Biosafety Laboratories 3&4

Biosafety Lab Level 3 (BSL-3): Healvita Cleanroom is building Biosafety Lab Level 3 (BSL-3) which are 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. 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. The laboratory has special engineering and design features.

Healvita Cleanroom is also building Biosafety Lab Level 4 (BSL-4) which is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease. The control systems used in these facilities are complex and represent the most critical elements of institutional HVAC systems.

Personnel Protection (Biosafety) vs Product Protection (Cleanroom) Principles

The term biosafety is used to describe safe methods for handling infectious materials in the laboratory. The purpose of biosafety is to reduce or eliminate exposure of laboratory personnel, associated persons, and the outside environment to potentially infectious agents. A biosafety lab is not a cleanroom and Health and Safety is the dominant concern. Personnel who work in a laboratory handling infectious substances are at risk of exposure to the agents they handle and laboratory acquired infections (LAIs) are not uncommon.

Aerosolised pathogens present a serious risk in terms of inhalation, ingestion and contact with mucous membranes. Their infection routes are well developed and therefore safe working protocols aligned with correct equipment selection and PPE are critical in controlling LAIs. These factors have driven the increase in high containment facilities and the need to contain the increased risks involved. Biosafety is provided by a combination of operational practices, containment equipment and facility design. The most important aspects of biosafety are the practices and procedures used by trained laboratory personnel. The World Health Organization’s Laboratory Biosafety Manual states that “no biosafety cabinet or other facility or procedure alone guarantees safety unless the users operate safe techniques based on informed understanding.” It is the responsibility of everyone involved including managers, laboratory staff, maintenance personnel, vendors, etc. to act, operate and behave in a safe and compliant manner.

Risk Assessment

Risk assessment is the first critical step in the selection of an appropriate containment level for the microbiological work to be carried out. A detailed local risk assessment should be conducted to determine whether work requires biosafety containment level 1, 2, 3 or 4 facilities and operational practices. In addition to the inherent characteristics of the biological agent, the following factors associated with the laboratory operation should also be carefully analysed:

  • potential for aerosol generation
  • quantity
  • concentration
  • agent stability in the environment (inherent biological decay rate)
  • manipulation including amplification
  • type of work proposed (e.g., in vitro, in vivo, aerosol challenge studies)
  • use of recombinant organisms

The World Health Organisation gives four classifications of organisms according to risk group and these are used to categorise the relative hazards of infective organisms. The factors used to determine which risk group an organism falls into is based upon the particular characteristics of the organism, such as:

  • pathogenicity
  • infectious dose
  • mode of transmission
  • host range
  • availability of effective preventive measures
  • availability of effective treatment

High Containment Biosafety Design Principles

It is the specific responsibility of the design and construction team with clear direction from the Biosafety User Group to design and build high containment biosafety labs in such a way as to take into account all the risks, expected operation and the likely lifecycle of the facility including quirks, faults, unexpected events and challenges. In this regard decisions should be science based with good engineering biosafety control principles and practice.

At Hazard Group 3 and 4 these pathogens produce very serious human diseases, are life threatening and often untreatable. They are considered to be readily transmitted from one individual to another, or from animal to human or human to animal, through direct or indirect means of infectious route. The concept of the Primary Containment barrier of using BioSafety Cabinets (BSCs) with appropriate equipment and processes contained within, such as centrifuges with sealed rotors or safety cups is well developed. Significant emphasis is now placed on appropriate personal protective equipment (PPE) including a minimum of lab coats, head and shoe protection, gloves and protective eyewear. In an increasing number of cases different levels of personalised respiratory headsets or complete isolating breathing suits are being used which allows the use of chemical showers as a decontaminating exit process.