Guidance

Formaldehyde: general information

Updated 22 July 2024

Overview

Formaldehyde is a colourless, corrosive, flammable gas with a pungent, suffocating odour.

Uses of formaldehyde

Formaldehyde is produced in large quantities industrially. It is mainly used to produce other chemicals and in the production of resins. Formaldehyde resins are used as adhesives and binders in many different industries that produce wood products, pulp and paper, synthetic fibres, plastics and coating and textiles. Formaldehyde–urea resin is used as an insulating material in building construction. Formaldehyde may also be used under restriction in the EU as a preservative in cosmetics and nail hardening products.

Formaldehyde at approximately 5% in a solution with water is used as a disinfectant and fumigant in hospitals, ships, dwellings and animal handling facilities, as it is effective in killing most bacteria, viruses and fungi.

A solution of approximately 37% formaldehyde is commonly known as formalin and is used to store and preserve tissue samples in laboratories and museums.

How formaldehyde gets into the environment

Formaldehyde can occur naturally in the environment from the breakdown of methane by sunlight, as a result of forest and bush fires, and from volcanic activity. Formaldehyde breaks down quickly in the environment and is removed from the air by sunlight, rain and biodegradation.

Formaldehyde is released during the combustion of organic materials, and as such may be present in smoke from wood fires, automobile emissions, tobacco smoke and from burning incense. It can also be released into the environment following formaldehyde –urea resin building materials during construction and installation.

Formaldehyde may also be released into the environment from clothing, carpets, furniture, adhesives, paints, varnishes, lacquers, detergents and cleaning agents and waxes. As formaldehyde is used industrially it may also enter the environment from workplaces where it is manufactured or used.

Exposure to formaldehyde

Formaldehyde is produced naturally in small amounts in the human body. It also occurs naturally in fruits and some foods, at levels unlikely to cause harm.

As formaldehyde may also be present naturally in the environment, individuals may come into contact with very low levels of formaldehyde in air.

The general public may be exposed to formaldehyde from contact with consumer products that contain it. Low level exposure from the correct use of these products would not be expected to cause adverse health effects. Other indoor air sources of exposure to formaldehyde include tobacco smoking, cooking, incense burning and building materials.

Exposure to formaldehyde may also occur if it is used where you work: safe levels are enforced to protect employees who may be exposed to formaldehyde at work. Such levels are below those that are thought to cause harmful effects.

How exposure to formaldehyde could affect your health

The presence of formaldehyde 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 that 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.

Inhalation of formaldehyde can lead to irritation of the nose, mouth and throat. In severe cases, respiratory distress and swelling of the larynx and lungs may occur.

Ingestion of formaldehyde can cause burns and ulcers in the stomach or intestines in the early stages after ingestion. Formaldehyde ingestion may also cause chest or abdominal pain, nausea, vomiting, diarrhoea and gastrointestinal tract haemorrhage. Other clinical features include rapid breathing, yellowish discolouration of the skin, blood in the urine and kidney failure.

Exposure of the eyes to vapour or splashes of formaldehyde causes irritation with immediate stinging and burning with spasm of the eyelids and tearing.

Skin contact with formaldehyde can cause skin irritation and allergic contact dermatitis (allergic response caused by contact with a substance leading to reddening or rash on the skin). Skin contact with high concentrations of formaldehyde solutions can cause blisters and hives.

Formaldehyde and cancer

Formaldehyde has been classified as a cancer causing chemical in humans by the International Agency for Research on Cancer (IARC).

There is evidence that formaldehyde causes nasal tumours (tumours of the nose) and leukaemia in industrial workers exposed over long periods of time (years). However, exposure over short periods of time is unlikely to have the same level of risk.

Vulnerable people

People with breathing problems such as asthma may be more sensitive to the effects of formaldehyde. Individuals who are sensitised to formaldehyde may develop an allergic response (for example allergic contact dermatitis) when they are exposed to formaldehyde.

Pregnancy and children

There are limited data available on the direct effects of exposure to formaldehyde during pregnancy. Therefore, is not possible to draw any definitive conclusions. Effects on the unborn child are more likely to occur if the exposure to formaldehyde causes the mother to become unwell.

Children

Children will be affected by formaldehyde in the same way as adults. However, the effects seen in children may potentially be more severe.

What to do if you are exposed to formaldehyde

Low level exposure from the correct use of products that contain formaldehyde would not be expected to cause any adverse health effects.

Please see below for advice following accidental exposure formaldehyde:

• remove yourself from the source of exposure
• if you have ingested formaldehyde solution, seek medical advice. Do not make yourself sick
• if you have inhaled formaldehyde you should seek medical advice
• if you have formaldehyde solution on your skin, remove the soiled clothing (not over the head), wash the affected area with lukewarm water and soap for at least 10 to 15 minutes
• treat the area as a burn and seek medical attention if symptoms develop
• if you have got formaldehyde in your eyes, remove contact lenses, irrigate the affected eye with lukewarm water for at least 10 to 15 minutes and seek medical advice

Additional sources of information

• NHS.UK:
  • information on burns and scalds
  • information on acid and chemical burns
• UKTIS: best use of medicines in pregnancy