We use only high quality parts, from glass to silica free ceramics, there are no glues, the PCBs are lead free, no components contain mercury, all accessories are food/medical grade and temperature rated. All structure materials used inside are non-toxic and heat rated to temperatures much higher than the maximum operating temperature.
We do not use thermal paste. In the oven assembly of our portable devices we use a small amount (approximately 0.05g) of a very high quality powdered ceramic material to seal the connection between the thermocouples and wires. The ceramic powder is mixed with water to create a putty that is pure ceramic, completely safe and not thermal paste. The putty is used to seal the connections, then it is solidified in place with a high-temperature baking process. After the baking process, the material has the exact same composition as the ceramic heating element itself, and is completely safe for use; it safely insulates electricity, it withstands temperatures up to 1,800°F (982°C), it is silica free, inorganic, non-toxic, odorless, and extremely stable, so there is no potential for off-gassing or harmful fumes of any kind.