Across southwestern Ontario, there are an estimated 27,000 inactive oil and gas wells. These historical oil and gas exploration wells, along with the environmental, health, and safety risks they pose, are receiving increased attention.
Abandoned Well Increases Project Cost
A September 18, 2025, article discussed how these often-unidentified wells affect projects. In 2024, Lambton County, Ontario, allocated $125,000 to replace underground fuel storage tanks with aboveground tanks. During the project, soil and groundwater contamination were discovered, along with a wooden casing of an abandoned oil well.
In an article (The Independent), they state that the Ontario Ministry of Natural Resources and Forestry (MNRF) said, “There was no record or information relating to this well.”
Therein lies the problem: there are no apparent government records for many of these wells.
Assessment of a property for the potential presence of historical wells requires what amounts to some geological sleuthing, using a variety of methods/sources of data and information. Some of the things we do involve research at local libraries, historical museums, historical societies, interviews, site inspections, etc.
A deeper investigation to confirm the location of these wells may include a geophysical survey, sample collection (vapour and soil), and laboratory analysis.
Other tools can be used, including drones with magnetic sensors and laser imaging. Some researchers are starting to pair topographical maps with artificial intelligence. See the December 2024 report from the (US) Berkeley Lab.
In Lambton County, $89,000 has been spent on the abandoned wells and the associated soil and groundwater impacts. They have also allocated an additional $250,000 for the project.
According to the report, Lambton County does not know how long it will take to complete its project.
The remnants of historical oil and gas exploration in Ontario pose a potential risk to human health and the environment (Photo by Delfino Barboza on Unsplash).
Brant County Abandoned Wells
The issue of abandoned oil and gas wells was discussed in a meeting in Brant County, Ontario. According to the MNRF, there are 269 well records for the county, and missing data for about 100 of those wells (Penticton Herald).
The article in the Penticton Herald states, “Brant is one of nine municipalities — along with Haldimand and Norfolk counties — working with the ministry to tackle this problem.”
In June 2025, the CBC reported on the issue of abandoned oil and gas wells in Brant County. They quote Rebecca Comley, the acting medical officer of health for Grand Erie Public Health, who said, “Legacy wells can be a source of potentially dangerous gases such as hydrogen sulfide. Leaking hydrogen sulfide into the atmosphere, into the air, especially in contained spaces, can cause a very dangerous health risk.”
The County of Brant has an informational flier, “Legacy Oil and Gas Wells.”
Norfolk County Abandoned Wells
Finally, Norfolk County, Ontario, is another community experiencing problems associated with abandoned oil and gas wells.
In August 2025, the CBC reported that a well dating back to 1910 was plugged, which, in turn, caused pressure to build and five new wells to “erupt before a relief well was drilled to ease the pressure.”
From the CBC, “In 2015, the Ministry of the Environment ordered that the relief well be plugged, which caused a half-dozen new wells to open up. In 2017, the pressure and higher water levels caused gas to push its way through a layer of clay in the ground, causing it to bubble up through area waterways from newly formed gas springs.”
Residents have complained about hydrogen sulphide odours and impacts to water. In some areas in Norfolk County, a sign warns of health risks associated with the odours. Norfolk County has a page dedicated to the ongoing issues in the community.
Environmental Consulting Help
The remnants of historical oil and gas exploration in Ontario pose a potential human health and environmental risk. They also pose a financial risk for owners or future investors of property who may unknowingly purchase property with these wells.
Dragun Corporation has experience in assessing properties for the potential presence of oil and gas wells. If you would like to discuss how we can help you, contact Christopher Paré, P.Geo. at 519-948-7300, Ext 114. Also, see our Abandoned Oil and Gas Wells Page.
Alan Hahn drafted this blog. Alan has an undergraduate degree in Environmental Studies and completed a graduate program in Environmental Management. He has worked in environmental management for more than 45 years. He has written hundreds of blogs and articles. His published work includes HazMat Magazine, BizX Magazine, Michigan Lawyers Weekly, GreenStone Partners, Manure Manager Magazine, and Progressive Dairy.
Christopher Paré, P.Geo, reviewed this blog. Chris is a senior geoscientist and manager of Dragun’s Windsor, Ontario, office. Chris has more than 30 years of experience on projects ranging from environmental site assessments (Phase One/Two ESA), excess soils, remedial investigations, soil and groundwater remediation, Permits to Take Water, Records of Site Conditions, vapour intrusion, and site decommissioning. Chris is a frequent speaker, author, and expert witness. See Chris’ bio.
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