Frequently-Asked Questions about Anhydrous Ammonia


April 26, 2019

What is ammonia?

Anhydrous ammonia (NH3) is the foundation for all nitrogen (N) fertilizers. Although almost 80 percent of the earth’s atmosphere is comprised of nitrogen, it is not in a chemically and biologically unusable form for plants. Using a complex method called the Haber-Bosch process, nitrogen is captured from the air, combined with a hydrogen source and converted into a form that can be used by growing plants. Ammonia in this form is also known as ammonia gas or anhydrous (“without water”) ammonia. At room temperature, ammonia is a colorless, pungent-smelling gas and is lighter than air. At minus 28 degrees Fahrenheit, ammonia is stored as a liquid. Ammonia easily dissolves in water. 


Why is it important?

Fertilizers account for 50 percent of global food production.  Nitrogen is an essential element for plant, animal and human life. It is found in water, soil and air, and is a source of much needed nitrogen for plants and animals.


How is ammonia applied as a fertilizer? 

When anhydrous ammonia is applied directly into the soil, it is a pressurized liquid that immediately becomes a vapor after leaving the storage tank. Anhydrous ammonia is always injected at least 10 to 20 cm below the soil surface to prevent its loss as a vapor back to the atmosphere. Various types of tractor-drawn applicators are used to place the NH₃ in the correct location. 


How is it regulated?

•    Anhydrous Ammonia held at retail facilities is regulated at both the federal and state levels. Agricultural retailers who handle, transfer, transport or otherwise work with ammonia must hold commercial drivers’ licenses, be trained to   understand the properties of ammonia, become competent in safe operating practices, and be able to take appropriate actions in the event of a leak or an emergency. Refresher training should be completed at least every three years. The federal government and some states have a regulatory exemption from these rules for grower-operated farm equipment.

•    The U.S. Department of Transportation (DOT) requires each pressurized vessel transporting a hazardous material in commerce on a public highway to be equipped with a legible American Society of Mechanical Engineers (ASME) data plate. DOT does allow tanks with missing or illegible data plates, provided they are inspected once every 5 years and undergo a visual, thickness, and pressure tests.

•    Each nurse tank must be equipped with the following safety equipment and features:

  • For first aid purposes, at least 5 gallons of clean water in a container designed to provide ready access to the water for flushing any area of the body contacted by ammonia;

Some states also require nurse tanks to be equipped with the following:

  • A legible decal depicting step-by-step ammonia transfer instructions; and
  • A legible decal listing first aid procedures to follow if injured by ammonia.

•    Facilities storing anhydrous ammonia in quantities of 10,000 lbs. or more are required to have an EPA-approved Clean Air Act Risk Management Program plan to address accidental releases of ammonia. Each facility covered under the act is required to conduct an offsite consequence analysis for a worst‐case accident, a hazard assessment and an accident prevention program.


Ammonia Safety

Handling anhydrous ammonia requires careful attention to safety. When at storage facilities, prior to transit and during field application, appropriate personal protective equipment must be utilized. Since it is water soluble, free ammonia will rapidly react with body moisture such as lungs and eyes to cause severe damage.

  • Fertilizer retailers take exceptional care in handling ammonia by utilizing specialized equipment that is inspected and certified, ensuring personnel are extensively trained and providing specialized personal protective equipment for employees.
  • The fertilizer industry is committed to the safety of its employees and members of the communities in which it operates. Training for emergency responders is conducted by state fertilizer associations, individual companies and TRANSCAER® (Transportation Community Awareness and Emergency Response), an industry-supported national outreach effort that assists communities to prepare for and to respond to an ammonia transportation incident.  


External Links:

•    ATSDR Guidelines for medical management of acute exposure to ammonia

•    TRANSCAER® emergency responder training for ammonia releases

•    ResponsibleAg an industry-driven initiative that provides retailers with tools to assess their compliance with applicable federal relations

•    Asmark Institute A national resource center serving the agricultural retail industry. Asmark serves retail agribusinesses, state and national trade associations, educational institutions and government agencies.


Media contact: Kathy Mathers