# PPE Requirements BSL-2 vs BSL-3: Key Differences The core difference is this: at BSL-2 you wear task-based PPE such as a laboratory coat, gloves, and face protection when a splash or splash-generating procedure is anticipated, while at BSL-3 you wear a defined protective ensemble for every entry, including dedicated solid-front or wrap-around laboratory clothing, double gloves, eye protection, and respiratory protection such as an N95 or higher-class respirator, because the agents handled there are transmitted by the airborne route and can cause serious or lethal infection. The rule of thumb is simple. If the organism can infect you through the air you breathe, the laboratory is engineered and dressed for BSL-3. If the organism is a moderate-hazard agent that spreads mainly by direct contact, inoculation, or splash, and standard microbiological practice plus a biological safety cabinet contain the risk, BSL-2 practice and PPE apply. This article is written for bench staff, laboratory supervisors, and biosafety professionals who need a working answer to the question of PPE requirements BSL-2 vs BSL-3, not a restatement of the risk group tables. It walks through what each level demands, then compares the two on the criteria that actually decide which ensemble you put on, gives worked scenarios from real bench situations, and closes with the mistakes that show up most often in inspections and competency assessments. ## What BSL-2 and BSL-3 Actually Mean for the Person at the Bench [Biosafety levels](/knowledge/diagnostics/emerging-tech/biosafety-levels-1-4-a-decision-framework-for-diagnostic-laboratories), abbreviated BSL, are graduated sets of containment practices, facility features, and protective equipment defined in the CDC and NIH reference document Biosafety in Microbiological and Biomedical Laboratories, commonly called the BMBL. The levels run from BSL-1 for well-characterized agents not known to consistently cause disease in healthy adults, up to BSL-4 for dangerous and exotic agents. Most clinical and teaching microbiology operates at BSL-2. Work with agents such as Mycobacterium tuberculosis, certain arboviruses, SARS-CoV-2 culture, and other organisms with genuine aerosol infectivity moves into BSL-3. The distinction that drives PPE is route of exposure. A BSL-2 agent typically causes disease through ingestion, mucosal splash, percutaneous inoculation, or, for some agents, limited droplet exposure. PPE therefore concentrates on your hands, your mucous membranes, and your street clothing. A BSL-3 agent produces disease through inhalation of infectious aerosols. Aerosols are small enough to bypass a surgical mask and to linger in room air, so the PPE program extends to the respiratory tract and, in many programs, to full coverage of skin and hair. Two supporting concepts keep the PPE discussion honest. The first is the biosafety risk assessment, the documented process of identifying the agent, its route of transmission, the procedures that generate aerosols or splashes, the volume and concentration handled, and the competence of the staff, then selecting containment and PPE to match. The BMBL treats the risk assessment as the foundation of every biosafety decision, and the difference between PPE requirements BSL-2 and BSL-3 is really the output of that assessment applied to two different hazard profiles. The second concept is task-based versus entry-based PPE. At BSL-2, PPE selection is task-based, meaning the risk assessment of a specific procedure decides whether you add a face shield or a fluid-resistant gown. At BSL-3, PPE is entry-based, meaning the full ensemble is required for the room itself, regardless of how brief or mundane the planned task appears. A third distinction matters for staffing decisions. BSL-3 work requires personnel to demonstrate documented competency before unsupervised access, and entry is restricted to people listed on the laboratory roster. BSL-2 laboratories still control access, but the expectation is supervision of trained personnel rather than formal clearance. This is where microbiology biosafety training becomes the practical gate. A technologist who has completed general biosafety orientation and BSL-2 competency is not automatically qualified for BSL-3 entry. The respiratory protection program, fit testing, and agent-specific training must be complete first. ## PPE Requirements BSL-2 vs BSL-3: Side-by-Side Comparison The table below is the core of the comparison. It reflects the standard requirements as written in the BMBL and adopted by institutional biosafety programs across clinical, research, and teaching laboratories. | Element | BSL-2 | BSL-3 | |--|--|--| | Baseline agents | Moderate-hazard agents associated with human disease, percutaneous or mucosal exposure routes | Indigenous or exotic agents with potential for aerosol transmission and serious or lethal disease | | Laboratory coat or gown | Laboratory coat, fluid-resistant gown, or apron worn over street clothes, removed before leaving the laboratory | Dedicated solid-front or wrap-around gown, scrub suit, or coverall worn for all room entry, removed in the anteroom or at the exit boundary | | Street clothing protection | Coat or gown over street clothing is acceptable | Street clothing is not worn under BSL-3 laboratory clothing in most programs, dedicated uniforms laundered by the facility are standard | | Gloves | One pair of gloves when handling agents, contaminated surfaces, or equipment, changed when torn or contaminated | Two pairs are common practice, outer gloves changed on exiting the room or between tasks, inner gloves remain for the session | | Eye and face protection | Required when a splash or spray is anticipated, safety glasses, goggles, or a face shield over the mask | Eye and face protection required for all work with agents or infected material inside the room, not only when a splash is anticipated | | Respiratory protection | Not required at the room level, surgical or procedure masks may be used for source control or splash reduction | Respiratory protection such as an N95 filtering facepiece respirator or powered air-purifying respirator is required by most programs, fit testing is mandatory | | Footwear | Closed-toe, low-heeled shoes, dedicated or covered when wet procedures are planned | Closed-toe shoes or dedicated footwear, shoe covers or dedicated BSL-3 shoes when specified by the local risk assessment | | Head and body coverage | Standard coat coverage, hair restrained | Many programs require full coverage of skin and hair, surgical hoods or bouffant caps when aerosol-generating tasks are planned | | Where PPE is donned | Inside the laboratory at the entry, or at the bench for task-based items | In the anteroom before crossing into the laboratory space, following a written donning sequence | | Where PPE is removed | Coat removed at the door, gloves removed inside and hand hygiene performed before exit | Removal in a defined sequence inside the laboratory or in the anteroom, hand hygiene at each step, outer gloves and gowns treated as contaminated | | Biological safety cabinet | Required for aerosol-generating or splashing procedures with the agent | Required for all open manipulation of the agent, Class II cabinets are standard, respirator use does not substitute for cabinet containment | | Access control | Restricted while work is in progress, doors remain closed | Controlled, lockable access, entry limited to rostered trained personnel, a log of entries and exits is expected | | Facility features that shape PPE | Directional airflow not required, standard laboratory ventilation | Negative pressure relative to adjacent spaces, inward directional airflow, exhausted air not recirculated to other spaces, which supports PPE removal in a clean anteroom | | Symbol and signage | Universal biohazard sign at the entrance listing the agent and contact information | Biohazard sign plus entry requirements, PPE requirements posted at the door, and emergency contact details for all personnel including after-hours numbers | Reading the table from top to bottom, the pattern is clear. BSL-2 PPE protects against discrete events, a splash here, a needlestick there. BSL-3 PPE assumes that the room air itself is a hazard, so protection is continuous, layered, and tied to a one-way flow of personnel and material from clean to dirty and back. ## BSL-2 PPE in Detail ### The baseline ensemble BSL-2 practice begins with the assumption that any work involving human-source material or a Risk Group 2 agent carries the possibility of percutaneous or mucosal exposure. The standard ensemble is a buttoned laboratory coat or fluid-resistant gown, a pair of disposable gloves, and safety glasses with side shields or goggles. This baseline is worn whenever infectious material is present in the room, not only when you are actively handling it. Coats stay buttoned. Gloves are changed when torn, when contaminated, when you touch a keyboard or phone, and always before touching clean surfaces such as a door handle or an elevator button. Gloves deserve a specific note. Disposable nitrile gloves are the default because they resist a wide range of chemicals used on the microbiology bench and tolerate frequent changes better than latex. Double gloving is not a BSL-2 requirement, but many programs adopt it for spill cleanup or for work with high-concentration cultures because a breached outer glove then reveals a protected inner layer rather than bare skin. ### Task-based additions under the biosafety risk assessment The difference between PPE requirements BSL-2 and BSL-3 becomes most visible in the middle layer of BSL-2 practice, where the risk assessment of a specific task adds protection. Grinding tissue, vortexing unfixed cultures, homogenizing sputum, using a blender or bead mill, or performing any procedure with a genuine splash potential triggers the addition of a full face shield over a surgical mask, or a fluid-resistant gown over the coat. Work at an open bench with a Risk Group 2 agent should not happen at all. Anything likely to create an aerosol goes inside a certified Class II biological safety cabinet, which is a ventilated enclosure with HEPA-filtered laminar airflow that protects the operator, the product, and the environment. A mouth pipette is prohibited at every level. Pipetting aids, splash guards on centrifuges, and sealed rotors are standard engineering controls that reduce the PPE burden, and using them is part of competency, not an optional refinement. ### When to use PPE requirements BSL-2 When to use PPE requirements BSL-2 is a question with a short operational answer. Use the BSL-2 ensemble whenever the laboratory handles agents classified as Risk Group 2, and whenever the laboratory handles any human clinical specimen, blood, body fluid, or tissue, because those materials are handled under universal precautions regardless of the confirmed organism. Routine bacteriology on plated isolates, biochemical identification work, blood culture bottle sampling, urinalysis on unspun specimens, staining of smears, and setup of molecular extractions from clinical material all fall in this range. The teaching laboratory is a special case of BSL-2. Instructional microbiology labs are restricted spaces, not public areas, and entry requires closed-toed shoes and personal protective equipment, a point made explicit in the published literature on laboratory access policy after a case in which a service animal in training forced a reexamination of who may enter the room and under what conditions [1]. That case is a useful reminder for biosafety risk assessment, because nonstandard entrants, visitors, custodial staff, and equipment technicians all need an assessment before they cross the door, and the PPE that protects a trained technologist does not protect an untrained guest who cannot be relied on to keep gloves on or to avoid touching the bench. ### What BSL-2 PPE does not cover A laboratory coat and gloves do not protect the respiratory tract against an infectious aerosol. That is the boundary of BSL-2. If an agent in your laboratory has plausible aerosol infectivity at the concentrations handled, for example concentrated preparations of M. tuberculosis or aerosol challenge material, the work belongs in BSL-3 containment regardless of how routine the procedure looks. Concentration matters as much as the agent name, which is why the risk assessment is documented per procedure and not per species alone. ## BSL-3 PPE in Detail ### The entry-based ensemble BSL-3 PPE is defined before you reach the door. Most programs specify a dedicated scrub suit or disposable coverall, a fluid-resistant solid-front or wrap-around gown or coverall over it, two pairs of gloves, eye protection such as goggles or a full face shield, closed dedicated footwear or shoe covers, and head cover when hair coverage is required. Street clothes do not enter the laboratory space in most institutions. The BMBL language is that laboratory clothing protects street clothing from contamination, and that front-buttoned coats are unsuitable at BSL-3 because a wrap-front design closes the barrier across the torso. The reason for full coverage is aerosol deposition and secondary transfer. Particles settling on hair, exposed forearms, or uncovered skin can be carried out of the containment boundary and transferred to the face during doffing. Covering skin and hair reduces the surface area available for that transfer and simplifies decontamination. ### Respiratory protection Respiratory protection is the defining PPE difference at BSL-3. Most institutional programs require at minimum a fit-tested N95 filtering facepiece respirator for all entries, and many upgrade to a powered air-purifying respirator, abbreviated PAPR, for procedures with high aerosol potential, for staff who cannot achieve a seal with a disposable respirator because of facial hair or facial anatomy, or for extended procedures where a PAPR is more tolerable. Fit testing is the procedure that verifies a tight-fitting respirator seals against the wearer's face, using either a qualitative agent such as saccharin or Bitrex aerosol or a quantitative particle-counting method. It is repeated at the interval set by the institutional respiratory protection program and after any change in facial structure, weight change, or respirator model. A common question is whether the respirator substitutes for the biological safety cabinet. It does not. Primary containment at BSL-3 is a layered system. The cabinet holds the aerosol at the source, the room airflow removes what escapes the cabinet, and the respirator protects the breathing zone of the person. Remove one layer and the others carry more load. The BMBL treats respiratory protection as an adjunct to, never a replacement for, primary containment. ### Entry, exit, and the one-way flow BSL-3 PPE functions only inside a controlled sequence. Entry follows a written donning order, typically hand hygiene, inner gloves, dedicated scrubs or coverall, respirator checked with a seal check, gown, eye protection, outer gloves, then crossing into the laboratory. Exit reverses the order with hand hygiene between steps, and it happens inside the laboratory or the anteroom so that contaminated outer layers never cross the clean boundary. Some programs add a chemical shower on exit, some add an airlock dwell time, and specifics vary by institution and by agent. The nonnegotiable principle is that the sequence is written, posted, and practiced until it is automatic. Autonomy matters under stress. A staff member responding to a centrifuge failure, a spill outside the cabinet, or a suit breach is executing a doffing sequence while cognitively loaded. Written sequences posted in the anteroom, with a trained buddy available for doffing assistance, are the standard mitigation and are part of what competency training verifies. ### Facility features that support the PPE program The BSL-3 room itself carries several engineering requirements that shape how PPE works. The room is held at negative pressure relative to adjacent spaces with inward directional airflow, and exhaust air is not recirculated to other parts of the building. Access is controlled and lockable. Windows are sealed. These features mean that the anteroom can function as a genuine gowning and degowning boundary, which is what makes entry-based PPE practical. A BSL-2 laboratory with no anteroom cannot support BSL-3-style doffing logistics, which is one more reason the two levels cannot simply swap PPE lists. ## The Criteria That Decide Real Choices ![Decision path asking about aerosol route, concentration and procedure, leading to a BSL-2 or BSL-3 ensemble choice.](/article-images/illustrations/ppe-requirements-bsl-2-vs-bsl-3-bsl-level-triage.webp) When a supervisor asks whether PPE requirements BSL-2 or BSL-3 apply to a given task, five criteria decide it. First, route of transmission. If inhalation of an aerosol is a credible route of infection for the agent at the concentration handled, containment moves to BSL-3 and respiratory protection follows. This is why diagnostic work on sputum for AFB (acid-fast bacilli, the smear and culture workflow for mycobacteria) is performed in BSL-3 laboratories or in BSL-2 laboratories with BSL-3 practices and respiratory protection for aerosol-generating steps, a hybrid arrangement the BMBL permits when the facility cannot support full BSL-3. Second, dose and concentration. The same organism can sit at BSL-2 in a diagnostic aliquot and require BSL-3 practices when concentrated, purified, or grown to high titer for research. Dilution and fixation change the risk assessment. Formalin-fixed, paraffin-embedded tissue is handled under far lighter precautions than fresh infected tissue from the same animal or patient. Third, procedure. Open manipulation, sonication, homogenization, centrifugation without sealed rotors, and animal work generate aerosols. Closed-system extraction, sealed centrifugation, and fully contained automated analyzers do not. The risk assessment scores the procedure, not just the agent. Fourth, staff competency. Respiratory protection is only as effective as the seal and the discipline of the wearer. A program that cannot deliver fit testing, seal checks, and doffing practice is not ready to run BSL-3 work, and the biosafety risk assessment should treat that gap as a containment failure before it becomes an exposure. Fifth, supply resilience. The pandemic exposed this criterion at scale. A survey of diagnostic laboratories registered with the Indian microbiology external quality assessment scheme, EQAS, documented that laboratory professionals reported reusing N95 respirators during the COVID-19 response and traced the strain on infection control practice to surging demand and supply gaps [2]. Reuse of filtering facepiece respirators, extended wear, and crisis-capacity strategies are recognized contingencies, but they degrade the protection margin that BSL-3 PPE is designed to provide, and a program planning BSL-3 work must plan respirator supply as part of the containment budget, not as an afterthought. ## Worked Scenarios ### Scenario 1, routine blood culture workup A [clinical microbiology](/knowledge/diagnostics/microbiology/clinical-microbiology-from-specimen-collection-to-pathogen-identification) technologist samples positive blood culture bottles for Gram stain and subculture. The agent is unknown, the specimen is human source, and the bottle can be handled with closed manipulation. Biosafety risk assessment classification is BSL-2 with universal precautions. PPE is a buttoned laboratory coat, nitrile gloves, and safety glasses with side shields. A needle is used to sample the bottle, so sharps discipline and a sharps container at the bench carry most of the actual injury risk. If the technologist cracks open a bottle or handles a leaking one, a face shield and fluid-resistant gown are added. No respirator is required. ### Scenario 2, AFB smear and culture The same laboratory receives sputum for mycobacterial examination. Smear preparation can be performed at BSL-2 using a biosafety cabinet and drop-and-cover technique, where the smear is covered with fixative before it moves. Culture setup, plate growth manipulation, and any grinding or concentration step generate aerosols of M. tuberculosis and require BSL-3 containment, or BSL-2 with BSL-3 practices including respirator use where an approved hybrid arrangement exists. The PPE difference in practice is concrete. The technologist now dons a fit-tested N95, a wrap-front gown or coverall, double gloves, and full eye protection before opening the culture, and doffs through a defined sequence afterward. The difference between PPE requirements BSL-2 and BSL-3 in this one laboratory is not a philosophical debate, it is a change of ensemble between two benches on the same morning. ### Scenario 3, diagnostic molecular testing during an outbreak A laboratory scales up molecular testing during a respiratory outbreak. Sample inactivation, extraction, and amplification for diagnostic purposes are generally BSL-2 work because diagnostic protocols use chemically inactivated specimens, and this is the context in which most of the 721 laboratories in the EQAS survey expanded RT-PCR capacity during the COVID-19 response, with the majority gaining accreditation and participating in external quality assessment during that period [2]. The PPE lesson from that period is less about the BSL number and more about the practical integrity of the ensemble. A companion survey of PPE manufacturing and certification during the same pandemic found that regulatory specifications focused on synthetic blood penetration testing, abbreviated SBPT, which tests whether fabric blocks pressurized synthetic blood, while remaining silent on air permeability and water vapor transmission rate, so garments certified for barrier performance could still be almost unwearable, with extremely poor breathability that discouraged correct and consistent use [3]. For the BSL-3 worker, that finding translates directly. A gown that meets the barrier test but fails the comfort test gets worn wrong, worn loose, or removed early, and each of those outcomes erodes protection. End-user trials in which staff wear the garment through real tasks before the institution commits to a purchase are the practical response. ### Scenario 4, the teaching laboratory A general microbiology course handles Risk Group 1 and 2 organisms, environmental isolates, and stains. The level is BSL-2, and the PPE program is deliberately simple so that students can learn it reliably, closed-toed shoes, laboratory coats, safety glasses, and gloves, with specific rules about eating, drinking, applying cosmetics, and personal item storage. The published discussion of a guide dog in training brought into a microbiology teaching lab concluded that such laboratories are restricted spaces requiring closed-toed shoes and PPE, and that animals not fully trained for the environment cannot be admitted because they endanger both the animal and the students [1]. For a biosafety officer, the transferable point is that PPE requirements are part of a broader access policy, and access policy belongs in the written risk assessment. ## Donning, Doffing, and the Comfort Factor ![Five-step exit sequence from outer gloves to hand hygiene, with hand hygiene between steps inside the laboratory or anteroom.](/article-images/illustrations/ppe-requirements-bsl-2-vs-bsl-3-bsl3-doffing-order.webp) Donning and doffing errors cause more contamination events than donning and doffing design would predict, which is why both levels require written sequences and supervised competency verification. The general order moves from cleanest to most contaminated layers on the way in, and from most contaminated to cleanest on the way out, with hand hygiene at defined points. At BSL-3, the sequence typically runs, hand hygiene, inner gloves, dedicated clothing, respirator with a user seal check, gown or coverall, eye or face protection, outer gloves. On exit, outer gloves are removed first and decontaminated or discarded, eye protection next, gown next, respirator last while still protected by inner gloves, then hand hygiene again. Gloved hands never touch the front of the respirator during removal. Two practical evidence points shape how programs buy and train with this equipment. The first is the certification gap described above, where barrier testing without breathability testing produced gowns that failed in the field on comfort, and where the proposed remedy was proactive involvement of end users in comfort testing and field trials across real clinical settings before certification [3]. The second is the reuse pressure seen during the pandemic response, where 41.4 percent of laboratory professionals in the EQAS survey reported reusing N95 respirators, a figure that documents how quickly supply constraints convert a theoretical no-reuse rule into routine practice [2]. Programs that plan for respirator supply, stock rotation, and extended-use guidance in advance avoid being forced into crisis decisions during an actual event. ## Training and Competency Microbiology biosafety training is the mechanism that turns PPE requirements from a posted list into reliable behavior. A complete program for BSL-2 includes general biosafety orientation, agent-specific training, hands-on demonstration of cabinet technique and spill response, and periodic competency assessment. For BSL-3, the program adds respiratory protection training, fit testing, donning and doffing drills with observation and feedback, buddy-system doffing practice, emergency procedures for suit breach and medical events inside containment, and documented sign-off before independent work. The pandemic experience documented in the EQAS survey included substantial investment in laboratory capacity building and infection control practice changes, and the lesson reported across participating laboratories was that infrastructure upgrades and credentialing, such as accreditation steps and external quality assessment participation, had to proceed together with staff training for either to hold under load [2]. Competency is perishable. Programs that retrain on a fixed schedule, observe donning and doffing at least annually, and use drills rather than sign-and-file quizzes detect the drift that otherwise accumulates between inspections. ## Common Mistakes and Limitations The most frequent errors in applying PPE requirements BSL-2 vs BSL-3 are operational, and each has a direct fix. Wearing the BSL-2 ensemble into a BSL-3 task. The classic example is smear setup for AFB performed without respiratory protection because the laboratory "is a BSL-2 lab." Level is a property of the procedure and the agent at the concentration handled, not a property of the room number on the sign. If the risk assessment assigns BSL-3 practices to a task, the BSL-3 ensemble goes on. Treating the respirator as cabinet insurance. Staff sometimes believe a fit-tested N95 lets them work more casually at the open bench. At BSL-3, open manipulation of the agent occurs only inside the cabinet, and respirator discipline does not change that rule. Doffing by feel. Removing a gown or respirator by grabbing the front surface with contaminated gloves transfers agent to the hands and face. Buddy doffing and mirror-assisted self-doffing in the anteroom reduce this error, and observation during competency checks catches it. Assuming certified barrier equals wearable. The certification experience during COVID-19 showed that gowns meeting synthetic blood penetration standards could have extremely poor air permeability, so comfort testing and end-user trials belong in the procurement process, not after it [3]. Ignoring the comfort and fit feedback loop. A respirator that fails a seal check on one face shape, or a coverall that restricts fine pipetting movements, gets modified by the wearer in ways that void protection. Reporting discomfort and fit problems is part of the job, not a complaint, and program leads should treat the first report as data. Skipping the risk assessment for visitors and support staff. Custodial staff, equipment service engineers, and students carry no muscle memory for laboratory PPE. The teaching laboratory literature makes the point that a restricted space with PPE requirements cannot admit untrained entrants or uncontained animals without a documented assessment [1]. One limitation belongs in plain language. Published BSL requirements define minimums and framework, and every institution adapts them through its own biosafety committee, written [biosafety manual](/knowledge/diagnostics/emerging-tech/biosafety-manual-development-a-template-for-diagnostic-laboratories), and local risk assessments, so the specific ensemble at your bench may be stricter than the general description here. Individual exposure concerns, symptom questions, and prophylaxis decisions need an occupational health clinician, and this article does not replace that evaluation. ## Frequently Asked Questions ### Can I wear BSL-3 level PPE while working in a BSL-2 laboratory? Yes, nothing prohibits wearing more protection than the level requires, and task-based upgrades such as double gloves, a fluid-resistant gown, or a face shield are exactly how the BSL-2 risk assessment works. The reverse is never true, BSL-2 PPE is not acceptable for a task or room assigned BSL-3 practices. ### Do all BSL-3 entries require a respirator? Most institutional BSL-3 programs require a fit-tested N95 or higher-class respirator for every entry, and a PAPR for high-aerosol procedures or for wearers who cannot achieve a seal. Because respiratory protection requirements are set by the institutional program and the agent-specific risk assessment, confirm your own facility's written policy, and treat fit testing as a prerequisite to any BSL-3 access. ### Is double gloving required at BSL-3? Double gloves are common practice at BSL-3 and are required by many institutional programs, because the outer pair absorbs contamination and is removed at the exit boundary while the inner pair protects during doffing. At BSL-2, a single pair of gloves is the standard baseline, with double gloving added for spills or high-concentration handling. ### How often do I need fit testing for respirator use in a BSL-3 laboratory? Fit testing is repeated on the schedule set by your institution's respiratory protection program, commonly annually, and is always repeated after a change in respirator model, a significant change in facial structure or weight, or any observed seal failure. A user seal check is performed by the wearer at every donning, which is separate from and does not replace fit testing. ### Does a biological safety cabinet make respiratory protection unnecessary at BSL-3? No. The cabinet, the room airflow, and the respirator are three layers of containment, and removing one increases the load on the others. All open manipulation of BSL-3 agents happens in the cabinet, and the respirator remains part of the required ensemble. ### What training is required before someone can work at BSL-3? A written program typically requires general biosafety orientation, agent-specific training, cabinet competency, respiratory protection training with current fit testing, observed donning and doffing drills, emergency procedure training, and documented supervisor sign-off before unsupervised entry. Completion of BSL-2 competency alone does not qualify a technologist for BSL-3 access. ## Sources 1. [Who Let the Dogs Out? A Plea for Official Guidelines on Service Animals in the Teaching Laboratory.](https://pubmed.ncbi.nlm.nih.gov/31768207/) 2. [Indian microbiology EQAS registered laboratory's capacity building and infection control practices during the COVID-19 pandemic in India: Lessons learnt and gaps identified.](https://pubmed.ncbi.nlm.nih.gov/36266150/) 3. [Breathability and Safety Testing of Personal Protective Equipment: "Human-comfort" Factor Remains Undefined.](https://pubmed.ncbi.nlm.nih.gov/33603295/)