Light micrograph of a section through a lung with asbestosis, a chronic inflammatory disease caused by the inhalation of asbestos fibers. Asbestos fibers have been stained prussian blue by Perl's method. The presence of the fibers elicits an immune response that leads to inflammation and scarring of the lung tissue. Symptoms include shortness of breath and pain. Those exposed to asbestos are also at greater risk of lung cancer and mesothelioma (cancer of the mesothelium which lines the internal organs). HFW=130um.