Biosafety Level 3 (BSL-3) is a set of safety protocols used in laboratories that work with pathogens that can cause serious or potentially lethal diseases through inhalation. Facilities operating at this level are designed to prevent the escape of these microorganisms into the environment. BSL-3 labs require specialized ventilation systems, controlled access, and personal protective equipment (PPE) to ensure the safety of researchers and the public. In a BSL-3 laboratory, researchers may study diseases such as tuberculosis or West Nile virus. These labs are equipped with features like sealed windows, negative air pressure, and self-closing doors to minimize the risk of exposure. Proper training and strict adherence to safety guidelines are essential for anyone working in these environments.