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.

It can be safe to live in a house with asbestos as long as the asbestos-containing materials are intact, in good condition, and not disturbed. Asbestos becomes dangerous only when its fibers are released into the air, which happens if the material is damaged, crumbling, or disturbed during renovation work. If you suspect asbestos is present, do not disturb it. Instead of removal, materials in good condition can sometimes be encapsulated. It is recommended to have regular professional inspections to monitor the condition of the asbestos and prevent health risks from potential exposure.

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.

Professionals use specialized equipment and techniques to detect asbestos, radon, and VOCs.