By Meetkumar Patel, Canada Summer Jobs student with Rescue Lake Simcoe Coalition
Every winter, Ontario gears up for a familiar ritual: pouring 3 to 5 million tonnes of road salt across streets and highways like confetti at a frozen parade. We are told it’s the cost of safety. Yet beneath that white layer of comfort lies a deteriorating reality. Salt isn’t merely battling ice, it’s stealthily declaring war on our roads, bridges, and our precious waterways and ecosystems.
The Science Of Salt
The average road salt (NaCl) does not just melt ice, it infiltrates into concrete. Chloride ions penetrate concrete and steel, setting off a chemical cascade. According to the Ontario Structure Inspection Manual (2008), chloride-induced corrosion is enemy number one when it comes to deck deterioration. MTO’s own 2022 study found that once chloride concentrations exceed 0.05% by mass of concrete, reinforcing steel corrodes. Rust expands causing cracking, spalling, and structural failure. Just a sprinkle too much, and concrete begins to crumble.
Can high-tech bandages stop the budget bleeding?
Ontario’s bridges tell a grim story. In the few cases where MTO has recognized the threat, they’ve intervened. On the North Otter Creek Bridge near Walkerton (2003), Highway 404 Highway 7 overpass, Kirkwood Avenue Overpass (Ottawa), Highway 401 King street overpass (Cambridge), MTO installed galvanic anode systems to protect the reinforcing steel from further corrosion. Within the system, MTO installs zinc rods in concrete, which redirects corrosion and extends lifespans. But even high-tech bandages can’t stop all the bleeding.
The Cartier Bridge on Highway 17 (Québec) needed a complete deck replacement costing $6.5 million in 2021 because of salt damage. The Gardiner Expressway in Toronto is experiencing a multibillion-dollar restoration, featuring a $6.8 million galvanic casing to fix pier substructures damaged by chloride infiltration. These are striking instances but comparable corrosion is unseen, yet common and found on numerous roads, bridges, and pipes that have been long overlooked.
The grown-up version of tightrope-walking is taking place in various municipalities, and officials need to weigh road safety against deteriorating infrastructure. Ontario’s unchecked urban sprawl, combined with its harsh winters, has made it the epicentre of Canada’s salt corrosion crisis. According to the Transportation Association of Canada (2013), Canadians spend over $1 billion annually on winter maintenance, studies by the U.S. Transportation Research Board suggest that salt corrosion costs in North America may total $3–5 billion annually, including impacts on roads, bridges, and vehicles with 30–40% of Canadian side of burden falling on Ontario. Environment Canada (2004) also cautioned that salt corrosion costs the nation “billions each year.” In the Lake Simcoe watershed, the LSRCA (2019) noted that 45% of urban locations surpass safe chloride limits, compelling municipalities to spend on costly stormwater upgrades. Ontario’s expansion isn’t merely covering green areas, it’s hastening infrastructure deterioration and environmental damage, one salty winter at a time.
A Salty Cry for Help: Lake Simcoe Watershed.
In the Lake Simcoe watershed, that harm is actual and quantifiable. Barrie’s 2024 capital plan designates $98 million for roads, bridges, and stormwater systems; their Salt Management Plan highlights salt as a primary cause of deterioration. York Region, meanwhile, invests between $1.0 and 1.3 billion in infrastructure renewal annually (2024 and 2025) and has committed over $7 billion over the next decade, $2.7 Billion allocated to transportation projects and $4.64 billion to water and wastewater projects. The region’s “Salt responsibility” plan verifies that corrosion is directly linked to exposure to salt. Taxpayer dollars are being spent to create the problem with excessive salting, then to repair the damage to infrastructure, and finally to address ecological impacts.
Information from the Lake Simcoe Region Conservation Authority (LSRCA) indicates that chloride levels in the lake are increasing by 0.7 mg/L annually, with current concentrations around 49 mg/L, getting close to the chronic toxicity limit of 120 mg/L. Monitoring in impacted tributaries like Hotchkiss and Western Creeks (Barrie) frequently notes levels of 6,000–26,000 mg/L, surpassing acute toxicity thresholds of 640 mg/L and resulting in the deaths of fish, amphibians, and essential aquatic insects.
These human-made “dead zones” result directly from excessive salting. During the winter of 2012–13, a total of 60,613 tonnes of chloride (more than 90,000 tonnes of salt) were distributed throughout the watershed. This amounts to 150 kg (330 lbs) of chloride for each individual annually, primarily sourced from local roads (43%) and regional streets (30%), with lesser contributions from highways and parking areas, though these last two tend to be hot spots for salt. The LSRCA model predicts that 64% of Lake Simcoe watersheds would reach chloride levels detrimental to aquatic organisms, affecting as many as 45 species, at the anticipated built scenario in 2031.
In order to confidently quantify the lifecycle costs of salt, it would be helpful if municipalities identified corrosion-related repair expenses from salt damage from general infrastructure restoration in their budgets.
The Rescue Lake Simcoe Coalition calls on you to act. We are advocating for Limited Liability for the Snow and Ice Management sector, in Ontario, to support their businesses’ viability while complying with prescribed maintenance training and standards for salt reduction. So far, 19 municipalities have passed our Ontario Salt Pollution Coalition motion, asking Ontario to act on salt pollution. But local people can also help make their municipalities greener. Check out our map and if your municipality isn’t listed, get in touch with your local councillor and ask them to support our campaign by passing our motion. More info here: https://saltcoalition.ca/#take-action. Businesses and individuals can sign our petition to assist in halting salt pollution in Ontario at the same link.
Each signed petition, every question posed, and every story told about deteriorating roads and bridges amplifies our united voice.
References:
LSRCA (2023). Identification of Salt Vulnerable Areas in the Lake Simcoe Watershed. Link
LSRCA. “Salt.” webpage. Link
Town Of Georgina, Lake Simcoe Science, Sodium Chloride. Link
Ontario Ministry of Transportation & Vector Corrosion (2003). Distributed Galvanic Anode Trial – North Otter Creek Bridge. Link
Vector Corrosion (2022). Galvanic Corrosion Protection. Link
Winter, J.G., et al. (2011). Increasing chloride concentrations in Lake Simcoe and its tributaries, WQ Res. J. Canada 46. Link
CCME (2011). Canadian Water Quality Guidelines for the protection of aquatic life: Chloride. Link
Road salt is bad for the environment, so why do we keep using it? Link
Syntheses of Best Practices Road Salt Management. chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.tac-atc.ca/wp-content/uploads/roadsalt-1.pdf?
Review of Progress: Code of Practice for the Environmental Management of Road Salts 2014 to 2019. Link
Ontario Ministry of Transportation. (2008). Ontario Structure Inspection Manual. Retrieved from https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubsPortal.html
Ontario Ministry of Transportation. (2022). Bridge Condition Report. (Referenced data on chloride threshold of 0.05% mass corrosion). Available through MTO Technical Reports Archive.
City of Toronto. (2019). Strategic Rehabilitation Plan for Gardiner Expressway. Retrieved from https://www.toronto.ca/community-people/get-involved/public-consultations/gardiner-rehabilitation
Rescue Lake Simcoe Coalition. (n.d.). Stop Salt Pollution in Lake Simcoe [Petition]. Retrieved from https://win.newmode.net/ospc/stopsaltpollution
Lake Simcoe Region Conservation Authority. (2023). Chloride Trends & Watershed Impact Report. Retrieved from https://www.lsrca.on.ca
City of Barrie. (2024). Capital Plan Summary: Roads & Infrastructure. Retrieved from https://www.barrie.ca
York Region. (2023). Salt Management Plan. Retrieved from https://www.york.ca
Financial Accountability Office of Ontario. (2022). Infrastructure Backlog & Renewal Costs Report. Retrieved from https://www.fao-on.org/en/Blog/Publications/infrastructure-spending
Watersheds Canada. (2023). Salt Impact on Aquatic Life. Retrieved from https://watersheds.ca
https://content.ampp.org/ampp/proceedings-abstract/CONF_MAR2023/2023/1/60101