Asbestos fibers can cause serious illnesses when inhaled including lung cancer and mesothelioma. Long or high exposure to asbestos fibers increases health risks as low levels in ambient air do not typically cause problems. Asbestosis is a lung condition caused by inhaling asbestos fibers which scar and thicken lung tissue over many years and can lead to serious medical issues or death if exposure continues. Asbestos use should be stopped and substitutes used instead since it can cause rare cancers and death among those with high exposure to its fibers.