Unlike some home problems, such as water damage or pest infestations, asbestos can be very difficult to spot. Asbestos is a mineral in the form of microscopic fibers and was previously used in building materials for its bonding and fireproofing abilities. Insulation, roof shingles, ceiling tiles, floor tiles, pipe wrappings, soundproofing materials, and textured paint features like popcorn ceilings are common sources of asbestos, particularly in homes built before 1980.

Age is perhaps the biggest indicator of asbestos, as legislation passed in the 1970s labeled asbestos as dangerous and regulated its use in building materials. Signs of age in the form of wear and tear or material degradation are also indicators that asbestos fibers may be leaking into the air, but ultimately, it’s difficult to detect with the naked eye. If you have reason to suspect asbestos in your home, it’s best to hire a certified asbestos inspector.

If you have an older electrical system with fraying wires and other signs of damage, removal  may be the best course of action. When asbestos begins to break down, it's more likely to become airborne, increasing the risk of health issues when it's inhaled.

However, if the system is in good condition and doesn't have visible signs of wear or damage, leaving it alone may be the safest course of action. An asbestos abatement and removal professional can help you determine the best way to proceed.

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.

Knob and tube wiring is an older type of electrical wiring that's no longer used and generally not considered safe. However, some homes still have it, or may have a knob and tube wiring system that was incorrectly modified or rigged to work with a modern electrical system. Knob and tube wiring may contain asbestos insulation, but the only way to know is to have the material professionally tested.