What it is
The question I get most, so here’s the chemistry in one breath: silicone is a rubber built on a silicon–oxygen backbone — the same Si–O bond as glass and sand — with methyl groups hanging off it. It is not a carbon-backbone plastic like polyethylene; it’s a cross-linked elastomer made from quartz-derived silicon. That backbone is why it stays flexible from freezer to oven, doesn’t need plasticisers, and doesn’t soften-and-shed at kettle temperatures the way thermoplastics do.
Why it’s safer
The Si–O bond is stronger and more heat- and UV-stable than the C–C bonds of ordinary plastics. Cured food-grade silicone is largely unreactive, tolerates 200 °C+, and contains none of the usual suspects — no BPA, no phthalates. As a replacement for plastic in seals, lids and moderate-heat bakeware, the evidence supports it.
The honest caveats
It’s never 100% cured. Finished silicone contains residual small cyclic siloxanes (D4, D5, D6) and oligomers that migrate into food — worst into fatty foods at high oven temperatures. Germany’s BfR caps volatiles at 0.5% and found materials under 0.1% kept migration below ~50 µg/kg agency, while flagging genuine data gaps on oligomers; kidney and endometrial effects appeared in high-dose animal studies (BfR at EFSA, 2023) animal. Its practical advice I follow: temper new bakeware — bake it empty, ventilated, once — before it meets food.
It sheds particles when thermally aged. Repeated steam sterilisation etches silicone baby-teat surfaces, releasing micro- and nano-sized elastomer particles — an infant could ingest >0.66 million such microparticles by age one (Nature Nanotechnology, 2021) lab. So “silicone doesn’t shed” is false under repeated high heat; it sheds siloxane particles rather than conventional plastic ones. Whether those are more benign is not yet answered. Retire anything gone sticky, chalky or cracked.
Quality varies. Platinum-cured silicone leaves cleaner residues than peroxide-cured; the folk “pinch test” (white stress-marks = cheap filler) is a hint, not a lab result. Buy items declaring BfR XV or FDA 21 CFR 177.2600 compliance.
What I do
Silicone stays in my kitchen in supporting roles — jar-lid seals (two of my “plastic-free” lids have them, as the kit’s honesty section admits), spatula heads at moderate heat. I keep it away from hot-and-fatty jobs — no oiled silicone trays under the grill — and nothing silicone gets steam-blasted repeatedly. For the original question “is silicone safe?”: safer than the plastic it replaces, on current evidence, and demoted the moment it degrades.