Safety & Environmental Protection Service

Assessing Risks of Work with Biological Agents and Hazards

Your biological COSHH risk assessment should start with the basic information about the project or activity and the principal investigator who is responsible for management of the work. The project title should state the biological agents and hazards involved and nature of the work. Provide the name of the principal investigator or manager, management unit, date and the location or building where the work will be carried out. You should provide details of the experience, qualifications and training received in genetic modification and the use of biological agents and hazards for all the people who will be doing the work.

Definition of Biological Agents and Hazards

Biological agents can be pathogens, toxins, allergens or carcinogens. Biological hazards include biological agents, any material which contains biological agents or any other biological substances which are not classified as biological agents. COSHH defines biological agent as a microorganism, cell culture or human endoparasite, whether or not genetically modified, which may cause infection, allergy, toxicity or otherwise create a hazard to human health. A microorganism is defined as a microbiological entity, cellular or non-cellular, which is capable of replication or of transferring genetic material, and a cell culture is defined as the in-vitro growth of cells derived from multicellular organisms. The definition of biological agents includes microorganisms, parasites, the microscopic infectious forms of larger parasites, cell cultures and nucleic acids. Animal and plant health laws basically define animal pathogens and pests and plant pathogens and pests as harmful to the environment or economy. Biological hazards may encountered where you are intentionally working with biological agents such as in research, teaching and diagnosis, or where you are unintentionally working with them during in activities such as healthcare, travel, construction, maintenance, gardening and agriculture.

Classification of Biological Agents

Biological agents are classified according to the risks to human health, animals, plants and the environment. COSHH classifies human pathogens into four hazard groups while SAPO classifies animal pathogens into four hazard groups and various plant health laws ad classifies plant pathogens and pests into multiple groups.

Classification of Human Pathogens

Human pathogens are classified by COSHH into four hazard groups (HG 1 - 4) according to these criteria.

• Ability to cause infection.
• Severity of the disease that may result.
• Risk that infection will spread to the population.
• Availability of vaccines and effective treatment.

The four hazard groups of human pathogens and the basis of their classification are as follows.

• Hazard group 1 (HG 1): Biological agent that is unlikely to cause human disease.
• Hazard group 2 (HG 2): Biological agent that can cause human disease and may be a hazard to employees but is unlikely to spread to the community and there is usually effective prophylaxis or treatment available.
• Hazard group 3 (HG 3): Biological agent that can cause severe human disease and may be a serious hazard to employees and it may spread to the community but there is usually effective prophylaxis or treatment available.
• Hazard group 4 (HG 4): Biological agent that causes severe human disease and is a serious hazard to employees and it is likely to spread to the community and there is usually no effective prophylaxis or treatment available.

The HSE ACDP Approved List of Biological Agents list is not exhaustive so if a biological agent is not included it does not automatically fall into hazard group 1 and it should be classified according to its level of risk using the definitions given in COSHH. If there is any doubt as to which of two alternative hazard groups is the most appropriate then the agent must be assigned to the higher one. Biological agents that are classified as hazard group 1 are not necessarily safe since they may cause harm under specific circumstances. The list also provides the following additional information on pathogens.

• A: Known to have allergenic effects.
• T: Toxin production.
• V: An effective vaccine is available.

In some cases such as for attenuated strains of pathogenic microorganisms it is possible to reclassify a biological agent to a lower hazard group than that given for the agent on the list. This must only be done by consultation with and obtaining permission from HSE.

Classification of Animal Pathogens

Animal pathogens are classified by SAPO into four hazard groups (HG 1 - 4) according to these criteria.

• Ability to cause infection.
• Severity of the disease that may result.
• Risk that infection will spread to the population.
• Risk of damage to the environment or economic loss.
• Availability of vaccines and effective treatment.

The four hazard groups and several special groups of animal pathogens and the basis of their classification are as follows.

• Hazard group 1 (HG 1): Disease producing organisms which are enzootic and do not produce notifiable disease.
• Hazard group 2 (HG 2): Disease producing organisms which are either exotic or produce notifiable disease, but have a low risk of spread from the laboratory.
• Hazard group 3 (HG 3): Disease producing organisms which are either exotic or produce notifiable disease and have a moderate risk of spread from the laboratory.
• Hazard group 4 (HG 4): Disease producing organisms which are either exotic or produce notifiable disease and have a high risk of spread from the laboratory.
• Foot and Mouth Disease: There is special classification for foot and mouth disease virus.
• Rabies: There is special classification for rabies and rabies related viruses.
• Arthropods: There is special classification for vectors and parasites.

Classification of Plant Pathogens and Pests

Plant pathogens are classified by plant health laws into multiple groups depending on their role in disease in the UK.

The COSHH, SAPO and other relevant classifications are not complementary and the requirements are very different for the classification, containment and control of human pathogens, animal pathogens, plant pathogens and pests. Compliance with one does not absolve you and your workers from responsibilities under the other and in all cases where there is any discrepancy between COSHH, SAPO and other relevant requirements then the higher requirements must be followed. Where an agent is listed by COSHH, SAPO and other relevant then all sets of requirements for risk assessment and control must be satisfied.

Biological Agents and Hazards

You should describe the exact nature of the work and the biological agents and hazards which will be used or to which people or the environment could be exposed in the work. There may be intentional or unintentional exposure to bacteria, viruses, fungi, parasites or infectious materials in the work. Biological agents and hazards might include hazard group 1 pathogens, hazard group 2 pathogens, hazard group 3 pathogens, toxins, carcinogens, allergens, human primary or continuous cell cultures, animal primary or continuous cell cultures, human cells or tissues, animal cells or tissues, human blood, patient contact, animals, plants, soils and environmental materials. Your work may involve potential exposure to biological agents and hazards such as teaching, research, laboratory work, fieldwork, travel, people, microorganisms, animals, plants, estate, facility, construction, maintenance, cleaning, visitors or contractors. Give details of how often the biological agents and hazards will be used, the activity carried out, or how often people will be exposed to the biological agents and hazards. You should briefly describe the specific methods involved and whether it will be small, medium or large scale work. You should provide details of the maximum amount or concentration of the biological agents and hazards used or to which people could be exposed. Fieldwork in the UK or overseas may lead to exposure to various local or exotic biological agents and hazards.

Pathogens, Toxins, Allergens and Carcinogens

Pathogens are microorganisms such as bacteria, viruses, fungi and parasites which can colonise humans and cause infection and harm to health. You should provide details of whether they are pathogenic, toxic, allergenic, carcinogenic or environmental hazards. Microorganisms may be obligate opportunist pathogens, zoonotic pathogens capable of infecting humans and animals, or environmental pathogens. Pathogens vary greatly in their ability to cause infection and may be weakly or highly infectious. Infectious doses will vary enormously depending on the pathogen, strain and physical condition of the organism, exposure route and host resistance. In some cases it is not the microorganism which is harmful but microbial products. Some microorganisms produce powerful toxins which are harmful to humans. Toxigenic microorganisms can be transmitted by many routes although they do necessarily not need to be viable for their toxins to cause harm since the microbial toxins can be hazardous. Inhalation, ingestion or injection of toxigenic microorganisms or toxins can cause infection or toxigenicity. Many biological agents or hazards including animals, plants, microorganisms or their products can be allergenic and cause mild or severe hypersensitivity reactions such as occupational asthma, dermatitis or anaphylaxis. Once sensitized then very low concentrations of allergens may elicit allergic hypersensitivity reactions. Sometimes the consequences of an exposure may be sufficiently severe for the person to be unable to safely continue working in areas where they might be exposed to the agents or hazards. Some biological agents are carcinogens and can cause cancer. Some biological hazards such as humans and animal tissues, cancer cells and cell lines may contain cancer viruses.

Host and Tissue Specificity

Some microorganisms and pathogens infect a broad range of host species while others infect very few or are species specific. Some pathogens have complex life cycles involving more than one host species and some stages but not others may be hazardous. Humans, animals or plants may be end hosts and not normally transmit infections. Some pathogens may infect a variety of tissues while others are tissue specific. Remember that microorganisms can evolve and adapt so they may infect different host species or tissues to those expected.

Pathogenicity

Pathogenicity or virulence is the measure of the harm that may be caused by a pathogen such as human, animal or plant disease or environmental damage. Some pathogens have highly virulent strains and avirulent or attenuated strains (eg vaccine strains). Attenuated strains may act as opportunist pathogens or revert to virulence. Attenuated strains may still be harmful and there have been many laboratory infections involving vaccine strains.

Humans, Animals, Plants and the Environment

Human and animal bodies, organs, tissues, cells, samples, blood, body fluids or waste materials may contain biological agents. Clinical samples could include samples from patients, volunteers or post mortem specimens. Human and animal tissues and cell cultures including primary or continuous cell lines and cancer cell lines are potentially hazardous because they may contain biological agents. Plant tissues and cell cultures may contain pathogens, toxins, carcinogens or allergens. Animals may carry zoonotic pathogens which are harmful to humans. Experimental animals from laboratory suppliers may be screened for several common specific pathogens but the risks are much greater in wild animals or experimental animals that have been in contact with wild animals. Cages, excreta, bedding and equipment used to trap or handle animals may be contaminated with biological agents and hazards. Plants, plant pathogens and pests, plant toxins and allergens may be hazardous to humans or the environment. Environmental samples can contain pathogenic organisms which may be unintentionally concentrated or propagated in the laboratory. Microorganisms isolated from the environment should be treated as potentially pathogenic until shown to be otherwise.

Routes of Exposure or Release

You should provide details of the potential routes of exposure to or release of the biological agents or hazards. The potential for biological agents or hazards to cause harm will depend upon the exposure route and nature of any disease or damage. Biological agents or hazards may be harmful to people by one or more of the following exposure routes of inhalation, ingestion, injection or absorption. Atypical routes of exposure may lead to unusual symptoms or misdiagnosis by medical practitioners. There are multiple routes of exposure through air, land or water to animals, plants or release to the environment. Routes of exposure may be unknown and may be different from the natural route in the laboratory. You should provide details of any hazardous aerosols which might cause airborne exposure that could be produced by the work. You must carefully consider the risks of harmful exposure or release if things go wrong such as the absence or failure of control measures or in a serious incident.

Disease or Damage Caused by the Biological Agents and Hazards

You should provide details of any human, animal or plant diseases or environmental damage associated with exposure to or release of the biological agents or hazards. Infection and disease are complex processes affected by multiple host, agent and environmental factors (eg agent genotype, host genotype, virulence, host immunity). Humans, animals or plants have many physical, chemical and biological and immunological defence mechanisms. Exposure to biological agents or hazards may lead to asymptomatic, subclinical, acute, chronic, persistent or fatal infections or other diseases or damage. Some biological agents or hazards may be hazardous only to an exposed person, animal or plant while others may be hazardous to other people, close contacts, community or the environment. The effects of exposure to some pathogens may be delayed. You should use relevant sources of information to find out as much as you can about any diseases or damage associated with the biological agents and hazards in your work. Do not assume that a biological agent is safe if there is any uncertainty especially if you are dealing with novel agents or isolates but adopt the precautionary principle that until proven otherwise they are harmful.

Who Might be at Risk

You should provide details of who will be doing the work and if any other people will be affected by the work. Specify which persons might be directly or indirectly at risk of exposure to the biological agents and hazards in the work including staff, students and other persons. Consider whether any particular groups of people might be at increased risk or adversely affected by the work and might not be able to do the work. These include new or expectant mothers, young persons under 18, disabled workers, those allergic to particular biological agents and hazards, and employees who may be more susceptible to some illnesses because of their individual health status. Immunocompromised people may be very susceptible to infection. There may be aspects where other people who are not members of your department or team such as collaborators, visitors, cleaners and porters may be affected by the work and the risks to these people also needs to be evaluated and controlled.

Risk Evaluation

You have considered the ways by which harm could be caused from exposure to the biological agents and hazards in your work. You will then need to make an assessment of the overall level of risk of harm to human health and the environment from exposure to biological agents and hazards in the work.

Assessment of Risk to Human Health

You need to decide on the level of risk to human health from exposure to biological agents and hazards in this work. Please note that this is the level of risk prior to the use of controls. You will then select the necessary control measures which are required to reduce the level of exposure to the lowest level that is reasonably practicable and in any case to a level which is adequate to protect human health. To help you estimate the level of risk you should use the information below and the risk estimation matrix. This will give you an estimate of the potential risks to human health of the work which will be either effectively zero, low, medium / low, medium or high.

Assessment of Risk to Environment

You need to decide on the level of risk to the animals, plants and other aspects of the environment from exposure to biological agents and hazards in this work. Please note that this is the level of risk prior to the use of controls. You will then select the necessary control measures which are required to reduce the level of exposure to the lowest level that is reasonably practicable and in any case to a level which is adequate to protect the environment. To help you estimate the level of risk you should use the information below and the risk estimation matrix. This will give you an estimate of the potential risks to human health of the work which will be either effectively zero, low, medium / low, medium or high.

Estimating the Risk Level

The risk of the activity is determined by evaluating both the biological agents and hazards and the potential for exposure to them and how they are used in the work. The level of risk of exposure to the hazard is calculated from a combination of the likelihood and consequences of the hazard in the given circumstances.

• Consequences of hazard (severe, modest, minor, negligible).
• Likelihood of hazard (high, medium, low, negligible).

Risk = Likelihood x Consequences = Effectively Zero, Low, Medium / Low, Medium or High.

In practice an estimate of the level of risk can be calculated using a risk estimation matrix.

 

Consequences of Hazard	Likelihood of Hazard
	High	Medium	Low	Negligible
Severe	High	High	Medium	Effectively Zero
Modest	High	Medium	Medium / Low	Effectively Zero
Minor	Medium / Low	Low	Low	Effectively Zero
Negligible	Effectively Zero	Effectively Zero	Effectively Zero	Effectively Zero