Salt Dome

This is one of eighteen (18) salt storage facilities in the City of Toronto. The City typically uses from 130,000 to 150,000 tonnes of salt annually to clear ice and snow from city streets. This is enough to cover the football field at the SkyDome to a depth of about 20 metres.

Salt Dome in Don Valley, May 2007 ‐ Stores road salt for use on Toronto streets in winter

Salt is not what one would call environmentally friendly. It corrodes cars, damages bridges, kills trees and plants and poisons our lakes, streams and groundwater. It is a significant enough hazard that in 2001, Environment Canada listed road salt under Schedule 1 of the Canadian Environmental Protection Act as an environmentally toxic substance. There is strong disconnect between the science which confirms the environmental impact on Ontario’s drinking waters, lakes and rivers, and the fact that road authorities in Ontario continue to apply large quantities of road salts for de-icing our roadways. While road salts are assumed to be the cheapest method of de-icing winter roadways, this does not consider the more than six billion dollar annual damage cost to built infrastructure in North America due to the use of this corrosive material and its damage to the ecosystem.

The proponents of salt tell us that it is readily available at low cost and highly efficient. It keeps our roads safe. Salt spread on our streets can reduce injuries during a winter storm by up to 90 percent. On the one hand, we have a chemical that saves lives and keeps our economy on the move; on the other hand, a chemical that causes environmental damage. If you are an environmentalist, you want to campaign against it, but if you are responsible for keeping roads clear, you emphasize the safety benefits.

The City of Toronto’s Transportation Services Division knows the risks of road salt to the environment and has made changes to reduce the amount of salt entering the environment. It has developed salt management plans to reduce environmental impairment without compromising safety. These include ways to reduce environmental impacts, implementing best management practices; providing training, keeping records and reviewing results annually so that improvement can continue. Some helpful techniques used are electronic controls synchronizing spreading with vehicle rates; pre-wetting with liquid anti-icers to make salt more efficient and to keep it on the roads; treating roads with liquid de-icers before storms to prevent snow and ice bonding to the pavement; infrared thermometers to determine road temperatures; and weather stations that monitor road conditions continuously.

The reduction in salt use is balanced with the need to keep roads and sidewalks safe for users at a reasonable cost. This not only reduces environmental damage and damage to cars and bridges, but saves money at the same time. “While it is difficult given the variability of weather conditions to accurately assess just how much salt we have saved, our best assessment is that we have reduced salt consumption by about 15 percent - approximately 20,000 tonnes a year. Based on a direct cost of about $50 per tonne to buy salt and another $25 per tonne in additional costs to store, manage and spread the salt, that amounts to a saving of about $1.5 million a year.” Environmental protection is good economics.

For more about the city’s plan go to this site

RiverSides Stewardship Alliance, a Toronto based non-profit organization dedicated to helping communities protect and restore water quality in urban watersheds, has developed a campaign to prevent road salt contamination of rivers, groundwater and drinking water sources, “The Low-Salt Diet,” that questions our over-reliance on road salts. Road salt runoff from roadways, parking lots, and storage facilities goes directly into our rivers and lakes via the storm sewer system. Road salt contaminated meltwater flows over the impervious roadways or parking lot surfaces, into a curb catch basin inlet or gutter, into a storm sewer and finally ends up in a nearby creek, river or lake.

For more on the environmental perspective go to

For a RiverSides report on the road salt issue and recommendations about what to do, got to this page