Laboratory Safety-2 PDF

Chapter 3 Laboratory Safety 2 Clinical laboratories should try to utilize engineering controls such as containment devices as best possible if infectious hazards cannot be eliminated or substituted. Pathogenic organisms are classified according to their associated risk group and designated as ei...

Chapter 3 Laboratory Safety 2 Clinical laboratories should try to utilize engineering controls such as containment devices as best possible if infectious hazards cannot be eliminated or substituted. Pathogenic organisms are classified according to their associated risk group and designated as either Risk Group 1, 2, 3, or 4, with Risk Group 4 being the highest risk. It is important to know the risk group(s) of the organism(s) that may be present to properly evaluate the exposure risks (e.g., if the organism is transmissible by the inhalation route, etc.). ABSA International, the American Biological Safety Association, provides a free and searchable database for pathogenic organisms that can be consulted when conducting their own laboratory and task-specific risk assessments for the organisms they may handle. Determining what risk group level(s) the organisms that may be handled in a laboratory will help determine the proper laboratory biosafety level, features, and safety practices used. Laboratory design and associated safety practices are classified as ‘Biological Safety Levels’ (or Biosafety Levels) (BSL) and are designated as BSL-1 through BSL-4, with BSL-4 being the highest level of containment. Most clinical laboratories operate at a BSL-2 level, and a relatively smaller number will have a fully functional BSL-3 laboratory space. BSL-3 labs will commonly conduct higher-risk work such as handling cultures of Mycobacterium tuberculosis, mycology samples, or routine work with Risk Group 3 or 4 organisms. (Note: Most clinical laboratories will never work with a Risk Group 4 pathogen. Risk Group 4 pathogens are typically handled only in specialized high containment reference or research laboratories.) 3-1. Risk Groups and Biosafety Levels Risk Group 1 (no or low individual and community risk) 38 | P a g e A microorganism that is unlikely to cause human or animal disease. Risk Group 2 (moderate individual risk, low community risk) A pathogen that can cause human or animal disease but is unlikely to be a serious hazard to laboratory workers, the community, livestock or the environment. Laboratory exposures may cause serious infection, but effective treatment and preventive measures are available and the risk of spread of infection is limited. Risk Group 3 (high individual risk, low community risk) A pathogen that usually causes serious human or animal disease but does not ordinarily spread from one infected individual to another. Effective treatment and preventive measures are available. Risk Group 4 (high individual and community risk) A pathogen that usually causes serious human or animal disease and that can be readily transmitted from one individual to another, directly or indirectly. Effective treatment and preventive measures are not usually available. Countries (regions) should draw up a national (regional) classification of microorganisms, by risk group, taking into account: 1. Pathogenicity of the organism. 2. Mode of transmission and host range of the organism. These may be influenced by existing levels of immunity in the local population, density and movement of the host population, presence of appropriate vectors, and standards of environmental hygiene. 3. Local availability of effective preventive measures. These may include: prophylaxis by immunization or administration of antisera (passive immunization); sanitary measures, e.g. food and water hygiene; control of animal reservoirs or arthropod vectors. 4. Local availability of effective treatment. This includes passive immunization, post exposure vaccination and use of antimicrobials, antivirals and chemotherapeutic agents, and should take into consideration the possibility of the emergence of drug-resistant strains. Biosafety Levels Laboratory facilities are designated as basic – Biosafety Level 1; basic – Biosafety Level 2; containment – Biosafety Level 3; and maximum containment – Biosafety Level 4. Biosafety level designations are based on a composite of the design features, construction, containment facilities, equipment, practices and operational procedures required for working with agents from the various risk groups. Table relates but does not “equate” risk groups to the biosafety level of laboratories designed to work with organisms in each risk group. 39 | P a g e Typically, most routine specimens in a clinical laboratory can safely be handled in a BSL-2 lab following standard precautions with standard BSL-2 PPE. However, there may be some specimens and associated work that may require additional precautions or safety practices. Examples of common BSL-2 level specimens and work in clinical labs:  Stool culture and testing for enteric pathogens like Salmonella  Setup and interpret urine cultures  Blood chemistry testing  Antibiotic sensitivity testing  Streptococcus testing Examples of less common higher risk specimens and work in clinical labs that may require additional PPE or other safety considerations:  Suspected Neisseria meningitidis testing  Mycobacterium tuberculosis culture work  Respiratory and wound aspirate specimens for culture  Subculture positive blood cultures  Known aerosol generating procedures PPE commonly worn in a typical BSL-2 clinical lab setting following standard precautions and lab safety practices, include:  Lab coat  Gloves (nitrile)  Safety glasses and/or face shields (at times)  Respiratory protection (at times) Based on a risk assessment, when there may be additional or special circumstance hazards present in the lab, enhanced precautions, otherwise commonly known as “BSL-3 practices,” may be necessary to implement in a BSL-2 setting. Additional PPE that may be commonly worn in a “BSL-2 enhanced” setting following enhanced precautions and lab safety practices can include the use of:  Solid front gown  Double gloves (nitrile)  Disposable shoe covers  Respiratory protection (e.g., N95, PAPR) According to the CDC/NIOSH Hierarchy of Safety Controls: 40 | P a g e   PPE should be considered the “last line of defense” against potential exposures and other workplace hazards.  PPE does not reduce or eliminate the hazard(s) that may be present.  PPE is not a substitute for engineering controls and prudent work practices, and PPE should be used in conjunction with other controls to ensure safety when possible. There are several types and manufacturers of PPE that labs can appropriately select from based on their identified work hazards. PPE will vary based on a laboratory-specific and activity or procedure-specific risk assessments. Sometimes, a lab needs to use enhanced precautions or add PPE based on a risk assessment. Examples of which can include:  When infectious aerosols or droplets may be generated.  When working with a higher risk or higher volume pathogen(s).  When there is a lack of or limited use of containment or engineering controls (e.g., no biological safety cabinet available). There may be times when the Laboratory Director or Safety Officer determines that enhanced precautions or ‘BSL-3 practices’ (e.g., use of double gloves, solid front gown, or respiratory protection) are needed based on a risk assessment, such as:  When working with organisms that may be transmitted by the inhalation route and are normally handled at BSL-3, but a BSL-3 laboratory is not readily available.  When certain higher-risk organisms are suspected, such as Brucella spp., Coccidioides spp., Blastomyces dermatitidis, Francisella tularensis, Histoplasma capsulatum, Mycobacterium tuberculosis, MERS-CoV, SARS, highly pathogenic influenza, etc. Risk Biosafety Laboratory Laboratory Safety Equipment Group Level Type Practices Basic Basic None, open bench 1 Biosafety Teaching GMT work Level 1 Research Primary health GMT plus Basic services, protective Open bench plus BSC 2 Biosafety diagnostic clothing, for potential aerosols Level 2 services biohazard sign research Special As Level 2 plus Containment BSC and/or other diagnostic special clothing, 3 Biosafety primary devices for all services, controlled Level 3 activities research access, 41 | P a g e  directional airflow Class III BSC, or positive As Level 3 plus Maximum pressure suits in Dangerous airlock entry, containment conjunction with Class 4 pathogen shower exit, Biosafety II BSC double-ended units special waste Level 4 autoclave (through the disposal wall), filtered air 3-2. PPE (Personnel Protection Equipment) Selection of PPE The first step in this selection process is to determine the types of hazards that exist in your lab: a lab hazard analysis must be conducted to identify the hazards. Below are some points to consider when doing the hazard analysis: Identify all hazards that may require protection. This should include a list of the chemicals, biological, and radioactive materials involved along with all other potential physical hazards such as abrasion, tearing, puncture, and temperature (cryogenic), light (lasers, welding), noise, and vibration. Nature of potential contact. Will the contact be splash, occasional or continuous immersion? Other types of contact or exposure potential include spray (pressurized or nonpressurized), mist (continuous or intermittent), vapors (gaseous contact) and dust. Contact location is very important. Which part of the body is most likely to get exposed to the hazards? Consider protection to the eyes, face, skin, nose, mouth, body and feet. Consider the type of engineering controls available in the lab (e.g.: fume hood, glove box)? Review SOP, SDS and other hazard information to determine appropriate PPE to wear based 42 | P a g e on chemical hazards encountered. Mandatory Minimum PPE Requirement Protective eye wear Lab coat Closed-toed shoes Chemical resistant gloves (when working with hazardous substances) Eye Protection Eye protection is required (but not limited to): When chemicals, glassware, or a heating source is being used When dust or fumes are present When using preserved specimen When working with solid materials or equipment under stress, pressure, or force that might cause fragmentation or flying particles When an activity generates projectiles, or uses elastic materials under stress (e.g., springs, wires, rubber, glass), or causes collisions There are three basic types of eye and face protection which will meet the majority of University laboratory requirements. These are: safety glasses (with side shields), goggles, and face shields. Safety glasses Safety glasses must have side shields and must be worn whenever there is a possibility of objects striking the eye, such as particles, glass, or metal shards. Many potential eye injuries have been avoided at the University by wearing safety glasses. Safety glasses may not always provide adequate protection from chemical splashes as they do not seal to the face. Safety glasses may be adequate where the potential splash is minimal. Ordinary prescription glasses do not provide adequate protection from injury to the eyes and could even be hazardous to the wearer. Goggles Chemical splash goggles should be worn when there is a high potential for splash from a hazardous material. For example, goggles should be worn when working with glassware under 43 | P a g e reduced or elevated pressure and when glass apparatus is used in combustion or other high temperature operations. Chemical splash goggles shall have indirect ventilation so hazardous substances cannot drain into the eye area. Some can be worn over prescription glasses. Face shields Face shields are in order when working with large volumes of hazardous materials, either for protection from splash to the face or flying particles. Face shields must be used in conjunction with safety glasses or goggles. The following examples where a face shield should be used: 1) where glass apparatus is evacuated, recharged with gas, or pressurized; 2) when pouring corrosive liquids; 3) when using cryogenic fluids; 4) when combustion processes are being carried out; 5) where there is a risk of explosion or implosion; 6) when using chemicals that can cause direct damage to the skin; and 7) when using chemicals and biological agents that can be rapidly absorbed into the body via any path e.g. through the skin, eyes or nose. Prescription spectacles Prescription spectacles (as distinct from prescription eye protectors) are generally inadequate against flying objects or particles and could even be hazardous. For persons requiring eye protection in addition to sight correction, the use of prescription spectacles worn with additional protection, e.g. over glasses, wide vision goggles or clip-ons will be necessary. Contact lenses Contact lenses may be worn in the laboratory, but do not offer any protection from chemical contact. If a contact lens becomes contaminated with a hazardous chemical, rinse the eye(s) using eyewash and remove the lens immediately. Contact lenses that have been contaminated with a chemical must be discarded. Respiratory Protection The Occupational Safety and Health Administration (OSHA) have strict requirements for respirator (e.g., full-face mask or N-95 filter mask) use. Even a simple paper filter mask is 44 | P a g e subject to OSHA rules. These requirements include a medical questionnaire and a respirator fit test for all users. This is necessary because wearing a respirator increases the work of breathing, which may cause health problems for some people. To avoid these problems, it is best to prevent inhalation exposures by using engineering controls, (e.g., increased room ventilation, fume hoods and gloveboxes) rather than respirators. If you must wear respirators, contact the Occupational Health Office of Safety. We will help you conform to OSHA regulations. Lab Coats (Refer to Lab Coat Policy-hyper link) Lab coats: Provide protection of skin and personal clothing from incidental contact Prevent the spread of contamination outside the lab (provided they are not worn outside the lab) Provide a removable barrier in the event of an incident involving a spill or splash of hazardous substances Selection of Lab coats: Lab coats are available in a variety of materials and provide varying degrees of protection. Examples include: splash resistant coats, static free coats, chemical resistant coats, and flame resistant coats. Please make sure that the coat you are selecting provides the type of protection that is appropriate for your needs. The first step in this selection process is to determine the types of hazards that exist in your lab and the reasons for the lab coats. The table below (taken from the Columbia University website) provides information on some typical lab coat materials available, with guidance on use and limitations. There is little or no information provided by manufacturers or distributors about the capability of a lab coat for a combination of hazards. A coat that is “flame resistant”, such as treated cotton, may not be chemical resistant or acid resistant. The term “flame resistant” refers to the characteristic of a fabric that causes it not to burn in air. There are limited criteria for testing lab coat materials with respect to typical lab use scenarios, and some of the information is anecdotal. 3-3. Hand Protection 45 | P a g e Gloves Protective gloves should be worn when handling hazardous materials, chemicals of unknown toxicity, corrosive materials, rough or sharp-edged objects, and very hot or very cold materials. When handling chemicals in a laboratory, disposable latex, vinyl or nitrile examination gloves are usually appropriate for most circumstances. These gloves will offer protection from incidental splashes or contact. When working with chemicals with high acute toxicity, working with corrosives in high concentrations, handling chemicals for extended periods of time, or immersing all or part of a hand into a chemical, the appropriate glove material should be selected, based on chemical compatibility. Never reuse disposable glove. When selecting the appropriate glove, considered the following: Degradation Rating Breakthrough Time Permeation Rate SDS Recommendation Maintenance, Testing and Replacement Always inspect PPE for damage (tears, holes, worn elastic, etc.) and contamination prior to use. All PPE must be: checked for defects on a regular basis, eg. perished tubing, holes in gloves, etc. If an item cannot be properly cleaned or becomes damaged it should be discarded. When in doubt, throw it out. Reusable PPE should be immediately cleaned after each use with the appropriate cleanser (usually soap and water). Disposable items should only be used once and replaced when contaminated. Always assume PPE is contaminated: it is worn to protect against hazardous substances. Remove PPE prior to exiting the lab to help prevent the spread of contamination. Be sure you know the proper methods for putting on, taking off, and fit-checking any PPE worn. 46 | P a g e Storage of PPE Separate from chemicals and other contaminants. Store away from sources of heat. Do not store under heavy objects. Be aware that some equipment may have a limited shelf life. 3-4. Safety Data Sheet ( SDS) The SDS is divided into 16 sections which provide detailed information about the respective chemical: 1. Product and Company Identification 2. Hazards identification 3. Composition / Information on Ingredients 4. First Aid Measures 5. Fire Fighting Measures 6. Accidental Release Measures 7. Handling and Storage 8. Exposure Controls / Personal Protection 9. Physical and Chemical Properties 10. Stability and Reactivity 11. Toxicological Information 12. Ecological Information 13. Disposal Considerations 14. Transport Information 15. Regulatory Information 16. Other Information 47 | P a g e Understanding Manufacturer Labels The original label from the supplier or manufacturer must remain attached to the container. Below is an example of the basic parts of a GHS-Compliant Label that include: 1. Product Identifier - Should match the product identifier on the Safety Data Sheet. 2. Signal Word - Either use "Danger" (severe) or "Warning" (less severe). 3. Hazard Statements - A phrase assigned to a hazard class that describes the nature of the product's hazards. 4. Precautionary Statements - Describes recommended measure to minimize or prevent adverse effects resulting from exposure. 5. Supplier Identification - The name, address and telephone number of the manufacturer or supplier. 6. Pictograms - Graphical symbols intended to convey specific hazard information visually. 48 | P a g e  The most important lab biosafety rules 3-5. Bloodborne Pathogens What are bloodborne pathogens? Bloodborne pathogens are infectious microorganisms in human blood that can cause disease in humans, or Bloodborne pathogens are microorganisms such as viruses or bacteria that are carried in blood and can cause disease in people These pathogens include, but are not limited to, hepatitis B (HBV), hepatitis C (HCV) and human immunodeficiency virus (HIV). Needlesticks and other sharps- related injuries may expose workers to bloodborne pathogens. Workers in many occupations, including first responders, housekeeping personnel in some industries, nurses and other healthcare personnel, all may be at risk for exposure to bloodborne pathogens. What can be done to control exposure to bloodborne pathogens? In order to reduce or eliminate the hazards of occupational exposure to bloodborne pathogens, an employer must implement an exposure control plan for the worksite with details on employee protection measures. The plan must also describe how an employer will use engineering and work practice controls, personal protective clothing and equipment, employee training, medical surveillance, hepatitis B vaccinations, and other provisions as required by OSHA's (Occupational Safety and Health Administration) Bloodborne Pathogens Standard (29 CFR 1910.1030). Engineering controls are the primary means of eliminating or minimizing employee exposure and include the use of safer medical devices, such as needleless devices, shielded needle devices, and plastic capillary tubes. 49 | P a g e You Are at Risk! Healthcare workers come into contact with materials that may contain bloodborne pathogens. Bloodborne pathogens are infectious organisms, usually viruses, that live in human blood and body fluids. The bloodborne pathogens that are most likely to be present in human body fluids and are, therefore, of greatest concern to healthcare workers are:  Hepatitis B virus (HBV)  Hepatitis C virus (HCV)  Human immunodeficiency virus (HIV) Currently, most workers in the United States are unlikely to encounter the Ebola virus or individuals with Ebola Virus Disease (EVD). However, healthcare workers are at greater risk for occupational EVD exposure than workers in most other professions. OSHA’s requirements and recommendations for protecting workers at greater risk for EVD exposure are discussed at the end of this course. Components of the OSHA Bloodborne Pathogens Standard 50 | P a g e  1. Exposure Control Plan 2. Preventive measures o Hepatitis B vaccination o Standard precautions 3. Methods of control o Engineering and work practice controls o Personal protective equipment o Housekeeping o Labeling 4. Accident occurs What to do if an exposure in Standard Precautions The consistent use of standard precautions protects health care workers from exposure to bloodborne pathogens. Standard precaution guidelines state that all blood and body fluids should be handled as if they are infectious and capable of transmitting disease. Standard precautions apply to:  Blood  Body fluids  Secretions (except sweat*)  Excretions  Non-intact skin  Mucous membranes *Note that sweat is listed among the body fluids that can transmit the Ebola virus. 3-6. Methods of Control If you follow this hierarchy of controls presented to the right, you will minimize the risk of infection from exposure to bloodborne pathogens and other potentially infectious materials. The next few pages will acquaint you with these ways to keep yourself safe. 51 | P a g e Engineering Controls Engineering controls are devices that isolate the worker from the hazard of exposure. Examples include:  Self-sheathing needles (top right)  Sharps disposal containers (middle right)  Disposable resuscitation bags (bottom right)  Biological safety cabinets  Hand washing facilities  Splash shields Proper use of engineering controls in your workplace will help protect you from bloodborne pathogens. Work Practice Controls Work practice controls specify how to perform a task. Wherever there is a risk of exposure to bloodborne pathogens or other potentially infectious materials (OPIM), these restrictions apply:  No smoking  No eating or drinking  No applying cosmetics or lip balm 52 | P a g e   No handling contact lenses  Food and beverages cannot be kept in refrigerators, freezers, shelves, cabinets, or countertops where blood or OPIM are present.  No mouth pipetting Sharps A sharp is any object that can penetrate the skin. Examples include:  Needles  Scalpels  Broken glass It is important to handle and dispose of sharps properly to prevent injury and potential infection. Needles, Safety Needles, and Needleless Systems Most hospitals use some form of needle/holder combination that incorporates a needle safety device. This device has a mechanism that will cover the needle after use. It must be activated as soon as the task is completed. The device that is pictured here is just one of many options that are currently available. There are also needleless systems that use special adapters that can be attached to some intravenous lines and will permit blood to be obtained without the use of needles. Sharps Safety Summary DO... place all needles and other sharps in puncture-resistant sharps disposal containers as soon as possible after use. use extreme caution or a safety device when removing a scalpel blade from its handle. DO NOT... recap, bend, shear, or break needles. 53 | P a g e remove needles from needle holders or disposable syringes. fill sharps containers above the line on the sharps container that indicates maximum fill (no more than 3/4 full). 3-7. Exposure Incident Even after taking all the proper precautions, there is still a small chance of an exposure incident. An Exposure incident occurs when: Blood or another potentially infectious body fluid comes into direct contact with mucous membranes or non-intact skin. Parenteral exposure means: Exposure occurring as a result of piercing the skin barrier through needlesticks, cuts, or abrasions. If an Exposure Occurs If an exposure occurs, wash the affected area immediately with soap and water. Contact your supervisor immediately, regardless of the situation or the time of day. Your supervisor will refer you for an immediate evaluation and any necessary treatment. Confidentiality will be maintained and your blood will be tested only with your consent. Avoiding Exposure Using safe work practices will help prevent infection caused by exposure to bloodborne pathogens.  Always think about how to perform each task in a way that minimizes your risk.  Ensure that you are using the proper engineering controls and PPE for the task.  Ask your supervisor if you are unsure how to accomplish the task safely. 54 | P a g e