|Calcium Magnesium Acetate (CMA) is made of dolomitic lime and ascetic acid. It is the only ice melter that is biodegradable, non-toxic, environmentally safe and pet friendly. However, it is not sold at regular retail stores because of its impractical price. It is mainly used on areas that need special protection from the environment, ie. airports, bridges, tunnels, etc. Though it is by far the safest ice melter, it does not work well when temperatures dip below 20 degrees.