Biological hazard
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A biological hazard or biohazard is a biological substance that poses a threat to (primarily) human health. This can include medical waste, samples of a microorganism, virus or toxin (from a biological source) that can impact human health. It can also include substances harmful to animals. The term and its associated symbol is generally used as a warning, so that those potentially exposed to the substances will know to take precautions. There is also a biohazard HCS/WHMIS logo which utilizes the same symbol.
In Unicode, the biohazard sign is U+2623 (☣).
The sign was also used on the posters for the movie 28 Days Later, about a highly contagious disease sweeping the United Kingdom.
Biohazardous agents are classified by UN number:
- UN 2814 (Infectious substance to Humans)
- UN 2900 (Infectious substance to Animals)
- UN 3291 (Medical Waste)
Levels of biohazard
The United States' Centers for Disease Control and Prevention (CDC) categorizes various diseases in levels of biohazard, Level 1 being minimum risk and Level 4 being extreme risk.
- Biohazard Level 1: Bacillus subtilis, canine hepatitis, E. coli, varicella (chicken pox). At this level precautions against the biohazardous materials in question are minimal, most likely involving gloves and some sort of facial protection. Decontamination procedures for this level are similar in most repects to modern precautions against everyday viruses (ie: washing ones hands with anti-bacterial soap, washing all exposed surfaces of the lab with disinfectants, etc).
- Biohazard Level 2: Hepatitis B, hepatitis C, influenza, Lyme disease, salmonella, scrapie.
- Biohazard Level 3: Anthrax, BSE, HIV, mumps, West Nile virus, SARS, smallpox, tuberculosis, typhus, Yellow fever.
- Biohazard Level 4: Bolivian fever, Dengue fever, Ebola, Hanta virus, Lassa virus, and other various hemorrhagic diseases (mostly of African descent). When dealing with biological hazards at this level the use of a Hazmat suit and a self-contained oxygen supply is mandatory. The entrance and exit of a level four biolab will contain multiple showers, a vacuum room, an ultra-violet light room, and other safety precautions designed to destroy all traces of the biohazard. Multiple airlocks are employed and are electronically secured to prevent both doors opening at the same time. All air and water service going to and coming from a level 4 biolab will undergo similar decontamination procedures to eliminate the possibility of an accidental release.
See also
References
- Baldwin, C. L., & Runkle, R.S. (1967). Biohazards symbol: development of a biological hazards warning signal. Science, 158, 264–265. Pubmed unique identifier [6053882].
External links
- ["Biosafety in Microbiological and Biomedical Laboratories"], official CDC guide.
- ["Symbol Making"], an account of the development of the symbol.
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