Legionnaires’ disease

Legionnaires’ disease is an airborne disease caught by inhaling small droplets of contaminated water. It is not contagious and is not known to spread directly from person to person. It cannot be caught by drinking contaminated water.

Legionella bacteria are common in natural water sources such as rivers, lakes and reservoirs, usually in low numbers. The risk of the disease is present when water is stored or recirculated in man-made water systems. Contamination can develop and spread in purpose-built systems like cooling towers, evaporative condensers, hot and cold water systems and whirlpool spas, humidifiers, air-washers, emergency showers and indoor water fountains. Problems develop when bacteria spread quickly through water-based systems in warm temperatures (between 200C to 450C).

In 2012, there two legionnaires’ outbreaks in Edinburgh and Stoke-on-Trent which caused five deaths and left more than 120 members of the public ill.

On the 25 November 2013, the HSE released the new (version 4) of the Approved Code of Practice (ACOP) Legionnaires’ Disease: The control of Legionella bacteria in water systems (L8).

The ACOP, along with supporting Technical Guidance, provides practical advice to employers on how to control the risk of legionella bacteria in water systems. In an attempt to provide more detailed guidance on the prevention of Legionnaires’ disease, the HSE has revised the ACOP L8 significantly.

The revised version gives a clearer distinction between the legal requirements and guidance. These include identifying and assessing sources of risk, preparing a scheme to prevent or control risk, implementing, managing and monitoring precautions, keeping records of precautions and appointing a manager to be responsible for others.

The main changes are removing Part 2, the technical guidance, which is published separately in HSG274, and giving the following issues ACOP status:

• risk assessment;

• the specific role of an appointed competent person, known as the “responsible person”;

• the control scheme;

• review of control measures; and

• duties and responsibilities of those involved in the supply of water systems.

On 15 February 2014, the European Commission granted the HSE (acting on behalf of the UK) derogation from the national Biocidal Products Regulations 2011. This means that from 15 February 2014, UK water treatment systems using elemental copper for legionella control can continue to use it until the industry provides data on the different types of copper used for approval by the European Commission.