Occupational lung diseases are occupational diseases affecting the respiratory system, including occupational asthma, black lung disease (coalworker's pneumoconiosis), chronic obstructive pulmonary disease (COPD), mesothelioma, and silicosis. Infectious lung diseases can also be acquired in an occupational context. Exposure to substances like flock and silica can cause fibrosing lung disease, whereas exposure to carcinogens like asbestos and beryllium can cause lung cancer. Occupational cases of interstitial lung disease may be misdiagnosed as COPD, idiopathic pulmonary fibrosis, or a myriad of other diseases; leading to a delay in identification of the causative agent.