It is not recommended to drill into asbestos siding because doing so can release hazardous asbestos fibers into the air. The safest way to handle asbestos-containing materials is to have a professional remove or encapsulate them.

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.

Asbestos fibers can stay airborne for 48 to 72 hours, depending on the home's ventilation. Fibers can linger longer in enclosed spaces with poor airflow. Because the fibers are microscopic, they can easily remain suspended, making them difficult to detect without professional equipment.

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.