The Government of Saskatchewan is committed to protecting the health and safety of its citizens, ensuring that residential development occurs at an appropriate distance from oil wells. This is important as sour gas, a byproduct of drilling and oil production at many wells, can lead to severe health issues, including death.
Sour gas is a naturally occurring gas that contains significant amounts of hydrogen sulfide (H2S). The concentration of H2S varies depending on numerous factors, such as the extraction method and the geological formation containing the oil. Sour gas concentration is measured in parts per million or ppm. H2S can have serious health impacts at various concentrations:
|Concentration (ppm)||Health Effects|
|0.01 – 0.3||Odour threshold|
|1-20||Offensive odour; possible nausea; tearing of the eyes or headaches with prolonged exposure|
|20-50||Nose, throat and lung irritation; digestive upset and loss of appetite; sense of smell starts to become fatigued; acute conjunctivitis or eye irritation may occur resulting in pain, tearing and light sensitivity|
|100-200||Severe nose, throat and lung irritation; ability to smell odour completely disappears|
|250-500||Pulmonary edema, which is a buildup of fluid in the lungs|
|500||Severe lung irritation; excitement; headache; dizziness; staggering; sudden collapse or knockdown; unconsciousness and death within a few hours; loss of memory for the period of exposure|
|500-1000||Respiratory paralysis; irregular heartbeat; collapse and death without rescue|
|>1000||Rapid collapse and death|
(Source: Government of Alberta. Aug 2010. Workplace Health and Safety Bulletin: Hydrogen Sulphide at the Work Site.)
The Government of Saskatchewan administers the Integrated Subdivision Approval Process, which reviews all applications for subdivision of land outside of 10 Saskatchewan cities that have been designated as approving authorities. Through amendments approved in The Subdivision Regulations, 2014, residential development is now required to have a setback of 125 metres from oil wells. This subdivision setback was made consistent with the standards in The Oil and Gas Conservation Regulations, 2012, which have required the setback since July 1, 2013.
When a subdivision application is received and oil wells are identified on the plan of proposed subdivision, the application is assessed by obtaining a gas analysis from the company operating the well and considers the characteristics of the oil well in order to determine the appropriate setback. Some aspects considered include the potential concentration of H2S in the well, any connected flow lines and batteries and the type of oil well.
- Typically a separation of 500 metres between sour gas wells with H2S concentrations over 100 ppm and residential development is recommended. An H2S concentration of 100 ppm is considered immediately dangerous to life and health; and
- The 125 metre setback is normally waived for wells that have been properly decommissioned and abandoned.
In order to protect the health and safety of potential residents, subdivisions may require redesign to ensure a buildable site can be located outside the setback distance. In some cases where a nearby oil well is too close to a proposed residential parcel and a suitable site cannot be safely located, the application may be refused. In the event of a refusal, the applicant may initiate an appeal of the decision with the Saskatchewan Municipal Board.
The Integrated Subdivision Approval Program addresses the potential health and safety risks associated with residential development near sour gas producing oil wells. However, municipalities may still be issuing development permits for dwellings near wells. Municipalities are encouraged to consider the risks related to sour gas producing oil wells and to ensure that residential development occurs in safe and appropriate locations. Municipalities should consider amending their planning bylaws in order to address this matter and to establish setback distances consistent with the safety factors for development close to oil wells.
When landowners sign agreements with oil companies, they should ensure that the possible health and safety risks associated with the oil well are discussed and considered, including the potential impact the oil well may have on the future use of their property. It is unlikely the oil companies and landowners are considering land use impacts resulting from the placement of an oil well when signing leases for oil wells.