Silicone
Silicone
Silicone is a synthetic polymer built on silicon and oxygen rather than carbon. It's heat-resistant and durable, so it's used for bakeware, lids, seals and baby teats. We count it as plastic but always label it separately, so you can decide.
By PlasticFreeHome Research Team · Not yet reviewed by an editor · Updated 21 October 2026
- Also called
- silicone rubber, polysiloxane, food-grade silicone, platinum silicone
- Type
- Silicone
- Found in
- baking moulds and mats, stretch lids and food bags, baby bottle teats and soothers, seals in jars, flasks and kettles, spatulas and oven gloves, menstrual cups
- Heat
- Heat-resistant, which is why it's used for bakeware. Clean new moulds before first use and stay within the maker's temperature limit.
- Recycling in the UK
- Not recyclable in UK household collections, and silicone parts can disrupt plastic recycling. Some brands run take-back schemes.
What it is
Silicone is a synthetic polymer, polysiloxane, whose backbone is made of silicon and oxygen atoms instead of the carbon chains of most plastics. It's soft, flexible, stable across a wide range of temperatures and doesn't become brittle quickly, which is why it's used for bakeware, stretch lids, food bags, seals and baby teats.
Is silicone plastic?
Under our definition, yes: it's a synthetic polymer. But it behaves differently from most plastics, and many people are comfortable using it. So we always label it separately. A product with silicone in a food-contact part can't be called plastic-free on this site, but you'll always see "silicone" named, so you can choose. See is silicone plastic?
What can come out of it
Silicone can contain small, volatile siloxanes left over from manufacturing. Good-quality food-contact silicone is "post-cured" by the maker, baked to drive most of them off.
A German study baked cakes in 14 new silicone moulds. Siloxanes were found in the indoor air and in the cakes, mostly at the edges where the cake touched the mould, and the moulds with the most siloxanes gave the highest air levels. Air levels fell when a mould was reused. The authors judged contamination with the best-known siloxanes (D4 to D6) to be low, but said food may matter more for the heavier ones. They advised cleaning new moulds before first use and keeping to the maker's temperature limits.
How to use it more safely
- Wash new silicone bakeware before first use.
- Don't exceed the stated maximum temperature, and keep it away from direct grills and flames.
- Buy from established retailers; very cheap moulds are more likely to be poorly cured.
- Replace items that become sticky, cracked or smell when hot.
- For storage, glass with a lid avoids the question: plastic tubs → glass, cling film → lids.
Recycling
Silicone isn't collected in household recycling, and WRAP flags silicone valves in caps as disruptive to plastic recycling. Use silicone items for as long as possible; some brands take their products back.
Related guides
Sources
- Fromme et al. (2019), Environment International — new silicone baking moulds released siloxanes into cakes and indoor air; the authors advise cleaning moulds first and keeping to the maker's temperatures
- WRAP (2022), Polymer choice and recyclability guidance — which plastics are recyclable in the UK, and why PVC and polystyrene are not
Swaps involving silicone
Reheating in plastic tubs → glass containers
Heating food in plastic is the single clearest route for plastic particles into what you eat. Glass fixes it.
Swap first · about 600 g of plastic a year
Cling film → lidded containers or beeswax wraps
Cling film is single-use plastic in direct contact with food. A plate on a bowl does the same job for free.
High priority · about 400 g of plastic a year
Disposable pads → organic cotton or reusable options
Most disposable pads are largely plastic. Cotton and reusable options cut that, with honest trade-offs.
Worth doing · about 600 g of plastic a year