This disease is a virulent form of pneumonia. Inhaling airborne droplets or particles containing legionella bacteria, which are small enough to pass deep into the lungs, causes infection. As these bacteria are common in all water sources they can be found in most water systems in buildings. Under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992, you must notify your local authority if you have an air conditioning system, which has a cooling tower. Do remember that the system will require routine checks and maintenance to prevent the growth of legionella bacteria.
Micro-organisms are subject to the Control of Substances Hazardous to Health Regulations 2002 (COSHH). A duty is therefore placed on employers to carry out an assessment and to prevent, or adequately control exposure to risks of legionellosis under those regulations.
The Approved Codes of Practice on the prevention and control of legionellosis issued by the Health and Safety Executive places responsibility on employees and others to:
1. identify and assess risks of legionellosis
2. avoid the use of systems that would give foreseeable risk of legionellosis, or where this is not ‘reasonably practicable’ prepare a written scheme for minimising the risk from exposure.
3. implement and manage the scheme of precautions including the appointment of a person, or persons, to take managerial responsibility and to provide supervision.
4. keep appropriate records.
It is possible to control the conditions, which allow the bacteria to multiply by suitable design, manufacture, installation, operation, maintenance and treatment of water systems.
References/Further Guidance
The Control of Legionella Bacteria in Water Systems (L8)
Leaflet IAC(L) 27 (rev) – Legionnaires Disease