The most important lab safety rules everyone should follow
Written by Éva Mészáros01. December 2021
To ensure your lab never makes the news with headlines like ‘Smallpox vials discovered in storage room’,1 ‘Anthrax exposure resulted from breakdown in safety protocol’,2 or ‘Live polio virus solution accidentally released into local water’,3 you should follow the lab safety rules below. They apply to all general research labs, and are based on the principle of containment, which allows you to protect yourself, your colleagues, the environment, and the population from unintentional exposure to biological agents.
Table of contents
General lab safety precautions
Please note that although this article intends to cover the major rules, it is not exhaustive. You should complement it by reading the safety documents provided by your lab, and ensure that you comply with local and national regulations.
The biosafety officer should brief you on local laws and the lab's emergency plans and rules before you start working in a new lab. If you have to use equipment you've never previously worked with, or perform experiments that include unfamiliar steps, ask a colleague for additional training.
Designate storage areas, make sure aisles, safety exits and safety equipment are not obstructed, and keep your work zone clean and tidy.
Document experiments and lab activities properly. This is crucial to ensure reproducibility, meet regulations, and enable any problems to be traced back to their source.
Where necessary, stick hazard signs on equipment, lab containers and materials to warn your colleagues about potential dangers. People often forget about this when aliquots of hazardous substances are removed from the original container and stored separately. Every container used should be individually labeled. Please also note that the biohazard sign is usually an orange-red color in the US (left), and yellow in Europe (right).
Never work alone to guarantee that help is always available in case of an emergency, and don't use headphones, so you can hear alarms. Always leave the lab to eat, drink or apply cosmetics, and don't sniff or taste liquids, for example, to find out what's in an unlabeled tube or bottle. If working alone is unavoidable, carry a lone worker device with you. Lone worker devices offer safety features such as a help button or worker-down detection.
If an accident happens despite all the precautionary measures, it should be documented and reported to the biosafety officer. His or her contact details, as well as other emergency phone numbers, should be displayed in a clearly visible location, for example, on the door of the lab.
Lab safety equipment
A lab is usually equipped with several pieces of safety equipment. Make sure you know where they are located and how to use them in case of emergency. In addition, following the rules below will ensure the equipment is ready for use at all times.
First aid kits
Periodically verify that your first aid kits are complete and, if some items are past their expiry date, discard and replace them.
Since every lab works with a different set of hazardous and non-hazardous chemical and biological agents, the contents of your spill kits must be tailored to your lab's specific needs. Common items include4,5:
- Personal protective equipment (PPE)
- Polypropylene containers and chemical resistant bags
- Sharps containers and autoclave bags
- Clean-up tools, such as dustpans, scoops or brushes
- Absorbent materials, such as paper towels, pads, vermiculite, sand or clay
- Neutralization and treatment materials for acid, alkali and solvent spills
- Disinfectants for biological spills, for example, bleach
Refill the kit immediately after cleaning up a spill so it is always ready for use.
Regularly test your eyewash stations. Besides a visual inspection, you should turn it on, or, if it's not plumbed in, check that the flushing fluid reservoir is full and has not passed its expiry date.6
Activate your safety showers on a regular basis to see if they are working as intended. It is important that the flow rate is sufficient and that the temperature is in the tepid range.7
Fire blankets and fire extinguishers
Mount your fire blankets on the wall and replace them as soon as they have been used to extinguish a fire or for spill control.8 It is also important to stock your lab with the right fire extinguishers as there are many different types – including those made for ordinary combustibles, flammable liquids and gases, electrical equipment or combustible metals and metal alloys9 – and to have them regularly inspected.
Safety storage cabinets
Keep flammable and combustible materials in safety storage cabinets that offer features such as double-walled steel construction with an insulating space, or raised door sills to contain spills.10 Acids and bases must be stored in separate cabinets, since they would react violently if both leaked.
Personal protection and hygiene rules
Stick to the 'dress code' and hygiene rules outlined in this section to protect yourself from hazards and contamination.
Wear closed toe shoes and long pants when going to the lab. Do not wear jewelry and loose clothing. Avoid clothing made of synthetic fibers if you're working with flammable liquids and tie your hair back if you wear it long.
Personal protective equipment
PPE is the last line of defense between you and harmful materials. It generally includes a lab coat, eye protection and gloves.
- Lab coat: Make sure that your lab coat fits correctly and is always closed, and stored separately from street clothing when not in use.
- Eye protection: You can use face shields, safety glasses and safety goggles to protect your eyes. Choose the type of eye protection according to the hazards present. For example, safety goggles offer the highest level of protection from splashes, mists, vapors and fumes because they form a protective seal around the eyes.11 Be aware that regular glasses don't provide adequate shielding; you need to wear additional eye protection. If you decide to wear contact lenses instead of glasses, never put them back in your eyes if they fall out.
- Gloves: When wearing gloves, always pull them over the cuffs of your lab coat and check that their material is suitable to protect against the biological agents or chemicals that you're going to handle. Use nitrile gloves if you are allergic to latex, as they are better suited for sensitive skin and more chemically resistant.
Never touch your face when working in gloves. This decreases the risk of transferring harmful substances from the gloves to your face, and also prevents bacteria from your skin from getting onto sterile lab surfaces. Finger dab hygiene tests (Figure 1), where you place your fingers on an agar stripe that is then incubated, can be used to illustrate the difference between a new pair of gloves and one that has been used for a while (Figure 2). The second hygiene rule concerns PPE and hand washing. Start by taking off your lab coat, eye protection and gloves, and wash your hands thoroughly before touching the door handle and leaving the lab. This helps to avoid contaminating public areas and office spaces, including computer mice and keyboards.
How to use common lab equipment
Another important aspect of lab safety, which has a significant impact, is knowing how to use lab equipment correctly. In this section, we'll briefly discuss the key points to consider in addition to regular maintenance.
Working in a biosafety cabinet
Biosafety cabinets (BSC) of different types are used to protect you, the environment and the products in the cabinet from aerosols and contamination when handling biologically hazardous materials. Before starting to work in a BSC, you have to purge and disinfect it, and arrange your materials in a logical order, from clean to contaminated. Avoid fast and side-to-side arm movements, and move your arms in and out of the cabinet as little as possible during your experiment. Once finished, clear the cabinet and disinfect it again. For more detailed information, read our article on how to use a biosafety cabinet.
Working in a fume hood
Fume hoods protect you and your lab from vapors and gases created by volatile chemicals. To guarantee safe operation of the fume hood, make sure you position your experimental set-up at least 15 cm (6 inches) away from the front opening so that you can immediately close the sash whenever it is necessary. Keep the sash as low as possible while you work as it acts as a safety shield between yourself and the chemicals you are using. After finishing an experiment, place hazardous materials in a closed container before taking them out of the fume hood and shut the sash before you leave.12,13
Using an autoclave
Autoclaves use heat in the form of pressurized steam to kill microorganisms such as bacteria and spores. As the heat needs to penetrate throughout the entire load, pack the autoclave loosely and don't stack items on top of one another. It's recommended that the items to be sterilized are placed in autoclave bags and then a secondary container, for example, a box, to prevent leaks inside the instrument. When autoclaving bottles, always loosen their caps or lids to avoid breakages due to pressure differences. To verify whether an autoclave cycle has been successful, add chemical indicators like tapes with heat sensitive ink, or biological indicators such as spore strips or disks, to your load.
Working with open flames
Only use Bunsen burners in areas free from combustible materials and chemicals producing flammable vapors. To further reduce fire hazards, never leave an ignited Bunsen burner unattended and remember to shut off the gas after use. However, a leak is still possible, and you should consider using a safety Bunsen burner independent from gas distribution systems. This solution adds an extra layer of security as the gas valve closes automatically when the flame is extinguished.
Working with aspiration systems
Aspiration systems are used to aspirate, collect and dispose of biological liquid waste. Many labs work with 'do-it-yourself' systems consisting of a vacuum flask connected to a water jet pump. As these don't protect the vacuum source from contamination and are often tedious to empty, ready-to-use aspiration systems offering additional features such as an overflow protection or shatterproof bottles are safer to use.
Working with pipettes
Pipettes are the most commonly used lab tools and using them correctly can help you prevent (cross-) contamination and aerosol generation. First of all, clean the outer surface of your pipette at least daily and whenever it gets contaminated. The interior of your pipette should not normally come into contact with your samples, but if it does, decontaminate it immediately. Detailed instructions on how to clean and decontaminate pipettes can be found here and we've also put together a blog describing best pipetting practices to help you get accurate and precise results without generating aerosols. Last, but not least, although it should be common sense by now, never pipette by mouth!
Safe laboratory practices and procedures
Aside from proper handling of laboratory equipment, it is crucial to follow the safe laboratory practices and procedures listed below to prevent injuries, infections and accidents.
Preventing aerosol production
Laboratory-acquired infections often result from inhalation of aerosols. It is therefore necessary to pay special attention when working with aerosol-producing equipment. For example, place centrifuges in a BSC or use internal aerosol containment devices such as sealed buckets or rotors, and open them in a BSC after centrifugation. Vortex mixers, blenders and sonicators must also be operated inside a BSC, and should routinely be checked for signs of deterioration.
Working with sharps
Be careful when handling sharps like syringes, tweezers and scissors, or bits of broken glass or plastic, especially when they have been contaminated with biological agents. Immediately dispose of used sharps in dedicated puncture proof bins and treat them as infectious waste until autoclaved.
Heating agarose in the microwave
Put the buffer solution and agarose powder in an unsealed container that is large enough to allow room for boiling and expansion. The agarose solution could become superheated and boil unexpectedly after heating in the microwave. You therefore need to wear heat-resistant gloves and point the opening of the labware away from you when handling hot agarose. Wait until the agarose solution has cooled down to a temperature of 50 to 60 °C before you add dyes (especially ethidium bromide) and pour the mixture into trays.14,15
Frequently wipe down your work surfaces and devices with a disinfectant solution to prevent cross-contamination and exposure to pathogens. The disinfectant solution needs to be appropriate for the biological agent being handled, within the expiry date, at the correct concentration and applied for the right contact time. Additionally, it has to be chemically compatible with your work surface or device. If disinfectant residues could cause damage or be harmful for your skin, wipe them away with sterile water.
Chemical spills: In case of a minor chemical spill, alert people in the immediate area, put on appropriate PPE, confine the spill and use the spill kit to absorb and, if necessary, neutralize it. Major chemical spills require the assistance of safety and emergency personnel.16
Biological spills: Slowly mop up minor biological spills with absorbent materials such as paper towels and disinfect the spill area. When a major biological spill occurs, leave the area – if possible – to allow aerosols to settle. Then put on appropriate PPE, mop it up, and disinfect the spill area.
Transporting biological agents
To avoid spills, be cautious when transporting biological agents. Always put them into labeled, shatterproof plastic containers and close them before transportation in the lab. On top of that, it is advisable to place the containers to be transported in a rack, on a tray or, if the agent is highly hazardous, in a locked plastic box with absorbent material.
The same rules apply during transportation within the building, and you must also use a labeled transport box, decontaminating the surface before leaving the lab. If possible, avoid passing communal areas such as cafeterias on your way to your colleague's lab and use a trolley tray for high sample numbers.
When transporting biological agents between buildings, use at least two layers of packaging with sufficient absorbent material, and ensure that the outermost container is shatterproof, impervious and labeled with the sender, recipient and contents.
Storing and disposing of biological waste
Handle biological waste with the same care and caution as if working with biological agents. Label the containers and immediately store them in a designated place marked by a biohazard sign. The storage containers need to be shatterproof and no more than 75 % full. Avoid accumulation of large volumes of waste by regularly deactivating and disposing of it. More detailed information on the disposal of biological liquid waste can be found here.
The set of lab safety rules explained above can help you prevent accidents. However, the guidelines are only effective if they are followed by every lab member. We therefore suggest that you check if the safety policies of your lab are up to date and share this article with your colleagues.