biohazards

Biohazards are biological substances that threaten human or animal health or the environment. They include infectious agents such as bacteria, viruses, fungi, and parasites, as well as their toxins and other potentially infectious materials, including certain recombinant or synthetic agents. The term is used in safety, public health, and laboratory contexts to describe hazards arising from biological materials. Assessing a biohazard considers pathogenicity, transmission, stability, and exposure risk.

Classification and containment: Biohazards are categorized by risk groups and biosafety levels (BSL-1 to BSL-4), which guide containment and practices. Practices include facility design, engineering controls, administrative controls, and PPE. Higher-risk agents require higher containment. The goal is to prevent exposure to personnel and release to the environment.

Exposure and risk: Common routes include inhalation, ingestion, dermal contact, and injection. Healthcare, research, and waste-handling activities can create exposures without proper controls. Outcomes range from mild symptoms to severe disease, environmental contamination, or service disruption. Biohazards also include toxins and other hazardous biological materials, not only organisms.

Management and response: Core measures include risk assessment, training, vaccination where available, and surveillance. Controls follow a hierarchy: elimination or substitution when possible, engineering controls, administrative controls, and PPE. Safe handling, decontamination, sterilization, and waste disposal are essential. Incident reporting and post-exposure management are common regulatory requirements.

Regulatory and ethical context: Guidelines from OSHA, CDC/NIH, and WHO govern biosafety, biosecurity, and public health. Dual-use research and ethical considerations emphasize balancing scientific progress with safety. Public health preparedness involves surveillance, outbreak response, and risk communication to minimize harm from biohazards.