Some older storage heaters (pre 1972) contain asbestos. Which is quite safe unless they are dismantled.
There is a list of models that contain asbestos if there is any indication in an offer or request for the bricks from a storage heater. They can be repurposed as outside ovens, due to their good heat retention and resistance qualities.
Link to a site providing the link - https://www.armco.org.uk/asbestos-survey-news/storage-heaters-that-contain-asbestos/
For disposal of asbestos guidelines, see Asbestos.