Ammonia

The Chemical

Anhydrous Ammonia is a compound of Nitrogen and Hydrogen with the formula NH₃

Ammonia is toxic and flammable in some concentrations. Ammonia has a strong sour odour so any leaks are generally quickly identified, whereas other refrigerants are odourless leading to delays in discovering leaks.

The predominant route of human exposure to ammonia is inhalation. Anhydrous ammonia is an upper respiratory irritant in humans, causing immediate irritation to the nose and throat. Acute accidental exposure can lead to death due to airway obstruction.  The skin and eyes are also extremely sensitive to airborne ammonia or ammonia dissolved in water and exposure can cause lesions. In the case of a skin or eye splash with anhydrous ammonia, frostbite can also be an issue.

Anhydrous ammonia dissolves rapidly in water to form ammonium hydroxide – a corrosive alkaline solution.

Its Uses

Ammonia is often used as a refrigerant. Ammonia has an ozone depletion rate of zero and a global warming potential less than 1. With a high latent capability Anhydrous Ammonia is both cost effective and environmentally friendly and therefore often the refrigerant of choice.

First Aid

Of all alkalis, ammonia is the most likely to damage the eyes. Low concentrations cause rapid onset of eye irritation. With high concentrations of the gas or with concentrated ammonium hydroxide then there is likely to be rapid swelling, and sloughing of the surface cells of the eye may occur causing temporary or permanent blindness. Responders should ensure they wear appropriate PPE and RPE before assisting a casualty.

Decontamination

Diphoterine® is extremely effective in decontaminating ammonia splashes to tissues. Its flushing action will remove chemical from the skin and eyes. Diphoterine® will quickly bind the hydroxide ions limiting damage and the hypertonic nature of the solution limits the progression of the damaging chemical into the tissues.