This page is mainly for employers of people who may be exposed to hazards from biological agents through their work. It explains what these hazards are and signposts you to guidance on how to protect workers from them.
There is separate guidance for workers on preventing infection.
What biological agents are
A biological agent is a micro-organism that may cause infection, allergy, toxicity or other hazard to human health.
Biological agents at work that can cause infections and disease to employees include:
- micro-organisms such as bacteria, fungi, viruses or parasites
- agents such as proteins that cause transmissible spongiform encephalopathies (TSEs)
Some biological agents are referred to as zoonotic. These are naturally carried by animals but, if passed to humans, they can cause diseases known as zoonoses.
Emerging biological agents (for example COVID) can cause outbreaks which, in very rare occasions, might expand worldwide to cause a pandemic. There is information on the roles of government and employers in preparing for and responding to a pandemic.
The law on biological agents
The main legislation relevant to controlling the workplace risks of exposure to biological agents is the Control of Substances Hazardous to Health Regulations (COSHH).
There is specific HSE guidance about the law on infections at work.
Incidental exposure
Incidental exposure to biological agents can happen when your work activity brings you into contact with material containing biological agents, such as blood, body fluids, contaminated water or waste material.
Our content on incidental exposure to biological agents includes:
- how employers should prevent incidental exposure
- specific guidance for industries and workplaces
Deliberate work
Deliberate work is where biological agents are intentionally handled, propagated, processed, or manipulated as part of planned work activity.
Exposure can occur as a result of deliberate work with a biological agent in:
- microbiological containment facilities, such as those found in research and development, teaching or diagnosis
- production facilities (pharmaceutical or veterinary medicine)
Classification of biological agents
In UK legislation, biological agents are classified according to the following:
- ability to cause infection
- severity of disease
- risk that infection may spread to the community
- availability of vaccines and effective treatment
Biological agents are classified into one of 4 hazard groups.
The classification is set out in the Approved List of biological agents, which includes information on how to classify agents that have not been included in the list.