	Alberta ambient air quality guideline for 1 hour.
10-20	-	Exposure at which eye irritation begins.
50-100	-	Exposure at which eye damage occurs.
150-250	-	Exposure concentration causing olfactory nerve paralysis, diminished sense of smell and decrease sense of danger.
320-530	-	Exposure levels leading to pulmonary edema with the possibility of death.
530-1000	-	Exposure levels that cause strong stimulus of the central nervous system and rapid breathing, which leads to loss of breathing.
800	5 minutes	Concentration at which 50% of the population will perish (LC50).
>1000	1 second	Exposure causes immediate collapse with loss of breathing.

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