When the macrophage engulfs the fibers, they get destroyed due to the size of these fibres. The entry of more macrophages to attack the free fibre releases enzymes and free radicals, which has the potential to damage the lung cells. Fibers, with diameters smaller than 3 micrometers, can even penetrate cell membranes.
As a result of damage, the lung tissue gets fibrosed. Initially, the damage is localized and confined to a small area, The person then starts developing symptoms of lung disease. As the exposure to asbestos continues, the fibrosis extends and sometimes the entire lung becomes scarred.
Scarring of the alveoli or air sacs leads to respiratory distress in the affected individuals.