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Different levels of laboratory containment are required depending on the microbiological agent that is being used. The levels of containment for the organisms parallel the biohazard groups to which microbiological agents have been assigned by the Advisory Committee on Dangerous Pathogens (ACDP).

Hazard Group 1 agents such as Saccharomyces cerevisiae require less stringent controls than organisms belonging to Hazard Group 3, eg (Shigella dysenteriae (Type 1) or Yersinia pestis), or Hazard Group 4, eg (Guanarito or Junin viruses). Work must take place in a safe and tidy manner as biohazard group 1 organisms may have unwanted effects on those whose susceptibility to infection may be affected, for example because of pre-existing conditions, medication, compromised immunity, pregnancy or breast-feeding or those who suffer from allergies. 

Work with organisms of a particular hazard group can take place in a higher category of laboratory but cannot take place in a lower category of laboatory e.g. work with HIV or M. tuberculosis must always take place in containment level 3 laboratories. 

The levels of containment are a mixture of physical properties (eg laboratory equipment, security control) and the standard operating procedures for carrying out work. These are designated in the document, The Management, design and operation of microbiological containment laboratories(PDF), produced by the Advisory Committee on Dangerous Pathogens. 

St George’s, University of London does not have any containment level 4 facilities and work with organisms of biohazard group 4 must not take place. Different levels of access and training apply to containment apply to biohazard containment level 3 facilities (PDF) compared to biohazard containment level 2 facilities (PDF). 

Containment level 1

  • Suitable protective clothing to be worn, needs to be determined by risk assessment (laboratory coats, gloves, masks, eye protection, overshoes).

  • Suitable supervision, information, instruction and training to be given.

  • Protocols to be in place for dealing with and reporting accidents, spills and incidents.

  • First aid arrangements to be documented.

  • Specified disinfection procedures to be documented.

  • Specified waste procedures in place, which must be validated.

  • Bench surfaces impervious to water and easy to clean.

  • Bench surfaces to be resistant to acids, alkalis, solvents, disinfectants.

  • Hand wash basin to be located at point of exit to the laboratory with taps that can be operated without using one’s hands, plus liquid soap and paper towels.

  • Observation window.

  • Protocols in place to minimise aerosol production.

  • Autoclave to be on site.

  • Equipment and control measures to be tested and maintained in accordance with current legislation, standardsand guidance.

  • No mouth pipetting, chewing, eating, drinking, smoking, licking of labels, application of cosmetics, taking medication, handling contact lenses, storage of food or drink for human consumption.

  • No wearing of open-toed footwear.

Containment level 2

Must meet requirements of containment level 1, plus:

  • access restricted to authorised personnel

  • keep door closed

  • display a biohazard sign

  • written training records to be kept

  • occupational health advice

  • workplace to be maintained at negative pressure if mechanical ventilation is installed

  • efficient vector control for designated home office areas, CBUs & BSUs

  • safe storage of biological agents

  • where aerosols are produced any infective material to be handled in a microbiological safety cabinet, or other suitable containment

  • autoclave to be present within the building

  • lone working procedure

  • permit to work to be issued for access to service engineers, estates, cleaners etc

  • offices must not be accessed via laboratory

  • organisms in this class include Klebsiella pneumoniaeNeisseria gonorrhoeae and Neisseria meningitidis.

Containment level 3

Must meet requirements of containment level 2, plus:

  • workplace to be separated from any other activities in the same building

  • extract air to be High Efficiency Particulate Air (HEPA) filtered

  • workplace to be sealable to permit fumigation, this must be validated on an annual basis

  • workplace to be maintained at negative pressure

  • bench and floor surfaces impervious to water and easy to clean (and walls in Home Office designated areas, CBUs or BSUs)

  • organisms in this class include Brucella abortus, Mycobacterium tuberculosis, Plasmodium falciparum and Trypanosoma brucei rhodesiense.



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