Former Canada Creosote Plant site
The Canada Creosote Company operated a wood treatment plant in downtown Calgary from 1924 to 1962. It was located on the south side of the Bow River. It used creosote, a mixture of 200 chemicals to preserve wood products such as railway ties and power poles. Over time, these chemicals migrated into and under the Bow River and into the communities on the north side of the Bow River (referred to collectively as North Bow communities).
The creosote compounds can exist in various states and interact with soil, air and water (groundwater and river water). Most of the chemical compounds found in creosote do not dissolve in water and called non-aqueous phase liquids (NAPL). NAPL fall into one of two categories: dense non-aqueous phase liquids (DNAPL), which will sink downward and move along the bedrock and light non-aqueous phase liquids (LNAPL), which will sit on top of the water table.
The Alberta government examined various remediation and management options. In 1995, a containment wall and groundwater collection system was constructed on the south bank of the Bow River to prevent ongoing migration of contamination from the former Canada Creosote plant site in to the Bow River.
The City of Calgary owns the land on the south side of the Bow River including the former Canada Creosote plant site. The City of Calgary has been managing and operating the containment system since 1997. The Alberta government continues to work with the City of Calgary regarding this site and its ongoing management.
Additional information on the south side of the Bow River and the former Canada Creosote plant can be found at:
Further information can be found on the City of Calgary’s:
The Alberta government has monitored the Bow River from 1989 to 2002 and again from 2011 to 2013. The results can be found at:
North Bow Communities
North Bow Environmental Monitoring Program
The Alberta government, with cooperation from Alberta Health, Alberta Health Services and the City of Calgary continues to monitor the plume to determine if there is a potential risk to human health. The Alberta government has taken the lead and established a monitoring program in the communities on the North side of the Bow River (North Bow Communities). Advisian (WorleyParsons Group) is currently contracted to monitor and determine the nature and extent of potential contamination on the North side of the Bow River. This five year (2017-2021) program will include:
- regular sampling of new and existing monitoring wells
- annual analysis and reporting of the sampling data
- development of a comprehensive Human Health Risk Assessment for the community
- providing technical support to Alberta Government hosted open house public consultation sessions
Results - North Bow Environmental Monitoring Program
2010 to 2011
A field assessment program was conducted to update historical site information and the human health risk assessment. See the 2011 notification letter delivered to area residents:
- Hillhurst Community Resident Package Letter (PDF, 205 KB)
The North Bow River Phase 1 Environmental Assessment Report was completed in 2011. It evaluates potential areas of environmental concern.
2011 to 2013
A series of field programs were conducted to install and sample groundwater and soil-vapour monitoring probes. The following letters were sent to residents prior to work being conducted:
- 2011 Hillhurst Community Resident Letter (PDF, 92 KB)
- 2012 Hillhurst Community Resident Letter (PDF, 19 KB)
Elevated levels of some compounds were found in groundwater at monitoring well MW10-6 at the site. Results are detailed in the following report:
2014 to 2015
Further assessments were conducted to understand conditions near groundwater-monitoring well MW10-6. See the prior notification that area residents received at:
- Hillhurst Community Resident Letter (PDF, 27 KB)
Additional groundwater and soil-vapour monitoring wells were installed and monitored as part of this expanded program. To ensure nearby residents were not at risk, a residential air-monitoring program was conducted at select houses near MW10-06. A summary of the results can be found at:
2017 to 2018
On April 25, 2017, West Hillhurst residents received letters regarding ongoing environmental monitoring in their neighbourhood. Additional work, completed as part of the first year, is summarized in the 2017 Environmental Assessment Report.
- Hillhurst Community Resident Letter (PDF, 47 KB)
- 2017 North Bow Environmental Assessment Report (PDF, 12.5 MB)
2018 to 2019
Additional delineation work was completed in 2018 as part of the North Bow Environmental Monitoring Program. Work is summarized in the 2018 Annual Environmental Report.
- 2018 North Bow Annual Environmental Report (PDF, 27.4 MB)
2019 to 2020
Additional delineation work was completed in 2019 as part of the North Bow Environmental Monitoring Program. Work is summarized in the 2019 Annual Environmental Report.
- 2019 North Bow Annual Environmental Report (PDF, 6.5 MB)
Health risk assessments
The Alberta government has monitored soil, soil vapour and groundwater at the site. This information is used to develop a conceptual site model which is an important technical component of a risk assessment.
Risk Assessments were completed in 2004 and in 2014.
- Canada Creosote Site – North Bow Human Health Risk Assessment
- Canada Creosote Site – North Bow Screening Level Risk Assessment Update (PDF, 11 KB)
With the collection of new environmental monitoring data, understanding of the site will be improved and it is anticipated that the Risk Assessment will be updated in 2020/21.
Community Information Session
Due to COVID-19, an in-person community information session was not held. Instead updated information can be accessed below:
- posters explaining the site history and upcoming work: Canada Creosote Site History (PDF, 13.0 MB)
- highlight sheets: Community Info Session Highlights (PDF, 82 KB)
Exposure and risks
Residents are unlikely to be exposed to creosote. However, vapour inhalation in areas without ventilation, such as basements, may be possible if homes are close to creosote contamination. The current monitoring program includes work to confirm the risk is negligible.
Health risks depend on the amount, duration and frequency of exposure. The most common risks are:
- respiratory irritation from breathing in creosote vapour
- skin damage from long-term skin or air contact
Long-term exposure, especially through continued direct-skin contact, can result in some cancers.
Within soil there are small pockets where vapour and dissolved chemicals can accumulate. When structures such as basements intersect these pockets, vapour can migrate from the soil into the structure.
Modern homes are constructed to be energy-efficient and well-sealed. This means that vapours that enter the building may accumulate in the basement. They present a potential risk to humans if inhaled.
Critical factors for increased vapour exposure are when the level of water in the Bow River is low and in the winter when air exchange in houses can be lower.
Sampling is done at these times to ensure that a conservative, worst-case scenario is always represented.
Your water is safe to drink. The potential of creosote in areas of West Hillhurst does not affect drinking water. Residents of Calgary get their water from Calgary Water Services. The water supply is not from groundwater sources.
The water mains that provide water to the North Bow communities are part of a pressurized closed system of metal, jointless pipe. This ensures that no contamination can enter the drinking water delivery system.
A carcinogenic compound is a compound that can lead to cancer. An example of a carcinogenic compound is benzene, which people can be exposed to from tobacco smoke and vehicle fuel.
Incremental lifetime cancer risk (ILCR)
ILCR is the risk above what would be normally experienced by the general population from background environmental exposures. The cancer risk is considered acceptable if the calculated ILCR is less than or equal to 1-in-100,000 (≤ 1 x 10-5).
Hazard quotient (HQ)
HQ estimates the risk of health effects other than cancer occurring when a person is exposed to a chemical over their lifetime. HQ can be calculated for each pathway of exposure such as ingestion or inhalation, or for a target organ.
Chloroform is often detected in soil and groundwater in urban settings with chlorinated drinking water systems. Chloroform is generated when chlorine reacts with organic matter.
Connect with Alberta Environment and Parks:
Environment and Parks
2nd Floor, Deerfoot Square
2938 11 Street NE
Calgary, Alberta T2E 7L7
Connect on health-related questions:
Connect with the City of Calgary for public inquiries:
Phone: 311 (in Calgary)
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