threat to the health of living organisms, primarily that of humans. This can include

medical waste or samples of a microorganism, virus or toxin that can affect human health.

It can also include substances harmful to other animals.

The term and its associated symbol are generally used as a warning, so that those potentially

exposed to the substances will know to take precautions. The biohazard symbol was developed

in 1966 by Charles Baldwin, an environmental-health engineer working for the Dow Chemical Company

on the containment products. It is used in the labeling of biological materials

that carry a significant health risk, including viral samples and used hypodermic needles.

In Unicode, the biohazard symbol is U+2623.

Classification Bio hazardous agents are classified for transportation

by UN number: Category A, UN 2814- Infectious substances

affecting humans and animals: An infectious substance in a form capable of causing permanent

disability or life-threatening or fatal disease in otherwise healthy humans or animals when

exposure to it occurs. Category B, UN 2900- Infectious substances

affecting animals only: An infectious substance that is not in a form generally capable of

causing permanent disability of life-threatening or fatal disease in otherwise healthy humans

and animals when exposure to themselves occurs. Category B, UN 3373- Biological substance

transported for diagnostic or investigative purposes.

Regulated Medical Waste, UN 3291- Waste or reusable material derived from medical treatment

of an animal or human, or from biomedical research, which includes the production and

testing of biological products. Levels of biohazard

The United States Centers for Disease Control and Prevention categorizes various diseases

in levels of biohazard, Level 1 being minimum risk and Level 4 being extreme risk. Laboratories

and other facilities are categorized as BSL 1-4 or as P1 through P4 for short.

Biohazard Level 1: Bacteria and viruses including Bacillus subtilis, canine hepatitis, Escherichia

coli, varicella, as well as some cell cultures and non-infectious bacteria. At this level

precautions against the biohazardous materials in question are minimal, most likely involving

gloves and some sort of facial protection. Biohazard Level 2: Bacteria and viruses that

cause only mild disease to humans, or are difficult to contract via aerosol in a lab

setting, such as hepatitis A, B, and C, influenza A, Lyme disease, salmonella, mumps, measles,

scrapie, dengue fever. "Routine diagnostic work with clinical specimens can be done safely

at Biosafety Level 2, using Biosafety Level 2 practices and procedures. Research work

can be done in a BSL-2 facility, using BSL-3 practices and procedures.

Biohazard Level 3: Bacteria and viruses that can cause severe to fatal disease in humans,

but for which vaccines or other treatments exist, such as anthrax, West Nile virus, Venezuelan

equine encephalitis, SARS virus, tuberculosis, typhus, Rift Valley fever, HIV, Rocky Mountain

spotted fever, yellow fever, and malaria. Among parasites Plasmodium falciparum, which

causes Malaria, and Trypanosoma cruzi, which causes trypanosomiasis, also come under this

level. Biohazard Level 4: Viruses and bacteria that

cause severe to fatal disease in humans, and for which vaccines or other treatments are

not available, such as Bolivian and Argentine hemorrhagic fevers, Marburg virus, Ebola virus,

hantaviruses, Lassa fever virus, Crimean–Congo hemorrhagic fever, and other hemorrhagic diseases.

Variola virus is an agent that is worked with at BSL-4 despite the existence of a vaccine.

When dealing with biological hazards at this level the use of a positive pressure personnel

suit, with a segregated air supply, is mandatory. The entrance and exit of a Level Four biolab

will contain multiple showers, a vacuum room, an ultraviolet light room, autonomous detection

system, 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 Biosafety Level 4 lab

will undergo similar decontamination procedures to eliminate the possibility of an accidental

release. Symbol

The biohazard symbol was developed by the Dow Chemical Company in 1966 for their containment

products. According to Charles Baldwin, an environmental-health engineer who contributed

to its development: "We wanted something that was memorable but meaningless, so we could

educate people as to what it means." In an article he wrote for Science in 1967, the

symbol was presented as the new standard for all biological hazards. The article explained

that over 40 symbols were drawn up by Dow artists, and all of the symbols investigated

had to meet a number of criteria: Striking in form in order to draw immediate

attention; Unique and unambiguous, in order not to be

confused with symbols used for other purposes; Quickly recognizable and easily recalled;

Easily stenciled; Symmetrical, in order to appear identical

from all angles of approach; Acceptable to groups of varying ethnic backgrounds.

The chosen symbol scored the best on nationwide testing for memorability.

The design was first specified in 39 FR 23680 but was dropped in the succeeding amendment.

However, various US states adopted the specification for their state code.

See also Biological agent

Biosafety level Planetary protection and Interplanetary contamination

Public health References

Notes

Bibliography

External links "Biosafety in Microbiological and Biomedical

Laboratories", official CDC guide. "Prevention of Biological Hazards", EU-OSHA

"Symbol Making", an account of the development of the symbol in 1966.

"BioSeal Systems", Biosafety level 4 containment. Biohazard Remediation Compliance Overview