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1 Introduction, Overview, and Recommendations A. INTRODUCTION This book is about the safe handling and disposal of hazardous biological materials in the laboratory. These materials consist of infectious agents, per se, as well as substances actually or potentially contami- nated with them. A large number of laboratory workers handle such materials as part of their daily routine. The number has been estimated to be about 500,000 in the United States, but that number is probably a gross underesti- mate. The persons at risk are primarily the labora- tory workers themselves, but the risks may extend to others: students, custodial and maintenance workers who must enter laboratories, handlers of shipped materials, sanitation workers, and all who work in or pass through building areas adjacent to the labora- tory. For the purposes of this book, the term "risk" refers to the probability of acquiring an occupa- tional infection, rather than to the severity of the resulting disease. Such risk is actually much lower than it is popularly perceived to be: the great major- ity of organisms handled in the laboratory are either not known to be hazardous or are of minimal poten- tial hazard to laboratory personnel; in any case the risk of exposure can be reduced to a very low level by the use of the simple, prudent practices described in this book. Furthermore, there is little or no risk to the community at large: disease outbreaks in the United States attributable to the escape of infectious agents, either from laboratories or from waste dis- posal sites, have been extremely rare. The general concepts set forth in this book apply to many Apes of laboratories: academic, industrial, and governmental research laboratories; hospital, phy sicians', veterinanans', and dentists' laboratories; teaching laboratories; blood banks; and analytical laboratories that handle potentially infectious materi- als (e.g., clinical, diagnostic, and food laboratories). We have included a section on biosafety in large- scale production facilities, because laboratory work- ers are often involved in the scale-up of benchtop operations to the pilot plant level. We have restricted ourselves to agents infectious to humans: strictly animal and plant pathogens are not addressed, although many of the practices rec- ommended here are useful in the prevention of their spread. We deal only briefly with the hazards associ- ated with biological products (e.g., toxins and immu- noactive materials), and we have chosen not to in- clude the subject of recombinant DNA, given its extensive coverage elsewhere [134,136] and the fact that the hazard presented by an organism is not re- lated to the use of recombinant technology in its production but rather to the relative pathogenicity of the donor organism, the nature of the vector, and the hardiness of the recipient (host) organism. We do not deal in this book with problems specific to hospi- tal wards, to nosocomial infections, or to environ- mental situations such as the presence of legionellas in water tanks. This book is designed to serve as an introductory guide to biological safety in the laboratory; the prin- ciples and practices described, however, are general ones, and the readers must decide how best to apply them in their own circumstances. Specific applica- tions will vary with such factors as the design of the local facility and equipment, the procedures in use, the nature of the potential exposure, and the workers' susceptibility. Our text is addressed to all who are responsible 1
2 for the safety of others, including the chief executive officer of the institution, departmental chairpersons and managers, project directors, and laboratory su- pervisors; it is also addressed to the individual labo- ratory workers, who share the responsibility for their own safety as well as the safety of those around them. Although we have tried to be comprehensive in our treatment of the general principles of biological safety in the laboratory, we have dealt only briefly with specific practices that are fully treated else- where. A list of pertinent references is provided, and the reader is urged to consult them for a more com- plete treatment of the subject. In particular, labora- tory workers who come into contact with human blood, body fluids, or tissue should pay special atten- tion to the practices described in the proposed guide- lines on "Protection of Laboratory Workers from Infectious Disease Transmitted by Blood and Tis- sues," published by the National Committee for Clini- cal Laboratory Standards [901, and the Centers for Disease Control publication, "Recommendations for Prevention of HIV Transmission in Health-Care Workers" [341. Finally, we call the reader's attention to Appen- dix A, which reprints in its entirety the Centers for Disease Control (CDC)/National Institutes of Health (NIH) publication entitled Biosafety in Microbiologi- cal and Biomedical Laboratories, published in 1984; Appendix B. the 1988 "Agent Summary Statement for Human Immunodeficiency Viruses (HIVs)," the etiologic agent of AIDS; and Appendix C, "Recom- mendations for Prevention of HIV Transmission in Health-Care Settings" from the Morbidity and Mor- tality Weekly Report of the CDC. Together, these documents provide guidance for the handling of most infectious agents that pose significant risks in the laboratory. B. OVERVIEW The remainder of this book is divided into four chapters: Chapter 2 deals with the epidemiology of laboratory-acquired infections; Chapter 3 with the safe handling of infectious materials; Chapter 4 with the safe disposal of infectious materials; and, Chap- ter 5 with safety management. Following is a brief overview of these chapters. BIOSAFETY IN THE LABORATORY Chapter 2. Descriptive Epidemiology of Occupational Infections of Laboratory Workers To determine the rate of occupationally related infections among laboratory workers, it is necessary to know both the number of actual infections over a given period of time and the number of persons who are at risk. As discussed in this chapter, neither figure is known; however, the data presented here give some qualitative appreciation of risk and group pathogens into high-risk and low-risk categories. Thus, from the beginning of the twentieth century until the present, the `'top five" (highest-risk) organ- isms handled in laboratories have been the agents of brucellosis, Q fever, typhoid fever, viral hepatitis, and tuberculosis; organisms in the category of lowest risk have included rabies virus, Creutzfeldt-Jakob agent, Vibrio cholerae, Clostridium tetani, C. botu- linum, and HIV. These rank orders are changing, however, with changes in the prevalence of the mi- croorganisms in the general population, and in the frequency with which they are handled in the labora- tory. Chapter 3. Safe Handling of Infectious Agents The material in this chapter falls into two catego- ries. The first category, comprising Sections A through E, deals with the biological materials that may be hazardous: pathogenic microorganisms; organisms posing special risks; vertebrate animals and insects; · cell cultures; and · necropsy and surgical specimens. In each case, there is a discussion of the special precautions that should be taken in handling the or- ganism or the infectious material. The second category, comprising Sections F through K, deals with the general procedures and equipment that make it possible to handle biohaz- ardous materials safely. Section F. "Good Labora- tory Practices," lists seven basic rules of biosafety; these are reprinted in the set of recommendations at the end of this chapter (Section C.3~. The same good laboratory practices are recom- mended for persons working with plant-specific pa
INTRODUCTION, OVERVIEW, AND RECOAIMENDATIONS thogens, animal-specific pathogens, and other viable microorganisms not associated with human disease. The remaining sections deal with the following topics: · transportation and shipment of biomedical materials, labeling of specimens, prevention of aerosol and droplet generation, containment equipment, personnel protective equipment, biosafety in large-scale production, and small-volume clinical laboratories. Once again it must be emphasized that the prin- ciples and practices described in this book are general ones, and the readers must decide how best to apply them under their own special circumstances. Chapter 4. Safe Disposal of Infectious Laboratory Waste In the United States, biological laboratory waste presents an occupational, rather than a public health, hazard. For the reasons discussed in this chapter, outbreaks of infectious disease attributable to such waste have not occurred or are extremely rare as a result of highly effective sanitation measures. These measures include physical barriers in the form of well-constructed drains, sewers, and refuse contain- ers, along with properly constructed and operated sewage treatment plants, sanitary landfills, and mu- nicipal incinerators. Thus the public's health is pro- tected even if infectious waste is introduced untreated into a municipal sewage treatment facility, a sanitary landfill, or a solid waste incinerator. The potential for exposure to infectious agents does exist, however, for workers who generate, handle, and process biological laboratory waste. These work- ers can be protected effectively from exposure by a number of simple procedures, of which the principal ones are as follows: segregation of infectious from noninfectious waste; · on-site treatment, including chemical decon- tamination, use of the steam autoclave or incinera- tor, and appropriate packaging for transport; and · personal protection, in the form of protective clothing, gloves, and handwashing. Mixed waste, which contains infectious agents and radioactive or chemically hazardous materials, re- quires special processing. The primary responsibility for the safe handling and disposal of infectious waste lies with the labora- tory that generates the waste, but waste haulers and managers of treatment facilities and sanitary landfills also share in the responsibility. Chapter 5. Safety Management This chapter outlines the administrative responsi- bilities associated with biosafety in the laboratory and recommends some general practices for dealing with them. As described here, an effective safety management program includes the following: clear goals, well-defined responsibilities, mandatory safety rules, written safety plans, safety committees, effective safety communications, emergency preparedness, and auditing of laboratory operations. Also, as discussed in this chapter, every institu- iion or laboratory should have a biosafety manual that addresses the following topics: · policy and goals, · safety organization, · medical programs, · laboratory procedures for labeling and han- dling specimens, preventing aerosol and droplet generation, properly using needles, discarding materials, steam autoclaving and disinfecting, cleaning-up of spills, using and maintaining safety cabinets, controlling insects and other pests, and working with animals, · safety equipment, · waste disposal, and · emergencies. The above outlines for a safety plan and a bio- safety manual can serve as a rough checklist for those who are responsible for day-to-day safety in He laboratory. Chapter 5 also deals with the proper design, op- eration and maintenance of facilities; safety training; risk assessment; record keeping; medical surveillance; and regulation and accreditation.
4 C. RECOMMENDATIONS On the basis of the considerations discussed in this report, the committee recommends He following actions; they are presented in the order in which they appear in the text 1. Immunization Employees handling clinical specimens or infec- tious agents should be immunized with the vaccines required for admission to elementary school, or have documented immunity. Personnel working with blood, serum, or other body fluids should be immu- nized against hepatitis B. Immunizations with other available vaccines, including experimental products, should be considered on an individual basis. (See Chapter 3, Sections B and E, and Chapter 5, Section D.) _ _ _ _ - - - BIOSAFETY IN THE LA~OMTORY 2. Serum Bank The establishment of a serum bank should be considered for employees, depending upon the job situation and management policy. Specimens should be collected at the time of employment and others taken periodically Hereafter. (See Chapter 3, Sec- tion B. and Chaps 5, Section D.) 3. AvoWing Exposure to Infectious Agents The following seven laboratory practices should be observed at all times. . Do not mouth pipette (Figure 1.1). · Manipulate infectious fluids carefully to avoid spills and the production of aerosols and droplets (Figure 1.2~. · Restrict the use of needles and syringes to those procedures for which there are no alterna lIGURE 1.1 Do not mouth pipette. Regrettably, many laboratory workers have been taught to pipette by moldy, a practice that has led to a significant number of laboratory-acquired infections. These individuals should be required to give up the old practice and to learn to use the pipetiing aids that are now available for any application. Any device requiring mouth suction should be considered unsafe and inappropriate for use in the biological laboratory. Courtesy, John H. Richardson.
INTRODUCTION, OVERVIEW, AND RECOMMENDATIONS fives; use needles, syringes, and other "sharps" carefully to avoid self-inoculation; and dispose of "sharps" in leak- and puncture-resistant contain- ers. · Use protective Laboratory coats and gloves. · Wash hands following all laboratory activi- ties, following the removal of gloves, and immedi- ately following contact with infectious materials (Figure 13~. · Decontaminate work surfaces before and after use, and immediateb after spills (Figure 1.4~. · Do not eat, drink, store foods, or smoke in the Laboratory. 5 In working with specific etiologic agents, the NIH/ CDC guidelines reprinted in Appendix A should be followed. (See Chapter 3, Section F.) 4. Transportation and Shipment of Specimens All shipments of biological materials, cell cul- tures, and infectious agents should be made in accor- dance with the applicable regulations of the U.S. Public Health Service, He U.S. Department of Trans- portation, He U.S. Department of Agriculture, and the U.S. Postal Service. (See Chapter 3, Section G.) FIGURE 1~2 Manipulate infectious fluids carefully to avoid spills end the production of aerosols end droplets. This photomicrograph shows the copious production of aerosols and droplets when the last drop in a pipette is blown out. Enough material can be aerosolized by such practices to create an infectious dose of some agents. Courtesy, Nation- al Institutes of Health FIGURE 13 Wash hands following all laboratory activi- ties, following He removal of gloves, and immediately following contact with infectious agents. Courtesy, John H. Richardson.
BIOSAFETY IN THE LABORATORY FIGURE 1.4 Decontaminate work surfaces before and after use, and immediately after spills. Courtesy, National Institutes of Heals. 5. Labeling of Specimens All clinical specimens should be regarded as in- fectious and handled accordingly, whether or not they bear special hazard warning labels. (See Chap- ter 3, Section H.) 6. Biosafety In Large-Scale Production The principles and practices described for the control of biohazards in benchtop operations should be applied to the propagation of microorganisms in large-scale production processes. (See Chapter 3, Section K.) 7. Safe Disposal of Infectious Laboratory Waste Just as with chemically hazardous waste, the gen- erators of infectious laboratory waste have the re sponsibility to ensure that their waste is safely handled from "cradle to grave." Treatment and disposal of infectious waste by conventional methods such as solid waste incineration, sanitary landfills, and sew- age treatment plants are adequate to protect He pub- lic's health. Th,e risk of occupationally acquired illness, however, is present for workers who handle infectious waste. The following recommendations are presented to reduce this risk: · institutions should establish a waste man- agement plan for the collection, segregation, con- tainment, treatment, and disposal of infectious waste; · workers involved in the handling of infec- tious waste should be informed of the potential hazard and should be proficient in the use of the necessary safeguards for their own protection; · incineration, the method of choice for the decontamination of infectious waste, should be used whenever possible; and
INTRODUCTION, OVERVIEW, AND RECOMMENDATIONS the principles of containment should be ap- plied to all steps in the chain of handling infec- tious waste, from generation to disposal. (See Chapter 4.) 8. Administrative Organization and Responsibility The institution should have an overall safety, occupational health, and environmental protection program that includes biosafety in the laboratory and provides for compliance with federal, state, and local government regulations. The program should pro- vide safety training for all laboratory, maintenance, and housekeeping personnel, for members of the medical staff, and for students who will come into contact with infectious materials in the course of their studies. The responsibility for safety in a department or other administrative unit lies with its chairperson or supervisor. However, all individuals must accept responsibility for carrying out their work in a way that protects them and their fellow workers. Respon- sibility for safety must be clearly defined. There should be a biosafety manual that sets forth the following: safety policy, goals, and organization; medical program; laboratory procedures; safety equip- ment; waste disposal methods; and emergency pro- cedures. (See Chapters 4 and 5.) 9. Facilities In order to provide an optimum environment for biohazardous work, facilities must be properly de- signed, constructed, validated, maintained, and used. Plans should be reviewed by the appropriate safety officer before construction begins, and again after 7 the building has been completed but before work with infectious materials begins. Final construction (as-built) drawings should always be available for future reference. (See Chapter 5, Section B.) 10. Medical Program Laboratories should have a medical program that is targeted to the potential risks and hazards of its op- erations. There should be a regular analysis of the collected data. Some employees may be found to have personal health conditions that place them at increased risk when performing certain laboratory functions. In such cases, a careful assessment should be made of the potential for exposure; if the exposure cannot be eliminated or reduced, consideration should be given to changing jobs or tasks. Employees should be informed completely about the potential risks and, to the extent possible, should be involved in the decision-making process. (See Chapter 5, Section D.) 11. Emergencies Every laboratory organization has the responsi- bility to establish a specific emergency plan for its facilities and to be equipped to implement it. The plan should include the laboratory building as well as individual laboratories. For the building, the plan should include evacuation routes, shelter areas, medi- cal treatment, and procedures for reporting accidents and emergencies. It should be reinforced by drills and simulated emergencies, and should include liai- son with local emergency groups as well as commu- nity officials. For individual laboratories, the plan should cover such events as spills, fires, equipment failure, and accidents. (See Chapter 5, Section E.)