Good Biosafety Lab Practices

Good Housekeeping

Work areas must be free of clutter, and cleaned regularly. Wet mopping is the preferred method to dry sweeping or the use of ordinary vacuums which create aerosols. Work surfaces are decontaminated once a day and after any spill of potentially viable material. Decontamination is covered in Section IV. D and spill clean up in Section IV. F. of the Biosafety Manual.

Hand Washing

Laboratory workers must wash their hands after handling biohazards or animals, after removing gloves and before leaving the laboratory area.

Laboratory Traffic - Restrict it!

This requirement must be enforced rigorously with respect to biohazards and recombinant DNA in BSL-2, BSL-3 and BSL-4 laboratories. (There is no BSL-4 laboratory at the University of Washington.) See Appendix B. for additional information of the use of the Biohazard Sign.

  • Access to a BSL-2 laboratory is restricted (i.e. the door to laboratory is closed and the Biohazard Sign is displayed) when use of biohazards is in progress.
  • Entry to a BSL-3 laboratory is restricted by a double set of doors which remain closed at all times and the Biohazard Sign is permanently affixed to the door.

Minimization of Aerosols

All procedures are performed carefully to minimize the creation of aerosols. Additional information on the minimization of aerosols is found in Section IV. C. of the Biosafety Manual.

Personal Protective Clothing

Specific rules concerning personal and protective clothing must be devised by the principal investigator. It is important to recognize that hair, beards, personal clothing and shoes can effectively disseminate infection. (see section above on fomites).

  • Laboratory Coats

  • BSL-1 laboratory: not required for biohazard protection but may be necessary when working with chemicals, radioisotopes, etc.

    BSL-2 laboratory: laboratory coats, gowns, or smocks are worn while working in the laboratory area. Before leaving the laboratory area for a non-laboratory area (cafeteria, library, administrative offices), this protective clothing is removed and left in the laboratory. Gloves are worn when handling infected animals and when there is potential skin contact with biohazards.

    BSL-3 laboratory: all the rules for BSL-2 laboratory apply and in addition laboratory clothing that protects street clothing (solid front or wrap-around gowns, scrub suits or coverall) is worn in the laboratory. Laboratory clothing is not worn outside the laboratory, and it is decontaminated before laundering or disposal.

    Double gloving and tight fitting cuffs on laboratory clothing or sleeve protectors are useful.

    Gloves are worn when handling infected animals and when there is potential skin contact with biohazards. Molded surgical masks or respirators are worn in rooms containing infected animals.

  • Facial Protection

  • Facial barrier protection is required for activities where there is a potential for spattering biohazards onto the mucous membranes of the mouth, nose and eyes.

    Full face shields made of lightweight transparent plastic (shaped like a welders face shield) are the preferred means of facial protection. They offer excellent protection of the entire face and neck region. They are easily decontaminated. If face shields are not used, a mask and eye protection should be used.

    A surgical mask offers protection of the nose and mouth. Either soft or preformed masks are effective.

    Ordinary prescription glasses are not adequate eye protection. Plastic, wraparound safety glasses that fit over regular glasses should be used. If there is substantial hazard for splattering, safety goggles with a plastic cushion seal should be used.

    Alternatives of facial barrier protection.

    • Perform the manipulations in a Class I or Class II biological safety cabinet.

    • Purchase or construct a splash shield that can be set on the bench top to provide a physical barrier. A clear plastic shield provides an effective barrier from potential splashes from opening tubes. It is not effective for manipulations that create major aerosols. Such manipulations must be performed in a biological safety cabinet.

  • Gloves

    The type of glove and use will vary according to procedures involved.

    In the laboratory, non-sterile exam gloves of thin latex or vinyl are used to protect the hands from contamination with biohazards. However, these gloves are not intended to provide protection from punctures caused by sharp instruments or broken glass. Research at Harborview Medical Center found that vinyl gloves have frequent leaks and provide unreliable protection.

    • Gloves must always be visually checked for defects before using. (i.e., look at gloved hands)
    • Gloves should be changed frequently. Care should be taken not to touch skin with the outer surface of the gloves when removing. Wash hands immediately after gloves are removed.
    • Gloves are removed prior to handling non-contaminated items such as doorknobs, or telephones. Gloves are not worn outside the laboratory area.
    • Do not wash or disinfect gloves for reuse. Detergents may cause enhanced penetration of liquids through undetected holes, and disinfectants may cause deterioration.
    • Gloves are decontaminated prior to disposal. (i.e., treated as biohazardous waste)

    General purpose utility gloves (rubber household gloves) should be used for housekeeping chores, instrument cleaning and decontamination procedures. These gloves may be decontaminated and reused but they must always be checked for punctures, tears or other evidence of deterioration before using.

    Stainless steel mesh gloves protect against injury caused by large sharp edges. This type of glove is ideal for cleaning areas where small pieces of glass are frequently found.

Pest Control

Pest control is best accomplished by maintaining good housekeeping. A good sanitation program is fundamental to the control of vermin and should include a program of storage, collection and disposal of solid wastes. Caulking of cracks and crevices in the room is also important. The University of Washington employs a licensed pest control operator to control vermin in strict accordance with applicable laws and regulations. Contact Environmental Health and Safety (685-1026) if vermin problems are suspected so that a control program can be implemented.

Procedures Which Can Produce Aerosols

Most Severe Severe Less Severe Least Severe
Shaking and blending with high speed mixers Opening lyophilized culture Grinding tissue with mortar and pestle Re-suspending packed cells
Forceful ejection of fluid from pipette or syringe   Decanting supernate fluid after centrifugation Inserting hot loop in culture
    Releasing vacuum on freeze-dryer Withdrawing culture sample from vaccine bottle
    Releasing bubbles from a pipette  
    Spilling liquid on a hard surface  
    Opening tube within which air pressure may be different from that of room*  

*May occur when a tube is opened at a temperature different from that at which it was sealed or if the tube has been vacuum sealed.

Prohibited Activities

Applying cosmetics, placing any article in the mouth or other contact with mucous membranes is not allowed in the work area of the laboratory. Smoking is not permitted in any University building. Food shall not be stored in laboratory refrigerators or prepared/consumed with laboratory glassware or utensils. Food may be stored in cabinets and refrigerators marked for "FOOD ONLY". These must be located outside the laboratory work area.

Technical Proficiency

Careful self observation of techniques is the most important avenue to learning appropriate techniques. Laboratory workers must be aware of the potential hazards and must be trained and proficient in the necessary practices and techniques required for safe handling of biohazards. The principal investigator is responsible for providing or arranging for appropriate training for all personnel working in his/her laboratory.


All contaminated liquid or solid wastes are decontaminated before disposal.