This blog post started out as an attempt to list more environmentally-friendly de-icing products. Since Cuyahoga SWCD started making a serious effort to point out the dangerous impacts of rock salt and other chloride-based de-icers on water quality and aquatic life, we've been getting a lot of questions about what environmentally-friendly alternatives are available. Up until now, our responses have largely been limited to using more elbow grease and less salt.
While those recommendations are still solid advice, some additional research has turned up a few alternative de-icing agents that are less harmful to aquatic life. Disappointingly, the primary alternatives discovered – acetates and formates – are extremely difficult to find commercially. More often, you’ll find calcium magnesium acetate (CMA) as an additive to chloride-based de-icers, or blended with sodium chloride or magnesium chloride. Ideally, chloride-based de-icers would be avoided in order to protect water quality.
Unfortunately, many of the de-icers that are advertised as being “pet-friendly” or “environmentally-friendly” contain glycol mixtures, which can still be toxic to aquatic organisms, and have a high oxygen demand in aquatic systems (they use up a lot of oxygen in the water as they decompose).
Summary of Alternatives to Rock Salt
Calcium magnesium acetate (CMA) is formulated from dolomitic lime and acetic acid. It is effective to a temperature of ~0° F, but effectiveness decreases below 20° F. Like rock salt, it is generally available in granule or pellet form. There is some concern about its oxygen demand as it degrades in water, but a USGS study in Oregon found no negative water quality impacts from roads treated with CMA. Other acetate-based de-icers include Sodium Acetate and Potassium Acetate.
Formates, specifically Sodium Formate and Potassium Formateare often used as a de-icer on airport runways. Sodium formate is effective down to 0° F, while potassium formate functions at temperatures down to -20° F. Like CMA, formates do not persist in the environment, but rather degrade in water, so hypothetically the primary water quality concern is oxygen demand.
The one commercially available chloride-free alternative that I was able to find is Entry Fast Acting Liquid Ice Melt (https://chloridefree.com/). It is a potassium formate-based deicer. Limitations include that it requires spray application and it is substantially more expensive than rock salt and other chloride-based deicers.
Have you been able to track down any commercially available chloride-free de-icers? If so, let us know by commenting below!
Caveat #1: It is important to note that while these may be safer for water quality, the application of these products still introduces a substance into the environment that wouldn’t have been there otherwise.
Caveat #2: For the purposes of this blog post, we are considering the post-application impact of deicing agents on surface water quality. The upstream environmental impacts associated with the production of these materials have not been considered.
Caveat #3: This is by no means a comprehensive list of all alternative de-icers. The inclusion or exclusion of a product here should not be considered an endorsement or indictment of that product.
Blog Author: Jared Bartley, Rocky River Watershed Program Manager