Ammonia Inhalation Injury

It is hard to top the enjoyment of traveling the back roads in an RV. But just like boat, the constant maintenance can take a lot of the joy it. Things are constantly breaking, and the time you spend working on the RV is often more than you spend behind the wheel or camping out. This didn’t bother our patient, but unfortunately during one of his repairs he suffered a serious injury.

He had spent the last several weekends preparing his vehicle for the summer travels across the upper plain states. The refrigerator had not been cooling properly during his last trip, and he was determined to get it working. He felt for sure it was a coil in the boiler. Working alone, with the doors closed mind you, he carefully disassembled it. All of a sudden he was hit with with an envelope of noxious gas. He would tell us later he instantly knew the smell — ammonia.

He managed to get out of the door but stumbled down onto the driveway. He couldn’t stop coughing and became very short of breath. By the time he reached the hospital he was hypoxic and in significant respiratory distress. He was intubated and admitted to the ICU.

How RV Ammonia Refrigerators Works

There are 2 brands of refrigerators commonly found in RVs:

  • Dometic RV refrigerator
  • Norcold RV refrigerator

Both operate under the same principles. A sealed cooling element is heated either with a gas flame or an electric heating element. The cooling unit amounts to a series of tubes filled with an ammonia-based liquid. As heat is applied, the fluid circulates through the cooling unit drawing the heat out of the refrigerator.

Refrigerant grade anhydrous ammonia is a clear, colorless liquid or gas, free from visible impurities. It is at least 99.95 percent pure ammonia. Water cannot have a content above 33 parts per million (ppm) and oil cannot have a content above 2 ppm. Preserving the purity of the ammonia is essential to ensure proper function of the refrigeration system.

A strong ammonia smell inside the box, would indicate a leak in the evaporator section. If the unit has leaked for an extended amount of time the ammonia smell may no longer be present but you will probably hear a gurgling sound coming from the back of your refrigerator a few minutes after you turn it on.

Mechanism of injury

Inhalation of noxious gases and fumes, including nitric acid (solution of NO2 in water), sulfur dioxide (SO2), chlorine gas (Cl), and ammonia (NH3) can lead to acute injury by direct toxic affects on the oropharynx, larynx, trachea, and bronchial structures. This can cause mucosal sloughing and hemorrhage, which often manifests itself as coughing and hemoptysis.

However, even with relatively minor airway injury, the gases can condense and pool in the alveoli obliterating the capability for gas exchange resulting in further tissue damage and hypoxia. This can develop into ARDS (noncardiogenic pulmonary edema), irritant-induced asthma, or delayed onset of constrictive bronchiolitis (also known as bronchiolitis obliterans).

Bronchoscopy after ammonia inhalation

Our patient underwent direct laryngoscopy which demonstrated normal oropharynx and hypopharynx mucosa. On bronchoscopy he had moderate diffuse mucosal injury but only scant clear secretions.

Ammonia Inhalation Injury -- Trachea Figure 1. View of trachea and carina in a patient who suffered ammonia inhalation injury. Ammonia Inhalation Injury Bronchoscopy -- Right Main Bronchus Figure 2. View of right main stem bronchus in a patient who suffered ammonia inhalation injury. Ammonia Inhalation Injury Bronchoscopy -- Left Main Bronchus Figure 3. View of left main bronchus in a patient who suffered ammonia inhalation injury.

The patient did well. He was observed on mechanical ventilation for 24 hours, with do indication of increasing ventilator support requirements or development of pulmonary infiltrates on chest radiograph and lung ultrasound. He is being followed in Pulmonary Clinic for delayed effects.

2017-09-15T22:28:20+00:00October 14th, 2014|Case, Pulmonary, Toxicology|

About the Author:

Cardiac Intensivist, Resuscitationist, Emergentologist. Educator. Doodler. Friend. Most importantly, husband to my wife & superhero to my son.


  1. dave plummer m.d. October 18, 2014 at 4:51 pm - Reply

    Very nice Charles, thanks.

  2. Anonymous September 15, 2017 at 10:24 pm - Reply

    Did the ammonia leak into your camper like it did mine. Dometic has denied the fact the ammonia can come into the camper. The fridge has two huge holes around the tabs where you screw it to the cabinet and also you can see daylight from outside showing under the bottom of the fridge. I sent them pictures and I plan to get a fog machine and put in the back access and film it coming in the camper. I plan to send that video to the attorney general in order to hopefully get a world wide recall on this problem. I am not the only one that could have died from this leak. A family on here also could have died had their dog not awakened them and got them out of the camper. It has been over two months and you can still smell ammonia in the camper. I had the fridge removed immediately and for a month and a half you could not get within 20 feet of it and that was in the open air. I just had it put back in the camper so I could prove to the company that there is a defect in the manufacture of their fridge and the ammonia can come int the camper and kill you. They said the fact the cabinet was sealed would prevent the ammonia from coming in. The cabinet is sealed in the corners from top to bottom and all around the top and bottom of the cabinet. But that is not where it comes in. It comes in from below the bottom of the fridge and through the mounting holes at the top of the fridge behind the panel that has the on off buttons and such. I am warning every one if you have a dometic fridge in your camper pull the bottom metal plate and the control panel up top and you will clearly see where outside air can and will enter the camper. I had my ac on which circulates the inside air. It sucked the ammonia right in the camper while I was sleeping. My fingernails, hair and throat are still suffering from the effects of the 99.98% pure ammonia. Household ammonia is 10% and breathing it can cause problems so imagine what this will do to you if this happens to you like it did me the other family and God only knows how many other people. Please help by contacting the attorney general in Indiana and make a complaint when you find these open places where the ammonia can come in because if it develops a leak count your blessings if you live through it.

  3. James Acker October 30, 2017 at 8:49 am - Reply

    I Would like to ask you about this. Last week in a hotel in Italy I experienced a significant amount of ammonia coolant directly in the face. I now know it had leaked into main chamber (where items are stored for use in the minibar) about 2′ x 2.5′ x 1.5′ (guessing). I immediately was choking, experienced it being impossible to breathe, in or out, which lasted long enough for me to close the door, get to the bathroom area sink, splash water for what seemed like a very long time still not breathing. Then gradually was getting small breath. Went into the hallway and as I regained breathing had a coughing/burping fit for some minutes.

    After a while, maybe half hour I was feeling some better. Sore throat, more difficulty breathing, smell of ammonia in my nostrils for days. Got home and went to my doctor, and she didn’t seem to think or consider much, as I asked her if there could be lasting damage, scarring of the lungs, etc. I get the impression she didn’t understand that this was coolant, but rather was thinking of the type used for cleaning. I have not be examined at all by her or anyone. Question is can there be lasting damage, and should I see a different doctor?

    Thanks, if you can or would just give me a hint you can end to my email.

  4. Notcy December 3, 2017 at 7:26 pm - Reply

    There are two key disadvantages to using ammonia as a refrigerant.It is not compatible with copper and is poisonous in high concentrations.

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