A Case-Report of Chemical Pneumonitis and Burns from Pressurized Liquid Ammonia 

Case Report

A Case-Report of Chemical Pneumonitis and Burns from Pressurized Liquid Ammonia

Corresponding author:  Prof. Maria Stefanidou, Department of Forensic Medicine and Toxicology, Faculty of Medicine, National and Kapodistrian, University of Athens, 75 Mikras Asias, Athens 115 27, Greece,
Fax: +302107462410; Tel: +302107462415; Email: mstefan@med.uoa.gr


Anhydrous ammonia is widely used in industry and agriculture. Therefore, accidental exposure to it is relatively common. The autopsy findings of a 35-year-old woman who died shortly after exposure to anhydrous pressurized liquid ammonia during an industrial accident is presented. The victim showed chemical burns on her body surface and on her face, conjunctivitis and opaque cornea on both eyes, as well as pulmonary oedema and congested lungs with large areas of hemorrhage. These findings were consistent with injuries inflicted by a corrosive substance like ammonia. Such accidents can be prevented. The use of protective equipment should be mandatory and workplace physicians should be aware of the possible dangers of handling pressurized anhydrous ammonia and educate accordingly the workers.

Keywords: Ammonia; Occupational Exposure; Accident; Toxicity


Anhydrous ammonia is a colorless gas with an extremely strong smell. Its widespread use in industry and agriculture has resulted in a number of cases with significant exposure and burns of the victims. This chemical is a starting material for the manufacture of nitric acid and an ingredient for a number of explosives, synthetic fibres and fertilizers. Due to its endothermic nature, when going from liquid to gaseous state, ammonia has found applications as a refrigerant [1, 2].

Ammonia has a potential to cause grave damage due to its toxic, alkaline chemical nature. The high solubility of ammonia gas in water means that the exposure to a sufficient amount of this gas would probably cause injury similar to those caused by other alkalis. The parts of the body most susceptible to the insult are the skin, the eyes and the lungs [3]. The consequences of the cold injury that results from the evaporation of pressurized liquid anhydrous ammonia have been minimized or overlooked by other authors [4]. The chemical burns due to ammonia have been well documented, but the contribution of a cold (frostbite) injury has only recently been highlighted [5]. Cold injuries from other pressurized liquids and gases, like nitrous oxide, nitrogen, propane and helium, have been reported in the past [6-9].

This report presents a fatal case of a woman who suffered chemical and cold injury due to accidental exposure to pressurized ammonia and had a fatal outcome. The aim of this report is to alert the workers and the workplace physicians about the possible dangers and accidents that may happen during use and storage of pressurized liquid anhydrous ammonia.

Case Report

In a food industry which produced frozen dough, ammonia was used as a refrigerant and was stored in huge gas cylinders. An electrician, during his routine repairing work, accidentally loosened up the valve of a pressurized liquid ammonia cylinder resulting in an explosive release of ammonia gas. A 35 year- old woman, who was working near the electrician at the time of the accident, was exposed to large amounts of pressurized ammonia and she was found lying unconscious next to a burst ammonia pipe line. The woman, the electrician and 16 more workers, all of the same division, were immediately placed under a shower at the accident site for several minutes. All victims were transported to the nearest hospital. The electrician suffered from serious burns while the other 16 workers suffered from mild burns. The woman was pronounced dead on arrival. Neither worker was wearing any protective clothing, masks or goggles.

Gross Pathology of the Decedent

The body belonged to a white, well developed and well-nourished, 35 year-old woman. The victim’s body emitted strong smell of ammonia and showed chemical burns covering about 30% of the body surface. At the burnt areas, notably the face and limbs, the skin was peeled off exposing red and raw underlying tissues. The lips were red and raw and their superficial layer of mucosa was peeling due to an extensive burn. Both eyes showed conjunctivitis and opaque cornea. No other injuries were observed.

Burnt areas covered the most anatomic regions of the face, thorax, abdomen, cervical and scapular regions, right upper limb as well as gluteal region. The brain was congested and oedematous. The soft tissues of the thoracic wall were burnt. The skin was peeled off exposing red underlying tissues and ulceration of larynx, trachea and bronchi. Both lungs were oedematous, congested with large areas of haemorrhage. The trachea and bronchi were congested with mucous. The glottis was oedematous. The toxicological analysis of biological fluids was negative for medicinal drugs, drugs of abuse and alcohol.

The cause of death was determined as chemical pneumonitis and the autopsy findings were compatible with exposure to ammonia.


Exposure to ammonia is usually accidental and can take place during transfer of material from one cylinder to another, as a result of faulty equipment or after an explosion.

Anhydrous ammonia is showing a high alkaline reaction (pH 13+) and it is highly soluble in water. It can provoke multifactorial injuries when it comes to contact with skin, as it is highly corrosive and reactive with water rich tissues. As the reaction with water is exothermic and liberates heat energy, ammonia can cause thermal burns and cellular dehydration. Moreover, the pressurized liquid ammonia can also cause a cold (frostbite) injury due to evaporative freezing [4, 5, 10]. Ammonia is usually stored as a liquid under pressure (120 lbf/in2) at room temperature. When it is released through a small aperture it expands, resulting in vaporization and a large endothermic reaction. As the ammonia is released to the environment, it exceeds its boiling point (-33°C) and heat is sucked out of any tissue that comes in contact with it [11].The final outcome of ammonia exposure is a rapidly penetrating liquefactive necrosis of the exposed tissues, like moisture-rich areas of the body, such as the eyes and mucous membranes of the respiratory tract [4, 5, 10]. In cellular level, the reaction initiated by ammonia denatures proteins and saponifies lipids in the cell membrane, allowing further migration of the chemical deeper into the moisture-rich areas of the dermis and submucosa. Tissue destruction continues until the ammonia is neutralized [12].

The accidents involving anhydrous ammonia associate with significant morbidity and mortality [13, 14]. It has been reported that when accidents involving severe ammonia exposure occur, in most of the cases, the victims are unable to remove themselves from the area of contamination and the mortality rates are high [15-17]. Effects of ammonia inhalation include acute lung injury, progressive pulmonary dysfunction, oedema, inflammation, ulceration, haemorrhage, airway obstruction, atelectasis, pulmonary oedema, respiratory failure, and can result to death [18, 19].

In the case, the post-mortem findings of the decedent, as well as the history of case were consistent with exposure to a corrosive gas that is ammonia. The decedent did not wear protective clothing, a fact that undoubtedly led to more serious cutaneous injuries. Inhalation of ammonia by the victim led to chemical pneumonitis which was the cause of death. In the literature, it  is mentioned that injuries to the lungs and eyes are the more frequent and life threatening results of ammonia [20].

As ammonia is an extremely hazardous substance, special measures need to be taken on education of the proper use of transfer equipment as well as prevention of equipment failure. Automatic sprinklers, vapor tight electrical equipment, effective ventilation, good floor drainage and a large number of emergency exits for quick escape are needed. Employees need to be educated with respect to health hazards as well as protective measures including gas tight chemical goggles, self-contained breathing apparatus, rubber boots, gloves and complete gas suits in case of gas leaks [21, 22]. Contact lens use should be avoided because lenses collect the chemical and intensify the caustic effects. Most authors attribute the burns sustained from exposure to pressurized anhydrous ammonia to the strong alkali effects of the ammonia gas, and the severity of these injuries is directly related to the concentration of the ammonia and the duration of the exposure. In fact, most of the case reports in the literature emphasize the similarities of the cutaneous injuries due to ammonia to other alkali burns. However, alkali burns, although similar in appearance to frostbite injuries, tend to be more superficial. The clinicians should therefore be aware of the potential of deeper full thickness injury caused by cold injury from exposure to pressurized ammonia and need to be prepared to treat chemical burns. Workplace physicians should be aware of the possible dangers of handling pressurized anhydrous ammonia and inform accordingly the workers. They should ensure that in case of an accident, first-aid measures would be taken immediately. In any case, educating the workers in industries should be the first line of prevention of such accidents. The use of protective equipment, like uniforms, masks or goggles should be mandatory

Figure 1. Ammonia burns of the right hand.


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