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A problem that may occur in the laboratory is an overt biological spill. A spill that takes place in the open laboratory may create a serious problem. Every effort should be taken to avoid such occurrences. A spill poses less of a problem if it happens in a biological safety cabinet, provided splattering to the outside of the cabinet does not occur. Direct application of concentrated liquid disinfectant and a thorough wipe down of the internal surfaces of such cabinetry will usually be effective for decontaminating the work zone, but gaseous sterilants will be required to disinfect the interior sections of the cabinet. Each researcher must realize that in the event of an overt accident, research materials such as tissue cultures, media, and animals within such cabinets may well be lost to the experiment. A. Spill in the Open LaboratoryAdvance preparation for spill management is essential. A "spill kit" including leak proof containers, forceps, paper towels, sponges, disinfectant, respirators, and rubber gloves should be readily available. If potentially hazardous biological material is spilled in the laboratory, the first step is to avoid inhaling any airborne material by holding the breath and leaving the laboratory. Warn others in the area and go directly to the wash or change room area. If clothing is known or suspected to be contaminated, remove the clothing with care, folding the contaminated area inward. Discard the clothing into a bag or place the clothing directly in an autoclave. Wash all potentially contaminated body areas as well as the arms, face, and hands. Shower if facilities are available. Reentry into the laboratory should be delayed for a period of thirty minutes to allow the dissipation of the aerosol generated by the spill. Protective clothing should be worn when entering the laboratory to clean the spill area. Rubber gloves, autoclavable footwear, an outer garment, and a respirator should be worn. If the spill was on the floor, do not use a surgical gown that may trail on the floor when bending down. Take the " spill kit" into the laboratory room, place a discard container near the spill, transfer large fragments of material into it and replace the cover. Using a hypochlorite containing solution (1000 ppm available chlorine), iodopher solution containing 1600 ppm iodine or other appropriate disinfectant, carefully pour the disinfectant around and into the visible spill. Avoid splashing. Allow 15 minutes contact time. Use paper or cloth towels to wipe up the disinfectant and spill, working toward the center of the spill. Discard towels into a discard container as they are used. Wipe the outside of the discard containers, especially the bottom, with a towel soaked in a disinfectant. Place the discard container and other materials in an autoclave and sterilize. Remove shoes, outer clothing, respirator and gloves and sterilize by autoclaving or exposure to ethylene oxide. Wash hands, arms and face, or if possible, shower. B. Spill in a Biological Safety CabinetA spill that is confined to the interior of the biological safety cabinet should present little or no hazard to personnel in the area. However, chemical disinfection procedures should be initiated at once while the cabinet ventilation system continues to operate to prevent escape of contaminants from the cabinet. Spray or wipe
walls, work surfaces and equipment with a disinfectant. A disinfectant with a detergent has the advantage of detergent activity which will help clean the surfaces by removing both dirt and microorganisms. A suitable disinfectant is a 3% solution of an iodopher such as Wescondyne or a 1:100 dilution of house-hold bleach (e.g. Chlorox) with 0.7% nonionic detergent. The operator should wear gloves during this procedure. Use sufficient disinfectant solution to ensure that the drain pans and catch
basins below the work surface contain the disinfectant. Lift the front exhaust grill and tray and wipe all surfaces. Wipe the catch basin and drain the disinfectant into a container. The disinfectant, gloves, wiping cloth and sponges should be discarded into an autoclave pan and autoclaved. The above procedure will not disinfect the filters, blower, air ducts or other interior parts of the cabinet. If the entire interior of the cabinet needs to be sterilized, contact EH&S. C. Biological Spill Response GuidelinesThese guidelines are intended to assist the principal investigator, laboratory supervisor, and other responsible individuals who may be involved in the cleanup of biological spills. This guide outlines the basic procedures for dealing with some of the biological spills that may be encountered in a research laboratory. All lab personnel should refer to the specific spill response procedures before initiating their experiments. Biosafety Level 1 (BL1) Spill
Clean-up of BL1 Spill
Biosafety Level 2 (BL2) Spill
Clean-up of BL2 Spill
D. Engineering ControlsEngineering controls are tools or equipment that, when used properly, provide significant protection to the operator as well as other laboratory occupants. Examples include biological safety cabinets, autoclaves, and sharps containers. As is true of most tools, there are correct (proper) and improper ways to use engineering controls. Given that there are considerable adverse consequences if used improperly, correct usage of engineering controls is critical. When used properly, they have proven to be, in most circumstances, the most effective and practical way to achieve a safety goal. E. Biological Safety Cabinets (BSCs)BSCs are designed to provide personnel, environmental, and product protection when appropriate use/procedures are followed. They are among the most effective and commonly used primary containment devices in laboratories working with infectious agents. Three types of BSCs (Class I, II, and III) have been developed to meet various research and clinical needs. BSCs use HEPA (high efficiency particulate air) filters in their exhaust and/or supply systems. Biological safety cabinets must not be confused with other laminar flow devices or “clean benches.” Horizontal flow cabinets that direct air toward the operator should never be used for handling infectious, toxic or sensitizing materials. Class I and II biosafety cabinets, when used in conjunction with good microbiological techniques, provide an effective partial containment system for safe manipulation of moderate and high-risk microorganisms, (i.e. BL 2 and 3 agents). Class I Biological Safety Cabinetis a ventilated cabinet for personnel protection with an unrecirculated inward airflow away from the operator. This unit is fitted with a HEPA filter to protect the environment from discharged agents. A Class I BSC is suitable for work involving low to moderate risk agents, where there is a need for containment, but not for product protection. Class II Biological Safety Cabinetis a ventilated cabinet for personnel, product and environmental protection, which provides inward airflow and HEPA-filtered supply and exhaust air. There are three basic types of Class II BSCs: Type A, Type B, and 100% exhaust. Type B cabinets are further sub-typed into types B1, B2, and B3. The major differences between the three types is the percent of air that is exhausted or recirculated, and the manner in which exhaust air is removed from the work area. Class III Biological Safety Cabinet or glove boxis a totally enclosed ventilated cabinet, which provides the highest attainable level of protection to personnel, environment and product. The supply air is HEPA-filtered and exhaust air has two HEPA-filters in series. Work is performed in the cabinet through glove ports with Oring for attaching arm-length gloves to cabinet. It is important to note that laminar flow clean benches must not be utilized for work with biohazardous or chemically hazardous agents. Table 1 – Selection of a Biological Safety Cabinet through Risk Assessment.
Clean benches provide product protection by ensuring that the product is exposed only to HEPA-filtered air. They do not provide protection to personnel or the ambient environment. The correct location, installation, and certification of a biological safety cabinet are critical to its performance in containing infectious aerosols. All BSCs used for must be inspected and certified annually. Inspection and re-certification is mandatory if the cabinet is relocated, experiences major repairs or after a filter change etc. F. Safe and Effective Use of Biosafety Cabinets
Should paper towels be discarded in a biohazard container after washing hands?Paper towels should be discarded in a biohazard container after washing hands. Thoroughly washing hands will sterilize them. How long should the hands be lathered with soap and water?
Which of the following items should be disposed of in a biohazard bag?Only biohazardous waste should be placed inside red bags for disposal. Dispose of items such as plastic vaginal speculums, used specimen swabs, used glucose test strips, urine dipsticks, blood-soaked drapes and gloves, and anything contaminated with OPIM in a red bag.
Which of the following items should be disposed of in the sharps container?Place only sharps (as defined in OSHA's Bloodborne Pathogens standard, for example, contaminated syringes, needles, lancets, scalpels, infusion needle sets, connection needles, auto-injectors) in sharps disposal containers.
Which of the following steps are part of a thorough hand washing protocol?Follow Five Steps to Wash Your Hands the Right Way. Wet your hands with clean, running water (warm or cold), turn off the tap, and apply soap.. Lather your hands by rubbing them together with the soap. ... . Scrub your hands for at least 20 seconds. ... . Rinse your hands well under clean, running water.. |