What causes Legionnaires’ disease and how the risks can be managed

1. STARTING AT 12.30
Battles with the legion: What causes
Legionnaires’ disease and how the risks can be
managed
Please wear the headphones to listen to presentation

2. Battles with the Legion
- What causes Legionnaires’ disease and how the
risks can be managed.
Presented by
Dr Colin Purnell of Cogent Risk Management Ltd
on behalf of the BOHS
19th June 2014

3. 3
SETTING THE
BATTLE SCENE
What are we up against?

4. 4
Legionnaires’ Disease
• Named after an outbreak of
pneumonia in people attending a
convention of the American Legion
at a hotel in Philadelphia in 1976
• 179 people made ill and 34 died
(including passers-by)
• Causative agent eventually
identified to be a previously
unknown strain of bacteria,
subsequently named Legionella
pneumophila.
Bellevue-Stratford Hotel

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What is Legionnaires’ disease
Legionellosis - generic term - covers all
infections caused by legionella bacteria
Legionella bacteria cause two diseases:
 Legionnaires’ disease – a rare, severe
and potentially fatal form of pneumonia
 Pontiac fever - mild ‘flu-like’ illness
90% of Legionnaires’ disease cases are
caused by Legionella pneumophila.

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KNOW YOUR ENEMY

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Legionnaires’ Disease
Caused by inhaling a virulent strain of
Legionella pneumophila contained in very
small water droplets (aerosols)
Legionella bacteria penetrates deep into
the lung (alveoli)
Legionella bacteria invade alveolar
macrophages in which they reproduce in
large numbers.

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Legionnaires’ Disease
Infection Time On-set of symptoms in 2 - 10 days,
Symptoms Fever, chill, headaches, muscular
aches, dry cough, breathlessness,
diarrhoea, vomiting and delirium
Incidence 250 - 350 confirmed cases a year (UK)
Mortality Rate 10 - 15% for “healthy” people,
25 - 30% for hospital patients,
>50% for the immuno-suppressed
At Risk Groups 45 - 75+, alcohol drinker, smoker,
(males > females) immuno-suppressed, existing
respiratory or other disease, diabetes.

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Legionnaires’ Disease
Infective dose not known, but likely to be low,
Infection occurs mainly in people aged 50+,
Some infected persons are exposed for very
short periods and/or kilometres away from the
source,
Not everybody exposed develops
Legionnaires’ disease.

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Where are Legionella bacteria found ?
In Nature
• Soil, ponds, lakes and rivers.
In Man-made water systems such as:-
• Hot and cold water systems and spa pools
• Cooling tower water systems
• Ultrasonic misting systems
• Health and dental care equipment
Any water system that is capable of
supporting the growth of legionella bacteria.

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Water systems
Cooling towers,
showers, spa pools,
etc.
Amoebae
Biocide
(if added)
Legionella in
supply water,
dirt or air
Temperature
20 - 46°C
Nutrients,
+ Iron salts,
L-cysteine
Other
bacteria
Sludge, scale,
stagnation &
biofilms
Factors influencing the survival and
growth of legionella in water systems
pH 2 - 8.5

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How do Legionnaires’ disease outbreaks occur?
1. Legionella bacteria enters a water system,
2. Legionella bacteria are given suitable conditions
to multiply to hazardous levels in the water,
3. Aerosols containing a virulent strain of
Legionella bacteria are released into the air,
4. The aerosols are inhaled by susceptible persons
who may then develop Legionnaires’ disease.
All the above are required to cause an outbreak
of Legionnaires’ disease.

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EXAMPLES OF
BATTLES LOST

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Headline ‘News of the World’
following outbreak Legionnaires’ disease
at Stafford District General Hospital in 1985
“KILLER CLOUD PROBE
AS BUG’S TOLL REACHES 28”
175 people infected
28 people died
Source of the outbreak was a cooling tower and its
associated air conditioning system
Legionella bacteria entered the air of the out-patients
department of the hospital.

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How The Observer depicted Legionnaires’
disease at Stafford Hospital on 11 August 1985

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Major Legionnaires’ Disease Outbreaks
in UK since 1985
 London (1988) - source - cooling tower
 Corby (1997) - source - not identified
 Cardiff (2000) - source - ultrasonic mister
 Barrow (2002) - source - cooling tower
 Hereford (2005) - source - cooling tower
 Wales (2010) - source – not identified
Recent outbreaks (still under investigation)
• Edinburgh (2012) - suspected source - cooling tower
• Stoke (2012) - suspected source - spa pool.

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HSE INVESTIGATION OF PAST OUTBREAKS
• Make someone managerially responsible for
ensuring the requirements for control were
properly carried out,
• Prepare a “suitable and sufficient” risk
assessment,
• Implement a “robust” written scheme of
precautionary measures,
• Manage their water systems properly.
The organisations involved failed to:-

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FIGHTING THE BATTLE
BY MANAGING THE RISK

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Replaced L8 (2000)
APPROVED CODE OF PRACTICE & GUIDANCE
Revisions to L8 intended to
simplify and clarify the text.

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Removed the technical guidance from the
ACOP which is now published separately as
HSG274 - which has 3 parts.
Legionnaires’ disease – L8 (ACoP) 2013
MAIN CHANGE
Part 1 - Evaporative cooling systems
Part 2 - Hot & cold water systems
Part 3 - Other risk systems (includes spa pools).

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Control of legionella bacteria in water systems
Detailed guidance on spa pools
is currently provided in the 2006
HSE/PHE publication
”The Management of spa pools:
Controlling the risks of infection”
Currently being updated.

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OTHER CHANGES
 risk assessment - schematic now ACoP requirement,
 specific role of appointed competent "responsible"
person (and requirement for deputy),
 written scheme and what it should include,
 regular review of risk assessment and measures,
 the duties and responsibilities of those involved in the
design, manufacture & supply of water systems and
services (consultancy & maintenance).
The following issues now have ACOP status:

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ACOP - SCOPE AND APPLICATION
A “reasonably foreseeable risk” of exposure to
legionella bacteria exists for:-
(a) wet cooling water systems
(b) hot and cold water systems
(c) spa pools
(d) other risk systems
All these systems require a Risk Assessment.

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PURPOSE OF THE RISK ASSESSMENT
To enable a decision to be made on: -
the risk to health, i.e. whether the
potential for harm to health from
exposure is reasonably foreseeable
unless adequate measures are taken,
the necessary measures to prevent, or
adequately control, the risk from
exposure to legionella bacteria.

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Who should undertake the
risk assessment?
• The Duty Holder under ACoP L8 can select a
risk assessor – but retains responsibility for
the quality of the risk assessment,
• The risk assessment must be “suitable &
sufficient”,
• Must be completed by a “competent person”.

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“Suitable and Sufficient”
all the factors pertinent to the water
system’s use and operation have been
considered,
an informed and valid judgement has
been reached about the risks and the
steps which need to be taken to achieve
and maintain adequate control of
legionella in the water system.
Dutyholder must be able to demonstrate that:-

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• Primary duty is to eliminate (prevent) the
risk of exposure to legionella bacteria.
• Secondary duty is to control the exposure
risk by measures which do not allow
proliferation of the legionella organism and
reduce, SFARP, exposure of people to
(inhalable) water droplets (aerosols).
ACoP - Dutyholders

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INDG 458 - A brief guide for dutyholders
Provides information on the how dutyholders
should comply with their legal duties.

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PREVENTING OR CONTROLLING THE RISK
FROM EXPOSURE TO LEGIONELLA BACTERIA
• must be prepared where the risk assessment
shows that there is a reasonably foreseeable
(and unavoidable) risk,
• should be properly implemented and
managed,
• should specify measures to be taken to
ensure that it remains effective.
THE WRITTEN SCHEME

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THE WRITTEN SCHEME
The L8 ACoP Technical Guidance Parts 1,
2 and 3 provides detailed information of
the appropriate control measures and
water treatment regimes.
The written scheme must include an up-
to-date schematic of the water system.

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 Arrangements in place - to ensure that the
responsible person (or their appointed deputy) can
be contacted at all times,
 Emergency call-out procedures,
 Clear lines of communication - unambiguous and
regularly audited to ensure they are effective. This
also applies to contractors and consultants who may
be responsible for certain parts of the written
scheme.
IMPLEMENTATION OF THE WRITTEN SCHEME

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The management of the water systems involves:-
a) checking the performance and operation of
the system and its component parts,
b) inspecting the “accessible” parts of the system
for damage and signs of contamination,
c) monitoring to ensure that the treatment
regime continues to control to the required
standard.
Note: The above ACoP requirements were “guidance” in L8 (2000)
ACoP - REVIEW OF CONTROL MEASURES:
MONITORING AND ROUTINE INSPECTION

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Spa pool accessible parts
ACoP - inspect the “accessible” parts of the
system for damage and signs of contamination.

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Spa pool “inaccessible” parts !
Any “retained” risks must be considered in the
written scheme pending corrective action.

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• the responsible person(s) and their deputies,
• significant findings of the risk assessment,
• the written scheme and its implementation,
• details about the state of operation of the water system,
• results of any monitoring, inspection, tests or checks.
RECORD KEEPING
Dutyholder must ensure records are kept including:-
The L8 ACoP provides detailed guidance on exactly
what records should be kept for each type of water
system.

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Review
Policy and
Procedures
Water
System
Surveys
Risk
Assessment
Written
Scheme
ACoP L8 (2013) –
THE WATER SYSTEM MANAGEMENT CYCLE
Remedial
Works
Audit
RECORDS

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ROLE OF CONSULTANTS AND
WATER TREATMENT CONTRACTORS
• Water treatment programmes,
• Water hygiene services (including water sampling),
• Preparation of schematics, risk assessments and
written schemes,
• Inspection, cleaning & disinfection of systems,
• Provide training
“Help and assistance” does not absolve the dutyholder
from their responsibilities under ACoP L8 (2013).

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• Must ensure the control measures are designed and
implemented to be effective,
• Must provide adequate information on the correct and
safe use of products in all circumstances of their use,
• Must make the dutyholder or their responsible
person(s):-
 aware of any deficiencies in the risk assessment or
written scheme and
 aware of any limitations on their own expertise,
products or services.
SUPPLIERS OF PRODUCTS & SERVICES,
INCLUDING CONSULTANCY & WATER TREATMENT

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SOME FINAL COMMENTS

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CONSEQUENCES OF AN OUTBREAK
• Adverse publicity - media, politicians, public
• Inspection of site facilities - by LA, HSE, PHE
• Criminal proceedings
• Public - nearly always affected - people die
- possible manslaughter charges
• Civil Action - award of damages
• Financial costs - management time, legal fees,
fines, insurance premiums, etc.

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Sequence Based Typing (SBT)
DNA Profiling - Sequence Based Typing
(SBT) of Legionella pneumophila strains in
LD patients and environmental samples
now a routine investigation procedure
SBT can prove (unequivocally) that a
particular strain of Legionella pneumophila
bacteria in a water system was the same
strain that infected the people with
Legionnaires’ disease.

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WHAT ARE THE IMPLICATIONS FOR THE
DUTYHOLDER IF THINGS GO WRONG?
If the ACoP L8 (2013) provisions are not complied
with then a Court of Law will view it as proof of
contravention of legal requirements.

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THE FINAL COMMENT
An outbreak of Legionnaires’
disease has never been
caused by a clean and well
managed water system.

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ANY QUESTIONS?

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TECHNICAL GUIDANCE (HSG274)
PART 1 - EVAPORATIVE COOLING SYSTEMS
Considerably expanded covering:-
• Health and Safety Law and ACoP requirements
• Types and Designs and Operation
• Requirements of cooling water system treatment
• Desired outcome in terms of water quality
• Use of biocides and alternative treatments
• Inspection, cleaning and disinfection procedures.
• Monitoring water quality and understanding reports.

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TECHNICAL GUIDANCE (HSG274)
PART 2 – HOT AND COLD WATER SYSTEMS
Considerably expanded covering:-
• Health and Safety Law and ACoP requirements
• Types and Application of hot and cold water systems
• System design and commissioning requirements
• Checklists of inspection & maintenance requirements
• Water treatment - thermal & biocides (Cl2, ClO2, etc)
• Microbiological monitoring
• Cleaning and disinfection (thermal & chemical)
• Managing the duty: Shared premises & landlords
• Special consideration for healthcare & care homes.