Legionella Health and Safety FAQ’S

•  water is stored or re-circulated as part of your system;
• the water temperature in all or some part of the system is between 20-45 °C;
• there are sources of nutrients such as rust, sludge, scale and organic matters;
• the conditions are likely to encourage bacteria to multiply;
• it is possible for water droplets to be produced and, if so, if they can be dispersed over a wide area, e.g. showers and aerosols from cooling towers; and
• it is likely that any of your employees, residents, visitors etc are more susceptible to infection due to age, illness, a weakened immune system etc and whether they could be exposed to any contaminated water droplets. (Ref: Health and Safety Executive Legionnaires’ disease: A brief guide for dutyholders Page 2 of 5

The most common places where legionella can be found include purpose-built water systems, cooling towers, evaporative condensers, hot and cold water systems and spa pools. There are also a number of other systems that may pose a risk to exposure to legionella, e.g. humidifiers, air washers, emergency showers, indoor ornamental fountains etc.

Your risk assessment should include:

• management responsibilities, including the name of the competent person and a description of your system;
•  any potential risk sources;
•  any controls currently in place to control risks;
•  monitoring, inspection and maintenance procedures;
•  records of the monitoring results, inspection and checks carried out; and
•  a review date.

If you decide that the risks are insignificant and are being properly managed to comply with the law, your assessment is complete. You will not need to take any further action, but it is important to review your assessment periodically in case anything changes in your system.

• yourself;
• one or more workers; and/or
• someone from outside your business.

(Ref: Health and Safety Executive Legionnaires’ disease: A brief guide for dutyholders Page 3 of 5).

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

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. There are a number of external schemes to help you with this, for example: ‘The control of legionellosis: A recommended code of conduct for service providers.2’

You should, as appropriate:

•  ensure that the release of water spray is properly controlled;
• avoid water temperatures and conditions that favour the growth of legionella and other micro-organisms;
• ensure water cannot stagnate anywhere in the system by keeping pipe lengths as short as possible or by removing redundant pipework;
• avoid materials that encourage the growth of legionella. The Water Fittings and Materials Directory3 references fittings, materials, and appliances approved for use on the UK Water Supply System by the Water Regulations Advisory Scheme);
• keep the system and the water in it clean; and
• treat water to either kill legionella (and other microorganisms) or limit their ability to grow.

If you identify a risk that you are unable to prevent, you must introduce appropriate controls. You should introduce a course of action that will help you to control any risks from legionella by identifying:

•  your system, e.g. developing a written schematic;
• who is responsible for carrying out the assessment and managing its implementation;
• the safe and correct operation of your system;
• what control methods and other precautions you will be using; and
• what checks will be carried out to ensure risks are being managed and how often.

If you have less than five employees, you do not need to write anything down, although it is useful to keep a written record of what you have done. (Ref: Health and Safety Executive Legionnaires’ disease: A brief guide for dutyholders Page 4 of 5).

Records should include details about:

• the person or people responsible for conducting the risk assessment, managing, and implementing the written scheme;
• any significant findings of the risk assessment;
• the written control scheme and its implementation; and
• the results of any inspection, test or check carried out, and the dates.

This should include details about the state of operation of the system, ie in use/not in use.

These records should be retained throughout the period for which they remain current and for at least two years after that period. Records kept in accordance with the last bullet point above should be retained for at least five years.

If you have a case of legionellosis in an employee who has worked on cooling towers or hot water systems that are likely to be contaminated with legionella, you must report this under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR).