Safety in biological laboratories: risk management in work with human disease agents

introduction
Biological laboratories are essential research centers for developing drugs, understanding diseases, and studying the biology of microorganisms. However, biological laboratories also pose potential risks, especially when working with pathogens that can cause serious illness in humans. Safety in these laboratories is essential to ensure that workers, as well as the general public, are protected from infection and further harm.
Biological risk categories
Disease agents are divided into different levels of risk (Biosafety Levels, BSL), each level indicates the degree of risk involved in working with those agents and the steps that must be taken to protect workers and the environment:
1. BSL-1: This level refers to working with microorganisms that do not cause disease in healthy humans. Examples include types of bacteria such as *Escherichia coli* that are not pathogenic. These laboratories require minimal safety procedures, including avoiding bringing food and drinks into the laboratory and using basic protective equipment such as gloves.
2. BSL-2: This level involves working with pathogens that can cause disease in humans, but are generally not life-threatening and can usually be treated. Examples include *Salmonella* and *HIV*. Safety measures in BSL-2 laboratories include the use of eye shields, protective clothing, and the use of exposure control techniques such as biological safety cabinets.
3. BSL-3: This level refers to work with disease agents that can cause serious and possibly fatal illness through inhalation. Examples include *Mycobacterium tuberculosis* and *SARS-CoV-2*. BSL-3 laboratories require controlled air management, such as one-way ventilation and the use of negative pressure, in addition to advanced personal protective equipment such as masks and face shields.
4. BSL-4: This is the highest level, and refers to work with highly dangerous pathogens that have no available treatment or vaccine, such as *Ebola* and *Marburg*. BSL-4 laboratories require the use of airtight personal space suits and the use of completely sealed facilities designed to prevent any leakage of the pathogen.
Safety and protection measures
To ensure maximum safety in biological laboratories, a number of comprehensive safety measures must be taken, which relate to various aspects of laboratory work:
1. Personal Protective Equipment (PPE): This equipment is the first line of defense in preventing exposure to biological agents. For BSL-2 and above laboratories, this typically involves full protective clothing including lab coats, gloves, masks, face shields, and goggles.
2. Biological Safety Cabinets (BSCs): These cabinets allow safe work with biological agents by creating a protected area where experiments can be performed without exposing workers to risk. There are different types of BSCs that are suitable for different levels of biological risk.
3. Ventilation and Pressure Control: BSL-3 and BSL-4 laboratories must use special ventilation systems to ensure that air flows from clean air systems to contaminated areas. This includes the use of negative pressure to prevent the leakage of pathogens from the laboratory to the outside environment.
4. Training and Education : Workers in biological laboratories must undergo comprehensive and