Every winter, the United States spreads between 10 and 20 million tons of rock salt over icy roads. In total, the country spends $2.3 billion on de-icing for highways alone – this cost covers plowing, salt and other methods.

Salt is effective up to a certain point because it lowers the freezing temperature for water, but the environmental impacts can be devastating. A study from the University of Minnesota found that as much as 70 percent of road salt gets washed into waterways like lakes and rivers. This salt decreases fish populations and can alter their development.