In biological labs, there are specific precautions such as testing and certification that must be taken in order to protect personnel and their environment.

All of the biological organisms that are tested and handled are assigned a specific, numerical rating. These ratings are created by the Center for Disease Control and Prevention – widely known as biosafety levels.

Essentially, Biosafety levels are containment precautions. They’re required in any biological research facility in order to isolate dangerous organisms. And, your research equipment and lab rooms will need regular maintenance, testing and certification in order to maintain safety levels.

There are four different biosafety classifications, 1-4. And, we’ve broken them down to provide some more information on their distinctions.

Biosafety level signs from BSL-1 to BSL-4. Simple flat vector biohazard caution signs used in laboratory. Symbol of hazard caused by biological microorganism, virus or toxin

Biosafety Level 1 (BSL-1)

At the lowest level of the biosafety classification, level one is basically the least dangerous. Laboratory personnel are handling specimens with little risk of infecting healthy human beings. One example of a microbe with a level one rating (BSL-1) is a nonpathogenic strain of E. coli.

While handling BSL-1 specimens, the lab does not need to be furnished with advanced containment equipment. Nor does a BSL-1 lab need to be isolated from any of its neighboring facilities.

Safety precautions taken by personnel are standard for any scientific facility. Hand washing, personal protective equipment (PPE), decontamination of surfaces, and the prohibition of food and drink are mandated.

Biosafety Level 2 (BSL-2)

Biosafety level 2 (BSL-2) describes laboratories that work with pathogenic or infectious organisms that pose a moderate health hazard. Some examples of BSL-2 agents are the HIV virus and Staphylococcus aureus (staph infections).

Laboratories with a BSL-2 classification exercise similar precautions as those with a BSL-1 rating. However, there are a few enhanced policies in place to alleviate the risk of the specimens. Personnel working within a BSL-2 facility must proceed with more caution. They also must take enormous care in preventing any cuts or abrasions of the skin.

In a BSL-2 lab, personal protective equipment is mandated, including lab coats and gloves. Face shields and eye protection must be worn whenever necessary. Any procedures or tests that can lead to a harmful splash must be performed within a biosafety cabinet (BSC).

A biosafety cabinet (BSC) is an enclosed and ventilated space within the lab. Any technicians working with dangerous pathogens are required to do so within the BSC. When handling organisms with a rating of BSL-2 and up, a BSC is critical. At S.E.P.S., we provide biosafety cabinet testing and certification to ensure they meet NSF-49 guidelines and manufacturer specifications.

An autoclave, a pressure chamber used to sterilize equipment and instruments, is used for decontamination. Sinks and eyewash stations are situated throughout.

Personnel access into a BSL-2 lab is more restrictive than BSL-1. Unauthorized personnel are prohibited from entering the lab while work is being performed.

Biosafety Level 3 (BSL-3)

Laboratories that operate with a BSL-3 classification often handle organisms that can be fatal if inhaled. Some BSL-3 microbes include yellow fever, West Nile virus, and tuberculosis-causing bacteria.

These organisms are threatening enough that any facility handling them must register their work with government agencies. Anyone working in the lab must be kept under medical surveillance. They also must be immunized for the microbes they’re handling.

Clean air must be directed into the laboratory with an advanced airflow and ventilation system. Fume hoods are used in this lab setting to direct harmful vapors out. Your fume hoods will require regular testing and certification to ensure they are operating safely and effectively.

Additionally, requirements for a BSL-3 facility include the wearing of protective equipment, respirators, coveralls and wrap-around gowns. All work must be performed within a biosafety cabinet (BSC).

HEPA filtration is required for all BSL-3 labs, and S.E.P.S. technicians can test the integrity of your system.

Biosafety Level 4 (BSL-4)

Biosafety level 4 (BSL-4) labs are uncommon. While they’re rare, that doesn’t mean they don’t exist. BSL-4 is the very highest level of biological safety a facility can attain, and consequently, they handle the most exotic and deadly microbes.

Infections caused by microbes found within a BSL-4 facility are, more often than not, fatal. The most unsettling part is that there are no vaccinations or treatments for them. Two known examples of BSL-4 organisms are Ebola and Marburg viruses.

Any personnel operating within a BSL-4 facility are required to change clothing upon entering and shower immediately upon exiting. All materials must be decontaminated before staff leaves the facility. The staff must wear all the personal protective equipment described in the previous BSL safety ratings, as well as full-body, air-supplied suits. All work performed must be done within a Class III biosafety cabinet (BSC).

BSL-4 laboratories must be kept isolated and totally separate from neighboring facilities. They also feature intricate exhaust and ventilation systems, designed to constantly ensure the flow of clean air.




Working within a lab setting, particularly in biological sciences, can (in some scenarios) be hazardous. Knowing and understanding the various biosafety levels is an imperative way to ensure all personnel can work safely.

In any research environment, decontamination is of the highest priority. At S.E.P.S., we can provide you with scheduled testing and certification to guarantee your lab is operating with the highest of quality standards.

About SEPS Services

At S.E.P.S., we have over 18 years of experience providing services for various scientific facilities. Biosafety cabinet maintenance, certifications, scientific equipment decontamination and fume hood testing and certification are just a few of the services we offer. When it comes to the field of controlled environments, nothing but the very highest standards suffice. S.E.P.S. has the experience and expertise to collaborate in all scientific industries, including pharmaceutical and biological.

Bio Safety Cabinet in Lab