Silicone Bakeware Leach Chemicals Into Food, Study Finds

Silicone bakeware has long held a critical spot in home kitchens, thanks to its non-stick properties and heat resistance, making it easy to get muffins, bread, and other baked goods out of the oven. However, a new study published in the Journal of Hazardous Materials suggests that unwanted chemicals may be leaching into your food due to the material’s non-stick properties. 

In October, researchers from Canada published a study to determine whether silicone bakeware releases certain chemicals, known as cyclic siloxanes, during baking and whether these chemicals ultimately end up in our food. To find out, the team purchased 25 silicone baking products widely available in the Canadian market. The haul included everything from cupcake trays and doughnut molds to loaf pans and cookie sheets.

They then took the products and filled each with a mixture of sand and oil, designed to mimic high-fat foods, and baked them at 177°C (350°F) for one hour. While baking, the team collected air samples above the oven to measure the contaminants released into the room during cooking. Afterward, once the mixture was removed, they tested it as well.

The results showed that silicone bakeware can release cyclic siloxanes, which are commonly found in products from cosmetics to bakeware, that form during manufacturing into both food and indoor air during the baking process. According to the team, they identified 25 different types of siloxane chemicals in the bakeware. However, the total amount of these siloxanes varied widely, ranging from 680 to 4,300 micrograms per gram of silicone. They also found that items with a larger surface area in contact with the food (such as multi-cup muffin or doughnut trays) tended to transfer more siloxanes. 

The chemicals didn’t only migrate to food. The researchers found that during the baking process, the total concentration of siloxanes in the surrounding air reached an hourly average of about 646 micrograms per cubic meter, but dropped quickly once baking stopped. The authors also noted that their study shows that “children have a higher exposure level on a per-body-weight basis.”

There was at least some good news in the study. The authors discovered that siloxane levels decline sharply as bakeware is reused. They observed that chemical release decreased by approximately 95% after just three baking cycles, and continued to decline over each use.

The team also emphasized in their conclusion that they did not assess the health risks associated with these chemicals, as there is very limited scientific data on their effects. However, according to a 2024 review published in the Journal of Applied Toxicology, siloxanes, “particularly D4, D5, and D6,” can cause “significant endocrine disruption, reproductive toxicity, and liver toxicity.” 

If you’re concerned about these chemicals, the latest study’s findings indicate that pre-baking new trays or reusing molds, along with ensuring proper kitchen ventilation, is key to protecting yourself and your food. That way, all you need to focus on is enjoying those cupcakes.