Road salt must have a sodium chloride (NaCl) content of at least 97%, based on an analysis carried out on dry salt. The salt also contains anticaking agents (potassium or sodium ferrocyanide) up to an allowed maximum of 150 ppm (0.015%). No requirements have been defined for granularity. Traditionally, winter salt has had a maximum granularity of 5 mm and contained up to 5% fines (screen 0.125 mm). Potassium chloride (CaCl2) can only be used as a solution in small doses for moistening granular sodium chloride. Potassium chloride is usually procured as a ready-made 32-per-cent solution.

In groundwater areas, potassium or sodium formate have also been tested as more environmentally friendly alternatives to salting. However, potassium and sodium formate are considerably more expensive than regular salt, which limits their use. They are also not as effective for preventing slippery conditions as regular salt.

Read more about antiskid treatment and its impacts on the environment:

• De-icing of roads (Finnish Transport Infrastructure Agency) in Finnish
• Winter maintenance (ELY Centre) in Finnish
• Groundwater and soil (Finnish Transport Infrastructure Agency) in Finnish