I am always looking to learn more about how to run an eco-friendly kitchen and the more I learn the more I have come to realize that the first step is to pick the right cookware! Choosing eco-friendly cookware can make a big difference in your exposure to toxic chemicals and can even make your food taste better.
Traditional plastic cookware has been linked to leaching hormone-disrupting, carcinogenic chemicals into our food which is why I recommend non-toxic alternatives whenever I can. So when a reader recently asked me, “Candice, isn’t silicone eco-friendly cookware? Is silicone plastic?” I knew I had to clear some things up.
What is silicone?
Silicone is often confused with silicon but they aren’t the exact same thing. Silicon is made by heating silica (or silicon dioxide) at very high temperatures. Silica is one of the most common elements on earth - beach sand is basically pure silica! Silicone, on the other hand, refers to a separate group of man-made, synthetic polymers (or bonds of siloxane monomers) and organic compounds.
To the untrained eye, silicone looks and feels like a hybrid between rubber and plastic. So it comes as no surprise that silicone is marketed as the best of both worlds since it’s flexible and durable like synthetic rubber but is also easy to clean and moldable like synthetic plastic polymers.
For some bonus points silicone is also non-stick, malleable, and temperature resistant. All of these features make silicone a popular choice for kitchen utensils and cookware.
How is silicone made?
The process to make silicone starts with silica. Silicon is first isolated from silica under high heat. Next, the silicon is ground down into a fine powder where it will be mixed with methyl chloride. The mixture is then distilled and separated where dimethyldichlorosilane (the primary building block of silicone) can be pulled out and combined with water.
This will cause the hydrochloric acid and disilanol in the mixture to separate and the hydrochloric acid then acts as a catalyst for the disilanol to condense into polydimethylsiloxane. Polydimethylsiloxane has a siloxane bond — the backbone of silicone — and this allows the silicone to undergo a polymerization process where it will finally become silicone.
What is silicone used for?
Silicone isn’t just used for cookware! It has a wide range of applications including breast implants, textile coatings, toys, cosmetics, baby bottle nipples, period cups, and reusable baggies, like Stasher.
In a more industrial setting, you can find silicone in filters, windshield wipers, adhesives, lubricants, and engine gaskets. Silicone products can also be found in the medical field in implants, respiratory masks, IVs, and other healthcare devices.
What is food-grade silicone?
FDA-approved food-grade silicone is considered safe for use within the food manufacturing and processing industry. In 1979, the U.S. Food and Drug Administration (FDA) determined that silicon dioxide (the basic element that makes up silicone cookware) was safe to use as a food-grade material.
Less than a year later we started to see silicone products pop up on the market, starting first with spatulas. What concerns me is that the FDA hasn’t done much research since then and the answer to if silicone leaches chemicals into your food is still inconclusive.
What is medical-grade silicone?
Medical-grade silicone has been approved to use in medical devices and implants. For example, implants made in the US using medical-grade silicone are regulated by the Center for Devices and Radiological Health (CDRH) under FDA regulations. This kind of silicone has to pass some pretty rigorous tests before it can be certified medical grade - in other words, this is the highest quality silicone out there.
Is silicone plastic?
So enough beating around the bush, is silicone plastic? Not exactly… let’s chat about why.
Plastic vs Silicone
It is easy to get confused between silicone and plastic since they act quite similarly (and there are so many types of plastic out there). At a molecular level, silicone differs from plastic because plastic's molecular backbone contains both carbon and hydrogen, while silicone contains bonded silicon and oxygen (in some cases, carbon).
Is silicone safer than plastic?
We will get more into the details of this question later on. When plastic comes into contact with higher temperatures, it can off-gas and leach hazardous chemicals into the food we eat and the air we breathe. This we know for certain.
The verdict as to if silicone will do this as well is still up for debate. So while silicone is probably less toxic than plastic, by how much we just don’t really know for sure.
Silicone vs Rubber
Silicone and rubber do have some similarities. Natural rubber and silicone both contain some natural elements — silica with silicone and the Hevea brasiliensis tree with rubber. Synthetic rubber is also similar to silicon in some ways since it's also made from an artificial elastomer. They are also both durable and bendable which makes them valuable materials with many different uses.
How safe is silicone?
Is silicone toxic?
Most experts agree that silicone is non-toxic but the research is inconclusive and not everyone seems to agree here…
Health Canada has said in the past that “there are no known health hazards associated with use of silicone cookware” and that “silicone rubber does not react with food or beverages, or produce any hazardous fumes." This was a reference to “food grade” silicone so it should be noted that if you are buying silicone products that aren't food grade or medical grade, then you might be putting yourself and your family at risk.
Is silicone BPA-free?
Once consumers found out about all of the harmful effects of BPA we started to see better alternatives come out. Tritan plastic, for example, is BPA-free.
One of the best things about silicone is that it is also BPA (or Bisphenol A) free. This is extremely important since long-term exposure to BPA can cause some serious health issues. In fact, BPA can bind to estrogen receptors and affect human cell repair, energy levels, fetal development, and that is just a start.
Even though silicone is BPA-free, I think there are still tons of better, non-toxic, eco-friendly food storage containers and cookware on the market today that AREN’T plastic!
Tips for using silicone safety
- Give your silicone a quick wash before using it. This step reduces the likelihood of chemicals getting into your food and I recommend you do the same when purchasing ANY cookware.
- I would avoid putting silicone products in the dishwasher, this will cause them to wear down faster!
- Make sure your silicone item has fully dried out before you store it away or it might become discolored and tacky.
- Stay away from greenwashing when buying silicone! When you purchase silicone products, look for labels that would suggest it's of a higher quality/grade. You can test the quality of your silicone item by giving it a twist, if you see light streaks then your item might contain filler, this is a no-go.
Is silicone dishwasher safe?
So technically silicone is dishwasher safe, but that doesn’t mean that is the best way to clean your silicone products. Putting silicone products in the dishwasher will likely cause the product to wear down faster. Instead, use zero-waste dish soap to cut through the grease, and if necessary, add a little bit of baking soda.
Is silicone oven safe?
I have talked before about if silicone can go in the oven and the answer is still yes. Silicone cookware is considered “oven safe” for temperatures up to 428 degrees Fahrenheit (or 220 Celsius). As long as you follow the manufacturer's instructions and don't heat your oven past 428 degrees when baking with silicone, you should be fine.
Is silicone recyclable?
Silicone can be recycled multiple times, however, recycling silicone is considered “downcycling”. This means that the silicone will slowly degrade more and more after each subsequent use. When silicone is recycled, it is usually sent to a specialized recycling company where it will be melted down into an oil that is used as an industrial lubricant.
Sometimes silicone can be recycled into other household products. For example, Nimble makes Airpod cases from recycled silicone!
Unfortunately, because silicone usually needs to go to a specialized facility that can recycle the product properly, most consumers skip this step and throw their silicone products in the garbage where it will be sent to a landfill.
Is silicone biodegradable?
The Canadian Competition Bureau says for something to be considered biodegradable it should “not be made for a product or packaging, or component of a product or packaging, that releases substances in concentrations harmful to the environment".
So for silicone to be considered biodegradable, it must be able to break down quickly (with the help of microorganisms and with/without oxygen) and leave no chemicals behind that might harm humans or the natural environment.
So, is silicone biodegradable? Unfortunately like most synthetic polymers, silicone is not biodegradable. Some studies even go as far as to suggest silicone could take up to 500 years to fully break down!
If you are looking for “biodegradable plastic”, you are probably looking for bioplastic! While not a perfect choice, some bioplastics (that have not been mixed with synthetic materials) will biodegrade without leaving any harmful toxins behind.
Can silicone be composted?
Compostable and biodegradable are not the same thing! For an item to be compostable, an item must be able to break down with the presence of oxygen and microorganisms in the soil and eventually end up as a nutrient-rich soil amendment. With this definition in mind, silicone isn’t compostable either.
Pros and Cons of silicone
Now that we have answered all the big questions about silicone, I think we can best summarize all of this by looking at the pros and cons!
A final word on what is silicone
Silicone and plastic sure do have their similarities but they aren’t the exact same thing. Like plastic, silicone is moldable, transparent, and durable! But unlike plastic, there is a smaller chance of chemicals off-gassing or leaching into your food when exposed to heat with silicone.
Unfortunately, silicone you might find at the store isn’t always the highest grade and it might be mixed with fillers and other chemicals - this would mean your silicone cookware certainly isn’t biodegradable.
If you buy silicone, look for “food grade” or “medical grade” on the label, and be sure to bring it to an independent recycling center when you are done with it so you can be sure it was disposed of properly!