What Chemicals Are Used In Oven Cleaners?

by Lucy Bell-Young

The chemicals used in oven cleaners may cause concern in many people, but do they deserve the reputation? The trials and tribulations of oven cleaning are a necessary evil that most of us must face. Over time, various layers of grime, gunk and baked-on crud can accumulate inside your oven as a result of cooking, and some of this dirt can even lead to rust. Chemical oven cleaners are the real experts at cutting through these accumulations of grease, but they do come with their own set of drawbacks.

Chemicals used in oven cleaners are highly toxic and can cause harm if they’re ingested or come into contact with your skin. But does this mean that they’re unsafe to use full stop? This article will look at the science behind the chemicals used in oven cleaners, as well as highlight non-toxic alternatives you can use instead. 

Gloved hand cleaning oven rack with yellow sponge

How Toxic Is Oven Cleaner?

Oven cleaners are a concoction of chemicals, including things like caustic soda, dichloromethane and even ethylene glycol. That’s right, ethylene glycol, the chemical used in antifreeze also makes a cameo in your oven cleaner, and this is one of the reasons why these formulations can be very toxic if ingested.

The toxicity of a chemical is determined by how it interrupts or damages the normal functions of an organism. This makes many of the chemicals used in oven cleaners dangerous and, at the same time, very effective because of how they behave. That said, when handling these products, safety precautions should always be used, like protective gloves or face masks. Here are some examples of the most common toxic chemicals used in oven cleaners:

Caustic Soda

Also known as lye or sodium hydroxide, caustic soda is among the most common chemicals used in soaps, shampoos, unclogging liquids and, of course, oven cleaners. Its high corrosivity makes it great at cutting through oily and organic substances that build up in drains, ovens and pipes. Its effectiveness as an oven cleaning agent can be explained by its chemical properties:

  • Caustic soda is an alkaline substance, with a high pH value of 14, which makes it highly corrosive because it readily accepts protons
  • It’s very soluble in water, with a solubility of 119 g per 100 mL of water
  • When mixed with water, caustic soda has an exothermic reaction
  • Combined with its corrosivity, this makes it effective at dissolving unwanted gunk

When used in oven cleaner, caustic soda solution strips away the molecular bonds of organic materials that are stuck to the internal surfaces. It then loosens and breaks down this matter, making it much easier to remove. 


Ethers are a category of organic chemicals that have a very similar structure to alcohols, and it’s their chemical structure that makes ethers effective solvents. Because they don’t hydrogen bond to each other, they can dissolve the solute much more easily. In fact, they’re so good at doing this that the most common application of ethers is to dissolve oils, grease, resins and waxes. This is why ether compounds are often used in oven cleaners. 

While many different ethers can be used to clean ovens, they all have similar toxicity levels:

  • Ethers are highly volatile substances, meaning that they evaporate readily at room temperature
  • This means it’s easy to inhale them, which could irritate your eyes, mucous membrane and even respiratory system
  • When inhaled in high concentrations, ethers can cause feelings of inebriation, dizziness and even respiratory paralysis

Ethylene glycol

Another toxic chemical used in oven cleaners is ethylene glycol, an odourless and colourless liquid that has a deceptively sweet taste. Don’t be fooled, though, because this chemical is highly toxic if ingested:

  • In the body, ethylene glycol metabolises into glycolic acid, which then gets converted into oxalic acid
  • When combined with calcium, oxalic acid produces calcium oxalate crystals, which accumulate in vital organs 
  • A build-up of these crystals can cause renal failure, a loss of consciousness, brain damage, and may even be fatal

Ethylene glycol (C2H6O2) has many uses, but it’s popularly known as the main ingredient in antifreeze. It’s used in oven cleaners because it’s very effective at dissolving grease. It may come as a shock that such a toxic chemical is used in something that could have direct contact with your food, but the good news is that ethylene glycol is only toxic if directly ingested.  

Methylene Chloride

Last on our list of toxic chemicals used in oven cleaners is methylene chloride (CH2Cl2). Otherwise known as dichloromethane or methylene dichloride, this is a highly volatile and colourless liquid at room temperature, and is very toxic. Classified as a carcinogen, this chemical is dangerous to inhale and should not be touched with your bare hands. 

In spite of this, methylene chloride has a wide range of applications, from paint stripping and degreasing to decaffeinating coffee beans and manufacturing photographic films. In oven cleaners, methylene chloride is highly effective at stripping away stubborn layers of grime. Even still, because it’s so easy and dangerous to inhale, always ensure that you’re wearing protective equipment and using proper ventilation when handling products containing this chemical. 

Caustic Soda Flake in black bowl ceramic
Caustic soda is commonly used in oven cleaners because it has high alkalinity, making it effective at cutting through grease

Can Oven Cleaner Fumes Poison Food?

While oven cleaner fumes can be toxic given the chemicals they contain, it is reassuring to know that they’re also very volatile. Really, volatile? Yes! Volatile chemicals typically evaporate without accumulating as moisture on internal surfaces. Therefore, fumes from oven cleaners aren’t at risk of contaminating your food. The only time this would be a concern is if food was put in direct contact with the oven cleaner itself. 

If you want to stay on the safe side, however, there are a few precautionary measures you can take:

  • Remove all food items around the oven before cleaning it
  • Use a diluted amount of oven cleaner to weaken the chemicals
  • Thoroughly rinse your oven with water after you’re finished
  • Avoid switching the oven on before you’ve thoroughly rinsed it

What Is The pH Of An Oven Cleaner?

Oven cleaners are alkaline solutions, with a pH ranging between 11 and 13. This is because alkalis are very effective at cutting through all the grime and gunk that accumulate inside an oven: through saponification, alkalis emulsify fats into soaps, which are then more easily dissolved in water. 

In cases where the grease build-up is severe, stronger oven cleaners with a higher alkaline pH can be used. Solutions containing caustic soda are ideal in these situations because this chemical has a high pH of around 14. Proceed with caution when using these products, however, because high-alkaline oven cleaners can irritate the skin, and may even cause chemical burns. 

Is Oven Cleaner An Acid Or Alkali?

When the active ingredient is something like sodium hydroxide, a.k.a. caustic soda, oven cleaners have high alkalinity. Alkali cleaners such as these can strip away the molecular bonds of lipids and other organic materials. Sodium hydroxide in particular is very effective at breaking covalent and organic polymer bonds. In addition to this, alkaline cleaning solutions not only remove gunk from inside ovens, but also help to remove rust. 

While alkaline oven cleaners are corrosive, they don’t cause metal oxidation reactions. This leads us on to why acidic cleaners are not recommended for metal surfaces like ovens: put simply, they’re highly corrosive. Meanwhile, oven cleaners that have a neutral pH don’t damage or cause rusting to metal components, so only these and alkaline cleaners are recommended for ovens. 

Glass jar of baking soda next to tall bottle of vinegar
A non-toxic alternative to chemical oven cleaners is the baking soda and vinegar trick

Non-Toxic Alternatives For Oven Cleaners

If you’re still apprehensive, you can always make your own non-toxic alternative to oven cleaner. This is really easy and affordable to do, and only requires two ingredients: baking soda (an alkali) and vinegar (an acid). Here’s how it works:

  • When baking soda and vinegar are combined, they exchange atoms
  • Because baking soda is a base, it readily accepts a proton from the vinegar
  • This action transforms baking soda into water and carbon dioxide, releasing gas
  • The mixture will then appear to bubble and fizz, which loosens the grime

To make this yourself, all you have to do is mix baking soda with water to form a paste. Layer this onto your oven’s surfaces so that the baking soda can get to work breaking down the grease. Then, once it’s been sitting for a while, spray some vinegar over the paste to activate the fizzing. Let it sit for as long as possible before wiping away to ensure that all the grime is penetrated and loosened.

Bear in mind, however, that although this method is non-toxic to humans, it can have detrimental effects on your oven! Baking soda can actually discolour aluminium – so while this concoction is safe on steel, make sure to remove any aluminium oven racks before getting started. 

While chemicals used in oven cleaners are toxic, the risks they pose can be greatly minimised if you take some precautions, like wearing PPE (personal protective equipment). You can also dilute your oven cleaner if you’re concerned about it being too concentrated. 

It’s also worth keeping in mind that commercially available oven cleaners are subjected to strict chemical manufacturing regulations to ensure that they’re safe for use. That said, always read the labels or instruction guide to ensure that you’re using an oven cleaner as safely as possible.


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