Part I: Organisation and management
waste disposal

No infected material should leave the laboratory except when it is properly packed for transport to another laboratory. All pathological material, smears, cultures and containers should at least be disinfected and preferably sterilised before disposal or re-use. Sterilisation means the complete destruction of all organisms, while disinfection implies the destruction of organisms causing disease. Sterilisation is usually accomplished by heat and disinfection by treatment with chemicals.

Discarding contaminated laboratory supplies
A container with appropriate disinfectant should be present in the BSC into which used, contaminated pipettes, loops and grinding vessels should be placed. The container should be deep enough to ensure that discarded items are covered completely. Used pipettes, wire loops etc. should be soaked for two hours after which they can be washed, sterilised and re-used.

In the immediate proximity of the BSC there should be stainless steel buckets with lids, ready to receive discarded specimen containers and tubes with bacterial suspensions.

Contaminated fluids should not be poured down drains but discarded into autoclavable containers.

Glassware should be substituted with plastic whenever possible. Broken glassware should be removed by a brush and dustpan, tongs or forceps and decontaminated in an appropriate disinfectant before disposal.

Sputum containers
Plastic sputum containers should be disposed of by incineration. Used glass sputum containers can be recycled after boiling for 20 minutes, or preferably autoclaving at 121EC and thorough washing.

Applicator sticks, pipettes, wire loops
Wooden applicators and paper should be disposed of by incineration. Contaminated or used pipettes and wire loops should be soaked for two hours in a bactericidal solution, washed and sterilised before re-use.

Positive and negative slides
Positive slides should be broken and burnt/buried to prevent their re-use. Negative slides could be re-used after proper cleaning.

Autoclaving
Autoclaving is the optimal initial sterilisation procedure and staff should be carefully instructed in the correct procedure. Ideally, the autoclave should be inside the tuberculosis laboratory to prevent contaminated material from being discarded or washed before decontamination. Autoclaves should be tested periodically to ensure that chamber temperatures are high enough to kill all micro-organisms. Testing can be done by steriliser indicator tubes that change colour during an adequate sterilising process.

Articles should be autoclaved at a minimum temperature of 121EC for a minimum period of 15 minutes. Autoclavable disposal bags usually contain indicator strips that change colour to indicate adequate sterilisation. After autoclaving waste material may be burned or buried. Re-usable articles may be washed and re-sterilised.

Boiling and burning
Peripheral laboratories may not have autoclaves and an alternative must be provided for the disposal of specimen containers and other items. The simplest methods for treating infected material are boiling and burning. A domestic pressure cooker can be used in much the same way as an autoclave, although its capacity is limited. Alternatively, a boiler adapted from an oil-drum or petrol-can, can be suspended over a wood fire and infectious? material boiled for 60 minutes before washing or discarding by burning.