No, but it’s common that they do. Gravity furnaces weren’t terribly efficient so wrapping either the ductwork in asbestos, the furnace itself, or both, was something done regularly. This allowed the system to retain more heat. At the time, this greatly enhanced the efficiency of the furnaces but it wasn’t until later that we became aware of just how carcinogenic and dangerous asbestos could be.

If you think you’ve touched asbestos, do not put on a mask. This is important because you may take the asbestos fibers on your hands on trap them in the mask. Make your way to a sink and wash your hands thoroughly. Remove any clothes and seal them in a bag, then take a shower. Call your doctor and let them know you’ve been exposed to asbestos, and make sure you see them as soon as possible. The reason you keep the clothes is in case anyone wants to confirm the presence of asbestos.

The microscopic asbestos fibers do not cause eye irritation, throat irritation, or lung irritation. If you are inhaling fibers, you will not know it. This lack of immediate symptoms is one of the reasons why asbestos is so dangerous. You cannot know for certain if you are inhaling fibers, which is why you must wear safety gear if you could have any chance of an exposure while working.

While it's possible to cover asbestos tile with carpet, it's not recommended. Encapsulating tile beneath carpet doesn't eliminate the health risks. Over time, the asbestos tiles could degrade, releasing fibers into the air and potentially contaminating the carpet. Disturbance during carpet installation or removal might also release fibers.