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.

Unfortunately, home inspections do not check for asbestos because of the liability factor involved. That’s why you should hire a trained professional with specialized equipment to test for it. 

They will inspect all areas of the home and take samples of various materials to test. Opting for an asbestos inspection can prevent the risk of exposure to this hazardous material and save on costly repairs that may be required. 

If your home was built before 1989 and still has original vinyl, there’s a high probability of asbestos mixed into the old flooring, which can harm you and your family if it’s disturbed from removal. If you suspect that you have asbestos, you’ll want to call in an asbestos removal expert to evaluate the situation.