Occupational lung diseases are occupational, or work-related, lung conditions that have been caused or made worse by the materials a person is exposed to within the workplace. It includes a broad group of diseases, including occupational asthma, industrial bronchitis, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases (such as pneumoconiosis, hypersensitivity pneumonitis, lung fibrosis), infections, lung cancer and mesothelioma. These diseases can be caused directly or due to immunological response to a exposure to a variety of dusts, chemicals, proteins or organisms. Occupational lung diseases are occupational, or work-related, lung conditions that have been caused or made worse by the materials a person is exposed to within the workplace. It includes a broad group of diseases, including occupational asthma, industrial bronchitis, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases (such as pneumoconiosis, hypersensitivity pneumonitis, lung fibrosis), infections, lung cancer and mesothelioma. These diseases can be caused directly or due to immunological response to a exposure to a variety of dusts, chemicals, proteins or organisms. 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. Asthma is a respiratory disease that can begin or worsen due to exposure at work and is characterized by episodic narrowing of the respiratory tract. Occupational asthma has a variety of causes, including sensitization to a specific substance, causing an allergic response; or a reaction to an irritant that is inhaled in the workplace. Exposure to various substances can also worsen pre-existing asthma. People who work in isocyanate manufacturing, who use latex gloves, or who work in an indoor office environment are at higher risk for occupational asthma than the average US worker. Approximately 2 million people in the US have occupational asthma. Bronchiolitis obliterans, also known as constrictive bronchiolitis or obliterative bronchiolitis is a respiratory disease caused by injury to the smallest airways, called bronchioles. It has been reported to occur from exposure to inhaled toxins and gases including sulfur mustard gas, nitrogen oxides, diacetyl (used in many food and beverage flavorings), 2,3-pentanedione, fly ash and fiberglass. Chronic obstructive pulmonary disease is a respiratory disease that can encompass chronic bronchitis and/or emphysema. 15% of the cases of COPD in the United States can be attributed to occupational exposure, including exposure to silica and coal dust. People who work in mining, construction, manufacturing (specifically textiles, rubber, plastic, and leather), building, and utilities are at higher risk for COPD than the average US worker. Hypersensitivity pneumonitis (HP; also called allergic alveolitis, bagpipe lung, or extrinsic allergic alveolitis, EAA) is an inflammation of the alveoli within the lung caused by hypersensitivity to inhaled organic dusts. Numerous categories of ionizing radiation, chemicals and mixtures, occupational exposures, metals, dust and fibers have been linked to occurrence of lung cancer. Mesothelioma is a cancer of the mesothelium, part of which is the pleura, the lining of the lungs. Mesothelioma is caused by exposure to asbestos. Pneumoconiosis are occupational lung diseases that are caused due to accumulation of dust in the lungs and body's reaction to its presence. Most common pneumoconiosis are silicosis, coal workers’ pneumoconiosis (CWP), and asbestosis. Other examples include minerals (such kaolin, talc, mica), beryllium lung disease, hard metal disease and silicon carbide pneumoconiosis.