Formaldehyde: what is it, where is it and what are the health risks?

Formaldehyde is a chemical substance found in nature in the form of a colorless gas, but with a pungent and very unpleasant smell. We are all exposed to the vapors, fumes and residues of this gas despite the fact that many scientific studies have long proven its carcinogenic effects on the body. In addition to the gaseous solution, due to its high solubility, formaldehyde is also used in aqueous form (formalin) and stabilized with methanol.

In nature, formaldehyde is produced by some combustion processes and by the oxidative metabolism carried out by many living organisms. Even humans, even in small quantities, are unconscious producers of formaldehyde.

Certainly, it is one of the most widespread and ubiquitous chemicals in any environment, including the home. In the most significant quantities, it comes from car exhausts, some types of stoves, incinerators, and even cigarette smoke.

It is found in paints, dyes, cosmetics, conditioners, shampoos, lacquers, nail products, in certain smoked or fried foods. These are the main sources of exposure from which we should try to stay as far as possible.

What is formaldehyde

Also known as formaldehyde, this foul-smelling gas is the progenitor of the aldehydes and was first discovered in the mid-nineteenth century by a German chemist. Since then, its use has experienced an increasingly rapid and widespread diffusion in the construction industry, in carpentry, cosmetics and in the production of household hygiene products.

It is easily found in pressed wood, such as chipboard, but also in glues, fabrics and many other everyday products. Those working in these industrial sectors, or in funeral services, are more exposed.

Formaldehyde: meaning

The term formaldehyde derives from the English formaldehyde (formalin), or “form” (Ic) and “aldehyde”. The terms aldehyde formica and metanale are considered synonymous with this name.

Chemical formula of formaldehyde

Formaldehyde is the simplest chemical substance in the group of aldehydes, organic compounds that present the formile functional group (-CHO) in the structure. Its chemical formula is CH2O, its CAS number is 50-00-0. In the market it is also present in the form of aqueous solution with the name of formalin or as paraformaldehyde.

It is characterized by its high reactivity, biodegradability, high boiling point and high solubility in water. Once dispersed in the air, it is neutralized by the photochemical processes that cause it to precipitate.

Formaldehyde: odor

In the gaseous state, formaldehyde has an acrid, pungent odor and its vapors are irritating to mucous membranes and eyes. However, except for those who are exposed to formaldehyde for occupational reasons, it is very difficult to realize the presence of this substance by the smell.

It hides, in fact, in many body care products, such as shower gel, conditioners, lotions, shampoos, creams, etc. Being a product widely used in industry, rather than smell it is good to be guided by the careful reading of the labels of what we buy.

Is formaldehyde carcinogenic?

The IARC (International Agency for Research on Cancer) has confirmed the scientific evidence proving the carcinogenicity to humans of this gas, in relation to the development of some forms of cancer, such as:

  • nasopharynx cancer (nasopharynx);
  • leukemia;
  • nasal sinus cancer.

Since 2004, the same agency has included formaldehyde among Group I compounds, those that are certainly carcinogenic. The WHO also intervened on this issue by setting limits on formaldehyde concentrations in the air of 0.1 mg per cubic meter.

Human exposure to formaldehyde occurs mainly by air, rarely by direct contact with its liquid form. Once inhaled, this gas is broken down by the organism into formic acid and subsequently transformed into carbon dioxide.

Since these chemical processes are carried out in the mouth, in the upper respiratory tract and in the nose, these are the most sensitive anatomical parts to its effects. The least serious problems, however, are:

  • eye irritation;
  • nasal irritation;
  • inflammation of the throat;
  • sneezing;
  • cough;
  • fatigue;
  • skin erythema.

A certain amount of formaldehyde inevitably ends up in the blood, which is why it is important to take all necessary precautions to limit its accumulation in vital tissues and organs. In general, we should try to:

  • avoid the use of carpets and chipboard furniture;
  • always ensure the right air change and ventilation in domestic environments;
  • use safe and controlled heating sources;
  • try to buy materials with the words E1 (low concentration of formaldehyde);
  • use air conditioning devices or dehumidifiers to stabilize the domestic temperature (heat and humidity increase the release of formaldehyde in the rooms).

Where is the formaldehyde?

Enemy of human health, industry friend. This chemical is found practically everywhere, both in our homes and outside. In addition to the industry of wood, building materials, cosmetics and medical-sanitary products (disinfectants), the most worrying use of experts is food.

In particular, formaldehyde is present in foods subjected to preservation or disinfection processes. Its presence must be indicated on the product label with the initials E240.

Coatings, furniture, shelves, glues, paints and additives: the wood industry largely uses this chemical

Wood and furniture

The presence of formaldehyde is very widespread in construction and carpentry materials, mainly compensated, in pressed and chipboard panels, but also in glues, paints, additives and other products used in woodworking. For this reason it is important to pay attention to what you buy and prefer furniture with low concentrations of formaldehyde.

In particular, in the bedroom and in the rooms where you are staying for so long it is advisable to avoid the use of carpets and chipboard or plywood furniture. Better the solid wood (class FF – without formaldehyde) which are certainly more expensive but infinitely safer for health. If at home we have furnishings built with materials with a high risk of formaldehyde, before placing them in the rooms it is better to expose them to the open air and adequately ventilate the rooms.

Ikea furniture

In recent years, the growing attention to the dangerousness of this chemical substance for human health has turned the spotlight on a “giant” of the production of chipboard furniture and furnishing accessories: IKEA.

In fact, the Norwegian giant has often been at the center of fierce criticism from those who, rightly or wrongly, questioned the safety of the products of this brand. Here is the company’s answer:

“Ikea invests a lot of energy and resources in reducing formaldehyde emissions, focusing above all on the glue used for wood-based products. This commitment also extends to the procurement of materials and production techniques. We also work closely with suppliers to constantly improve and implement quality procedures.

As part of the quality assurance program, we carry out continuous tests on both materials and final products. IKEA requires all suppliers, with 24 hours notice, to be able to submit test reports and certificates that demonstrate compliance with IKEA requirements and applicable regulations.

Formaldehyde has been banned for many years in lacquers and paints used to make IKEA products. We want all our products to be safe and we are constantly working to improve materials and production methods. We collaborate constantly with the operators of the sector, in order to reduce the formaldehyde content, improve materials and production methods and reach an efficient production capacity “.


Formaldehyde is frequently used for making hair care products, in particular for shampoos, conditioners and related lotions that facilitate hair straightening. To identify formaldehyde in these products it is necessary to read the labels well and avoid products with formulations containing the words Imidazolidinyl Urea and Diazolidinyl Urea.

Products containing keratin, for example, almost always have very high concentrations of formaldehyde.

At home or at the hairdresser, be careful what you put in your head.


The European Community has banned the use of formaldehyde or formalin in cosmetics but not that of its substitutes, the so-called “formaldehyde cessors”. These are even more formidable chemical derivatives of the mother substance, which can be found on the labels of a large quantity of beauty products, cosmetics and nail varnishes. They are identified by the following names:

  • Benzylhemiformal;
  • Sodium hydroxymethyl glycinate (Sodium hydroxymethyl glycinate);
  • 2-Bromo-2-Nitropoane-1,3-Diol (Bronopol);
  • DMDM Hydantoin;
  • Quaternium-15;
  • methenamine;
  • Imidiazolidynyl urea and diazolidinyl urea.


Formaldehyde is contained in almost irrelevant quantities even in some vaccines. Concentrations are so low, however, that children are not exposed to any risk.

Occupational exposure to formaldehyde

The main sources of exposure for workers concern the following fields / industrial sectors in which significant quantities of this chemical are used or in which formaldehyde and its derivatives are produced:

  • production of phenol (bachelite) urea and melamine resins (plastics, adhesives and insulating foams);
  • painting and woodworking;
  • industrial synthesis of chemical compounds (1,4-butanediol, 4,4′-methylenediphenyl diisocyanate, pentaerythritol, hexamethylenetetramine);
  • preservatives;
  • disinfectant and sanitary fixatives;
  • funeral and necroscopic services (formalin).
  • In these work environments, formaldehyde concentrations must be constantly monitored and workers must be equipped with appropriate respiratory protection, as well as specific clothing.