Working principle of electric hand warmer, is there radiation?

There are also inferior hand warmers, the interior of which is actually an ordinary small electric stove, covered with a layer of asbestos material and made of metal material. This hand warmer is characterized by fast heating, but short heat preservation time.

Generally speaking, hand warmers have no radiation, even if the internal material has certain radiation, it is blocked by its metal shell.

However, the harmful gases and dust emitted by some inferior hand warmers can not be ignored.