The National Institute for Occupational Safety and Health (NIOSH), part of the Centers for Disease Control and Prevention (CDC), received two health hazard evaluation requests to evaluate the potential exposure of immigration employees to tuberculosis (TB) at two Federal facilities. This article describes what the investigators found and their recommendations for creating safer correctional facilities. What Is TB? Caused by the bacteria Mycobacterium tuberculosis, TB is spread from person to person through the air, where it can survive for several hours. When a person with active TB disease of the lungs or throat coughs, sneezes, speaks, or sings, TB bacteria are released into the air. Although this usually infects the lungs, it can also infect other body parts such as the brain, kidneys, or spine. The symptoms of active TB disease in any body part include feeling sick or weak, weight loss, fever, and night sweats. The symptoms of active TB disease of the lungs also include coughing, chest pain, and coughing up blood. In addition to an active TB infection, people who breathe air containing TB bacteria can become infected with "latent" TB infection. Those infected with latent TB have the TB bacteria in their bodies but do not not become ill because the bacteria are inactive. Thus, they do not have symptoms of active TB disease and cannot spread the bacteria to others. Approximately 5 to 10 percent of people with latent TB infection eventually develop the active disease during their lifetimes, especially if their immune systems become weakened. People with latent TB infection can be treated to prevent the development of active TB.