Prevention

• All procedures must be performed in such a way as to minimize or prevent the formation of aerosols and droplets (see Box 2).
• Mouth pipetting must be strictly prohibited.
• No materials should be placed in the mouth.

• Protective laboratory clothing must be worn at all times while staff are working in the laboratory. Protective clothing must not be worn outside the laboratory area (for example, in canteens, coffee rooms, offices, libraries, staff rooms and toilets).Laboratory coats and gowns must be stored separately from personal clothing. Clean gowns and used gowns must be stored in different areas of the laboratory.

• It is the responsibility of the laboratory manager to ensure that a biosafety management system is developed and adopted, as well as a safety or operations manual and a set of standard operating procedures.
• The manager should ensure that staff are trained and their technical competence evaluated for performing different procedures.
• Personnel should be advised of special hazards and be required to read the safety (or operations) manual as well as follow standard practices and procedures.

• The international biohazard warning symbol and sign must be displayed on the laboratory door.
• Only authorized persons should be allowed to enter the laboratory’s working areas.
• Children should not be authorized or allowed to enter the laboratory’s working areas.

A code of practice describes the laboratory practices and procedures essential for implementing good (that is, safe) microbiological technique. The laboratory manager should use the code of practice to develop written descriptions of procedures that should be followed to perform work safely. This safety or operations manual should also identify known and potential hazards, and specify practices and procedures to minimize the risks associated with such hazards.

All TB laboratories, regardless of the procedures being undertaken, should enact a set of essential biosafety measures to minimize risks. These measures affect:

1. codes of practice

2. equipment

3. laboratory design and facilities

4. health surveillance

5. training

6. waste handling.

Employee occupational health programmes should promote a safe and healthy workplace. This is accomplished by minimizing any exposures, promptly detecting and treating exposures, and using information gained from laboratory incidents and accidents to enhance safety precautions. A baseline medical checkup and provision for regular follow-up should be considered for all staff prior to commencing work in the TB laboratory.

TB laboratory facilities can be classified into three main levels of procedural risk, based on the activities being performed and their associated risks:

The laboratory manager should conduct regular audits to monitor risks and control measures. These can be done by reviewing reports of corrective actions taken after problems were identified earlier, thoroughly investigating incidents or accidents and implementing preventive measures, and ensuring that adequate resources are provided to maintain the necessary level of precautions. Documenting the risk assessment process and identifying mitigation measures are integral and important steps to ensure that biosafety measures selected and implemented are constantly improved.

Risk is the combination of the likelihood that a specific hazard will be encountered and the consequences of an event related to that specific hazard. Risks should be identified and categorized, and a determination should be made about which risks need to be controlled or minimized. The analysis of aerosolization risks described in this manual has led to the development of minimum biosafety requirements necessary for performing different procedures in TB laboratories.