Alert First Aid

BC Legislation

H2S – Hydrogen Sulphide (also called ‘sour gas’, ‘sewer gas’)

This is not an official source of information. It has been assembled as a convenience to students for reference and further study. Some extracts from official sources such as Regulations are provided. These are not guaranteed to completely cover all the material available in the Regulations. URL’s of those official sources are provided to allow the full text to be consulted.

Other sources of Hydrogen Sulphide Safety information for British Columbia:

OHS Guidelines Part 23 Oil & Gas

http://www2.worksafebc.com/publications/OHSRegulation/Guideline
Part23.asp

Safety at Work Petroleum (Oil & Gas)

http://www2.worksafebc.com/Portals/Petroleum/Home.asp

The following is © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Copyright Workers' Compensation Board of British Columbia
Richmond, B.C., Canada. All rights reserved.
Occupational Health and Safety (OHS) Regulation, B.C. Reg. 296/97 Part 23 - Oil and Gas
Definitions
"derrick" means a stationary or portable structure used to support the hoisting and lowering mechanism on a rig;

"rig" includes a derrick and all equipment that is directly involved with drilling or servicing a well;

"well" means an opening in the ground which

(a) is made or being made by drilling, boring, or in any other manner
    (i) for the purpose of obtaining oil, gas or crude bitumen or from which any oil, gas or crude bitumen is obtainable,
    (ii) for the purpose of developing or using a reservoir for the storage of natural gas, or
    (iii) for the purpose of obtaining geothermal energy,

(b) is made or being made by drilling or boring for the purpose of obtaining water to inject into an underground formation,

(c) is used, drilled or being drilled for the purpose of injecting gas, air, water, or other substance or a form of energy into an underground formation,

(d) is an evaluation well,

(e) is a test hole, or

(f) is drilled or being drilled to a depth of more than 600 m (2 000 ft) to obtain geological or geophysical information.
Application

23.2 This Part applies to
    (a) the exploration for oil, gas, crude bitumen, or geothermal energy,
    (b) drilling, operating and servicing a well,
    (c) producing, distributing and refining oil, gas, crude bitumen or geothermal energy from a well, and
    (d) ancillary processes associated with paragraphs (a) to (c).
Drill Stem Testing, Swabbing, Cementing, Well Servicing and Stimulation
General requirements
Gauging
23.26 A tank which contains or may contain a fluid with hydrogen sulfide as a component must have an external means of gauging its contents, or if manual gauging or sampling is required, the worker doing the gauging or sampling must use a supplied air respirator meeting the requirements of Part 8 (Personal Protective Clothing and Equipment) for use in an IDLH atmosphere, and must be visually monitored by another worker equipped with an equivalent respirator and capable of effecting a rescue of the worker doing the gauging or sampling.
Safe work procedures
23.5 (1) The employer must identify the work activities or circumstances, including releases of gases, that have caused or may cause significant risk of injury or occupational disease to workers.

(2) The employer must analyze the risks arising out of the work activities or circumstances identified under subsection (1) and implement safe work procedures if the activities or circumstances create a hazard.

(3) The procedures implemented under subsection (2) must state the number of workers involved, the steps to be followed and the safety equipment required.

23.64 (1) Drill stem testing procedures must conform to Alberta Recommended Practices for Well Testing and Fluid Handling, ARP 4.1 Drill Stem Testing, June, 1993.
Drill Stem Testing, Swabbing, Cementing, Well Servicing and Stimulation

General requirements
23.64 (1) Drill stem testing procedures must conform to Alberta Recommended Practices for Well Testing and Fluid Handling, ARP 4.1 Drill Stem Testing, June, 1993.
(2) During drill stem testing
    (a) motors and engines or other sources of ignition not required for the operation must be shut off, and
    (b) motor vehicles must not be permitted within 25 m (80 ft) of the well bore.

(3) The rig manager, testing supervisor and, if required, representatives of other contractors doing work must be present to ensure that
    (a) workers are trained to carry out their responsibilities during the test, and
    (b) the equipment supplied is in good repair and will function as designed.

(4) If liquids are recovered during drill stem tests
    (a) the liquids must be reverse circulated from the drill pipe,
    (b) prior to reverse circulating, drill pipe may be pulled from the hole using test plugs on every joint of drill pipe disconnected, until well fluids are encountered at the surface, and
    (c) if reverse circulation is not practicable due to a failure of the pump out sub, the drill pipe may continue to be tripped out of the hole with extreme caution, using test plugs and a mud can.

(5) If test fluid recovery is encountered during darkness
    (a) the liquids recovered must be reverse circulated, and
    (b) if reverse circulation is not practicable due to failure of the pump out sub, additional drill pipe must not be pulled and disconnected until daylight.

6) Whenever oil, water or gas has been encountered during drill stem testing,
    (a) tests for the presence of hydrogen sulfide must be done, and
    (b) if hydrogen sulfide is found, the sour fluids encountered must be reverse circulated to a vented tank not less than 50 m (165 ft) from the well, or to a flare pit.
Production and Plant Operations
Retaining walls and diked areas
23.77 (1) Retaining walls and diked areas must be provided with safe access.

(2) A worker must not enter a diked area unless
    (a) effective measures, including testing, have been taken to protect workers if hydrogen sulfide may be present,
    (b) testing for flammable gases and vapours, oxygen deficiency and harmful air contaminants is done if there are leaks or spills that may present a hazard to workers, and
    (c) testing for flammable gases and vapours is done before hot work takes place.

(3) Testing must be done for hydrogen sulfide before entry to any diked area where sour fluid is stored.