Corrosion Threat of De-Icing Salts and Road Salts

Close up of Effects of De-icing Salts being used on the road to melt snow.

Summary: For regions that experience snow, ice or freezing rains during the winter months, de-icing salts are a common method of keeping roads safe. But numerous studies have shown the harmful and hazardous effects of de-icing salts to the environment.


For regions that experience snow, ice or freezing rains during the winter months, de-icing salts are a common method of keeping roads safe. De-icing salts are applied to surfaces where there is icy build-up. The de-icing salts reduce the melting point of water and in doing so, prevents ice from forming.  However, numerous studies have shown road salts to be hazardous to the environment. The chemical make-up of salts used for de-icing purposes can include sodium chloride, calcium chloride, potassium chloride and magnesium chloride. When these small compounds are released into the environment, they can upset the existing balance of the ecosystem and affect the wildlife and plant life that reside there.


The Effects of De-icing Salts

To see the damaging effects of de-icing salts, one only needs to look at the corrosion they can cause on buildings and architecture. So undeniable is the evidence of road salt corrosion that the damage done is often compared to coastal architecture corrosion caused by natural sea salt. Buildings that are located in coastal regions experience corrosion from the abundant amount of sea salts that are released into the air and carried by wind, rain or traffic. Basically, that means that comparing the weather and humidity in an area where road de-icing salts are used, to a coastal region, provides a real world model of how much damage results from the use of road salts.

Damage is not limited to architecture and buildings close to where salts have been used, either. Moving vehicles, and especially heavy duty types, cause road salt mists to form in the air. These mists consist of either salt water or dry particles, which, depending on the environmental factors involved can travel up to 1.2 miles from the treated area.

In some studies, it has been reported that road salt particles were present as far up as the 59th floor of buildings.


Dangers of De-icing Roads Salts

De-icing salts not only cause corrosion, they also pose a real threat to water quality and vegetation. Runoff from deicing salts can end up in groundwater and fresh water sources, polluting drinking water reservoirs. High amounts of chlorides can affect the oxygen levels which could be toxic to fish and wildlife. 

On land, de-icing salts can cause significant plant damage – as seen in dried up or brown leaves and needles, loss in foliage or even premature plant death. Runoff from de-icing salts can end up in the soil and being absorbed by plant roots, and the sodium can cause soil compaction while reducing water infiltration, making it hard for plants to receive water.


The Necessity of De-Icers

However, de-icing of roads are a must for many regions. Ice-related highway and business closures can have significant economic impact and costs. The United States alone uses between 13.6 to 18 million metric tons (or 15 to 20 million tons) of de-icing salts per year as reported by TMR Consulting. In Canada, 3.6 to 4.5 million metric tons (4 to 5 million tons) are used per year. 70% of roads and populated areas in the United States experience snow, ice or freezing rain during the winter months. Considering the size of the geographic area that requires de-icing of roads, the negative impact of utilizing road salts is multiplied.

Despite compelling evidence of negative effects of de-icing salts on the environment, the use of road de-icing salts continues to grow. Even ‘sunbelt’ cities and towns are stocking salt in the event of freezing rains. De-icing salts are the cheaper option for keeper roads safe during winter months, but its negative implications on the environment must not be forgotten.

Aluminum is considered a highly corrosive resistant material; mainly because of the protective oxide film used in its construction. Road salts, which contain chlorides, can easily penetrate this protective film and cause corrosion. The only way to prevent corrosion, apart from ensuring that only a product such as DUST/BLOKR® is used for dust control and de-icing, is to regularly clean the surface and remove salt deposits. Aluminum corrosion is identified by a white or greyish dust forming on the surface of the metal.

Although not the most significant contributor to the corrosion of zinc building materials, salts do increase the rate of effect. However, it should be noted that in areas where road salts are used, zinc shows a marked increase in the rate of corrosion, and especially in sections of buildings where rain fall is unable to provide a natural run-off to wash away corrosive compounds.

Untreated carbon weathering steel shows high levels of corrosion, when exposed to road salt build up and residue. As long as the use of road salts continues, these materials require the application of expensive and labour intensive maintenance using protective paints. Again, it becomes apparent that the most cost effective solution to the problem of corrosion is to use a safer, environmentally friendly and non-corrosive product, such as DUST/BLOKR®.

Some stainless steel types, although non-corrosive even when submerged in salt water, are still affected by road salts. The reason for this is that, unlike sea water, road salts can build up around certain stainless steel applications. Studies have shown, time and time again, that road salts can affect any application that is subject to corrosion. DUST/BLOKR® has the potential to completely eliminate this problem, while also saving homeowners and businesses in the long run, and so, offsetting the initially higher cost of the product.


A Better Alternative

In partnership with Western University’s Departments of Chemistry, Civil Engineering, and Environmental Engineering, Cypher Environmental has been working on a 2-year research project investigating new environmentally friendly and non-corrosive de-icing solutions. Researcher Emily Verkuil presented her initial research earlier this year at the Canadian Chemistry Conference and Exhibition

This is an exciting development for Cypher as we have been working on introducing an environmentally friendly de-icing alternative to the harmful chemicals that are being used in common de-icing products.



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