Ammonia has desirable characteristics as a refrigerant, which have been well known for over a century. People in France first started using ammonia as a refrigerant in the 1850’s, and its use was brought to the United States in the 1860’s. By the 1900’s, ammonia refrigerators were being used in many commercial facilities to create blocks of ice, keep food cold, and produce other chemicals. Starting in the 1920’s, it was used in ice rinks.