Prevention

To incinerate hazardous waste properly requires an efficient means of controlling the temperature, and a secondary burning chamber. Many incinerators, especially those with a single combustion chamber, are unsatisfactory for dealing with infectious materials or plastics. If this type is used, such materials may not be completely destroyed, and the effluent from the chimney may pollute the atmosphere with microorganisms, toxic chemicals and smoke. However, there are many satisfactory configurations for combustion chambers.

Waste-management procedures must comply with all pertinent local or national requirements and regulations. Waste is anything that is to be discarded. The overriding principle in minimizing risks from waste is that all infectious materials should be decontaminated, incinerated, prepared to be buried or autoclaved. Discard bags should be used to segregate waste. Most glassware, instruments and laboratory clothing will be reused or recycled.

The principal questions to be asked before any objects or materials are removed from a laboratory are:

Human error and poor technique can compromise the best safeguards put in place to protect laboratory workers. Well informed, competent and safety-conscious staff are essential for preventing laboratory-acquired infections, incidents and accidents.

The proper design and construction of laboratory facilities contributes to the protection of all laboratory workers and provides a barrier that protects the community from TB aerosols that may be created with the laboratory. Specific features of the laboratory, including separated laboratory areas and a ventilation system, are secondary containment measures. The secondary barriers that are recommended for a laboratory depend on the procedures conducted and their associated risk of transmission.

Equipment should be selected to take certain general principles into account – that is equipment should be:

• The laboratory should be divided into “functionally clean” and “potentially contaminated” areas, with the clean areas reserved for administrative and preparatory work. Access to the clean areas and the contaminated areas must be controlled and enforced by the laboratory’s manager.
• The laboratory should be kept neat, clean and free of materials and equipment not used for performing routine work.

• 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.

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.