Is Silicone Biodegradable? Does It Breakdown?

What comes to mind when you think about the word 'silicone'? My first thought was cookware, like measuring cups, spatulas, silicone baking mats, and cake molds galore.

Available in a wide array of colors, durable, and widely regarded as eco-friendly options, it’s easy to forget what will happen to these silicone alternatives once they are worn through…

'What’s more, is silicone biodegradable? What is it even made of? As far as I can tell, It looks and behaves quite similarly to plastics. So is silicone plastic? What makes it so much better, safer, and eco-friendly?' What’s more, is silicone biodegradable? What is it even made of? '

As far as I can tell, It looks and behaves quite similarly to plastics. So is silicone plastic? What makes it so much better, safer, and eco-friendly?

All of these questions far supersede the benefits of a clean, worry-free bake when we consider the impact these kinds of choices stand to have on our health and our planet.

What is silicone?

If you were wondering if silicone is a plastic? It is, but silicones are a family of synthetic polymers of their own.

Silicone polymers can come in the form of liquids, gels, rubber, foams, or solids; and are all embraced for being more temperature resistant and durable than other plastics. They also have a low reactivity to chemicals, are quick-cooling, and are stain-resistant. 

Silicone polymers are used in various applications, from the healthcare and aerospace industries to textiles, construction, and cookware. So things like breast implants, engine gaskets, textile coatings, sealants, and measuring cups, of course, can all be made using these polymers, which are highly effective in all these industries. 

What is silicone made of?

Often confused with silicon, silicones contain silicon but are not the same. Silicon is derived from silica, one of the most common elements on Earth. Every time you go to the beach, you are most often first stepping into another kind of ocean, one made mostly of pure crystalline silica.

All those tiny rosy- or clear-colored gemstones are used to make silicon and later silicones. Silica is also widely used in other things like concrete, ceramics, and pottery, among other things.

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How is silicone made?

The process of making silicones starts with silica. It is heated to temperatures as high as 1800˚C to create isolated silicon. (SIMTEC, 2017) The silicon is then combined with methyl chloride (using heat),  followed by further reactions using other chemicals and more heat. While they are made largely using a naturally occurring and abundant element, the resulting materials are still synthetic polymers like other plastics. 

Is silicone biodegradable?

The answer depends on what we define as biodegradable since almost anything will naturally degrade over time. So let’s start by defining what counts as truly biodegradable. 

A given item or product is considered biodegradable when it can be broken down by microorganisms (like bacteria, fungi, or microbes) and be reabsorbed by the environment without causing pollution. (BBC Good Food, 2021) An apple core, for example, is generally considered biodegradable. 

Relevant regulatory bodies also support this definition. The Canadian Competition Bureau defines biodegradability as "a characteristic of a product or packaging that, concerning specific conditions, allows it to break down to a specific extent within a given time."

They also specify that claims of degradability "shall not be made for a product or packaging, or component of a product or packaging, that releases substances in concentrations harmful to the environment." Furthermore, and of great importance, "a claim that a product is biodegradable should be made only if it would be true in the circumstances in which the product is likely to be disposed of."

In the States, the US Federal Trade Commission specifies that items that do not completely decompose within one year after customary disposal would be deceptively labeled under degradable terms. (EPA, 2020)

So to be considered biodegradable, an item or product needs to break down by microorganisms within a specific amount of time, without leaving harmful chemicals behind, and be likely disposed of in ways that will support its degradation. 

Based on these criteria, silicones are not biodegradable because they are likely to take more than a year to degrade (once worn) and release harmful substances into the environment when they degrade as other synthetic polymers do. They are also most likely to wind up in landfills that do not support decomposition since they are designed to keep oxygen and sunlight out, which are needed for decomposition. 

How Long Does Silicone Take to Biodegrade?

It is still difficult to say how long it takes for silicones to degrade since biodegradation tests are difficult to perform on silicone polymers because they are so durable on several ends of the spectrum.

With low solubility and high vaporization rates, we are currently still left with a big question mark surrounding this question. (Clean Technologies and Environmental Policy, 2008) But if less durable plastics take between 1.8 and 2,500 years to degrade, we can safely say silicones will likely take a while. (ACS Sustainable Chem. Eng. 2020)

Is silicone toxic?

According to Health Canada, "silicone rubber does not react with food or beverages, or produce any hazardous fumes" and there are currently no known health risks associated with silicone cookware. However, they warn not to use silicone cookware at temperatures exceeding  220°C (or 428°F). 

Even though the external applications of silicones are the focus of our coverage here at The Eco Hub, it must be noted that while deemed similarly safe, the FDA does warn about using liquid silicone as an injectable filler for cosmetic purposes.

Liquid silicone may leave targeted areas blocking blood vessels in the brain, heart, lymph nodes, or other body parts, causing danger. (Healthline, 2019)

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What are some of the benefits of silicone? (pros and cons)

With that said, here are the pros and cons of using silicone products rather than single-use products: 

Can you recycle silicone?

Many people wonder if silicone plastic is recyclable and there are several ways to recycle it. You can start by contacting your municipal waste management services to see if they accept and recycle silicone products.

Chucking our old silicone products in the bin and crossing our fingers can contaminate the waste stream and comes at a cost to the waste management plant. If they do not accept silicone, you can look for companies like Terracycle to recycle old silicone products at a cost. 

Thankfully some companies are also beginning to offer take-back programs for the silicone products they manufacture and sell to us. Once worn, you can return the products to them for recycling. 

You can also try to recycle your worn silicone products at home by following these instructions. 

How bad is silicone for the environment?

It is hard to say, but silicone is arguably an eco-friendly option only because of the severe refuse problem that plagues our planet.

By opting for silicone straws, silicone storage bags, silicone cupcake liners, or silicone menstrual cups, we divert waste from the waste stream as many times as we use silicone alternatives instead of single-use products (plastic or otherwise).

In doing so, we help reduce the load on our landfills and ecosystems. Ultimately, silicone is not the most eco-friendly solution to our waste problem.

What’s the best way to recycle silicone?

Most of the silicone that is recycled is turned into industrial lubricant oil or lower-grade products. So the best way to recycle silicone seems to be whatever works best for you. If you know it will be recycled properly, commit to whatever is within your means. 

Is silicone more eco-friendly than plastic?

Compared to the commonly used plastics, which are filling up our oceans, killing wildlife, and winding up in our food chain, silicone is more eco-friendly than plastic.

To start, silicone is a safe alternative to plastic since it doesn’t leach into food and drinks; it is safely reusable for far longer than other plastics because it is durable and non-toxic; it helps to divert waste to landfills (or ocean) by providing a reusable alternative, and is less likely to wind up as litter because it is reusable. 

What are the advantages of using silicone to replace single-use plastics?

By reaching for a reusable silicone straw (or any other silicone alternative to single-use plastics) every time we need one, we keep that many single-use plastics from our landfills, ecosystems, and wildlife.

Silicone products are also much safer than commonly used plastics regarding temperature resistance and leaching. While some do not recommend heating food in silicone, silicone products remain much safer than single-use or generic plastic products.  

One of our favorite online zero-waste stores, Net Zero Co., carries a wide range of silicone products, all of which will make a good addition to your home.

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They have reusables to keep food prep fresh, bake, and store leftovers. Their silicone products do not contain any fillers and are FDA-approved. If you want to freeze food, like meat without plastic, look at their silicone sealer bags, they have a leak-proof seal that ensures your food stays fresh. Thanks to their versatility and size options, these bags can be used on the go, for school lunches, and more.

For smaller foods like half an avocado, lemon, or watermelon, you'll become obsessed with the stretch and seal silicone lids, also offered in larger sizes, making it even easier to keep food fresh longer. These are lifesavers and are an excellent alternative to saran wrap. They can also be used on round or square containers and have impressive air-tight quality.

The same goes for the fruit and veggie covers. These have been game-changers in my home.

For baking lovers, you will want to give the baking cups a go! They are way better than the single-use ones you might be accustomed to using. Instead of parchment paper, the silicone baking mat is a must-have in any zero-waste kitchen. It's durable, easy to wash, and comes in various fun colors. Both items are safe to use in the oven.

Net Zero Co. even has a Silicone Takeback Program, which we highly recommend you take advantage of if you have damaged silicone items you are trying to get rid of responsibly. It's so simple, email them (hello@netzerocompany.com), and they will email you a pre-paid return label, pack your stuff into a box and mail it to them.

Once received, they work with Terracycle to recycle the items properly. Use ECOHUB22 to get 22% off sitewide.

What is a good substitute for silicone?

Substituting for silicone all depends on what you are looking to substitute. For cookware, good substitutes for silicone include glass, ceramic, stainless steel, and beeswax wraps. If you are up for it, you can even make your DIY beeswax wraps. Compostable options (that are compostable) for things like cupcake liners and baking mats make wonderful biodegradable alternatives to silicone. 

Regarding teethers, pacifiers, and nipples (teats), BPA-free silicone options may not have a more eco-friendly alternative. Still, glass bottles (with a silicone sleeve), or bamboo and stainless steel dinnerware can make for healthier, more eco-friendly alternatives to silicone products designed for children. 

A final word about silicone

While it may be disappointing for some to learn silicones are not biodegradable, neither are they the answer to our non-stick dreams. They offer wonderful benefits like durability and reusability, making them a safer alternative to other plastics. However, they are only an eco-friendly option in comparison to other plastics. 

So, if you have to reach for silicone, don’t feel guilty if this works best for you. Making eco-friendly choices is also about accommodating your needs and capacities; we are equally about that at The Eco Hub.

Just remember to consider whether or not there are more eco-friendly alternatives to what you are looking for and whether or not you will be able to recycle the silicone item(s) you have selected once they are worn. 

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