Containment levels are classifications used to describe the safety measures required to handle biological agents, particularly in laboratories. These levels range from 1 to 4, with Level 1 being the least hazardous and Level 4 the most dangerous. Each level has specific protocols for equipment, facility design, and personnel training to minimize risks of exposure or contamination. Level 1 involves basic safety practices, while Level 4 requires the highest level of containment, including specialized suits and isolated environments. These levels help ensure that research involving pathogens, such as viruses or bacteria, is conducted safely and responsibly, protecting both researchers and the public.