As cold weather descends on the nation’s K-12 schools, the nonprofit 501c3 PC4HS group offers tips for choosing greener ways to de-ice concrete walkways including newer installations.
 
Preliminary steps involve the prevention of ice forming by removing snow before it compacts turning into ice, reducing the need for ice-melting chemicals, and closing off – where legally permitted – unneeded walkways, sidewalks, exterior stairs and roads that accumulate snow. If forecasts call for freezing rain, sleet, and/or wet, heavy snow, spreading ice-melting compound before (pretreating), during and after precipitation is most effective.
 
Develop, post and document a snow and ice-removal plan, including equipment, ice-melting chemicals and application guidelines for timely response to weather events. Include ergonomic and safety tips (such as correct snow-shoveling technique, and PPE such as gloves, goggles, earplugs) to prevent worker injury.
 
Non-chemical interventions to raise traction include sand, non-clumping cat litter, and dolomitic limestone.
 
Where ice-melting chemicals are needed, Green Seal recommends using potassium chloride- or magnesium chloride-based products rather than sodium chloride or calcium chloride. Ice melts are often blends of these substances, so look for desired major ingredients.
 
Exercise care near plants since all chlorides can be harmful to vegetation.  Potassium chloride or magnesium chloride products are safer for plants, concrete, and entryway flooring materials.  Acetate-based products may also be safe options, especially for newer concrete, though possibly harmful to aquatic life. Urea (aka, nitrogen fertilizer) is safer for concrete but does not work at low temperatures and can be harmful to waterways.  For newer concrete, check with the concrete supplier or installer for specific de-icing recommendations.
 
Granular, pellet, crystal or other solid ice-melt products, colored for visibility, can be helpful to provide traction and break bonds between ice and outdoor surfaces. Use a mechanical spreader for best coverage and to avoid waste and skin exposure.
 
Liquid ice melt is helpful in preventing ice from forming and for steeply sloped areas; use a sprayer and carefully control the spray to avoid unwanted application or exposure.
 
Since ice-melting products are temperature specific with distinct traits, read labels and select those that meet temperature and other criteria.
 
The U.S. EPA’s Design for the Environment (DfE) program notes environmentally-safer ice-melting products  at  http://www.epa.gov/dfe.
 
Environmentally-speaking, there are no perfect ice melting compounds, and prevention or removal is best where possible.