A winter chill, a winter storm, especially the first winter snow and ice session, send most people into their annual snow and ice management routine. Checking the condition of the snow shovel or snow removal machine usually starts the process. Often its followed by decisions regarding the purchase of deicers to maintain ice free walkways and driveways. Nobody, not even the dog, enjoys slipping on an icy sidewalk.
Reading the ingredients to interpret any green label claim helps differentiate between the fluff and real stuff. After three decades of research documenting the deicing power of a chemical named calcium magnesium acetate, or CMA for short, it remains the deicer of choice for the average residential home.
Comparatively less corrosive than salt, its primary market competitor, CMA remains the deicer of choice for large scale transportation projects such as highway and airport deicing. Over the past few decades, CMA deicers also gained space on store shelves in retail establishments catering to residential customers.
Consumers tend to think of salt as a fairly benign chemical in most environments, under limited use. However, when used extensively, salt based deicers can corrode sidewalks and driveways, causing cracks, and saturate the soil with salts, causing stress on lawn and garden plants.
Excessive salt on driveways and sidewalks also causes potential problems for pets, because the salt disturbs their paws. That's not to say that CMA deicers are totally pet safe. According to the Society for Prevention of Cruelty to Animals,
Acute ingestion of these calcium salts is unlikely to increase serum calcium concentrations because of the requirement of an acidic pH, parathyroid hormone, and vitamin D for absorption. They are, however, moderately severe irritants and may cause gastritis and conjunctivitis. Emesis is generally not warranted unless these salts have been ingested with other problematic substances. Treat gastric upset symptomatically.
Both yard scale and larger scale, salt based deicing projects also contribute to local water quality problems when the excess runoff reaches streams and other water bodies. While all salt based deicers share these weaknesses, those packaged with urea sodium chloride, a common fertilizer repackaged as deicer, create additional potential water problems, such as eutrophication, or algal blooms.
Magnesium chloride products sometimes get marketed as environmentally friendly, compared to other salt based deicers. As part of the salt based deicing group, they perform well under extreme low temperature conditions. Nonetheless, they are less environmentally friendly than the acetate deicers.
CMA, the most widely tested and used deicer in the acetate category, is a natural acid, soluble in water. It shares chemical properties with vinegar. Marketed under a variety of brand names, CMA and other acetate deicers often post "non salt based" or "environmentally friendly" labels on their packaging.
Given the wide variety of deicer packaging labels, checking the ingredients remains the only accurate way to evaluate any deicing product claim. Most bags on the shelf will list the ingredients and their percentage of the total package. Look for packages that provide the least amount of salt.
Pricing also differentiates salt based and acetate based deicers. More costly to produce, acetate deicers usually cost twice as much as their salt based competitors. Over the years, CMA retail prices decreased in correlation with increased consumer demand, and increased demand for its use in other applications such as a sulphur scrubbing ingredient in the coal sector of the utility industry. Twenty to thirty dollars for a fifty pound bag gets most homeowners through the winter.
Some of the extra costs can easily be justified based on a long term calculation of potential savings accrued by avoiding long term sidewalk and driveway repair costs. Proper use of CMA deicers also decreases the per use cost of applying CMA during heavy periods of winter snow and ice.
Despite marketing claims, CMA deicers are not intended as one step, snow and ice removal products. Consumers facing a foot of snow on the walkway still need to shovel and remove the snow prior to any deicer application.
Consumers intending to use half a bag of deicer to cover a foot of snow, expecting the snow on the sidewalk to subsequently melt, will be disappointed with the result.
Consumers can choose from either liquid or crystallized CMA deicers. Typically the liquid form works as a preventative tool, deterring side walk and driveway ice build up over the course of below freezing temperature nights. Most CMA packages recommend loosely spreading the crystallized form of the deicer directly on top of ice as an after the fact, ice control remedy.
© 2007-2016. Patricia A. Michaels.