In the basement of a 1920s home the original cast iron boiler was still sitting in the middle of the room. It appeared everyone who passed it they rubbed against it, put their hands on it and marveled at its size without thinking about its consequences.
This beast of a boiler had been replaced ten years earlier by the smaller forced air furnace (it’s left in the photo). At that time the new forced air furnace was installed the boiler should have been removed because the hard coating some what like plaster was in fact asbestos. Asbestos can be very dangerous to your lungs if the fibers which are often in the air get into your lungs as you breath.
Asbestos if untouched or is encapsulated (covered) does not pose a problem, but asbestos that is touched or rubbed an any manner releases invisible fibers into the air that can do serious damage to your lungs.
Asbestos removal should not be a homeowner weekend project, it should be undertaken by a professional state licensed contractor.