Anhydrous Ammonia

Health Information


Anhydrous Ammonia Health-Information Video Available


Anhydrous Ammonia Information for Health Care Professionals


What is anhydrous ammonia?

Anhydrous ammonia is a colorless, highly irritating gas with a sharp, suffocating odor.  People will notice the pungent odor at levels ranging from 5 – 50 parts per million (ppm).  Irritating effects generally begin at levels between 25-50 ppm.  More serious effects generally will not occur until levels are greater than 100 ppm.  


What are the immediate health effects of exposure to anhydrous ammonia?

Symptoms include burning of the eyes, nose, and throat after breathing even small amounts. With higher doses, coughing or choking may occur. Exposure to high levels of anhydrous ammonia can cause death from a swollen throat or from chemical burns to the lungs.


Eye exposure to concentrated gas or liquid can cause serious corneal burns or blindness.

Generally, the severity of symptoms depends on the degree of exposure.


What is the treatment for anhydrous ammonia exposure?

There is no specific treatment for the effects of anhydrous ammonia.  Immediate first aid includes providing fresh air, oxygen and flushing with water. 


Are any future health effects likely to occur?

Most people recover from a single low exposure to anhydrous ammonia without any delayed or long-term effects. After a severe exposure, injury to the eyes, lungs, skin, or digestive system may continue to develop for 18 to 24 hours, and delayed effects primarily to the respiratory system or the eyes are possible.


Anhydrous ammonia is not known to cause cancer.


What tests can be done if a person has been exposed to anhydrous ammonia?

If a severe exposure has occurred, blood and urine analyses, chest x-rays, pulmonary function testing and other tests may show whether the lungs have been injured. Testing is not needed in every case. Special eye examinations may also be conducted


What symptoms should I be most concerned about?

People who continue to experience coughing, difficulty breathing or shortness of breath, wheezing or high-pitched voice, chest pain or tightness, increased pain or a discharge from exposed eyes, increased redness or pain or a pus-like discharge in the area of a skin burn or stomach pain or vomiting should consult with a physician.


What is being done for the people exposed to anhydrous ammonia in the Minot area?

A program is being coordinated by First District Health Unit, Trinity Health, the North Dakota Department of Health and the Environmental Protection Agency to provide follow-up evaluation for people who experienced significant anhydrous ammonia exposure.


First responders, people living in the Tierracita Vallejo subdivision, and those who sought medical care or who experienced respiratory symptoms, will be contacted and offered the opportunity to complete a brief health questionnaire and to receive pulmonary function tests (PFT).  PFT results will provide information whether the respiratory system may have been affected by the exposure.  Those with significant PFT results will be referred to a health care provider for additional medical evaluation. 


People with PFT results in the normal range will be contacted in 1-2 months for a follow-up evaluation.  If they continue to have respiratory symptoms, a follow-up PFT will be offered.  Those with abnormal PFT results on the first PFT also will be offered a follow-up PFT. People with significant results on the follow-up PFT will be referred to a health care provider for additional medical evaluation. 


Guidelines for people returning to their homes include:


·     Food that was not in sealed packaging should be thrown away.  Food in the refrigerator should be safe to eat unless there was a power outage.  Perishable food items (meat, milk, etc.) in refrigerators where there was a loss of power should be discarded.  Foods in freezers during power outages are generally safe to eat unless the power is out for an extended time period.


Food in sealed containers, such as canned goods or those sealed in airtight plastic wrap or in plastic containers may be eaten after cleaning the container thoroughly with soap and water.


Food in boxes that have been opened, such as cereal, crackers, etc., that do not have an airtight seal, should be thrown away. 


If you are unsure about food products, a good general rule to follow is, “When in doubt, throw it out.”


·      These same general guidelines, apply to pet foods.  Pet food that had been left out should be discarded.  Pet food in sealed cans or in other airtight packages is safe after the outside of the container is wiped off with a wet cloth.  However, pet foods in bags that had been previously opened should be discarded.


Contact your veterinarian if your pet is experiencing symptoms which may be related to exposure to anhydrous ammonia.  These symptoms would be similar to those experienced by people, especially those involving difficulty breathing or other respiratory problems.  


·      There may be a white powder residual in your home.  This substance is ammonium hydroxide and occurs after anhydrous ammonia settles out after exposure to water.  It is similar to the ammonia used in general home cleaning.  If you notice any of this white powder on surfaces in your home, it can be safely cleaned up simply by using a wet cloth.  This substance could cause skin irritation, so rubber gloves should be used when cleaning.


If this white residue is on clothing or other fabrics, they can be cleaned in a washing machine.


Plates, silver ware and other eating utensils can be cleaned in a dishwasher or by washing with soap and water.


·      Avoid eating snow.  It is possible that the snow may be contaminated with small amounts of anhydrous ammonia and could cause skin irritation.  Direct skin contact with snow should be minimized.


Public health officials will be conducting continuing environmental and medical monitoring to provide further guidance to protect the health of people in the Minot community. 


Who should I contact for additional information?


If you experience health problems after returning to your home, or have any questions, please call First District Health Unit at 701-852-1376.   


Persons who experienced respiratory problems during the recent anhydrous ammonia incident, but who did not seek medical care also should contact First District Health Unit. Additional information is available at


Adapted from Ammonia Patient Information Sheet, Agency for Toxic Substances and Disease Registry, Centers for Disease Control and Prevention