Silicone products have become increasingly popular in recent years.
As people have become more concerned about harmful plastic chemicals, silicone has been touted as a non-toxic alternative to plastic. But is silicone actually safer?
Where is silicone found?
You can find silicone in colorful kitchen items, like pop-out muffin pans, oven mitts, and spatulas. But silicone exists beyond the kitchen.
Silicone is found in:
Coatings on waterproof outdoor-wear
“Green” dry-cleaning solvents
Some breast implants
Baby bottle nipples and pacifiers
Skincare, hair products, and makeup
Chances are, you’ve come into lots of contact with silicone products. What about this material allows it to find so many different uses?
What is silicone?
Silicones contain the elements silicon, carbon, hydrogen, oxygen.
Because of its properties, silicone seems to avoid all the problems with plastic:
It is resistant to high temperatures
It does not degrade upon reuse
It is recyclable
It is flexible and nonstick
It does not contain or leech toxic chemicals…or does it?
How is silicone produced?
The production of silicone requires many steps. First, pure elemental silicon is concentrated from sand or quartzite. Second, the pure silicon is processed with methyl chloride. Methyl chloride is made from either natural gas or coal.
One of the greatest appeals of silicone is that it lasts for a long time without degrading. So production costs may be outweighed by the fact that it can be used almost endlessly.
Silicone products are so durable that they are not biodegradable. To recycle it, silicone must go to a specialized facility.
Silicone in personal care products
Some silicone molecules are very small and are named with a letter (“L” or “D”) and a number, such as D4, D5, etc.
Different types of silicones are used in personal care products. One study found detectable levels of silicones D4, D5, D6, and D7 in:
The study estimated that women in the United States are exposed to 307 mg of silicones per day from their personal care products.
Are Silicones harmful?
Some types of silicones can harm both people and the environment.
Studies have shown that D4:
Can disrupt hormones and act like estrogen
Is carcinogenic, mutagenic, and toxic to reproduction
Is “very persistent” in the environment and “very bioaccumulative”.
Causes fetal loss in rats
D5, a similar compound was determined to not be an environmental concern at current levels. But it can accumulate in living things.
The European Chemicals Agency concluded that D4, D5, and D6 should be phased out of use. These compounds are persistent, bioaccumulative, and toxic.
Silicones in the kitchen
In the kitchen, silicones are not only in bake and kitchenware, but are also in:
Corks for alcoholic beverages
Gaskets for pressure cookers and electric kettles
Adhesive sealants in refrigerators
Food packaging as additives to plastics
Are these silicones getting into our bodies?
There are very few studies looking at silicone exposure from these items.
One study found that the harmful silicones D3, D4, and D5 leached from silicone baby bottle nipples into milk and infant formula.
Another study found that meat loaf prepared in a silicone mold contained high levels of silicone. But after a few uses of the silicone container, no further migration occurred.
Silicones are also used in food itself. Some silicones used for food processing. Silicone oils may be added to cooking oils to prevent foaming during frying.
Other silicone products
Silicone is also used to make waterproof outdoor gear like jackets and tents.
Menstrual cups are often made of silicone, but these must be medical grade (FDA approved).
Why does some silicone contain harmful chemicals?
The small silicones that migrate from food are non intentionally added. They are impurities that result from silicone production.
A great way to avoid these impurities is to use “platinum cured” or “platinum grade” silicone.
Silicone components may be toxic. These include:
Lower quality silicone bakeware can contain these chemicals. These items may discolor over time or create an odor while cooking.
You can easily avoid these lower quality silicones. To check, pinch and twist a small part of the silicone rubber. If the twisted part shows white color, the silicone is not pure. This is because pure silicone does not change color.
Any food contact substance, including silicone kitchenware, must adhere to FDA guidelines. These guidelines permit the use of silicone polymers in kitchenware. Unfortunately, harmful additives like phthalates are considered safe under these guidelines.
So FDA approval doesn’t mean it is safe to use silicone products in the kitchen.
The Pros and Cons of Silicone
Less natural gas and petroleum used for production (than plastic)
May be useful if no harmful additives are used and if D4, D5, and D6 are not ingredients or by-products of production
Has beneficial properties to many industries
Does not continue to degrade with use
May contain harmful additives or by-products
Is not biodegradable
In cosmetics and food-contact materials, it is not sufficiently regulated by the FDA
The bottom line
There is no doubt that silicone is a useful material for many applications.
As an alternative to plastic, silicone offers:
a longer lifetime
less reliance on the fossil fuel industry
In kitchenware, especially food storage or heating containers, food contamination is an issue.
As a first choice, we recommend glass or stainless steel alternatives. High quality (platinum grade) silicone is a good second choice. Avoid low quality silicones using the pinch and twist method.
Lastly, avoid personal care products that contain D4, D5, and D6.
You can check out our list of Approved Products to find personal care and household items that are free of harmful silicones.