Biological hazards - classifications

Substances considered to be biological hazards are any micro-organism, cell culture, or human endoparasite, whether or not genetically
modified, which may cause infection, allergy, toxicity or otherwise create a hazard to human health.

They are classified into hazard groups

1. Unlikely to cause human disease;
2. Can cause human disease and may be hazard to employees - unlikely to spread to the community and there is usually effective prophylaxis or treatment available;
3. Can cause severe human disease and may be a serious hazard to employees; it may spread to the community, but there is usually effective prophylaxis or treatment available;
4. Causes severe human disease and is a serious hazard to employees; it is likely to spread to the community and there is usually no effective prophylaxis or treatment available.

Reference