Berylliosis is a lung disease caused by exposure to beryllium, a toxic metal used in various industries, including aerospace and electronics. When inhaled, beryllium can trigger an immune response, leading to inflammation and scarring in the lungs. Symptoms may include coughing, shortness of breath, and fatigue. Diagnosis typically involves a combination of medical history, physical examinations, and tests such as chest X-rays or lung function tests. Treatment focuses on reducing symptoms and preventing further exposure to beryllium. In severe cases, corticosteroids may be prescribed to manage inflammation and improve lung function.