What Is Formaldehyde Used For?

Before we look at what formaldehyde is used for, it’s important to understand what it is. CH₂O is a chemical that many people associate with embalming or taxidermy because of how its aqueous form, called formalin, preserves tissue. But in reality, it has many industrial and household applications beyond this. 

You may be surprised to learn that this chemical can be found in several household items, and even in some foods. In this article, we explore some of the important uses of formaldehyde, and how it’s actually more common than you think. 

the chemical formula of Formaldehyde on a tablet with test tubes

Uses Of Formaldehyde

When dissolved in water, CH₂O becomes formalin, and this is most famously known as an embalming fluid that preserves organic tissue. In its pure form, however, formaldehyde is a colourless gas that has a strong, irritating smell. In this state, it’s commonly used in manufacturing building materials as well as many household products, but it can also be used as a precursor or ingredient in manufacturing other chemicals. Here are some of the common uses of formaldehyde:

  • Adhesive and coatings: It’s also important in the manufacture of many types of adhesives and glues, paper product coatings, as well as insulation materials.
  • Sanitary products: Many consumer products have to be disinfected before use. Formaldehyde is used as one of the primary industrial disinfectants when producing sanitary products like napkins, paper towels, and tissues.
  • Medical applications: Formaldehyde is a powerful antiseptic that can kill most viruses and fungi. It’s also used to treat parasitic infections and warts. The production of vaccines includes the use of formaldehyde to sterilise products. This chemical is also very effective at killing bacteria and preventing their growth. This makes it great for treating infections like UTIs.
  • Fossil fuel processing: CH₂O is essential in processing petroleum and natural gas, where it helps in improving the yield of fuels.
  • Food preservation: Formaldehyde occurs naturally in foods like fruit, vegetables, marine fish, crustaceans, and meat, where it’s a by-product of metabolism. The levels of naturally-occurring formaldehyde in food can be as high as 300 to 400 mg/kg. While it’s illegal to use CH₂O as a food preservative, some health regulatory agencies approve its indirect use in some materials that have contact with food, such as for the disinfection of food containers.
  • Automotive applications: CH₂O has an important role in making automobiles lighter and more energy efficient. It’s used in manufacturing resins, which in turn are used to make interior moulded components, as well as components under the bonnet that are resistant to high temperatures. Formaldehyde-based resins are also used in the manufacture of exterior primers, which have to be very durable. Clear coat automotive paint, tire cord adhesives, and brake pads are some of the products made from materials that use formaldehyde as a base.
Doctor using a syringe to pull vaccine out of ampule
Formaldehyde is used to sterilise vaccines by killing or weakening the pathogens inside

What Products Have Formaldehyde In Them?

Many products are manufactured using CH₂O, but few end products actually contain the chemical itself, because it has already undergone chemical reactions, i.e. it’s been used up. The formaldehyde in many of these products either changes into other chemicals, or is removed from the final product. Meanwhile, some goods have a naturally-occurring formaldehyde content, but at relatively low and non-toxic levels. Here are some examples of products that contain this chemical:

  • Resins: Resins that are used in composite wood products like plywood have formaldehyde in them. These resins are also used in manufacturing paint primers.
  • Building insulation: The formaldehyde in resins remains in products that are manufactured using resins. These include composite wood materials and building insulations.
  • Finishes: Some paints and lacquers that are used in households contain this chemical in trace amounts.
  • Burning: Anything that has hydrocarbon chains in it produces some formaldehyde when burned. This includes lit cigarettes and even wood-burning stoves.
  • Food items: Formaldehyde is a natural by-product of cellular metabolism. In a nutshell, this means that humans and other animals produce it. One way it’s produced in the human body is through the oxidation of vitamin B9 by enzymes. Similarly, plants and animals that we use as a food source can naturally produce CH₂O. 

What Foods Have CH₂O In Them?

Although CH₂O is an illegal additive in foods, it actually occurs naturally in many food items. This is because it’s a by-product of the metabolic activities that happen in all organisms, even including bacteria. How this works is pretty complicated, but it’s basically a result of the oxidation of tetrahydrofolic acid, which is a form of vitamin B9. This intermediate biochemical process is essential in producing DNA and some types of amino acids.

This means that fruits, vegetables, meat, fish, dairy products, and other related or derived products have some formaldehyde in them – but only at non-toxic levels. Here are some examples of naturally-occurring formaldehyde concentrations in food:

  • Meat and poultry contain around 5.7 to 20 mg/kg of formaldehyde
  • Milk: 0.01 to 0.8 mg/kg
  • Fish: 6.4 to 293 mg/kg
  • Sugar: 0.75 mg/kg
  • Coffee: 3.4 to 16 mg/kg
Skilled Artisan Carpenter Working on a Piece of Furniture with Epoxy Resin
Resins used for woodwork and paint primers contain formaldehyde

For those of you wanting to know whether there’s formaldehyde in everyday items, here’s a rundown:

Is There Formaldehyde In Hair Dye?

Chronic exposure to this chemical is very toxic, with it being able to cause damage to DNA. This makes it carcinogenic, explaining why the extensive and regular use of hair dye has been linked to higher cancer risks. This is because many hair dye products have quaternium-15, which can release CH₂O. 

But don’t worry too much – dyeing your hair regularly won’t give you formaldehyde poisoning, because only trace amounts are produced. Still, it depends on the product and its corresponding regulations, so always do your research! 

Is There Formaldehyde In Nail Polish?

Some nail hardeners and nail polish products contain formaldehyde, though it can be named on the product label as formalin or methylene glycol. In nail hardeners, this is actually a necessary chemical because it naturally bonds with the keratin protein in nails. As a result, the nail becomes harder. However, nails may eventually deteriorate and become brittle and break if the product is used too often. 

Is There Formaldehyde In Vaccines?

Vaccines require sterilisation in order to be safe to use. Small amounts of CH₂O are used to either weaken or kill the pathogens in vaccines. When used in this way, it doesn’t accumulate in the body or pose any health risks. 

Is There Formaldehyde In Cigarettes?

Any substance that has carbon compounds in them, like hydrocarbon chains, produces CH₂O when burned, especially if it’s an incomplete combustion. This is why CH₂O is formed in the cigarette smoke.

Is There Formaldehyde In Decaf Coffee?

Coffee beans naturally contain formaldehyde, though it’s at a trace, non-toxic level. Processing coffee beans either to instant or decaffeinated form requires methylene chloride or CH₂O to remove the caffeine. Therefore, some residue is left behind, but again, only in trace and non-toxic amounts.

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