Anhydrous ammonia is one of the most efficient and widely used sources of nitrogen for plant growth, making it a staple in modern agriculture. Despite its benefits, anhydrous ammonia is also one of the most hazardous chemicals used in agriculture. It is stored and transported under pressure as a liquid but becomes a gas at atmospheric pressure. The term "anhydrous" means "without water," therefore, anhydrous ammonia has a strong affinity for water and will seek out moist areas to combine with water, making the human body particularly vulnerable.

Health Effects of Exposure

Short-term exposure to anhydrous ammonia can lead to:

  • Irritation and burns to the eyes, nose, throat, and respiratory tract.
  • Skin burns and blistering.
  • Difficulty breathing.
  • Temporary or permanent blindness.

Long-term exposure or high concentrations can cause severe respiratory damage, including pulmonary edema (excess fluid in the lungs), and can be fatal.

Personal Protective Equipment (PPE)

To minimize the risks associated with handling anhydrous ammonia, it is important to wear appropriate personal protective equipment (PPE) including:

  • A face shield and/or goggles to protect your eyes and face from exposure. A combination of both offers the best protection. Never wear contact lenses, as ammonia can get under them, causing severe and permanent eye damage.
  • Rubber gloves that extend beyond the wrist and turn the cuff down to prevent ammonia from running down your sleeve. Ensure the gloves are properly rated for chemical protection against anhydrous ammonia.
  • Heavy-duty shirts and pants that cover all exposed skin. For added protection, wear chemical protective clothing that is specifically rated for anhydrous ammonia.

First Aid Measures

In the event of exposure to anhydrous ammonia:

  • Immediately flush eyes with copious amounts of water for at least 15 minutes.
  • Remove contaminated clothing and rinse affected skin with water for at least 15 minutes. Remember the sub-zero temperature of anhydrous ammonia can freeze clothing to the skin. Make sure to thaw the exposed area prior to removing clothing. Seek medical attention immediately after rinsing, even if symptoms appear to subside.
  • Seek medical attention for severe burns or if irritation persists.
  • Move the affected person to fresh air immediately.

Remember, safety doesn’t have to be difficult, simple steps, such as wearing the appropriate PPE, can prevent injuries.

Source: “Using Agricultural Anhydrous Ammonia Safely” University Extension, University of Missouri Columbia.