Guidance

Nitrobenzene: general information

Updated 22 July 2024

Overview

Nitrobenzene is a colourless or yellow oily liquid, with an odour of bitter almonds.

Uses of nitrobenzene

The main use of nitrobenzene is in the chemical synthesis of aniline, which is a chemical used in the manufacture of polyurethane foams. Nitrobenzene is also used industrially in the manufacture of some pharmaceuticals, dyes and rubbers, as a constituent in some polishes and paint solvents, and as a solvent in the refining of petroleum and cleaning of gun barrels.

Historically nitrobenzene was used in perfumes and as a flavouring known as ‘artificial oil of bitter almonds’ due to its strong odour. This use of nitrobenzene has long been discontinued due to its toxicity.

How nitrobenzene gets into the environment

Nitrobenzene does not occur naturally in the environment and as such is most likely to enter the environment from workplaces where it is manufactured or used.

Exposure to nitrobenzene

Nitrobenzene is not commonly present in household products, so the most likely place people might be exposed is in the workplace. However, safe limits are enforced to protect the employees. Such levels are below those that are thought to cause harmful effects.

How exposure to nitrobenzene can affect your health

The presence of nitrobenzene 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 by breathing, eating, or drinking the substance or by skin contact.

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
• if you were exposed to any other chemicals

Exposure to nitrobenzene vapours or liquid will cause irritation of the skin, eyes and respiratory tract. Ingestion of nitrobenzene may cause gastrointestinal irritation with nausea, vomiting and diarrhoea.

Nitrobenzene can be absorbed into the body following inhalation, ingestion or skin contact. The main symptom of exposure to nitrobenzene is a condition called methaemoglobinaemia, which affects the ability of the blood to carry oxygen. This condition is associated with:

• headache
• nausea
• vomiting
• weakness
• dizziness
• vertigo
• bluish discolouration of the skin
• rapid heart rate
• anaemia
• convulsions
• breathlessness

The symptoms may be delayed for up 1 to 4 hours following exposure. In some cases, nitrobenzene may cause jaundice (yellow discoloration of the skin), kidney failure coma and even death. Repeated exposure to nitrobenzene by any route may cause damage to the liver in addition to the effects resulting from a single exposure.

Nitrobenzene and cancer

The International Agency for Research on Cancer (IARC) has concluded that there is enough evidence in experimental animals, but not in humans, that nitrobenzene can cause cancer. Therefore, it has classified nitrobenzene as possibly having the ability to cause cancer in humans.

Vulnerable people

People with breathing problems such as asthma may be more sensitive to the effects of nitrobenzene.

Pregnancy and the unborn child

There is evidence to suggest that exposure to nitrobenzene during pregnancy, at concentrations that may harm the mother, may possibly cause adverse effects to the unborn child. For further information on chemicals and pregnancy, please visit medicinesinpregnancy.org.

Available evidence does not indicate that exposure to nitrobenzene during pregnancy will have a direct effect on the unborn child. However, if the exposure to nitrobenzene causes the mother to become unwell this may affect the health of the unborn child.

There is evidence to suggest that exposure to nitrobenzene can have an adverse effect on male fertility.

Children

Children exposed to nitrobenzene are expected to show similar adverse health effects to those seen in exposed adults. However, the effects are expected to be more severe in children as they are particularly susceptible to the adverse effects of exposure to nitrobenzene

What to do if you are exposed to nitrobenzene

It is very unlikely that the general population will be exposed to a level of nitrobenzene high enough to cause adverse health effects as it is not commonly used in the home in substantial quantities. However, if you have any health concerns regarding exposure to nitrobenzene seek guidance from your GP or contact NHS 111.

Additional sources of information

UKTIS Best Use of Medicines in Pregnancy

NHS.UK has more information on poisoning.

The information contained in this document from the UK Health Security Agency (UKHSA) Radiation, Chemicals and Environment Directorate is correct at the time of its publication. 

Email [email protected] if you have any questions about this guidance or [email protected] if you have any other questions.