"Biohazard" redirects here. For other uses, see Biohazard (disambiguation).
A biological hazard or biohazard is an organism, or substance derived from an organism, 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 (☣).
Biohazardous agents are classified for transportation by UN number:
UN 2814 (Infectious Substance, Affecting Humans)
UN 2900 (Infectious Substance, Affecting Animals)
UN 3373 (Diagnostic Specimen or Clinical Specimen or Biological Substance, Category B)
UN 3291 (Medical Waste)
Saturday, February 23, 2008
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:
Several kinds of bacteria and viruses including Bacillus subtilis, canine hepatitis, Escherichia coli, varicella (chicken pox), 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. Usually, contaminated materials are left in open (but separately indicated) trash receptacles. Decontamination procedures for this level are similar in most respects to modern precautions against everyday viruses (i.e.: washing one's hands with anti-bacterial soap, washing all exposed surfaces of the lab with disinfectants, etc). In a lab environment, all materials used for cell and/or bacteria cultures are decontaminated via autoclave.
Biohazard Level 2:
Various 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, HIV, scrapie.
Biohazard Level 3:
Various bacteria and viruses that can cause severe to fatal disease in humans, but for which vaccines or other treatment exist, such as anthrax, West Nile virus, Venezuelan equine encephalitis, SARS, smallpox, tuberculosis, typhus, Rift Valley fever, Rocky Mountain spotted fever, yellow fever.
Biohazard Level 4:
Exclusively viruses 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, dengue fever, Marburg virus, Ebola virus, hantaviruses, Lassa fever, Crimean-Congo hemorrhagic fever, and other various hemorrhagic diseases. 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 ultraviolet 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 Biosafety Level 4 lab will undergo similar decontamination procedures to eliminate the possibility of an accidental release.
Biohazard Level 1:
Several kinds of bacteria and viruses including Bacillus subtilis, canine hepatitis, Escherichia coli, varicella (chicken pox), 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. Usually, contaminated materials are left in open (but separately indicated) trash receptacles. Decontamination procedures for this level are similar in most respects to modern precautions against everyday viruses (i.e.: washing one's hands with anti-bacterial soap, washing all exposed surfaces of the lab with disinfectants, etc). In a lab environment, all materials used for cell and/or bacteria cultures are decontaminated via autoclave.
Biohazard Level 2:
Various 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, HIV, scrapie.
Biohazard Level 3:
Various bacteria and viruses that can cause severe to fatal disease in humans, but for which vaccines or other treatment exist, such as anthrax, West Nile virus, Venezuelan equine encephalitis, SARS, smallpox, tuberculosis, typhus, Rift Valley fever, Rocky Mountain spotted fever, yellow fever.
Biohazard Level 4:
Exclusively viruses 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, dengue fever, Marburg virus, Ebola virus, hantaviruses, Lassa fever, Crimean-Congo hemorrhagic fever, and other various hemorrhagic diseases. 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 ultraviolet 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 Biosafety Level 4 lab will undergo similar decontamination procedures to eliminate the possibility of an accidental release.
Rationale
Biocontainment can be classified by the relative danger to the surrounding environment as biological safety levels (BSL). As of 2006, there are four safety levels. These are called BSL1 through BSL4, with one anomalous level BSL3-ag for agricultural hazards between BSL3 and BSL4. Higher numbers indicate a greater risk to the external environment. See biological hazard.
At the lowest level of biocontainment, the containment zone may only be a fume hood that utilizes HEPA filters. At the highest level the containment involves isolation of the organism by means of building systems, sealed rooms, sealed containers, personal isolation equipment similar to "space suits" and elaborate procedures for entering the room, and decontamination procedures for leaving the room. In most cases this also includes high levels of security for access to the facility, ensuring that only authorized personnel may be admitted to any area that may have some effect on the quality of the containment zone. This is considered a hot zone.
At the lowest level of biocontainment, the containment zone may only be a fume hood that utilizes HEPA filters. At the highest level the containment involves isolation of the organism by means of building systems, sealed rooms, sealed containers, personal isolation equipment similar to "space suits" and elaborate procedures for entering the room, and decontamination procedures for leaving the room. In most cases this also includes high levels of security for access to the facility, ensuring that only authorized personnel may be admitted to any area that may have some effect on the quality of the containment zone. This is considered a hot zone.
The levels
Biosafety Level 1 is suitable for work involving well-characterized agents not known to consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment.[citation needed] Includes several kinds of bacteria and viruses including , Escherichia coli, Varicella (Chicken Pox), 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. The laboratory is not necessarily separated from the general traffic patterns in the building. Work is generally conducted on open bench tops using standard microbiological practices. Usually, contaminated materials are left in open (but separately indicated) trash receptacles. Decontamination procedures for this level are similar in most respects to modern precautions against everyday viruses (i.e.: washing one's hands with anti-bacterial soap, washing all exposed surfaces of the lab with disinfectants, etc). In a lab environment, all materials used for cell and/or bacteria cultures are decontaminated via autoclave. Laboratory personnel have specific training in the procedures conducted in the laboratory and are supervised by a scientist with general training in microbiology or a related science.
Biosafety Level 2 is similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment. Includes various 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, Dengue fever, Salmonella, Mumps Bacillus subtilis, Measles, HIVScrapie.
It differs from BSL-1 in that
laboratory personnel have specific training in handling pathogenic agents and are directed by competent scientists;
access to the laboratory is limited when work is being conducted;
extreme precautions are taken with contaminated sharp items; and
certain procedures in which infectious aerosols or splashes may be created are conducted in biological safety cabinets or other physical containment equipment.
Biosafety Level 3 is applicable to clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents which may cause serious or potentially lethal disease as a result of exposure by the inhalation route. Includes various bacteria and viruses that can cause severe to fatal disease in humans, but for which vaccines or other treatment exist, such as Anthrax, West Nile virus, Venezuelan equine encephalitis, Eastern equine encephalitis, SARS, Tuberculosis, Typhus, Rift Valley fever, Rocky Mountain spotted feve, Yellow fever.
Laboratory personnel have specific training in handling pathogenic and potentially lethal agents, and are supervised by competent scientists who are experienced in working with these agents. This is considered a neutral or warm zone.
All procedures involving the manipulation of infectious materials are conducted within biological safety cabinets or other physical containment devices, or by personnel wearing appropriate personal protective clothing and equipment. The laboratory has special engineering and design features.
It is recognized, however, that some existing facilities may not have all the facility features recommended for Biosafety Level 3 (i.e., double-door access zone and sealed penetrations). In this circumstance, an acceptable level of safety for the conduct of routine procedures, (e.g., diagnostic procedures involving the propagation of an agent for identification, typing, susceptibility testing, etc.), may be achieved in a Biosafety Level 2 facility, providing
the exhaust air from the laboratory room is discharged to the outdoors,
the ventilation to the laboratory is balanced to provide directional airflow into the room,
access to the laboratory is restricted when work is in progress, and
the recommended Standard Microbiological Practices, Special Practices, and Safety Equipment for Biosafety Level 3 are rigorously followed.
The decision to implement this modification of Biosafety Level 3 recommendations are made only by the laboratory director.
Biosafety Level 4 is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections, agents which cause severe to fatal disease in humans for which vaccines or other treatments are not available, such as Bolivian and Argentine hemorrhagic fevers, Smallpox (there is a vaccine), Marburg virus,Ebola virus, Hantaviruses, Lassa fever, Crimean-Congo hemorrhagic fever, and other various hemorrhagic diseases.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 ultraviolet 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 Biosafety Level 4 lab will undergo similar decontamination procedures to eliminate the possibility of an accidental release.
Agents with a close or identical antigenic relationship to Biosafety Level 4 agents are handled at this level until sufficient data are obtained either to confirm continued work at this level, or to work with them at a lower level.
Members of the laboratory staff have specific and thorough training in handling extremely hazardous infectious agents and they understand the primary and secondary containment functions of the standard and special practices, the containment equipment, and the laboratory design characteristics. They are supervised by competent scientists who are trained and experienced in working with these agents. Access to the laboratory is strictly controlled by the laboratory director.
The facility is either in a separate building or in a controlled area within a building, which is completely isolated from all other areas of the building. A specific facility operations manual is prepared or adopted. Building protocols for preventing contamination often uses negatively pressurized facilities, which, if compromised, would severely inhibit an outbreak of aerosol pathogens.
Within work areas of the facility, all activities are confined to Class III biological safety cabinets, or Class II biological safety cabinets used with one-piece positive pressure personnel suits ventilated by a life support system. The Biosafety Level 4 laboratory has special engineering and design features to prevent microorganisms from being disseminated into the environment. The laboratory is kept at negative air pressure, so that air flows into the room if the barrier is penetrated or breached. Furthermore, an airlock is used during personnel entry and exit.
Biosafety Level 5 does not exist, given that the protocols followed by a Biosafety Level 4 facility are as strict as technically feasible. In popular culture, this level has been referenced. However, the protocols used are usually so extreme they seem focused on preventing the object of study from being inadvertently contaminated by the researchers studying it than preventing the researchers from being inadvertently contaminated by what they are studying. The novel The Andromeda Strain by Michael Crichton, along with the 1971 film of the same name, directed by Robert Wise reference a fictional Level 5 facility. The novel Mount Dragon by Douglas Preston and Lincoln Child also references such a facility, and its measures likely have a similar purpose.
Biosafety Level 2 is similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment. Includes various 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, Dengue fever, Salmonella, Mumps Bacillus subtilis, Measles, HIVScrapie.
It differs from BSL-1 in that
laboratory personnel have specific training in handling pathogenic agents and are directed by competent scientists;
access to the laboratory is limited when work is being conducted;
extreme precautions are taken with contaminated sharp items; and
certain procedures in which infectious aerosols or splashes may be created are conducted in biological safety cabinets or other physical containment equipment.
Biosafety Level 3 is applicable to clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents which may cause serious or potentially lethal disease as a result of exposure by the inhalation route. Includes various bacteria and viruses that can cause severe to fatal disease in humans, but for which vaccines or other treatment exist, such as Anthrax, West Nile virus, Venezuelan equine encephalitis, Eastern equine encephalitis, SARS, Tuberculosis, Typhus, Rift Valley fever, Rocky Mountain spotted feve, Yellow fever.
Laboratory personnel have specific training in handling pathogenic and potentially lethal agents, and are supervised by competent scientists who are experienced in working with these agents. This is considered a neutral or warm zone.
All procedures involving the manipulation of infectious materials are conducted within biological safety cabinets or other physical containment devices, or by personnel wearing appropriate personal protective clothing and equipment. The laboratory has special engineering and design features.
It is recognized, however, that some existing facilities may not have all the facility features recommended for Biosafety Level 3 (i.e., double-door access zone and sealed penetrations). In this circumstance, an acceptable level of safety for the conduct of routine procedures, (e.g., diagnostic procedures involving the propagation of an agent for identification, typing, susceptibility testing, etc.), may be achieved in a Biosafety Level 2 facility, providing
the exhaust air from the laboratory room is discharged to the outdoors,
the ventilation to the laboratory is balanced to provide directional airflow into the room,
access to the laboratory is restricted when work is in progress, and
the recommended Standard Microbiological Practices, Special Practices, and Safety Equipment for Biosafety Level 3 are rigorously followed.
The decision to implement this modification of Biosafety Level 3 recommendations are made only by the laboratory director.
Biosafety Level 4 is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections, agents which cause severe to fatal disease in humans for which vaccines or other treatments are not available, such as Bolivian and Argentine hemorrhagic fevers, Smallpox (there is a vaccine), Marburg virus,Ebola virus, Hantaviruses, Lassa fever, Crimean-Congo hemorrhagic fever, and other various hemorrhagic diseases.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 ultraviolet 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 Biosafety Level 4 lab will undergo similar decontamination procedures to eliminate the possibility of an accidental release.
Agents with a close or identical antigenic relationship to Biosafety Level 4 agents are handled at this level until sufficient data are obtained either to confirm continued work at this level, or to work with them at a lower level.
Members of the laboratory staff have specific and thorough training in handling extremely hazardous infectious agents and they understand the primary and secondary containment functions of the standard and special practices, the containment equipment, and the laboratory design characteristics. They are supervised by competent scientists who are trained and experienced in working with these agents. Access to the laboratory is strictly controlled by the laboratory director.
The facility is either in a separate building or in a controlled area within a building, which is completely isolated from all other areas of the building. A specific facility operations manual is prepared or adopted. Building protocols for preventing contamination often uses negatively pressurized facilities, which, if compromised, would severely inhibit an outbreak of aerosol pathogens.
Within work areas of the facility, all activities are confined to Class III biological safety cabinets, or Class II biological safety cabinets used with one-piece positive pressure personnel suits ventilated by a life support system. The Biosafety Level 4 laboratory has special engineering and design features to prevent microorganisms from being disseminated into the environment. The laboratory is kept at negative air pressure, so that air flows into the room if the barrier is penetrated or breached. Furthermore, an airlock is used during personnel entry and exit.
Biosafety Level 5 does not exist, given that the protocols followed by a Biosafety Level 4 facility are as strict as technically feasible. In popular culture, this level has been referenced. However, the protocols used are usually so extreme they seem focused on preventing the object of study from being inadvertently contaminated by the researchers studying it than preventing the researchers from being inadvertently contaminated by what they are studying. The novel The Andromeda Strain by Michael Crichton, along with the 1971 film of the same name, directed by Robert Wise reference a fictional Level 5 facility. The novel Mount Dragon by Douglas Preston and Lincoln Child also references such a facility, and its measures likely have a similar purpose.
BSL-4 facilities by country
Australia
Australia operates three BSL-4 labs. These are
The Australian Animal Health Laboratory in Geelong (VIC).
The Virology Laboratory of the Queensland Department of Health at Coopers Plains (QLD).
The National High Security Laboratory, operating under the auspices of the Victoria Infectiou Diseases Reference Laboratory, in North Melbourne (VIC).
Brazil
Several research institutions such as University of São Paulo, Instituto Butantan and Instituto Adolf Lutz have BSL-3 laboratories to study infectious diseases or develop vaccines against Tuberculosis. It is not clear that Fundação Oswaldo Cruz actually operates a BSL-4 laboratoy in Rio de Janeiro. Original citation in this page: "The Fundação Oswaldo Cruz, a biomedical research institute of the Brazilian government, operates a BSL-4 in Rio de Janeiro".
Canada
Canada has one BSL4 facility, located at the National Microbiology Laboratory in Winnipeg. In the 1990s, a BSL-4 was constructed in Toronto, however, it never opened due to community opposition.
Czech Republic
Czech Republic has BSL4 lab at Centrum biologické ochrany Těchonín (Center of Biological Protection).
France
France maintains a P4 (for "pathogen" or "protection" level 4) laboratory, Laboratoire P4 Jean Mérieux in Lyon.
Gabon
The Centre International de Recherches Médicales de Franceville (CIRMF), a research organization supported by the French government, operates West Africa's only BSL-4 lab.
Germany
Germany currently has two L4 facilities: one located at the Philipps University of Marburg, Institute of Virology and the Bernhard Nocht Institute for Tropical Medicine in Hamburg. A new P4 lab is currently being built in Marburg and will take over the functions of the old L4 facility there. Also, another P4 lab is planned to be built at the Robert Koch Institute in Berlin.
Japan
Japan has a BSL4 lab at the National Institute for Infectious Diseases, Department of Virology I, Tokyo; however, currently work in this lab is only performed with BSL3 agents. Japan has also a non-operating BSL4 lab at the Institute of Physical and Chemical Research in Tsukuba. Both labs face community opposition.
India
India's BSL4 lab is High Security Animal Disease Laboratory (HSADL) located in Bhopal, India. It deals with all kinds of zoonotic organisms and emerging infectious disease threats.
Italy
Italy's BSL4 lab are at: - Istituto Nazionale Malattie Infettive, Ospedale Lazzaro Spallanzani, Rome. (National Institute of Infectious Diseases, Lazzaro Spallanzani Hospital.) - Azienda Ospedaliera Ospedale Luigi Sacco - Polo Universitario - (Milano). In that hospital there are also two special vehicles in BSL4 for transportation of infectious persons
Russia
VEKTOR State Research Center of Virology and Biotechnology, Koltsovo, Novosibirsk region. Other BSL4 facilities available during the Soviet era have been dismantled.
Singapore
The Defence Science Organization(DSO) National Laboratories operates a BSL-4 facility. With the announced goal of conducting autopsies during a potential deadly epidemic outbreak, Singapore also has a mobile BSL-4 autopsy facility, perhaps the only one of its kind in the world.
South Africa
The National Institute for Communicable Diseases, Special Pathogens Unit in Johannesburg, South Africa is one of two BSL4 labs in Africa.
Sweden
The Swedish Institute for Infectious Disease Control runs Scandinavia's only P4 laboratory in Solna.
Switzerland
The Institute of Virology and Immunoprophylaxis (IVI) in Mittelhäusern is the only publicly known laboratory in Switzerland to be classed as having biosafety level (BSL) 4. This laboratory only deals with animal disease which do not transmit to humans, and is the only P4 facility where complete isolation suits are not used.
A P4 laboratory was inaugurated on February 01, 2007 in the Teaching Hospital of Geneva.
Since November 12, 2007 the new High Containment Laboratory DDPS (SiLab) in Spiez is under construction and will start operations in 2010. This laboratory will comply with biosafety level (BSL) 4.
Taiwan
In Taiwan, two laboratories have BSL4. One is Preventive Medical Institute of ROC Ministry of National Defense, another is Kwen-yang Laboratory (昆陽實驗室) Center of Disease Control, Department of Health ROC.
United Kingdom
The United Kingdom currently has three BSL-4 laboratories, with another under construction. One is under construction at the National Institute for Medical Research in London, and the other has been built by the Ministry of Defence at Porton Down and is called the Chemical and Biological Defence Establishment. There is also a BSL-4 Laboratory in the Viral Zoonosis unit at the Health Protection Agency's Centre for Infections in Colindale.
United States of America
The U.S. maintains at least eight Biosafety Level 4 facilities, and is currently planning at least seven more:
Operational Facilities:
USAMRIID in Fort Detrick, MD ("old building")
CDC in Atlanta, GA (two buildings operational)
NIH's BSL-4 lab on the NIH Campus in Bethesda, MD (sometimes operates at BSL-3), never operated as a "hot" BSL4
NIH's BSL-4 lab at the Twinbrook III building, Rockville, MD (sometimes operates at BSL-3)
Southwest Foundation for Biomedical Research in San Antonio, TX
UTMB's Shope Laboratory in Galveston, TX
Georgia State University in Atlanta, GA (smaller "glovebox" facility)
The Division of Consolidated Laboratory Services lab (part of the Department of General Services of the Commonwealth of Virginia) in Richmond, VA (so-called "surge" BSL-4 capacity)
Facilities Under Construction and Planned:
USAMRIID in Fort Detrick, MD ("new building", in design)
Boston University's National Emerging Infectious Diseases Laboratory (NEIDL) in Boston, MA (under construction)
UTMB's National Biocontainment Facility in Galveston, TX (under construction)
DHS's National Biodefense Analysis and Countermeasures Center (NBACC) in Fort Detrick, MD (under construction)
DHS's National Bio and Agro-Defense Facility (NBAF), shortlisted July 2007; final site selection mid to late 2008
NIAID's Integrated Research Facility in Fort Detrick, MD (in construction- earliest operational date 2009)
NIAID's Rocky Mountain Laboratories in Hamilton, MT (in construction - earliest operational date 2009)
Australia operates three BSL-4 labs. These are
The Australian Animal Health Laboratory in Geelong (VIC).
The Virology Laboratory of the Queensland Department of Health at Coopers Plains (QLD).
The National High Security Laboratory, operating under the auspices of the Victoria Infectiou Diseases Reference Laboratory, in North Melbourne (VIC).
Brazil
Several research institutions such as University of São Paulo, Instituto Butantan and Instituto Adolf Lutz have BSL-3 laboratories to study infectious diseases or develop vaccines against Tuberculosis. It is not clear that Fundação Oswaldo Cruz actually operates a BSL-4 laboratoy in Rio de Janeiro. Original citation in this page: "The Fundação Oswaldo Cruz, a biomedical research institute of the Brazilian government, operates a BSL-4 in Rio de Janeiro".
Canada
Canada has one BSL4 facility, located at the National Microbiology Laboratory in Winnipeg. In the 1990s, a BSL-4 was constructed in Toronto, however, it never opened due to community opposition.
Czech Republic
Czech Republic has BSL4 lab at Centrum biologické ochrany Těchonín (Center of Biological Protection).
France
France maintains a P4 (for "pathogen" or "protection" level 4) laboratory, Laboratoire P4 Jean Mérieux in Lyon.
Gabon
The Centre International de Recherches Médicales de Franceville (CIRMF), a research organization supported by the French government, operates West Africa's only BSL-4 lab.
Germany
Germany currently has two L4 facilities: one located at the Philipps University of Marburg, Institute of Virology and the Bernhard Nocht Institute for Tropical Medicine in Hamburg. A new P4 lab is currently being built in Marburg and will take over the functions of the old L4 facility there. Also, another P4 lab is planned to be built at the Robert Koch Institute in Berlin.
Japan
Japan has a BSL4 lab at the National Institute for Infectious Diseases, Department of Virology I, Tokyo; however, currently work in this lab is only performed with BSL3 agents. Japan has also a non-operating BSL4 lab at the Institute of Physical and Chemical Research in Tsukuba. Both labs face community opposition.
India
India's BSL4 lab is High Security Animal Disease Laboratory (HSADL) located in Bhopal, India. It deals with all kinds of zoonotic organisms and emerging infectious disease threats.
Italy
Italy's BSL4 lab are at: - Istituto Nazionale Malattie Infettive, Ospedale Lazzaro Spallanzani, Rome. (National Institute of Infectious Diseases, Lazzaro Spallanzani Hospital.) - Azienda Ospedaliera Ospedale Luigi Sacco - Polo Universitario - (Milano). In that hospital there are also two special vehicles in BSL4 for transportation of infectious persons
Russia
VEKTOR State Research Center of Virology and Biotechnology, Koltsovo, Novosibirsk region. Other BSL4 facilities available during the Soviet era have been dismantled.
Singapore
The Defence Science Organization(DSO) National Laboratories operates a BSL-4 facility. With the announced goal of conducting autopsies during a potential deadly epidemic outbreak, Singapore also has a mobile BSL-4 autopsy facility, perhaps the only one of its kind in the world.
South Africa
The National Institute for Communicable Diseases, Special Pathogens Unit in Johannesburg, South Africa is one of two BSL4 labs in Africa.
Sweden
The Swedish Institute for Infectious Disease Control runs Scandinavia's only P4 laboratory in Solna.
Switzerland
The Institute of Virology and Immunoprophylaxis (IVI) in Mittelhäusern is the only publicly known laboratory in Switzerland to be classed as having biosafety level (BSL) 4. This laboratory only deals with animal disease which do not transmit to humans, and is the only P4 facility where complete isolation suits are not used.
A P4 laboratory was inaugurated on February 01, 2007 in the Teaching Hospital of Geneva.
Since November 12, 2007 the new High Containment Laboratory DDPS (SiLab) in Spiez is under construction and will start operations in 2010. This laboratory will comply with biosafety level (BSL) 4.
Taiwan
In Taiwan, two laboratories have BSL4. One is Preventive Medical Institute of ROC Ministry of National Defense, another is Kwen-yang Laboratory (昆陽實驗室) Center of Disease Control, Department of Health ROC.
United Kingdom
The United Kingdom currently has three BSL-4 laboratories, with another under construction. One is under construction at the National Institute for Medical Research in London, and the other has been built by the Ministry of Defence at Porton Down and is called the Chemical and Biological Defence Establishment. There is also a BSL-4 Laboratory in the Viral Zoonosis unit at the Health Protection Agency's Centre for Infections in Colindale.
United States of America
The U.S. maintains at least eight Biosafety Level 4 facilities, and is currently planning at least seven more:
Operational Facilities:
USAMRIID in Fort Detrick, MD ("old building")
CDC in Atlanta, GA (two buildings operational)
NIH's BSL-4 lab on the NIH Campus in Bethesda, MD (sometimes operates at BSL-3), never operated as a "hot" BSL4
NIH's BSL-4 lab at the Twinbrook III building, Rockville, MD (sometimes operates at BSL-3)
Southwest Foundation for Biomedical Research in San Antonio, TX
UTMB's Shope Laboratory in Galveston, TX
Georgia State University in Atlanta, GA (smaller "glovebox" facility)
The Division of Consolidated Laboratory Services lab (part of the Department of General Services of the Commonwealth of Virginia) in Richmond, VA (so-called "surge" BSL-4 capacity)
Facilities Under Construction and Planned:
USAMRIID in Fort Detrick, MD ("new building", in design)
Boston University's National Emerging Infectious Diseases Laboratory (NEIDL) in Boston, MA (under construction)
UTMB's National Biocontainment Facility in Galveston, TX (under construction)
DHS's National Biodefense Analysis and Countermeasures Center (NBACC) in Fort Detrick, MD (under construction)
DHS's National Bio and Agro-Defense Facility (NBAF), shortlisted July 2007; final site selection mid to late 2008
NIAID's Integrated Research Facility in Fort Detrick, MD (in construction- earliest operational date 2009)
NIAID's Rocky Mountain Laboratories in Hamilton, MT (in construction - earliest operational date 2009)
Saturday, February 16, 2008
Radioactivity
A phenomenon resulting from an instability of the atomic nucleus in certain atoms whereby the nucleus experiences a spontaneous but measurably delayed nuclear transition or transformation with the resulting emission of radiation. The discovery of radioactivity by H. Becquerel in 1896 marked the birth of nuclear physics.
All chemical elements may be rendered radioactive by adding or by subtracting (except for hydrogen and helium) neutrons from the nucleus of the stable ones. Studies of the radioactive decays of new isotopes far from the stable ones in nature continue as a major frontier in nuclear research. The availability of this wide variety of radioactive isotopes has stimulated their use in a wide variety of fields, including chemistry, biology, medicine, industry, artifact dating, agriculture, and space exploration. See also Alpha particles; Beta particles; Gamma rays; Isotope; Radioactivity and radiation applications.
A particular radioactive transition may be delayed by less than a microsecond or by more than a billion years, but the existence of a measurable delay or lifetime distinguishes a radioactive nuclear transition from a so-called prompt nuclear transition, such as is involved in the emission of most gamma rays. The delay is expressed quantitatively by the radioactive decay constant, or by the mean life, or by the half-period for each type of radioactive atom, discussed below.
The most commonly found types of radioactivity are alpha, beta negatron, beta positron, electron capture, and isomeric transition. Each is characterized by the particular type of nuclear radiation which is emitted by the transforming parent nucleus. In addition, there are several other decay modes that are observed more rarely in specific regions of the periodic table.
All chemical elements may be rendered radioactive by adding or by subtracting (except for hydrogen and helium) neutrons from the nucleus of the stable ones. Studies of the radioactive decays of new isotopes far from the stable ones in nature continue as a major frontier in nuclear research. The availability of this wide variety of radioactive isotopes has stimulated their use in a wide variety of fields, including chemistry, biology, medicine, industry, artifact dating, agriculture, and space exploration. See also Alpha particles; Beta particles; Gamma rays; Isotope; Radioactivity and radiation applications.
A particular radioactive transition may be delayed by less than a microsecond or by more than a billion years, but the existence of a measurable delay or lifetime distinguishes a radioactive nuclear transition from a so-called prompt nuclear transition, such as is involved in the emission of most gamma rays. The delay is expressed quantitatively by the radioactive decay constant, or by the mean life, or by the half-period for each type of radioactive atom, discussed below.
The most commonly found types of radioactivity are alpha, beta negatron, beta positron, electron capture, and isomeric transition. Each is characterized by the particular type of nuclear radiation which is emitted by the transforming parent nucleus. In addition, there are several other decay modes that are observed more rarely in specific regions of the periodic table.
Radioactive Emissions
Natural radioactivity is exhibited by several elements, including radium, uranium, and other members of the actinide series, and by some isotopes of lighter elements, such as carbon-14, used in radioactive dating. Radioactivity may also be induced, or created artificially, by bombarding the nuclei of normally stable elements in a particle accelerator. Essentially there is no difference between these two manifestations of radioactivity.
The radiation produced during radioactivity is predominantly of three types, designated as alpha, beta, and gamma rays. These types differ in velocity, in the way in which they are affected by a magnetic field, and in their ability to penetrate or pass through matter. Other, less common, types of radioactivity are electron capture (capture of one of the orbiting atomic electrons by the unstable nucleus) and positron emission—both forms of beta decay and both resulting in the change of a proton to a neutron within the nucleus—an internal conversion, in which an excited nucleus transfers energy directly to one of the atom's orbiting electrons and ejects it from the atom.
Alpha Radiation
Alpha rays have the least penetrating power, move at a slower velocity than the other types, and are deflected slightly by a magnetic field in a direction that indicates a positive charge. Alpha rays are nuclei of ordinary helium atoms (see alpha particle). Alpha decay reduces the atomic weight, or mass number, of a nucleus, while beta and gamma decay leave the mass number unchanged. Thus, the net effect of alpha radioactivity is to produce nuclei lighter than those of the original radioactive substance. For example, in the disintegration, or decay, of uranium-238 by the emission of alpha particles, radioactive thorium (formerly called ionium) is produced. The alpha decay reduces the atomic number of the nucleus by 2 and the mass number by 4:
Beta Radiation
Beta rays are more penetrating than alpha rays, move at a very high speed, and are deflected considerably by a magnetic field in a direction that indicates a negative charge; analysis shows that beta rays are high-speed electrons (see beta particle; electron). In beta decay a neutron within the nucleus changes to a proton, in the process emitting an electron and an antineutrino (the antiparticle of the neutrin, a neutral particle with a small mass). The electron is immediately ejected from the nucleus, and the net result is an increase of 1 in the atomic number of the nucleus but no change in the mass number. The thorium-234 produced above experiences two successive beta decays:
Gamma Radiation
Gamma rays have very great penetrating power and are not affected at all by a magnetic field. They move at the speed of light and have a very short wavelength (or high frequency); thus they are a type of electromagnetic radiation (see gamma radiation). Gamma rays result from the transition of nuclei from excited states (higher energy) to their ground state (lowest energy), and their production is analogous to the emission of ordinary light caused by transitions of electrons within the atom (see atom; spectrum). Gamma decay often accompanies alpha or beta decay and affects neither the atomic number nor the mass number of the nucleus.
The radiation produced during radioactivity is predominantly of three types, designated as alpha, beta, and gamma rays. These types differ in velocity, in the way in which they are affected by a magnetic field, and in their ability to penetrate or pass through matter. Other, less common, types of radioactivity are electron capture (capture of one of the orbiting atomic electrons by the unstable nucleus) and positron emission—both forms of beta decay and both resulting in the change of a proton to a neutron within the nucleus—an internal conversion, in which an excited nucleus transfers energy directly to one of the atom's orbiting electrons and ejects it from the atom.
Alpha Radiation
Alpha rays have the least penetrating power, move at a slower velocity than the other types, and are deflected slightly by a magnetic field in a direction that indicates a positive charge. Alpha rays are nuclei of ordinary helium atoms (see alpha particle). Alpha decay reduces the atomic weight, or mass number, of a nucleus, while beta and gamma decay leave the mass number unchanged. Thus, the net effect of alpha radioactivity is to produce nuclei lighter than those of the original radioactive substance. For example, in the disintegration, or decay, of uranium-238 by the emission of alpha particles, radioactive thorium (formerly called ionium) is produced. The alpha decay reduces the atomic number of the nucleus by 2 and the mass number by 4:
Beta Radiation
Beta rays are more penetrating than alpha rays, move at a very high speed, and are deflected considerably by a magnetic field in a direction that indicates a negative charge; analysis shows that beta rays are high-speed electrons (see beta particle; electron). In beta decay a neutron within the nucleus changes to a proton, in the process emitting an electron and an antineutrino (the antiparticle of the neutrin, a neutral particle with a small mass). The electron is immediately ejected from the nucleus, and the net result is an increase of 1 in the atomic number of the nucleus but no change in the mass number. The thorium-234 produced above experiences two successive beta decays:
Gamma Radiation
Gamma rays have very great penetrating power and are not affected at all by a magnetic field. They move at the speed of light and have a very short wavelength (or high frequency); thus they are a type of electromagnetic radiation (see gamma radiation). Gamma rays result from the transition of nuclei from excited states (higher energy) to their ground state (lowest energy), and their production is analogous to the emission of ordinary light caused by transitions of electrons within the atom (see atom; spectrum). Gamma decay often accompanies alpha or beta decay and affects neither the atomic number nor the mass number of the nucleus.
Radioactive Decay
The nuclei of elements exhibiting radioactivity are unstable and are found to be undergoing continuous disintegration (i.e., gradual breakdown). The disintegration proceeds at a definite rate characteristic of the particular nucleus; that is, each radioactive isotope has a definite lifetime. However, the time of decay of an individual nucleus is unpredictable. The lifetime of a radioactive substance is not affected in any way by any physical or chemical conditions to which the substance may be subjected.
Half-Life of an Element
The rate of disintegration of a radioactive substance is commonly designated by its half-life,which is the time required for one half of a given quantity of the substance to decay. Depending on the element, a half-life can be as short as a fraction of a second or as long as several billion years.
Radioactive Disintegration Series
The product of a radioactive decay may itself be unstable and undergo further decays, by either alpha or beta emission. Thus, a succession of unstable elements may be produced, the series continuing until a nucleus is produced that is stable. Such a series is known as a radioactive disintegration, or decay, series. The original nucleus in a decay series is called the parent nucleus, and the nuclei resulting from successive disintegrations are known as daughter nuclei.
There are four known radioactive decay series, the members of a given series having mass numbers that differ by jumps of 4. The series beginning with uranium-238 and ending with lead-206 is known as the 4n+2 series because all the mass numbers in the series are 2 greater than an integral multiple of 4 (e.g., 238=4×59+2, 206=4×51+2). The 4n+1 series, which begins with neptunium-237, is not found in nature because the half-life of the parent nucleus (about 2 million years) is many times less than the age of the earth, and all naturally occurring samples have already disintegrated. The 4n+1 series is produced artificially in nuclear reactors.
Because the rates of disintegration of the members of a radioactive decay series are constant, the age of rocks and other materials can be determined by measuring the relative abundances of the different members of the series. All of the decay series end in a stable isotope of lead, so that a rock containing mostly lead as compared to heavier elements would be very old
Half-Life of an Element
The rate of disintegration of a radioactive substance is commonly designated by its half-life,which is the time required for one half of a given quantity of the substance to decay. Depending on the element, a half-life can be as short as a fraction of a second or as long as several billion years.
Radioactive Disintegration Series
The product of a radioactive decay may itself be unstable and undergo further decays, by either alpha or beta emission. Thus, a succession of unstable elements may be produced, the series continuing until a nucleus is produced that is stable. Such a series is known as a radioactive disintegration, or decay, series. The original nucleus in a decay series is called the parent nucleus, and the nuclei resulting from successive disintegrations are known as daughter nuclei.
There are four known radioactive decay series, the members of a given series having mass numbers that differ by jumps of 4. The series beginning with uranium-238 and ending with lead-206 is known as the 4n+2 series because all the mass numbers in the series are 2 greater than an integral multiple of 4 (e.g., 238=4×59+2, 206=4×51+2). The 4n+1 series, which begins with neptunium-237, is not found in nature because the half-life of the parent nucleus (about 2 million years) is many times less than the age of the earth, and all naturally occurring samples have already disintegrated. The 4n+1 series is produced artificially in nuclear reactors.
Because the rates of disintegration of the members of a radioactive decay series are constant, the age of rocks and other materials can be determined by measuring the relative abundances of the different members of the series. All of the decay series end in a stable isotope of lead, so that a rock containing mostly lead as compared to heavier elements would be very old
Discovery of Radioactivity
Natural radioactivity was first observed in 1896 by A. H. Becquerel, who discovered that when salts of uranium are brought into the vicinity of an unexposed photographic plate carefully protected from light, the plate becomes exposed. The radiation from uranium salts also causes a charged electroscope to discharge. In addition, the salts exhibit phosphorescence and are able to produce fluorescence. Since these effects are produced both by salts and by pure uranium, radioactivity must be a property of the element and not of the salt. In 1899 E. Rutherford discovered and named alpha and beta radiation, and in 1900 P. Villard identified gamma radiation. Marie and Pierre Curie extended the work on radioactivity, demonstrating the radioactive properties of thorium and discovering the highly radioactive element radium in 1898. Frédéric and Irène Joliot-Curie discovered the first example of artificial radioactivity in 1934 by bombarding nonradioactive elements with alpha particles.
Tuesday, January 8, 2008
Theories of Metastability
Oscillatory Activity and Coordination DynamicsThe dynamical system model, which represents networks composed of integrated neural systems communicating with one another between unstable and stable phases, has become an increasingly popular theory underpinning the understanding of metastability. Coordination dynamics forms the basis for this dynamical system model by describing mathematical formulae and paradigms governing the coupling of environmental stimuli to their effectors.History of Coordination Dynamics and the Haken-Kelso-Bunz (HKB) ModelThe so-named HKB model is one of the earliest and well-respected theories to describe coordination dynamics in the brain. In this model, the formation of neural networks can be partly described as self-organization, where individual neurons and small neuronal systems aggregate and coordinate to either adapt or respond to local stimuli or to divide labor and specialize in function.In the last 20 years, the HKB model has become a widely-accepted theory to explain the coordinated movements and behaviors of individual neurons into large, end-to-end neural networks. Originally the model described a system in which spontaneous transitions observed in finger movements could be described as a series of in-phase and out-of-phase movements.In the mid-1980s HKB model experiments, subjects were asked to wave one finger on each hand in two modes of direction: first, known as out of phase, both fingers moving in the same direction back and forth (as windshield wipers might move); and second, known as in-phase, where both fingers come together and move away to and from the midline of the body. To illustrate coordination dynamics, the subjects were asked to move their fingers out of phase with increasing speed until their fingers were moving as fast as possible. As movement approached its critical speed, the subjects’ fingers were found to move from out-of-phase (windshield-wiper-like) movement to in-phase (toward midline movement).The HKB model, which has also been elucidated by several complex mathematical descriptors, is still a relatively simple but powerful way to describe seemingly-independent systems that come to reach synchrony just before a state of self-organized criticality.
Metastability in molecules
Metastability is the ability of a non-equilibrium state to persist for some period of time.Metastability in molecules is the ability of a non-equilibrium chemical state to persist for a long period of time.Usually metastability is due to a relatively slow phase transformation. For example, at room temperature, diamonds are metastable because the phase transformation to the stable graphite form is extremely slow. At higher temperatures, the rate of phase transformation is increased and the diamond will transform to graphite.Martensite is a metastable phase used to control the hardness of most steel. The bonds between the building blocks of polymers such as DNA, RNA and proteins are also metastable.IUPAC recommend that the term "metastable" be avoided and "transient" be used instead because "metastable" can misleadingly associate a thermodynamic term to a kinetic property, even though most transients are thermodynamically unstable with
Metastable isomers
Metastable isomers can be produced through nuclear fusion or other nuclear reactions. A nucleus thus produced generally starts its existence in an excited state that de-excites through the emission of one or more gamma rays (or, equivalently, conversion electrons), usually in a time far shorter than a picosecond. However, sometimes it happens that the de-excitation does not proceed rapidly all the way to the nuclear ground state. This usually occurs because of the formation of an intermediate excited state with a spin far different from that of the ground state. Gamma-ray emission is far slower (is "hindered") if the spin of the post-emission state is very different from that of the emitting state, particularly if the excitation energy is low, than if the two states are of similar spin. The excited state in this situation is therefore a good candidate to be metastable, if there are no other states of intermediate spin with excitation energies less than that of the metastable state.Metastable isomers of a particular isotope are usually designated with an "m" (or, in the case of isotopes with more than one isomer, m2, m3, and so on). This designation is usually placed after the atomic symbol and number of the atom (e.g., Co-58m), but is sometimes placed as a superscript before (e.g., 58mCo). Increasing indices, m, m2, etc. correlate with increasing levels of excitation energy stored in each of the isomeric states (e.g., Hf-177m2 or 177m2Hf).A different kind of metastable nuclear state (isomer) is the fission isomer or shape isomer. Most actinide nuclei, in their ground states, are not spherical, but rather spheroidal — specifically, prolate, with an axis of symmetry longer than the other axes (similar to an American football or rugby ball, although with a less pronounced departure from spherical symmetry). In some of these, quantum-mechanical states can exist in which the distribution of protons and neutrons is farther yet from spherical (in fact, about as non-spherical as an American football), so much so that de-excitation to the nuclear ground state is strongly hindered. In general these states either de-excite to the ground state (albeit far more slowly than a "usual" excited state) or undergo spontaneous fission with half lives of the order of nanoseconds or microseconds— a very short time, but many orders of magnitude longer than the half life of a more usual nuclear excited state. Fission isomers are usually denoted with a postscript or superscript "f" rather than "m," so that a fission isomer in e.g. plutonium 240 is denoted Pu-240f or 240fPu
Nearly-stable isomers
Most nuclear isomers are very unstable, and radiate away the extra energy immediately (on the order of 10-12 seconds). As a result, the term is usually restricted to refer to isomers with half-lives of 10-9 seconds or more. Quantum mechanics predicts that certain atomic species will possess isomers with unusually long lifetimes even by this stricter standard, and so have interesting properties. By definition, there is no such thing as a "stable" isomer; however, some are so long-lived as to be nearly stable, and can be produced and observed in quantity.The only nearly-stable nuclear isomer occurring in nature is Ta-180m, which is present in all tantalum samples at about 1 part in 8,300. Its half-life is at least 1015 years, markedly longer than the age of the universe. This remarkable persistence results from the fact that the excitation energy of the isomeric state is low and both gamma de-excitation to the Ta-180 ground state (which is radioactive and not particularly long lived) and beta decay to hafnium or tungsten are suppressed owing to spin mismatches. The origin of this isomer is mysterious, though it is believed to have been formed in supernovas (as are most other heavy elements). When it relaxes to its ground state, it releases a photon with an energy of 75 keV. It was first reported in 1988 by Collinsthat Ta-180m can be forced to release its energy by weaker x-rays. After 11 years of controversy those claims were confirmed in 1999 by Belic and co-workers in the Stuttgart nuclear physics group.Another reasonably stable nuclear isomer (with a half-life of 31 years) is hafnium-178m2, which has the highest excitation energy of any comparably long-lived isomer. One gram of pure Hf-178-m2 contains approximately 1330 megajoules of energy, the equivalent of exploding about 317 kilograms (700 pounds) of TNT. Further, in the natural decay of Hf-178-m2, the energy is released as gamma rays with a total energy of 2.45 MeV. As with Ta-180m, there are disputed reports that Hf-178-m2 can be stimulated into releasing its energy, and as a result the substance is being studied as a possible source for gamma ray lasers. These reports also indicate that the energy is released very quickly, so that Hf-178-m2 can produce extremely high powers (on the order of exawatts. Other isomers have also been investigated as possible media for gamma-ray stimulated emission.
Applications
These hafnium and tantalum isomers have been considered in some quarters as weapons that could be used to circumvent the Nuclear Non-Proliferation Treaty, since they can be induced to emit very strong gamma radiation. DARPA has or has had a program to investigate this usage of both isomers. However, given the difference in speed between a photon and a neutron, they can't be induced to chain react like a nuclear weapon, so there will probably never be such a weapon. Ta-180m is also one of the most expensive substances to procure in the world: It costs approximately $17 million per gram. In 1999, the entire world's supply of Ta-180m was only 6.7 milligrams.Technetium isomers Tc-99m (with a half-life of 6.01 hours) and Tc-95m (with a half-life of 61 days) are used in medical and industrial applications.
Decay processes
Isomers decay to lower energy states of the nuclide through two isomeric transitions:γ (gamma) emission (emission of a high-energy photon)internal conversion (the energy is used to ionize the atom)
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