Is The Blue Stuff They Spread After Ice Harmful?

Q: Before a snow or ice event, the city spreads something on the street in front of my house. They used this clumpy blue stuff which I find afterwards on my lawn and flower beds. What can be done to avoid harm? 

A: It all depends on what chemical was used. There are several product possibilities. Some are more harmful to plants than others. The product could contain potassium chloride, sodium chloride, urea, calcium magnesium acetate, or something else. If you’re not sure what is used, thoroughly soak the soil with water wherever the chemical is found. Repeat at least three times. If sodium chloride was used, gypsum can be applied to ameliorate damage from sodium.