How to Use a Biological Safety Cabinet: 5 Step Guide

In laboratories where safety is non-negotiable, a Laboratory Biosafety Cabinet (BSC) becomes an essential piece of equipment. Whether you’re working with infectious agents, cell cultures, or hazardous substances, knowing how to properly operate a biosafety cabinet is critical—not just for your safety, but for the protection of your colleagues and the integrity of your work.

This article will walk you through a 5-step practical guide on how to use a biological safety cabinet, infused with useful tips, best practices, and the “why” behind every action. Whether you're a student stepping into your first lab or a seasoned researcher looking to brush up, this guide will help you confidently handle your BSC.

What is a Laboratory Biosafety Cabinet?

A Laboratory Biosafety Cabinet (BSC) is more than just a piece of scientific equipment—it’s a critical safety barrier designed to protect lab personnel, samples, and the surrounding environment from biological hazards. If you’re handling infectious materials, cell cultures, or genetically modified organisms, the BSC is your frontline defense.

So, what exactly does it do?

A BSC is a ventilated enclosure that maintains a sterile work zone using high-efficiency particulate air (HEPA) filtration. These filters remove 99.97% of airborne particles, including bacteria, viruses, and fungal spores. Unlike a chemical fume hood, which protects only the user by venting fumes outside the building, a biosafety cabinet also protects your samples and the environment around you. It's a three-way shield—you, your work, and the world beyond.

There are three main types:

1. Class I BSCs protect the user and environment, but not the product.
2. Class II BSCs (most common in biomedical labs) offer protection for the user, product, and environment.
3. Class III BSCs are gas-tight enclosures used for working with the highest-risk pathogens (like Ebola or SARS-CoV-2).

Airflow is everything in a BSC. Inside, air is drawn through the front grille, filtered through HEPA filters, and recirculated or exhausted—depending on the cabinet type. This laminar airflow ensures contaminants stay out while your materials stay clean.

But even the best cabinet can’t do its job alone. It needs you—the user—to understand its function and treat it with respect. Misuse or neglect can instantly compromise its effectiveness, leaving both you and your research vulnerable.

Think of the Laboratory Biosafety Cabinet not just as equipment, but as a silent partner in your scientific journey. It’s always working to protect you—as long as you use it correctly.

Why Is It So Important to Use It Correctly?

Let’s be honest—a Laboratory Biosafety Cabinet can only protect you if you know how to use it properly. Far too often, safety gets taken for granted in busy labs, but when working with infectious agents or hazardous biological materials, there’s zero room for error.

Using a biosafety cabinet the right way isn’t just about protocol—it’s about personal responsibility and public safety.

Here’s why it matters so much:

1. Protects You from Exposure to Biohazards

When you’re pipetting a bacterial culture or handling human tissue samples, you're potentially working with harmful organisms. The BSC creates an invisible barrier of HEPA-filtered air to stop these pathogens from reaching your skin, lungs, or clothing. Improper hand movements, poor posture, or rushing your workflow can break this barrier, leaving you exposed.

2. Preserves the Integrity of Your Research

Imagine spending days on an experiment only to discover it was compromised due to contamination. Poor practices inside the cabinet—like overcrowding, rapid movements, or improper glove use—can introduce particulates or microorganisms into your samples, skewing your results or forcing you to start over.

3. Prevents Environmental Contamination

The BSC also protects your lab space and the wider environment. It captures aerosols and particles that might otherwise escape into the air. If you use the cabinet incorrectly, you risk releasing infectious materials that could put others in your lab at risk.

4. Maintains Compliance with Safety Standards

Most institutions and regulatory bodies (like CDC, WHO, or OSHA) require strict adherence to biosafety cabinet protocols. Failure to follow these guidelines can result in violations, lab shutdowns, or worse—serious infections.

Bottom line?

The biosafety cabinet is only as effective as the user. Respect it, follow proper procedures, and treat every session like it matters—because it does. Your safety, your results, and your credibility depend on it.

5-Step Guide on How to Use a Biological Safety Cabinet

1. Step 1: Pre-Use Preparation – Clean Hands, Clear Mind, Controlled Space

Before beginning any experiment inside a Laboratory Biosafety Cabinet (BSC), proper preparation is crucial. Skipping this step could compromise the safety of your samples, your environment, and most importantly, your health.

Start with personal hygiene. Always wash your hands thoroughly using antibacterial soap and warm water. Dry them completely before donning sterile gloves. Though it might seem routine, this simple practice prevents external contaminants from entering your workspace. Next, put on all required personal protective equipment (PPE)—including gloves, a lab coat or gown, and face protection as per your lab’s biosafety level.

Now, evaluate your BSC. Is it running? Has it been functioning for at least 10–15 minutes to establish sterile airflow? Most modern biosafety cabinets include airflow indicators or alarms—make sure everything is normal. If your laboratory biosafety cabinet uses HEPA filters, ensure they’ve been serviced recently and are in good condition.

Move on to cleaning. Disinfect the interior surfaces—work surface, sides, and sash—with a suitable disinfectant like 70% ethanol or an EPA-approved alternative. Always wipe from the back of the cabinet toward the front and from top to bottom to avoid spreading contaminants.

Before loading materials, mentally map your workflow. Determine which items are necessary, disinfect them thoroughly, and avoid bringing in excess equipment. Overcrowding can obstruct laminar airflow, defeating the purpose of the cabinet.

Lastly, review your experimental plan. A clear mind and a structured approach will minimize errors and reduce unnecessary movements inside the cabinet, which can stir up aerosols. Remember, the biosafety cabinet isn’t just a shield—it’s a controlled environment. What you bring into it matters just as much as what you keep out.

2. Step 2: Proper Loading – Strategic Setup for Seamless Workflow

Once the biological safety cabinet is prepped and sterilized, the next key step is to properly load your materials inside. This isn’t a task to be rushed. A well-thought-out setup ensures efficiency, safety, and contamination control throughout your procedure.

Start by bringing in only essential materials. Overloading the cabinet can block the front and rear grilles, which are vital for maintaining laminar airflow. A disrupted airflow means a compromised sterile field—and that’s a risk no researcher wants to take. Every item, from pipettes to sample containers, must be pre-disinfected with 70% ethanol or an appropriate solution before placement inside the BSC.

Organize your items logically to promote smooth, unidirectional workflow. Designate one side (usually the right or left, depending on your dominant hand) as the “clean” side for sterile supplies and the opposite side for “used” or potentially contaminated materials. The middle of the cabinet should remain clear for active work.

Place items at least four inches away from the front and rear grills. Never rest elbows or papers over these grilles—they facilitate continuous air filtration. Also, avoid placing large items (e.g., waste containers or centrifuge bottles) directly behind one another, which can obstruct airflow patterns and cause dead zones where contaminants accumulate.

If you're using a burner (though many labs discourage open flames in BSCs), ensure it’s equipped with a pilot flame and kept in a spot where it won't interfere with airflow. Alternatively, consider using a sterile heat block or an electric loop sterilizer for safer operations.

Once your setup is complete, pause and mentally review your workflow. Where will you reach first? Which hand will handle sterile tasks? A mindful setup saves time, ensures sterility, and reduces fatigue during long sessions at the biosafety cabinet.

3. Step 3: Working Inside the Cabinet – Mindful Movement and Method

Working inside a biosafety cabinet in the laboratory demands deliberate, measured actions. The goal is to maintain the protective airflow and sterility while minimizing disruptions that could spread contaminants or compromise samples. This step is where precision meets practice.

Begin by sitting comfortably, facing the cabinet directly with your arms resting lightly inside the sash opening. Keep movements slow and deliberate. Rapid motions—like swinging arms or abrupt lifting—disturb the airflow and generate turbulence, which can transport contaminants from non-sterile to sterile zones or even into your breathing zone.

Always work from clean to dirty. For example, when plating bacteria, start by retrieving sterile media, perform inoculation, and then dispose of pipette tips into the waste beaker. This workflow ensures that you’re not reintroducing pathogens into clean items. Also, minimize arm crossing. Design your workstation so that you don’t have to reach over samples or containers, reducing the chance of contamination.

Limit talking, sneezing, or coughing near the cabinet. If conversation is necessary, keep your face turned slightly away from the sash opening. Talking releases droplets and aerosols that can compromise your environment.

When using pipettes, avoid letting the pipette touch any surface inside the BSC. Always store it vertically in a sterile container or rack. Never mouth pipette—this is not only dangerous but also outdated and unacceptable under modern biosafety protocols.

Watch out for cross-contamination risks. For instance, don’t reuse gloves for multiple samples without changing them or disinfecting between tasks. If any spills occur, immediately stop your work, disinfect the area thoroughly, and allow the disinfectant to remain on the surface for at least 10 minutes.

Remember, your BSC is not a storage unit—it’s a clean zone. Keep your focus sharp and your movements efficient to maintain its integrity during use.

4. Step 4: Finishing Up – Decontaminate Thoroughly and Thoughtfully

After completing your work, proper decontamination is not just a courtesy—it’s a biosafety mandate. Leaving a lab biosafety cabinet dirty or cluttered could endanger the next user, allow contaminants to proliferate, and even compromise equipment longevity.

Begin by carefully sealing and removing any biological waste. Use double-sealed biohazard bags or containers and place them in designated bins outside the BSC. Do not drag items across the surface; instead, lift and remove them gently to minimize aerosol creation.

Next, remove all reusable materials (pipettes, racks, beakers, etc.) and wipe them down with disinfectant before taking them out of the cabinet. This step is often overlooked but essential to prevent transferring potential contaminants into the broader lab environment.

Now it's time to clean the cabinet itself. Using fresh disinfectant wipes or saturated gauze pads, wipe down every interior surface—walls, work surface, and sash. The cleaning pattern matters: go from the back to the front, and top to bottom, to ensure all contaminants are effectively captured and moved toward the exit zone. Pay special attention to corners and joints where buildup often hides.

Let the disinfectant sit for at least 10 minutes before proceeding. This “contact time” is vital for ensuring all microbial contaminants are neutralized. If your disinfectant requires a rinse step (like bleach), follow up with sterile water or 70% ethanol to remove residues.

Leave the BSC running for 5–10 minutes after cleaning. This allows any remaining aerosols to be cleared by the HEPA filtration system. Only then should you turn off the cabinet blower (unless lab protocol requires it to run continuously).

Lastly, dispose of gloves and PPE responsibly, wash your hands thoroughly, and document your session in the logbook. A clean cabinet today ensures a safe cabinet tomorrow.

5. Step 5: Shut Down Safely – Seal the Safety Circle

The final stage in using a biological safety cabinet in the lab is the shutdown process. Though it might seem like a formality, shutting down your BSC correctly helps preserve equipment function, protects colleagues, and maintains lab compliance with biosafety standards.

Start by verifying that all materials, tools, and waste have been removed or stored appropriately. Do a quick final pass across the work surface to ensure nothing has been left behind—especially sharps or chemical containers. Once the space is physically clear, take a moment to wipe the sash window from the outside using a clean cloth and disinfectant to remove any smudges or particles.

Next, turn off any additional equipment inside the cabinet—centrifuges, vortex mixers, or heating blocks. Some lab protocols may require you to unplug small equipment, while others prefer items to remain plugged in for monitoring purposes.

If your cabinet uses UV light for disinfection, activate it only after closing the sash completely and ensuring the area is vacated. UV light can be harmful to skin and eyes. Typically, a timer is used to operate the UV light for 15–30 minutes after work. Never leave the UV on during operation.

Then, switch off the cabinet’s blower fan and fluorescent light, unless your standard operating procedure dictates otherwise. Some labs prefer to keep the blower on continuously, especially in high-use areas, so always refer to institutional guidelines.

Finally, document your session in the BSC logbook. Include your name, time in and out, any incidents (e.g., spills, airflow issues), and any maintenance notes. This recordkeeping helps identify patterns and ensures accountability in shared lab spaces.

With that, your workflow is complete. You’ve closed the circle—ensuring safety, sterility, and responsibility from start to finish.

Final Thoughts – Practice, Precision, and Protection

A Laboratory Biosafety Cabinet is one of the most vital pieces of equipment in any lab handling biological agents—but its value is only realized when it's used with knowledge and care. From prepping your station and loading materials properly to practicing sterile techniques and shutting it down responsibly, every step matters.

Let’s recap the five key steps to using a BSC safely and effectively:

1. Pre-Use Preparation – Sanitize everything, plan ahead, and start with a sterile environment
2. Proper Loading – Arrange materials thoughtfully to promote sterile workflow
3. Working Inside – Use smooth, controlled movements and maintain focus
4. Finishing Up – Disinfect, decontaminate, and dispose of waste responsibly
5. Shut Down Safely – Power down, log your session, and leave the cabinet ready for the next user

Correct use of a biosafety cabinet ensures that your experiments stay accurate, your samples stay clean, and—most importantly—you stay safe.

In the world of lab research, precision and consistency aren’t just best practices—they’re survival strategies. Think of your BSC as a trusted ally. It’s there to protect you, but only if you do your part.