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Certified Health & Safety Consultant Canadian Red Cross Canadian Society of Safety Engineering

A Respiratory Protection Program for H2S Gas

A respiratory protection program  for Hydrogen Sulphide gas should be added to safety codes of practice for companies whose employees could be exposed to this toxic gas.  This should comply with CSA and NIOSH standards for respirators.

In Alberta, H2S, commonly known as Sour Gas, can naturally occur in petroleum reservoirs.  As a result of many deaths in the past from lack of personal protective equipment, it was discovered that a filtered cartridge or half mask respirator was inadequate protection from this poisonous gas.

Since H2S is considered an IDLH gas (Immediately Dangerous to Life and Health), the respiratory protection standard requires a positive pressure style mask.  For Self Contained breathing apparatus, there must be a minimum volume of 30 minutes of respirable breathing air.

Self Contained is the preferred style for workers who need independence of movement, want mobility to reach further areas or could conduct rescues.  The SCBAs have a cylinder, mask with a nose cup and positive pressure, harness and regulator. Positive benefits are mobility and no trip hazards when moving around. Negative aspects are that air time is limited, and they are bulky and heavy.

Supplied Air Breathing Apparatus (SABA) is the chosen system for longer term work and is lighter weight and less bulky. The advantage of this system is that workers entering confined spaces are able to access the space easier, have  longer term air supplies and can work as a team off an air cascade system. Disadvantages are that there is limited mobility, trip hazards, air that is not humidified and have to escape by disconnecting and using an egress cylinder.  This escape bottle is typically limited to 5 to 15 minutes and may not have an audible alarm to warn the worker that the air is running low.

A proper respiratory protection program should include the following key points:

1. Respirator selection and use .

2. Fit testing for tight-fitting respirators.This can be qualitative, quantitative or both.

3. Medical evaluation as some people have asthma or claustrophobia.

4. Various Procedures for a number of predictable  emergencies such as blow outs or rescues.

5. Preventative Maintenance procedures and a sanitary area for storage.

6. Supplied air respirators and operation of the cascade system.

7.  Routine and emergency situations procedures and training and drills.

8. Regular practice  care and maintenance of the respirator selected and donning and doffing.

9. Evaluating the effectiveness of the respiratory protection program and a schedule to reevaluate it .

10. Locations for SABAs and SCBAs at the worksite.

A respiratory protection program can help with the selection, fit, use, and maintenance of your breathing apparatus and will assist you in meeting the legislation and manufacturers specifications for H2S environments