History of Legionella

Working backwards

The first known case of Legionnaires’ disease was recorded at a conference of the American Legion in Philadelphia, where over 200 victims fell ill with cold and flu-like symptoms and 34 people lost their lives. It was in December 1976 that Dr Joseph McDade discovered and identified the bacteria, to be named Legionella pneumophila, as the cause of the disease.

Since then, scientists have worked back through history to determine whether similar outbreaks and symptoms could have been caused by the same bacteria, Legionella pneumophila - even before the discovery in 1976. In order to identify the cause of these cases to Legionella, survivors of the outbreaks were examined to find they had elevated levels of antibodies to L. pneumophila. There are now over 50 different species of Legionella bacteria.

Legionnaires’ disease in the UK

The first major outbreak in the UK was at Staffordshire Hospital in 1985, where over 100 patients fell ill with pneumonia-like symptoms, 28 of which died. An investigation traced the source of the outbreak to Legionella bacteria in an air-conditioning cooling tower.

In 2002, 180 people fell ill and seven people died after visiting a local leisure facility in Barrow-in-Furness, Cumbria. In the Health and Safety Executive (HSE) report that followed, it was recorded that this outbreak could have been avoided if risks had been properly acknowledged and managed. The outcome of the investigation showed that water management by the council was not acceptable; the cooling tower had not been chemically treated and there had not been any microbiological monitoring or system checks.

In 2012, an outbreak in Edinburgh caused 92 cases of Legionnaires’ disease, which lead to 4 fatalities. The source of the bacterial outbreak has been impossible to identify by the HSE.  To date, there have been no prosecutions.

Guidance in the UK

Following the outbreaks detailed above and cases identified every year, guidance was required to ensure that water systems are suitably managed.

Managing the risk from Legionella falls under The Health and Safety at Work Act 1974 and Control of Substance Hazardous to Health Regulations (COSHH). COSHH was first published in 1988 and it was this document, alongside HSE guidance, that started us on the route to where we are today.  The COSHH regulations give a framework of actions designed to assess, prevent or control risks from hazardous substances, including bacteria like Legionella. In addition, the Management of Health and Safety at Work Regulations (MHSWR) provide a framework for controlling health and safety in the workplace.

For business owners, property managers and estates managers, the presence of Legionella in their water systems is a serious issue. Guidance and legislation are regularly reviewed to manage the risk, with details of these revisions over time listed below:

1987 - Guidance Note EH48 (HSE) - the initial Guidance Note on Legionella.

1991 – Approved Code of Practice (ACoP) and Guidance HS(G)70 – The starting point of the documents we have today. It was first published by the HSE in 1991.

2001 – ACoP L8 – A new name and a revised, updated document published by the Health and Safety Commission (HSC); it combines the ACoP outlining legal requirements and technical guidance on how to manage the risk.

2010 – British Standard BS8580 – The first British standard for the undertaking of Legionella risk assessments. It outlines what is expected of a Legionella risk assessment, giving guidance on management audits, system inspections, risk scoring and reporting. Please note BS8580 was updated in 2019.

2013 - TM13 (published by the Chartered Institution of Building Services Engineers)

This document was first published in 1991, with an adaptation and revision of the publication in 2013. It gives guidance on design, installation, commissioning, operation and maintenance of all types of water systems.  

2013 - ACoP L8 revision 4 + HSG274 parts 1-3

The ACoP is now separate from the technical guidance. The revisions to the ACoP L8 guidance place more emphasis on the duty holder, making it much easier to understand the role and responsibilities when controlling the Legionella risk.

The Technical Guidance HSG 274 has been divided into three easier-to-read publications, on evaporative cooling systems, hot and cold water systems and other risk systems.

SOCOTEC keeping up with the times

In 1999, the Legionella Control Association was founded by British Association of Chemical Specialities (BACS) and the Water Management Society (WMSoc); the company has held Legionella Control Association Membership since 1999.

UKAS, the UK’s national accreditation body, granted its first ever accreditation for conducting Legionella risk assessments in 2010 – setting an internationally agreed standard for managing the risk of Legionella. In 2015, we certified as a UKAS accreditation inspection body no. 6123 for Legionella risk assessments under ISO/IEC 17020:2012.

In line with HSE’s Approved Code of Practice L8 and Technical Guidance HSG 274, SOCOTEC specialises in Legionella risk management to ensure clients are compliant through the undertaking of Legionella risk assessments, consultancy, bespoke Legionella training courses, water treatment and monitoring.

To further ensure the effective control of Legionella risk, SOCOTEC has developed its own in-house app for efficient data capture, as well as web-based electronic log books to enable clients to effectively manage their systems and monitor control activities. With this, we can support our clients in remaining compliant with the latest regulations.