ROAD CREW crystals begin melting ice and snow instantly to create a brine that breaks the bond of ice. Most ice melters stop at 20-25-F above zero. ROAD CREW works effectively down to -15-F below zero. Potassium chloride, sodium chloride, urea and any combination of the three are not reliable below +20-F. Not all Deicers are Created Equal. Performance is determined by: Melting Time Temperature Foot and Vehicle Traffic Shape and Composition of Deicer Particle   Tough on Ice and Snow, Easy on Plants and Concrete. Any deicer may be harmful to vegetation, but when used as directed, ROAD CREW will not damage trees, shrubs, flower beds, grass or concrete. The lower the chloride content, the lower the risk. The application of ROAD CREW results in one of the lowest amounts of chloride accumulation among commercial deicers.