Health & Safety Executive
Introduction to the Health and Safety at Work Act 1974
This guidance is for duty holders, which includes employers, those in control of premises and those with (health and safety responsibilities for others), to help them comply with their legal duties. It gives practical guidance on how to assess and control the risks due to Legionella bacteria.
Carrying
out a Legionella Risk Assessment and ensuring it remains up to date is required under health and safety law and is a key duty when managing the risk of exposure to Legionella bacteria.
Any
water system that has the right environmental conditions could potentially be a source for legionella bacteria growth. There is a reasonably foreseeable legionella risk in your water system if: water is stored or re-circulated as part of your system; the water
temperature in all or some part of the system may be between 20–45 °C; there are deposits that can support bacterial growth, such as rust, sludge, scale and organic matter; it is possible for water droplets to be produced and, if so, if they can
be dispersed; it is likely that any of your employees, contractors, visitors etc. could be exposed to any contaminated water droplets.
Health and safety law
Legionnaires’ disease:
The control of legionella bacteria in water systems. Approved Code of Practice1 gives specific information on the health and safety law that applies. In brief, general duties under the Health and Safety at Work Act 1974 (the HSW Act) extend to risks from
legionella bacteria, which may arise from work activities. The Management of Health and Safety at Work Regulations 1999 provide a broad framework for controlling health and safety at work (see www.hse. gov.uk/risk for more information). More specifically,
the Control of Substances Hazardous to Health Regulations 2002 (COSHH)3 provide a framework of duties designed to assess, prevent or control the risks from hazardous substances, including biological agents such as legionella, and take suitable precautions.
The essential elements of COSHH are:
Risk assessment
Prevention of exposure or substitution with a less hazardous substance if this is possible, or substitutes a process or method with a less hazardous one;
Control of exposure where prevention or substitution is not reasonably practical
Maintenance examination and testing of control measures, automatic dosing equipment for delivery of biocides and other treatment chemicals;
Provision of information, instruction and training for employees;
Health surveillance of employees where appropriate and if there is valid techniques for detecting indications of disease
where exposure may result in an identifiable disease or adverse health effect.
Under general health and safety law, duty holders including employers or those in control of premises must ensure the health and safety of their
employees or others who may be affected by their undertaking.
They must take suitable precautions to prevent or control the risk of exposure to Legionella.They also need to either understand or appoint somebody competent who knows how to identify and
assess sources of risk manage those risks, prevent or control any risks, keep records and carry out any other legal duties they may have.
Identify and Assess Sources of Risk
In conducting
an assessment, the duty holder must appoint a competent person or persons, known as the responsible person(s), to help them meet their health and safety duties, i.e. take responsibility for managing the control scheme. If the necessary competence, knowledge
and expertise do not exist, there may be a need to appoint someone externally.
The responsible person(s) appointed to take day-to-day responsibility for managing risks in their business will need to understand the water systems, any equipment associated
with the system, and all its constituent parts. They should be able to identify if the water systems are likely to create a risk from exposure to legionella bacteria by assessing if: water is stored or re-circulated in the system; the water temperature in
all or some parts of the system may be between 20–45 °C; there are deposits that support bacterial growth, including legionella, such as rust, sludge, scale, organic matter and biofilms; it is possible for water droplets to be produced and, if so,
whether they can be dispersed;