Guidance

Ammonia: general information

Updated 23 October 2024

Overview

Ammonia is a colourless, reactive gas that is lighter than air (approximately half as heavy) which dissolves readily in water. Ammonia has a strong smell, similar to urine, which can be detected by most people even in small amounts. Ammonia gas is non-flammable, but because at certain concentrations when mixed with air it could explode if ignited, it is treated as flammable. Solutions of ammonia are alkali and can be corrosive when concentrated. Ammonia solution may also be called ammonium hydroxide and aqueous ammonia.

Uses of ammonia

Ammonia is a very important industrial chemical. Ammonia gas is produced industrially by reacting hydrogen and nitrogen at high temperature and pressure. This reaction is known as the Haber-Bosch process.

There are many uses for ammonia including the production of fertilisers, plastics, synthetic fibres, dyes, explosives, and pharmaceuticals. In the home, ammonia is used in certain cleaning products and garden fertilisers.

How Ammonia gets into the environment

Ammonia in the environment comes from both natural and fabricated sources. It occurs naturally at low levels throughout the environment, released from the breakdown of organic waste matter. Local concentrations may be elevated where there is a lot of animal waste, such as in intensive farming environments for cattle, pigs, and chickens. Non-agricultural sources include sewage sludge, industry, and petrol vehicles fitted with catalytic converters.

Ammonia gas does not remain in the environment for long; it rapidly reacts to form ammonium compounds.

Exposure to ammonia

Ammonia is found in very small amounts in some foods, including vegetables and dairy products. It is also produced naturally in the human body by gut bacteria as they break down food. In the home, exposure may occur from certain cleaning agents and dyes; however, exposure is likely to be minimal if the products are used appropriately. Inappropriate mixing of cleaning products such as sodium hypochlorite and ammonia-based solutions may result in exposure to toxic gasses.

Exposure may occur in the workplace although safe limits are enforced to protect the employees. Such levels are below those that are thought to cause harmful effects.

Ammonia is produced from the natural breakdown of organic matter and so exposure to ammonia will occur at very low levels throughout the environment. Exposure to ammonia from the environment is not considered to pose a risk to human health.

How exposure to ammonia can affect your health

The presence of ammonia in the environment does not always lead to exposure. In order for it to cause any adverse health effects, you must come into contact with it. You may be exposed to ammonia by breathing or ingesting the substance, or by skin or eye contact with it. Following exposure to any chemical, the adverse health effects, you may encounter depend on several factors, including the amount to which you are exposed (dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals.

Breathing in low levels of ammonia may cause irritation to the eyes, nose and throat. High levels of ammonia may cause burns and swelling in the airways, lung damage and can be fatal. Ingestion of ammonia solutions can cause pain and burns throughout the digestive tract. In severe cases the respiratory system, stomach, and heart may be damaged, and death may follow.

Strong ammonia solutions may cause serious burns if splashed on the skin. At high concentrations, gases and fumes of ammonia can also cause corrosive damage to the skin. Splashes in the eye may cause damage which may be irreversible in some cases and can lead to loss of sight. The health effects of ammonia are usually immediate and long-term effects would not be expected after exposure to small amounts.

Ammonia and cancer

Ammonia has not been classified by the International Agency for Research on Cancer (IARC). It is not believed to cause cancer.

Vulnerable people

Asthmatics or individuals with other breathing problems may be more sensitive to the effects of ammonia.

Pregnancy and the unborn child

There are limited data available on the effects of exposure to ammonia on pregnancy and the unborn child. Effects on the unborn child are more likely to occur at levels that harm the mother.

Children

The effect of ammonia on children is likely to be the same as for adults. Ammonia containing products in the home should be stored in an appropriate container and kept out of the reach of children.

What to do if you are exposed to ammonia

You should remove yourself from the source of exposure.

If your skin is exposed to ammonia on your skin, remove soiled clothing (not over the head), wash the affected area with lukewarm water and soap for at least 10 to 15 minutes and seek medical advice.

If you are exposed to ammonia in your eyes, remove contact lenses, irrigate the affected eye with lukewarm water for at least 10 to 15 minutes and seek medical advice.

If you have inhaled or ingested ammonia, seek medical advice.

Additional sources of information

NHS.UK information on poisoning

NHS.UK information on how to deal with minor burns

UKTIS: best use of medicines in pregnancy

The information contained in this document from the UKHSA Radiation, Chemicals and Environment Directorate is correct at the time of its publication.

Email chemcompendium@ukhsa.gov.uk if you have any questions about this guidance or enquiries@ukhsa.gov.uk if you have any other questions.

Feedback Survey

Help us improve the compendium of chemical hazards by taking our short survey.