What form of Ammonia is primarily considered hazardous when it comes into contact with the skin?

Liquid ammonia is primarily considered hazardous when it comes into contact with the skin because it is highly corrosive. When liquid ammonia spills onto the skin, it can cause severe chemical burns or frostbite due to its low boiling point and rapid evaporation, which can chill the skin and underlying tissues.

In contrast, while ammonia gas and vapor can also be hazardous through inhalation or exposure to mucous membranes, they do not directly cause the same level of skin injury as liquid ammonia. Compressed ammonia, while it can be dangerous due to the pressure and potential for release, is not a form that typically makes direct contact with skin in a hazardous way. Thus, recognizing the specific dangers associated with the handling and exposure to liquid ammonia is crucial for safety training in industrial environments.