I personally have concerns with the safety of silicone bakeware. While I have no concerns with using silicone for storage purposes (such as with these reusable silicone food storage bags) I am concerned with heating silicone to the high temperatures required for baking. There is data that shows that when heated above 100°C or 212°F, silicone elastomers will migrate out of the silicone and at temperatures around 150°C or 302°F and higher, silicone elastomers start to degrade even further. What this means is that these breakdown products will start to migrate into the food you are cooking or baking at these temperatures, which is something that of course we want to avoid.