Former Canada Creosote Plant site
A wood treatment plant was operated in downtown Calgary on the south side of the Bow River from 1924 to 1962. 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). Monitoring of vapour and groundwater indicated contamination exists under the neighbourhood.
In 1995, a containment wall and groundwater collection system was constructed on the south bank of the Bow River to prevent ongoing migration and the City of Calgary has been managing and operating the containment system since 1997.
North Bow Environmental Monitoring Program
Since 2004, the Alberta government, with cooperation from Alberta Health Services and the City of Calgary, has conducted monitoring in the communities on the North side of the Bow River (North Bow Communities) to determine if there is a potential risk to human health. Recently, a five-year monitoring program designed to assess contamination levels in groundwater and soil vapour in the North Bow Community has concluded.
The work provided a better understanding of site conditions and the effect that seasonal variations could have on the contamination, ensuring that assessments related to public protection were appropriate.
Monitoring results
Groundwater and soil vapour monitoring results:
- appear to be consistent with previous results
- demonstrate no unacceptable risk to human health receptors
- indicate that there is no risk to human health
Indoor air, sub-slab vapour and soil vapour concentrations were below health-based criteria.
Monitoring may be required to provide assurance that there continues to be no unacceptable risk to human health receptors at the site. The Alberta government will continue to work with responsible parties and the City of Calgary to ensure appropriate action is taken.
All reports and results can be found on our Environmental Site Assessment Repository.
For ease of reference, the most recent reports are included here:
- 2020 North Bow Annual Environmental Report
- 2021 North Bow Annual Environmental Report
- North Bow Human Health Risk Assessment Report
Human health
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 are called non-aqueous phase liquids (NAPL).
Exposure and risks
The 5-year monitoring program confirmed there are no concerns to human health when compared to human health guidelines.
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.
Health risks depend on the amount, duration and frequency of exposure. The most common risks are respiratory irritation from breathing in creosote vapour, and skin damage from long-term skin or air contact.
Long-term exposure, especially through continued direct-skin contact, can result in some cancers.
Soil vapour
The soil vapour monitoring results demonstrate no unacceptable risk to human health receptors.
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.
Drinking water
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.
Additional information on the south side of the Bow River and the former Canada Creosote plant can be found at:
The Alberta government monitored the Bow River from 1989 to 2002 and again from 2011 to 2013. The results can be found at:
Contact
Connect with Alberta Environment and Protected Areas:
Email: [email protected]
Connect on health-related questions:
Health Link Alberta
Phone: 811 or 1-866-408-5465 toll free in Alberta
Local Medical Officer of Health
Phone: 403-943-1280
Connect with the City of Calgary for public inquiries:
Phone: 311 (in Calgary)