Sodium Azide Toxicity - Causes, Symptoms, and Treatment

What Is Sodium Azide?

Sodium azide is a chemical compound with the formula NaN3. Sodium azide can be described as the sodium derivative of hydrazoic acid. It is a white, odorless, crystalline, highly toxic substance that is commonly used as a preservative in many laboratory and industrial applications. It possesses various functions, such as acting as a mutagen, antibacterial agent, and explosive.

Sodium azide is also known as azium. It is soluble in water and organic solvents and is stable at room temperature, but it can decompose explosively when heated or exposed to certain metals. Sodium azide transforms rapidly into a toxic gas with a pungent odor when combined with water or acid. Similarly, it transforms into a toxic gas known as hydrazoic acid when it encounters solid metals.

What Are the Applications of Sodium Azide?

The medical applications of sodium azide include:

• Preservative: Sodium azide is used as a preservative in medical settings such as laboratories and hospitals. This prevents the growth of bacteria and fungi in biological samples, such as blood, plasma, and serum. It is added in very small amounts to the sample, which helps maintain its integrity and quality for further analysis.

• Research Tool: Sodium azide is used in various research studies as a tool to inhibit specific enzymes and metabolic pathways.

• Histological Analysis of Tissue Samples: It is used as an additive in a fixative solution containing glutaraldehyde for tissue sample analysis.

Other applications include:

• Sodium azide is commonly recognized as the substance present in car airbags. When a car crashes, an electrical charge triggers the explosion of sodium azide, which transforms into nitrogen gas inside the airbag.

• It is employed in agriculture for pest control.

• It is also utilized in explosives and detonators (devices that are used to initiate or trigger an explosive material)

What Is Sodium Azide Toxicity?

Sodium azide is a highly toxic chemical compound that can cause serious health effects if exposure occurs. Ingestion, inhalation, or skin contact are the routes of exposure for sodium azide toxicity. Sodium azide works by inhibiting cellular respiration, which is how cells use oxygen to produce energy. This results in cell death as they cannot produce sufficient energy to maintain their functions. The heart and brain are particularly vulnerable to sodium azide toxicity as they require high levels of oxygen for optimal functioning. Therefore, sodium azide can harm these organs more than others.

The National Institute for Occupational Safety and Health (NIOSH) recommends that the airborne exposure limit should not exceed 0.3 mg/m3 (milligram per cubic meter) at any given time. The airborne exposure limit should not exceed 0.1 mg/m3 in the form of hydrazoic acid at any given time. On the other hand, the American Conference of Governmental Industrial Hygienists (ACGIH) recommends a TLV (threshold limit value) of 0.29 mg/m3 at any given time. The threshold limit value as hydrazoic acid vapor should be 0.11 ppm (parts per million) or less at any given time.

What Are the Causes of Sodium Azide Toxicity?

The causes of sodium azide toxicity include:

• Inhalation: When sodium azide is released into the air, inhaling the dust or vapors that are generated could also result in an exposure. Prolonged exposure to high concentrations of sodium azide can lead to respiratory failure and death.

• Ingestion: If sodium azide is released into water, consuming the contaminated water could lead to exposure to sodium azide. Similarly, if food becomes contaminated with sodium azide, ingestion of the contaminated food could result in exposure to the chemical. Ingestion can occur accidentally or intentionally and can lead to death.

• Skin and Eye Exposure: Skin or eye contact also results in the entry of this chemical into the human body and develops symptoms. This type of exposure occurs during handling or through accidental spills.

• Accidental Explosions: Accidental explosions of sodium azide expose individuals to the toxic gas (hydrazoic acid). This can occur during the transportation, storage, or handling of sodium azide.

• Chronic Exposure: Long-term exposure to low levels of sodium azide leads to the accumulation of chemicals in the body. This usually happens in laboratories or factories due to the regular usage of this chemical.

What Are the Symptoms of Sodium Azide Toxicity?

The symptoms of sodium azide toxicity include the following:

• Coughing, discharge from the nose, shortness of breath, bradypnea (decrease in the rate of respiration), and chest pain occur due to exposure through inhalation. In severe cases, it can lead to respiratory failure and death.

• Nausea, vomiting, abdominal pain, and diarrhea may develop as a result of ingestion of this chemical.

• Headache, blurred vision, dizziness, confusion, seizures, and loss of consciousness may be present in some cases.

• Hypotension (low blood pressure), irregular heartbeat, and bradycardia (reduced heart rate) may develop in the late stages of a large amount of exposure.

• Skin contact with sodium azide can cause skin irritation, burns, redness, and rash. Exposure to the eyes can cause severe irritation, redness, pain, and vision loss.

How Can Sodium Azide Toxicity Be Diagnosed?

The diagnosis of sodium azide toxicity can be made with the help of the following methods:

• Medical History: A thorough medical history can help identify potential exposure to sodium azides, such as in occupational settings, or accidental ingestion or inhalation.

• Physical Examination: A physical examination may reveal symptoms such as respiratory distress, gastrointestinal distress, neurological symptoms, skin or eye irritation, or cardiovascular symptoms.

• Laboratory Tests: Laboratory tests can detect the presence of sodium azide or its metabolites in blood or urine samples.

• Imaging Tests: Imaging tests such as chest X-rays or CT (computed tomography) scans may be used to evaluate respiratory symptoms, such as pulmonary edema (presence of an excess amount of fluid in lungs).

• Electrocardiogram (ECG): An ECG may be used to evaluate heart-related symptoms, such as fluctuations in heart rate.

How to Treat Sodium Azide Toxicity?

Sodium azide toxicity can be managed in the following ways:

• Supportive Care: Supportive care may include oxygen therapy, intravenous fluids, and medications to manage symptoms such as nausea, vomiting, and seizures.

• Decontamination: Decontamination may be necessary in case of skin or eye exposure to sodium azide. This may involve washing the affected area for several minutes with sufficient amounts of lukewarm water or using specific decontamination solutions. Vomiting is induced with syrup Ipecac immediately after ingestion. Inducing vomiting is not advised if ingestion of sodium azide is either unknown or exceeds 30 minutes. Activated charcoal acts as a filter to remove the presence of excess sodium azide in the bloodstream.

• Supportive Therapy: In cases of respiratory or cardiovascular distress, supportive therapy may be required to stabilize the individual's condition. This may include mechanical ventilation or medications to manage blood pressure and heart rate.

• Hemodialysis: In cases of severe sodium azide toxicity, hemodialysis may be used to remove the toxin from the bloodstream.

• Antidotes: There are no specific antidotes for sodium azide poisoning.

Conclusion:

Sodium azide is a reactive substance that poses a severe health risk to anyone who comes into contact with it. It is crucial to handle this chemical with proper care and to follow strict safety procedures to minimize the risk of exposure. In suspected sodium azide toxicity cases, immediate medical intervention is required to initiate appropriate treatment and prevent further complications.