A biohazard (biological hazard) is any biological substance that poses a risk to human or animal health. This may be a microorganism such as a bacterium, virus, parasite or fungus, or a toxin produced by one of these organisms. Materials contaminated with infectious agents, such as needles used for blood draws or cultures of pathogens, are labelled with the biohazard symbol to warn of potential danger.
Explanation
The concept of biohazard covers a broad range of biological threats, from common infectious agents to highly dangerous pathogens. Hazardous organisms are grouped by risk based on how easily they cause disease, whether effective treatments exist and the severity of illness. At the lowest end are agents that rarely cause disease in healthy adults, while agents like HIV, hepatitis viruses and Mycobacterium tuberculosis are more serious and require stringent precautions. The most dangerous agents, such as Ebola or Marburg viruses, are handled only in high-containment laboratories. The familiar trefoil biohazard symbol, designed in 1966 for the Dow Chemical Company, is used internationally to mark containers, equipment and facilities that contain or may be contaminated with biohazardous materials. Its purpose is to alert people to use proper protective equipment and procedures.
Classification and control
Health agencies classify biohazards into four biosafety levels. Level 1 involves minimal risk agents and requires basic hygiene; Level 2 covers moderate-risk pathogens transmitted by contact or ingestion and calls for lab coats, gloves and controlled access; Level 3 includes serious airborne pathogens requiring respiratory protection and specialised facilities; Level 4 encompasses exotic agents that pose a high risk of life¯threatening disease, for which no vaccines or treatments exist, necessitating full-body positive-pressure suits and maximum containment. Proper handling includes risk assessment, training, vaccination when available, use of appropriate personal protective equipment, sterilisation and decontamination, and secure waste disposal. Legal frameworks regulate the transport and disposal of biohazardous waste to prevent accidental release into the environment.
Awareness of biohazards and adherence to safety protocols protect laboratory workers, healthcare providers and the public from infection and help contain outbreaks.
Related Terms: Biosafety Level, Pathogen, Blood Borne Infections, Personal Protective Equipment, Biocontainment