biohazard

Biohazard refers to any biological substance or situation that poses a risk to human health or the environment. This includes infectious agents such as bacteria, viruses, and prions; medical waste, blood and body fluids, cultures, and potentially toxic biological materials. The term is used in laboratory, healthcare, and public health contexts to signal the need for specific precautions.

Risk from biohazards depends on the agent, concentration, route of exposure, and the environment. Containment levels, designated as biosafety levels (BSL-1 to BSL-4), guide the selection of facilities, equipment, practices, and training. Examples: BSL-1 for nonpathogenic organisms; BSL-4 for dangerous agents with high lethality and no available treatment. Engineering controls include biological safety cabinets, sealed containers, and controlled access; PPE such as gloves, gowns, respirators.

Handling and disposal emphasize decontamination and waste segregation. Autoclaving or chemical sterilants kill biohazards before disposal. Biohazard wastes are placed in labeled, color-coded containers and transported by trained personnel under approved procedures. Safe storage and transport follow regulations to prevent leaks or exposure, including temperature control and secure labeling.

Laws and standards govern biohazards. In the United States, organizations rely on the Biosafety in Microbiological and Biomedical Laboratories (BMBL) guidance, OSHA's Hazard Communication and Bloodborne Pathogens standards, and similar international standards. The universal biohazard symbol, a trefoil within a circle, is used on containers and signage to indicate potential danger. It was designed in the 1960s and adopted globally.

History and impact: Biohazards have implications for clinical diagnostics, research, and emergency response. Proper risk assessment and training reduce exposure, protect workers, and help prevent environmental release.