While asbestos can’t be directly absorbed through the skin—the fibers are too big—skin contact can still produce symptoms. Contact dermatitis can flare up in sensitive individuals but in most cases, the danger from asbestos comes from inhaling the fibers, or dust, that is produced when asbestos is disturbed. If you touch asbestos by accident, immediately wash yourself and your clothes.

Asbestos is a carcinogen, meaning it increases the risk of cancer. Inhaling asbestos fibers is linked to several respiratory issues, including asbestosis, or scarring on the lungs, lung cancer, and mesothelioma, another type of cancer. There's also a link between asbestos exposure and an increased risk of colon cancer and other cancers of the digestive system.

Usually, the people most at risk for disease related to asbestos exposure are those who spend a lot of time working around the material without protection. Electricians who work with asbestos wire have a higher risk of developing mesothelioma or lung cancer due to their exposure.

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.

Bathroom tiles can contain asbestos, just the same as patio tiles or kitchen tiles. Remember that asbestos was used primarily for its insulative and fire-resistant properties, both of which are desired in a house. Before we knew asbestos caused cancers and other diseases, it made a lot of sense to include it in many different building materials, including bathroom tiles.