Health and Safety
Executive / Commission
Local authority circulars
To: Directors of Environmental Health/ Chief Environmental Health Officers of London, Metropolitan, District and Unitary Authorities and Chief Executives of County Councils.
For the attention of: Environmental Services / Trading Standards / Fire Authorities / Other
This circular gives advice to local authority enforcement officers
1 This circular provides general guidance for enforcement officers responsible for enforcing health and safety legislation at premises where there is a risk from legionellosis.
2 The majority of cases of legionnaires' disease (LD), are caused by the bacterium Legionella pneumophila, but there are many other species of the organism which have been implicated in human disease is a pneumonia, but other milder illnesses may be caused by these organisms. All illnesses due to legionella species are known collectively as 'legionelloses'; Pontiac Fever is one of the milder conditions. Legionella pneumophila is found in natural water supplies and in soil. It is also found in many recirculating and water supply systems. The precautions required to minimise the risk of infection are given in the Approved Code of Practice (ACOP). The prevention or control of legionellosis (including legionnaires' disease) (L8), and in an associated Health and Safety Series Booklet HS(G)70: The control of legionellosis including legionnaires' disease. A free leaflet on legionnaires' disease (AC(L)2 is also available.
2 Duties under the Health and Safety at Work etc Act 1974 (HSW Act) extend to risks from legionella arising from work activities. In addition, all harmful micro-organisms are subject to the Control of Substances Hazardous to Health Regulations 1988 (COSHH), and accordingly, the requirements to carry out an assessment, and to prevent, or adequately control exposure under those regulations will apply to risks of legionellosis.
3 This would be particularly relevant to persons cleaning or maintaining systems where legionella may be present, and when the increased risk to exposure will need to be taken into account in the assessment. COSHH also requires that the risk to "other persons" should be considered "so far as is reasonably practicable". This would include not only those who might work in an environment controlled by an air conditioning system or in premises served by a hot and cold water system, but also others (including members of the public) who might be exposed to emissions from wet cooling towers or evaporative condensers, or other aerosols which might contain viable organisms.
4 The Approved Code of Practice on the prevention and control of legionellosis (including LD) was issued by the Health and Safety Commission (HSC) in September 1991, and came into force on 15 January 1992. The ACOP provides a basic framework for preventing further outbreaks of the disease, giving advice on the requirements of HSW Act and a basic framework for preventing further outbreaks of the disease, giving advice on the requirements of HSW Act and COSHH. It places responsibility on employers and others to:
(a) identify and assess risks of legionellosis
(b) avoid the use of systems that give rise to a reasonably foreseeable risk of legionellosis or, where this is not reasonably practicable, prepare a written scheme for minimising the risk from exposure;
(c) implement and manage the scheme of precautions including the appointment of a person, or persons, to take managerial responsibility and to provide supervision; and
(d) keep appropriate records.
The ACOP also gives advice on the management, selection, training and competence of personnel, and sets out the responsibilities of manufacturers, importers, suppliers and installers of products and services.
5 By suitable design, manufacture, installation, operation, maintenance and treatment of water systems, it is possible to control the conditions which allow the bacteria to multiply. The precautions outlined in the ACOP and the associated guidance (HS(G)70), should be adopted for all water systems which may create a risk of legionellosis. To present a risk the system would have to incorporate water at temperatures between 20-45oC, have a nutrient supply, have areas of stagnation, have dispersal in a respirable aerosol/spray, and also have people present within the vicinity. Such situations may include water-cooled cooling towers, evaporative condensers, industrial sprays, showers and air conditioning plants, or places where spray could be generated incidently during the cleaning, repair and maintenance of the system. It should be recognised however, that the ACOP and HS(G)70 provide general guidance for manufacturers, installers and users etc; they do not prescribe specific conditions.
6 These regulations require the notification of wet cooling towers and evaporative condensers to local authorities (LAs) in whose area the equipment is situated, regardless of whether it is the LA or HSE that is the enforcing authority for the premises concerned. LAs should make available to HSE information from notifications relating to equipment on premises for which HSE has enforcement responsibility. The main purpose of this requirement is to assist inspectors in investigating outbreaks (2 or more confirmed related cases) thought likely to have arisen from wet cooling towers of evaporative condensers.
7 Although legionella is widespread, the risk it presents can vary enormously, so inspectors need to exercise caution and their professional skills in order to adopt an appropriate response. In many large and complex buildings a full inspection of the water system would prove difficult and time consuming. If buildings have significant potential sources of dissemination, the potential risk should be considered during routine inspection and the occupiers should be asked about the maintenance of the system, the frequency of cleaning, methods of disinfection etc.
8 In addition to the risks which may result from the dispersal of legionella into the atmosphere, other hazards may be present during monitoring and maintenance of water systems. It should be noted that water-treatment chemicals are often highly toxic. Great care needs to be taken to ensure that users and other occupants of a building are not affected, and that chemicals do not enter drinking water. Similarly, chlorination of water, whether directly, or by the use of sodium hypochlorite solution poses risks potential. Biocides should never be used in drinking supplies, and should not be discharged into store-water drains without the permission of the relevant water authority. When answering requests for advice, the information in the ACOP and HS (G)70 may be quoted. Susceptible water systems, where control measures are suspected of having broken down, or those implicated in an outbreak, should be turned off until disinfected, cleaned and disinfected again, unless the act of turning the system off will create a greater risk.
9 The British Standards Institution has produced BS7592; 1992 Methods for sampling legionella organisms in water and related maters. A draft standard DD211:1992 Methods for detection and enumeration of legionella organisms in water and related materials is being prepared.
10 If it is considered necessary to take enforcement action, for example, if part of a water system such as a feed tank is found to be open and demonstrably contaminated, technical advice and support may be sought from HSE via the ELO.
11 (a) The key figure in the investigation of any outbreak of a communicable disease, is the Proper Officer (or in Scotland, the Consultant in Public Health Medicine (CPHM), employed by the Health Board) appointed by the Local Authority under the Public Health (Control of Disease) Act 1984 and the Public Health (Infectious Diseases) Regulations 1988.
Local Authority means District Council, Port Health Authority, Metropolitan Council, and in London a London Borough, the Common Council of the City of London, and the Sub-Treasurer of the Inner Temple and the Under Treasurer of the Middle Temple respectively.
(b) Local Authorities have established incident plans to investigate major outbreaks of infectious disease, including legionella, which are activated by the Proper Officer who will invoke a Committee of Investigation. In Scotland, Local Authorities have jointly established Outbreak Control Plans with the Health Board. The CPHM would invoke the Outbreak Control Team when necessary. Also in Scotland, Legionellosis is a notifiable disease under the Public Health (Notification of Infectious Disease (Scotland) Regulations 1988 and would automatically be notified to the CPHM by reporting laboratories.
(c) The Committee of Investigation will include the Proper Officer (or CPHM) and a Variety of other professionals who work for Area Health Authorities, the Public Health Laboratory Service (PHLS), Communicable Disease Surveillance Centre (CDSC), and the Local Authorities. Where the Proper Officer (or CPHM) is not a Consultant in Communicable Disease/Medical Officer of Environmental Health (CCCD/MOEH) that person will be one of the AHA officers assisting the Proper Officer (or CPHM) in his inquiries. Sampling of suspected sources of infection is usually undertaken by Environmental Health Officers or Technical Officers acting under their direction and analysed by PHLS. The CDSC can provide epidemiological support to the Proper Officer (or CPHM).
(d) If only one case is diagnosed (which is designated as an "incident" and not an "outbreak") it is possible that no action will be taken, unless the case occurs at a premises where there are additional risk factors to be taken into account (eg. hospitals, nursing homes, and residential homes for the elderly) because of the type of occupant, in such circumstances even one case will be thoroughly investigated.
(e) The Local Authority is empowered under statutory nuisance provisions of Part II of the Environmental Protection Act 1990 to deal with "fumes or gases emitted from premises" and with "dust, steam, smell or other effluvia arising on industrial, trade or business premises where such are prejudicial to health or nuisance. A Notice must be served to abate the nuisance and on expiry of the time allowed the LA are empowered to abate the nuisance undertaking whatever action may be necessary in execution of the Notice whether or not proceedings the LA is also taking proceedings for non-compliance. The Proper Officer (or CPHM) may not however be the officer appointed to deal with these matters. In most Local Authorities the Chief EHO will have been delegated to deal with Part III of the EPA 1990, will also have appointed under HSW Act, and EHO's under his control will also have been authorised under his control will also have been authorised under both Acts. In some cases LA inspectors may consider a more expedient to exercise their powers to enforce compliance with HSW Act ss.2 and 3. If technical support for prosecution or notices under HSW Act is required, then the ELO should be informed. The ELO will then pass the details onto the relevant sections.
(f) Care must be taken to ensure any information necessary for prosecution or notice purposes is not destroyed or removed. Statements from key personnel should be taken early in the investigation. Particular attention should be paid to management systems. HSE may advised on the nature of evidence required in the collection of statements.
(g) Because of the complex nature of LD, the difficulty in identifying the source of infection, and the widespread presence of the bacterium, care must be taken to establish the proper evidence of risk. Even if a system is found to be contaminated, it cannot be assumed that is necessarily the source of infection of the known cases.
(h) Before the investigation, advice should be sought from the CCDC/MOEH or Senior Medical Employment Adviser (SEMA/FCG) to ensure that:
(i) no person involved in any enquiries is being exposed to risk; and
(ii) all identifiable potential sources of infection are isolated to prevent its spread
Again assistance may be sought from the local SEMA via the ELO.
12 HSW Act, and in particular COSHH, may be used for enforcement. This should normally be considered where a water system which may give rise to risk is found, and/or where a suitable and sufficient COSHH assessment has not been carried out, or when necessary precautions to control the risks have not been taken in accordance with the provisions of the ACOP. Prosecutions may be taken, and notices services, whether or not an outbreak has occurred. If the precautionary measures are manifestly below the standard outlined in the ACOP.
13 Because of widespread public concern about LD, inspectors will need to demonstrate that their powers have been appropriately exercised. Where a prosecution is proposed, the option of proceeding on indictment must be considered.
14 It will be necessary to ensure that any action following an outbreak or suspected outbreak, is coordinated between all the relevant agencies. However, inspectors should take enforcement action where required, although the views and actions of the other parties should be taken into account. Inspectors will need to be satisfied that the relevant demarcation of responsibilities for investigation, enforcement and provision of information to the employer, workforce, the public and the media have been agreed.
15 In cases of difficulty and in cases where a number of people have been affected, the ELO should be informed without delay.