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The Advisory Committee on Dangerous Pathogens (ACDP) produce an Approved List of Biological Agents which classifies various micro-biological agents into four different hazard groups depending on the organisms ability to infect healthy Individuals based on the following criteria.

  1. Is it pathogenic for humans?

  2. Is it a hazard to employees?

  3. Is it transmissible to the community?

  4. Is effective prophylaxis or treatment available?

The criteria are based upon those produced by the World Health Organisation.

The criteria do not take into account those who are immuno-compromised, who may be affected by cancer, being treated for a medical condition, the young, pregnant or breast feeding women. While a virus may be a low risk to a woman who is not pregnant or breast-feeding, it could cause problems to a pregnant woman, eg, Rubella.

Work on organisms in biohazard group 4 is not permitted within St George’s, University of London. All organisms must be contained appropriately, ie organisms of hazard group 3 must be used in containment level 3 facilities while organisms of hazard group 1 may be used in any facility. Work on hazard group 2 organisms must take place in containment level 2 facilities. An explanation of the different containment levels is available below. 

Hazard groups

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Hazard group 1

These organisms are unlikely to cause disease in a healthy individual but could cause disease in some one who is susceptible.

While a non-infectious biological agent may be classified as a hazard group 1 agent, substantial control measures may still be required, as it secrete toxins.

Hazard group 2

These can cause disease and may be a hazard to employees. In normal usage they are unlikely to spread to the community and there is usually an effective prophylaxis or treatment available.

For example Schistosoma mansoniAspergillus fumigatusBordetella pertussis and California encephalitis, Escherichia coli, Epstein-Barr virus, Mumps, Measles

Hazard group 3

These can cause severe human disease and may be a hazard to employees. The organism may spread to the community but there is usually an effective prophylaxis or treatment available.

For example Mycobacterium tuberculosis, Escherichia coli 0157, the blood borne viruses Hepatitis B, C. D and E

Hazard group 4

These organisms can cause severe human disease and are a serious hazard to employees. They are likely to spread to the community and there is usually no effective prophylaxis or treatment available.

These organisms are viruses or prions, eg Marburg, Crimean / Congo haemorrhagic fever and Kyasanur forest disease, Russian spring summer encephalitis.


Risk assessments

Risk Assessments must be conducted before using any biological agent whether they are primary cell lines derived from human or animal tissues or those produced by genetic modification.

The risks from the different organisms must be properly considered. This may the risk of infection being caused due to the agents mode of transmission, eg Mycobacterium Tuberculosis must be used in microbiological safety cabinet within containment level 3 laboratory due to the risk of inhalation, while needles and sharps should be avoided when using blood borne viruses such as Hepatitis, HIV.

The risk assessment must consider the means of waste disposal and any emergency procedures required.

Information on organisms

 Information on the effects of certain organisms is available from Public Health England which is part of the Health Protection Agency.


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