Asbestos dust damages the small airways, causing inflammation and scarring. Narrowing of these small airways, called bronchioles, prevents air from passing through the lungs normally. This makes breathing more difficult. As the bronchioles narrow, they make a whistling sound, called wheezing.

Asbestosis gradually develops over years of exposure. Symptoms develop after about 10 years of moderate to severe exposure. Cigarette smoking causes the damage to occur more quickly.

Asbestos was used as an insulating material for buildings and electrical wires. Asbestos has also been used in the manufacturing of fire-resistant clothing, cement and floor tiles, brake linings, and clutch linings. Although the use of asbestos has decreased, it is still used in the manufacturing of brake linings, and asbestos insulation remains in many workplaces and homes.