Legionella

What is Legionnaires’ disease?

Legionellosis is a collective term for diseases caused by legionella bacteria including the most serious, Legionnaires' disease, and the similar but less serious conditions of Pontiac fever and Lochgoilhead fever. Legionnaires' disease is a potentially fatal form of pneumonia and everyone is susceptible to infection. The risk increases with age but some people are at higher risk including:

  • people over 45 years of age
  • smokers and heavy drinkers
  • people suffering from chronic respiratory or kidney disease
  • people suffering from diabetes, lung and heart disease
  • anyone with an impaired immune system

Where does it come from?

The bacterium Legionella pneumophila and related bacteria are common in natural water sources such as rivers, lakes and reservoirs, but usually in low numbers and where the conditions rarely right for people to catch the disease from these sources.

Outbreaks of the illness occur from exposure to legionella growing in purpose-built systems where water is maintained at a temperature high enough to encourage growth. The most common systems that present a risk are cooling towers, evaporative condensers, hot and cold water systems and spa pools both in commercial and domestic premises. There are also other potential systems that may pose a risk to exposure to legionella including humidifiers, air washers, emergency showers and indoor ornamental fountains:

Further resources, including technical guidance, are available for each of the risk systems noted above.

If conditions are favourable, the bacteria may grow increasing the risks of Legionnaires' disease. It is therefore important to control the risks by introducing appropriate measures as outlined in 'Legionnaires' disease - The Control of Legionella bacteria in water systems (L8)':

How do people get it?

People contract Legionnaires' disease by inhaling small droplets of water (aerosols), suspended in the air, containing the bacteria. Certain conditions, which may also be present in the workplace, increase the risk from legionella if:

  • the water temperature in all or some parts of the system may be between 20-45°C, which is suitable for growth
  • it is possible for breathable water droplets to be created and dispersed, for example, aerosol created by a cooling tower, or water outlets
  • water is stored and/or re-circulated
  • there are deposits that can support bacterial growth providing a source of nutrients for the organism, for example, rust, sludge, scale, organic matter and biofilm

What are the symptoms?

The symptoms of Legionnaires' disease are similar to the symptoms of the flu and include:

  • a cough
  • shortness of breath
  • chest pain or discomfort, particularly when breathing or coughing
  • a high temperature
  • flu-like symptoms

Legionnaires' disease is not known to spread from person to person.

What to do if you think you might have contracted Legionnaires disease

If you develop the above symptoms and you are worried that it might be Legionnaires' disease, see your general practitioner.

It is not always easy to diagnose because it is similar to the flu. A urine or blood test will be helpful in deciding whether an illness is Legionnaires' disease or not.

Under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (NI) 1997 (RIDDOR), employers must report any cases of legionellosis in an employee who has worked on cooling towers or hot and cold water systems that are likely to be contaminated with legionella.

Are there Legionella risks in my workplace?

Any water system, with the right environmental conditions, could be a source for legionella bacteria growth. There is a reasonably foreseeable legionella risk if your water system:

  • has a water temperature between 20–45°C
  • creates and/or spreads breathable droplets, for example, aerosol created by a cooling tower, or water outlets
  • stores and/or re-circulates water
  • likely to contain a source of nutrients for the organism to grow, for example, rust, sludge, scale, organic matter and biofilms

Hot and cold water systems

There are various systems available to supply hot and cold water services that range in size, scale and complexity. All can present a foreseeable risk of exposure to legionella. Temperature control is the traditional and most common strategy for reducing the risk of legionella in hot and cold water systems. Cold water systems should be maintained, where possible, at a temperature below 20°C. Hot water should be stored above 60°C and distributed so that it reaches a temperature of 50°C (55°C in healthcare premises) within one minute at the outlets. 

Before assessing the risks associated with these systems, you need to understand the type of system, its constituent parts and operation. Often employers may wish to appoint a suitably competent water management company to help with this.

The Approved Code of Practice: Legionnaires' disease: The control of Legionella bacteria in water systems (L8) contains practical guidance on how to manage and control the risks in your system:

The following publication provides technical guidance on the management of Legionella in hot and cold water systems:

What are the duties of an employer?

If you are an employer, or someone in control of premises, including landlords, you must understand the health risks associated with legionella.

All systems require a risk assessment but not all systems will require elaborate control measures. A simple risk assessment may show that the risks are low and being properly managed to comply with the law. If such cases, your assessment may be complete and you may not need to take any further action, but it is important to review your assessment regularly in case anything changes in your system.

General duties under the Health and Safety at Work (Northern Ireland) Order 1978 extend to risks from legionella bacteria which arise from work activities. More specifically, the Control of Substances Hazardous to Health Regulations (Northern Ireland) 2003 (COSHH) provide a framework of actions designed to assess, prevent or control the risk from bacteria like Legionella and take suitable precautions. 

The Approved Code of Practice: Legionnaires' disease: The control of Legionella bacteria in water systems (L8) contains practical guidance on how to manage and control the risks in your system and information on how employers can comply with their legal duties in relation to legionella.

As an employer, or a person in control of the premises, you are responsible for health and safety and need to take the right precautions to reduce the risks of exposure to legionella. You are required to ensure that:

  • risk is identified and assessed
  • risks are managed
  • any risks are prevented or controlled
  • the correct records are kept and maintained
  • any other duties are carried out

Identify and assess sources of risk

As an employer, you are required to ensure a suitable and sufficient risk assessment is completed. You may be competent to carry out the assessment yourself but, if not, you should call on help and advice from either within your own organisation or from a suitably competent external contractor.

Your risk assessment should include:

  • an up-to-date plan showing the layout of the plant or water system, including parts temporarily out of use (a schematic diagram is sufficient)
  • a description of the correct and safe operation of the system
  • the precautions to take
  • checks to carry out to ensure the written scheme is effective and the frequency of such checks
  • the remedial action to take if the written scheme is shown to be not effective

If you conclude that there is no reasonably foreseeable risk or the risks are low and are being properly managed to comply with the law, your assessment is complete. You may not need to take any further action at this stage, but any existing controls must be maintained and the assessment reviewed regularly in case anything changes in your system.

Manage the risk

As an employer, or person in control of premises, you must appoint someone competent to help you meet your health and safety duties and to take responsibility for controlling any identified risk from exposure to legionella bacteria. A competent person, often known as the responsible person, is someone with sufficient authority, competence, necessary skills, knowledge of the system, and experience. The appointed responsible person could be one, or a combination of:

  • yourself
  • one or more workers
  • someone from outside your business

If there are several people responsible for managing risks, e.g. because of shift-work patterns, you must make sure that everyone knows what they are responsible for and how they fit into the overall risk management of the system.

If you decide to employ contractors to carry out water treatment or other work, it is still the responsibility of the competent person to ensure that the treatment is carried out to the required standards. Remember, before you employ a contractor, you should be satisfied that they can do the work you want to the standard that you require.

Preventing or controlling the risk

You should first consider whether you can prevent the risk of legionella by looking at the type of water system you need, for example a mains fed hot and cold water system will present less risk than a tanked system. The key point is to design, maintain and operate your water services under conditions that prevent or adequately control the growth and multiplication of legionella.

If you identify a risk that you are unable to prevent, you must introduce a course of action i.e. a written control scheme, that will help you to manage the risk from legionella by implementing effective control measures. Areas that should be considered include:

  • the system (a schematic diagram is sufficient)
  • who is responsible for carrying out the assessment and managing its implementation
  • the safe and correct operation of the system
  • what control methods and other precautions will be used
  • what checks will be carried out, and how often will they be carried out, to ensure the controls remain effective

Precautions should, where appropriate, include the following:

  • avoiding water temperatures between 20°C and 45°C and conditions that favour the growth of legionella bacteria and other microorganisms
  • avoiding water stagnation which may encourage the growth of biofilm
  • avoiding the use of materials that harbour bacteria and other microorganisms, or provide nutrients for microbial growth - the Water Fittings and Materials Directory references fittings, materials, and appliances approved for their compliance with the UK legal requirements for plumbing fittings and water using appliances
  • controlling the release of water spray
  • maintaining the cleanliness of the system and water in it
  • using water treatment techniques
  • taking action to ensure the correct and safe operation and maintenance of the water system

You should also ensure that all employees involved in work that may expose an employee or other person to legionella are given suitable and sufficient information, instruction and training. This includes information, instruction and training on the significant findings of the risk assessment and the appropriate precautions and actions they need to take to safeguard themselves and others.

Keeping records

If you have five or more employees you have to record any significant findings, including those identified as being particularly at risk and the steps taken to prevent or control risks. If you have less than five employees, it is still useful to keep a written record of what you have done.

Records should include details of the:

  • person or persons responsible for conducting the risk assessment, managing, and implementing the written scheme
  • significant findings of the risk assessment
  • written control scheme and details of its implementation
  • details of the state of operation of the system, ie in use/not in use
  • results of any monitoring inspection, test or check carried out, and the dates

Other duties

Under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (Northern Ireland) 1997 (RIDDOR) cases of legionellosis are reportable if a doctor notifies the employer and the employee’s current job involves work on water service systems located in the workplace which are likely to be a source of contamination.

Additionally, under the Notification of Cooling Towers and Evaporative Condensers Regulations (Northern Ireland) 1994, you must notify your local authority in writing, if you have a cooling tower or evaporative condenser on site, and include details about where it is located. You must also tell them if/when such devices are no longer in use. Notification forms are available from your local authority/environmental health department.

Scalding

There is a risk of scalding where water comes out of taps at temperatures above 44°C. In certain facilities, for example, care homes, this is especially so for whole-body immersion in baths and showers of vulnerable patients, the very young, elderly people, and people with disabilities or those with sensory loss who may not be able to recognise high temperatures and respond quickly.

As an employer you have a legal duty to assess the risk of scalding and to adopt appropriate measures to control it. Your approach will depend on the needs and capabilities of patients or residents. For most people, the scalding risk is minimal where water is delivered up to 50°C at hand-wash basins and a hot water warning notice may be sufficient. However, where vulnerable people can get access to baths or showers and the scalding risk is considered significant, the fitting of a thermostatic mixing valve (TMV) Type 3 is required to prevent water being discharged at more than 44°C.

Further information and guidance

Additional information relevant to healthcare settings

Key legislation

 

 

 

 

 

Related to Legionella

Most recent publications

Managing legionella during COVID-19 lockdown

06 May 2020

Decontamination units: Control of legionella bacteria

10 July 2017

See related publications

Most recent news items

Increased risk associated with the operation of Wet Cooling Plant and Coronavirus outbreak

19 March 2020

Access to information

How to request information from the Health and Safety Executive Northern Ireland including Freedom of Information (FOI) and the use of our Publication Scheme.