[Jeffhs]

In some Zenith table radios of the '50s-'60s, there was a small block of asbestos mounted to the inside top of the cabinet (my C845, and probably my K731 as well, each have such a block mounted somewhere above the chassis). I don't remember why this asbestos block was in the cabinet in the first place, but I do remember seeing warnings here on VK against handling it due to the dust hazard. (Asbestos was also used as insulating material in devices such as roasters that operated at high temperatures.) Breathing asbestos dust is very harmful (as has been noted here by others), as the stuff can and will get into your lungs, possibly causing cancer. This is probably, even likely, why asbestos is rarely (if ever) used in appliances today.