Silicone bakeware as a source of human exposure to cyclic siloxanes via inhalation and baked food consumption

Silicone-based bakeware is widely used due to its heat resistance, flexibility, and non-stick properties. However, concerns have emerged regarding the potential migration and release of siloxanes from these products into food and indoor air during baking. This study evaluates human exposure to cyclic siloxanes via ingestion and inhalation, using silicone bakeware purchased on the Canadian market. Based on composition analysis, concentrations of total cyclic siloxanes (D4 - D16) in 25 bakeware products ranged from 680 µg/g to 4300 µg/g. Migration of siloxanes into food was assessed using Miglyol 812 N oil mixed with sand as a food simulant, while airborne emissions were measured at the same time during 60-minute baking sessions at 177 °C. The analytes were measured using GC/MS. The average concentration of the sum of D4 - D16 in baked food simulants was 105 µg/g. One-hour average concentrations of the sum of D4 - D16 in indoor air reached 646 µg/m³ , and declined rapidly post-baking. Migration into food simulants was influenced by bakeware type, surface area, and fat content. Repeated baking shows a steady decline in migration and emissions, suggesting depletion of siloxanes in the products over time. On a per-body-weight basis, daily intake estimates indicate that young children have the highest exposure in both ingestion of baked food and inhalation exposure of room air during baking. Heavy congeners (D7 - D16) contributed to the majority of daily intake of cyclic siloxanes from baked food. These findings highlight silicone bakeware as a source of cyclic siloxane exposure for the general population in Canada.