Build Canada Housing — Concerns over Siting on Contaminated Properties

Summary brief re. Federal Build Canada Housing properties portfolio
November 4, 2025

• Build Canada Homes proposals aim to house millions over a few years, according to the Canada Strong report.
• Plans include many projects on potentially contaminated ex-military and shipyard sites.
• The present Build Canada housing proposals are a small sample of the projects contemplated according to the Housing and Infrastructure Project Map.

It is increasingly clear that the extent, diversity and severity of toxic contamination may be under-recognized for at least some of the Build Canada Homes sites. For example,

• the Build Canada Homes website largely omits histories of military sites;
• environmental contaminant testing is limited;
• migration of toxicants may be missed;
• important contaminants may be omitted; or
• samples may be collected at times or under conditions (e.g., indoor air samples from ventilated spaces) that minimize detection of contaminants.

In other words, assumptions and protocols may limit or under-estimate the extent of toxic contamination and hazards of building on these sites.

Projects’ Details

Housing projects are outlined on the Canada Lands Company website in two locations, with some projects on both lists (as of early November 2025):
https://www.clc-sic.ca/build-canada-homes and https://www.clc-sic.ca/enabling-new-housing

Toxicant identification: The following brief overviews regarding proposed Build Canada sites are compiled from these and other linked sources. Concerns are highlighted, but with a paucity of data it is not possible for us to address hazards or risks comprehensively. Contaminants identified on the government web pages are primarily established hazardous toxicants, that must be tracked under the National Pollutant Release Inventory (see lists for 2022-2024  and 2025-2028), or declared “toxic” under the Canadian Environmental Protection Act. CEPA-toxic substances may, for example, cause cancer, disrupt hormone systems and development, cause inflammation and chronic disease, and damage organs.

Routes of Exposure
Toxins contaminating construction sites may be mobilized in groundwater, taken up by roots of plants (including deep roots of trees) and disbursed via foliage, and distributed in dust and surface runoff. Housing on toxic sites is vulnerable to infiltration of chemicals through foundations, just as is well known for naturally occurring radon. Fruits and vegetables may accumulate toxicants, increasing exposures via ingestion.

Territorial Acknowledgement
From coast to coast to coast, we gratefully acknowledge ancestral lands of Indigenous peoples, upon which Canadian Forces Bases have been established, and lands are being considered for housing.

Canada Build sites concerns — November 4, 2025

Nova Scotia

Shannon Park, NS

Build Canada does not mention previous contamination, but this was previously a highly contaminated military base (arsenic and hydrocarbons were identified), which has undergone expensive cleanup with a view to building a stadium (https://www.cbc.ca/news/canada/nova-scotia/ottawa-to-spend-millions-cleaning-up-shannon-park-by-spring-1.4899246). Risks associated with now-planned housing are vastly greater than those posed by a stadium. The sports facility would be open to the outdoors, have a thick barrier (e.g., concrete and asphalt) over toxic grounds. The stadium would generally be visited occasionally, rather than being domestic living spaces.

Quebec

Wellington Basin, Montréal, QCis an industrial site that has been in use since 1820. The Wellington Basin was the Lachine Canal’s largest basin. It was previously used primarily for the trans-shipment of coal, which leaves a toxic legacy. This basin is now filled in, with no remediation or containment noted. The ship yard would also have been contaminated with petrochemicals (oil/fuel), lead (from paint, pipes and solder), asbestos, and additional materials being shipped, such as ores or chemicals as well as coal.

Pointe de Longueuil – Longueuil, QC
Longueuil has an important history in Quebec, including shipping and defence of the ports. Concerns on the south shore of the St. Lawrence River would be similar to the Wellington Basin opposite, on the north shore.

The federal government website is silent regarding environmental concerns, reading more like a sales brochure, stating that the goal for Pointe-de-Longueuil is to develop a new “destination district” on some of the last available south-shore St. Lawrence River waterfront lots, “with spectacular views of the St, Lawrence River, Montréal and Montérégie.” The planned “iconic” district or “village” will include almost 5,000 new housing units, of which at least 1,000 (or 20%) will be non-market.

Restricting access to this important, iconic riverfront appears to be a possibility, “The development of riverbanks and 900,000 square feet of parks will provide privileged river access for residents and all citizens in the region.” This development is still being planned, and apart from land, Build Canada Homes contributions are unclear. Should public access to what are presently iconic public lands be forfeited?

125 Houde Street Montréal, QC is part of Canada Lands’ Côte-de-Liesse property. It was formerly occupied by the National Film Board, where it fostered the emergence of Canadian cinematography. Mixed use, including housing, is being developed close to future rapid transit.

Ontario

Arbo Downsview, Toronto, ON 

The Arbo neighbourhood is approximately 25 hectares (62 acres) and is one of five planned neighbourhoods surrounding Downsview Park. A mature woodlot is at the heart of the neighbourhood. The site was once part of the former Canadian Forces Base Toronto. The National Pollutants Release Inventory reports that cleanup is complete, but oddly there is no reporting of perfluorinated chemicals, even for Site 70602003 – Fire Fighting Training Area (Downsview).
“INCOMPLETE ENVIRONMENTAL ASSESSMENT” is noted.

Historically, trees may have been planted on contaminated sites to reduce migration of toxicants, and to provide rich soil microbiological diversity that hopefully will speed natural break-down of organic contaminants such as spilled fuels. Bioremediation of halogenated (chloro- and fluoro-) chemicals has very limited success reported in the natural environment.

1495 Heron Road, Ottawa, ON was developed by the Sisters of the Congregation of Notre Dame during the 1960s, and was purchased by the Government of Canada in 1973 to be used as the Federal Study Centre. Presently asbestos abatement and removal of some buildings is completed. Some buildings are being renovated for housing. Apart from more common urban contaminants such asbestos (said to be abated) and lead in paint and plumbing, we know of fewer environmental concerns for this site, that was used for contemplation and study. A major caveat is that the brief online documentation does not mention uses prior to 1960.

Wateridge Village, Ottawa, ON is a 125-hectare (310 acre) site formerly home to Canadian Forces Base Rockcliffe. Land at 370 Codd’s Road, 800 Winisik Street is planned for approximately 495 units of housing with a minimum of 30% dedicated to affordable housing. CONTEXT: The base was primarily dedicated to military housing before being decommissioned in 1994. The City of Ottawa approved a larger Community Design Plan in 2015, including approximately 5,300 homes, 9 parks, 3 school sites, 6.1 hectares (15.0 acres) of designated employment lands and approximately 14,000 square metres (150,000 square feet) of commercial/retail floor space. We note that CFB Rockliffe also included an airfield, with related environmental contaminants. This small airfield accommodated propellor airplanes, which are powered to this day with leaded fuel; lead contamination would have affected air quality (see US Environmental Protection Agency regarding aviation lead pollution) and can contaminate lands, vegetation and groundwater under flight paths for take-off and landing.

Manitoba

Naawi-Oodena, MBis situated in SW Winnipeg on the former Canadian Forces Base Winnipeg—a merger of the now-demolished former Kapyong Barracks, and the Royal Canadian Air Force Station Winnipeg (co-located on the civilian airport). Asbestos contamination was acknowledged. At a minimum lead and other toxic metals from old paint and ammunition are anticipated, as well as typical, difficult-to-remediate airbase contamination including petrochemicals and halogenated (brominated, chlorinated and fluorinated) de-icing and flame retardant chemicals. 

Alberta

Village at Griesbach Edmonton AB (and here)

It appears that important contaminants may not have been addressed before building on Griesbach. In 2010, the Edmonton Journal discussed building housing on the old Griesbach military base. “There wasn’t just asbestos in the aging buildings — there was asbestos cladding on the old steam lines. Since the military had used some of the land for fuelling heavy equipment, parts of the property were contaminated with hydrocarbons, PCBs [polychlorinated biphenyls] and mercury. Rather than haul tonnes of earth away, says McIvor, they tried to clean soil on-site, using micro-organisms to break down the spilled oil, gasoline and diesel fuel.”

Prevent Cancer Now notes: Microorganisms may or may not have degraded the hydrocarbons—this should be validated—but the toxic, persistent PCBs would probably have remained. The fate of the mercury is uncertain, but as an element it will never degrade. Mercury is neurotoxic, and causes birth defects and chronic diseases. If microbes methylate mercury it will become bioavailable and bioconcentrate in organisms (most famously in aquatic life, contaminating fish). All mercury salts and compounds are toxic, particularly to the foetus and children. In any case, these two families of contaminants (hydrocarbons and mercury compounds) have not been addressed directly. It is important that they be assessed to guide any necessary remediation, to detect and address any health risks for present day residents, and to prevent harms to new residents.

Currie – Calgary, AB (see also https://currielife.ca)

The Currie barracks were built during the 1930s, and was a core military training location for over 60 years. Over this period, it hosted an air strip for pilot training, and was home to Lord Strathcona’s Horse (Royal Canadians) and 1st Battalion, Princess Patricia’s Canadian Light Infantry. There is no mention of remediation of the site for contaminants common to military training facilities outlined above, including (but not exclusively) lead and asbestos, hydrocarbons, pesticides, and chlorinated and fluorinated substances.

Due diligence before disposing of properties?

Before the Federal Government disposes of real property, Treasury Board specifies activities to ensure due diligence, as below. We have concerns that the present vetting of Build Canada Homes sites may be subpar.

Real property practitioners must conduct due due diligence before acquiring, disposing, or transferring administration of real property:

• Environmental Condition must be ascertained and reported in all instances.
• Environmental Performance must be ascertained only when acquiring, but not when disposing of real property.

Is the Government of Canada gifting toxic sites?

Background and ongoing risks to Canadian Armed Forces (CAF)

Toxic contaminants, known to be on military sites, could well be major factors in the neurological and other illnesses, cancers and deaths among DND employees in particular locations. This must not be a legacy passed to families via Build Canada Homes.

The work of many “fact finders” pressed issues of contaminants at CFB Gagetown, where training grounds were defoliated with older herbicides contaminated with persistent organic pollutants. Presently, DND staff and trainees are annually exposed to newer chemicals (e.g., glyphosate).

More recently Erin Zimmerman is illuminating toxicant-related illnesses in the Canadian Armed Forces, particularly on air bases. Erin discovered that her unusual health challenges resulted from contaminants infiltrating her workplace—administration building 143 and hangar at CFB Moose Jaw. Information from 15 Wing Moose Jaw now indicates over 200 sicknesses and over 40 deaths over the past decade, at this small air-force base.  

Examination of the air quality report for Building 143 revealed key protocol amendments that would reduce detections, such as the removal of specific testing and human receptor pathways. Testing was completed during periods of high ventilation, rather than after the building was shut down or ventilation reduced (i.e., after hours or over the weekend).

Moose Jaw is not unique. All air force bases will be contaminated with petrochemicals including fuel, oil and solvents; persistent and toxic polychlorinated biphenyls (PCBs); and fluorinated chemicals for de-icing and fire-fighting. Hangers, shops and training areas are directly impacted by chemicals used on-site, while administrative buildings are also infiltrated by toxins in contaminated soil and groundwater.

Solutions with the 2025 budget?

Canada’s national defence is built on the health of the military forces. Canada cannot afford the health impacts of contaminants on military bases and training grounds, either presently or following conversion to housing.

The 2025 Federal Budget sets aside $115 billion over five years for infrastructure renewal and modernization, with $30 billion for defence and security.

With government providing a credible financial base, and DND aligned on modernization, climate resilience and environmental performance, it is the time to address long-standing infrastructure related health issues.

Environmental health must feature in the urgent Build Canada, as well as military upgrading.

To discuss and for further information, Email: info@preventcancernow.ca