Sodium Nitrate


Sodium nitrate—also known as Chile saltpeter—is an organic nitrate salt. It is a naturally occurring mineral and its chemical symbol is NaN03. At room temperature, the compound exists as a white crystalline solid. Sodium nitrate is highly soluble in water and ammonia and is non-flammable. The compound is a strong oxidising agent. When heated to temperatures above 538°C, the compound explosively decomposes. In the 19th century, sodium nitrate was known as “white gold”. It has been categorised as the International Cancer Research Agency as likely to cause cancer to humans. [1]    

Uses [1]

Sodium nitrate is used in a number of different ways, including in the food, energy and gardening sectors. In the food industry, the compound is most commonly used as a preservative and as a way to add colour (usually red or purple) to processed meats. The compound is also used as an ingredient in several fertilisers; it also acts as an oxidiser in fireworks. Sodium nitrate can also be found in some instant ice packs. It is used in the transfer and storage of heat in solar panel plants and can be used as a substitute “ingredient” in gunpowder.   

Routes of Exposure [3]

 Sodium nitrate is naturally found in fruits, vegetables and grains, including carrots, celery and spinach.

High doses of sodium nitrate are usually found in crop fertilisers.

Another route of high exposure is drinking water (both from a well and other sources), if nitrate compounds enter it.

Health Effects

Sodium nitrate poisoning affects a range of systems including the blood, cardiovascular and integumentary systems. 

Acute Effects [3]

Severity of symptoms depend on the level and type of exposure.

If there are high concentrations of sodium nitrate in fruits and vegetables, the first signs will show after four hours.

If sodium nitrate is ingested, the symptoms will first show after an hour. 

A characteristic sign of (sodium) nitrate poisoning is brown-tinged blood in stool.

Sodium nitrate exposure can also cause blue mucous membranes, nail beds and lips; nausea, vomiting, stomach cramps; yellowing of the white part of the eye and liver pain. 


Chronic Effects [3]

Sodium nitrate is toxic to multiple body systems. Long-term exposure to the compound will cause a prolonged state of hypoxia. This will result in a disturbance to all tissues across the body. In children, hypoxia as a result of sodium nitrate poisoning results in delayed mental and physical development, impaired heart and blood vessel functioning, a decrease in the effectiveness of the immune system, and an increased irritability.


~h2First Aid Measures [4]

·   Ingestion: If sodium nitrate is ingested, rinse mouth and DO NOT induce vomiting. Immediately call a doctor or a poison centre.

·   Skin contact: In case of skin or hair contact, remove/take off all contaminated clothing and immediately rinse exposed skin with mild soap and water. Do not re-wear clothing until it has been decontaminated. Call a poison centre.

·   Eye contact: Rinse eyes carefully with water for several minutes. Check for and remove contact lenses if easy to do so. Continue rinsing. Only obtain medical attention if symptoms persist. 

·   Inhaled: Take victim to the nearest fresh air source and monitor their breathing. Allow them to rest and contact a medical professional. 

·   General: Never administer anything by mouth to an unconscious, exposed person.

Exposure Controls/Personal Protection [4]

·   Engineering controls: Emergency eyewash fountains and safety showers should be accessible in the immediate area of the potential exposure. Ensure there is adequate ventilation. Whenever possible, material should be handled in a laboratory.

·   Personal protection: Safety glasses, protective and dustproof clothing, glove, an apron and an appropriate mask. 

Regulation [5]

~h2United States:

The Occupational Safety and Health Administration (OSHA) has set an 8-hour time weighted average (TWA) concentration for sodium nitrate of 15mg/m3.

Australia [6]

There is no specific TWA set for sodium nitrate. However, Safe Work Australia has set an 8-hour time TWA for dust limits of 10mg/m3. It should be highlighted that the TWA values are likely to be higher than the biological standards exposure level for the compound; therefore, all reasonable steps must be taken to minimise the level of exposure to a level well below the workplace standard.