# Chapter 3 - Principles of Biosafety

3.1 Introduction   
A fundamental objective of any biosafety program is the containment of potentially harmful   
biological agents. The term “containment” is used in describing safe methods, facilities and   
equipment for managing infectious materials in the laboratory environment where they are being   
handled or maintained. The purpose of containment is to reduce or eliminate exposure of   
laboratory workers, other persons, and the outside environment to potentially hazardous agents.   
The most important element of containment is strict adherence to standard microbiological   
practices and techniques. Knowledge of standard microbiological practices and techniques is gained   
through a combination of training and experience.

3.2 Engineering Controls   
Engineering controls eliminate or reduce the exposure of individuals to hazards in the laboratory   
through the use of specialized equipment. In most cases, engineering controls will be the primary barrier   
between hazardous materials and the individual. Engineering controls include:   
 Biological safety cabinets (BSCs) (discussed in Appendix A)  
 Other enclosures  
 Safety centrifuge cups  
 Retractable needles  
3.3 Personal Protective Equipment   
Personal protective equipment (PPE) is equipment that the individual wears to protect them from   
exposure to hazards in the laboratory. PPE is generally intended to be a secondary barrier meaning that   
it is to be used in conjunction with engineering controls to protect the user. PPE may be used a primarybarrier when engineering controls are not possible or feasible.PPE worn should be based on the hazard   
present and can include:  
 Gloves  
 Safety glasses or splash goggles  
 Lab coat  
 Gown  
 Shoe covers  
 Boots  
 Respirator (includes dust masks)  
 Face shield  
3.4 Facility Construction and Design   
The design and construction of the facility provides a secondary barrier to protect persons outside the   
laboratory. PI’s are responsible for providing facilities commensurate with the laboratory’s function and   
the recommended biosafety level for the agents being manipulated. The recommended secondary   
barrier(s) will depend upon the risk of transmission of specific agents. For example, the exposure risks   
for most laboratory work in BSL-1 and BSL-2 facilities will be direct contact with the agents, or   
inadvertent contact exposures through contaminated work environments. Secondary barriers in these   
laboratories may include separation of the laboratory work area from public access, availability of a   
decontamination facility (e.g., autoclave) and hand washing facilities.