International Clearing House for Major Chemical Incidents
A WHO Collaborating Centre
Public Health and Chemical Incidents
Guidance for National and Regional Policy Makers in the
Public/Environmental Health Roles
1999
The International Programme on Chemical Safety (IPCS), established
in 1980, is a joint venture of the United Nations Environment
Programme (UNEP), the International Labour Organisation (ILO), and the
World Health Organization (WHO). The overall objectives of the IPCS
are to establish the scientific basis for assessing risk to human
health and the environment from exposure to chemicals, through
international peer-review processes, as a prerequisite for the
promotion of chemical safety, and to provide technical assistance in
strengthening national capacities for the sound management of
chemicals.
The Inter-Organization Programme for the Sound Management of
Chemicals (IOMC), was established in 1995 by UNEP, ILO, the Food and
Agriculture Organization of the United Nations, WHO, the United
Nations Industrial Development Organization, and the Organisation for
Economic Co-operation and Development (Participating Organizations),
following recommendations made by the 1992 United Nations Conference
on Environment and Development to strengthen cooperation and increase
co-ordination in the field of chemical safety. The purpose of the IOMC
is to promote co-ordination of the policies and activities pursued by
the Participating Organizations, jointly or separately, to achieve the
sound management of chemicals in relation to human health and the
environment.
WHO Collaborating Centre for an International Clearing House for
Major Chemical incidents
Director: Professor Gary Coleman, University of Wales Institute,
Cardiff, UK
Associate Directors: Professor Stephen Palmer, University of Wales
College of Medicine, Cardiff, UK
Professor Phillip Routledge, University of Wales College of Medicine,
Cardiff, UK
First published in 1999 by WHO Collaborating Centre for an
international Clearing House for Major Chemical Incidents.
(c) 1999 WHO Collaborating Centre for an International Clearing House
for Major Chemical Incidents.
ISBN 1-902724-10-0
Photocopying: You may freely reproduce parts (only) of this
document. However, we do ask that you acknowledge the source.
Further copies are available from: WHO Collaborating Centre for an
International Clearing House for Major Chemical Incidents, University
of Wales Institute, Cardiff, Western Avenue, Cardiff, CF5 2YB, UK.
Tel: +44 02920 416852
Fax: +44 02920 416803
e-mail: healthchem@uwic.ac.uk
http://www.healthchem.uwic.ac.uk
Contents
PREFACE
STRUCTURE OF THIS DOCUMENT
PART 1 - GUIDANCE FOR PUBLIC HEALTH POLICY MAKERS
Introduction
The public health problems of acute chemical incidents
The problems caused by the lack of public health involvement
Roles at the national level
Recommended actions at Government level
Roles at the local level
Recommended actions at the local level
PART 2 - THE PUBLIC HEALTH / ENVIRONMENTAL FUNCTIONS IN THE
MANAGEMENT OF ACUTE CHEMICAL INCIDENTS
Background information
Planning and preparedness
Routine activities
Helping to deal with incidents
Assessing the impact on the health of the public
Remediation, restitution and rehabilitation
Guidelines and legislation required
PART 3 - A MODEL FOR THE PUBLIC HEALTH / ENVIRONMENTAL HEALTH
MANAGEMENT Of CHEMICAL INCIDENTS
International functions
National functions
Local functions
PART 4 - APPENDICES
A - Editorial Panel
B - Groups contributing to the policy document
C - Individuals contributing to the working groups
D - Conclusions from the IPCS working groups
E - Examples of major chemical incidents
F - Diagram of incident site risk zones
G - Diagram of pathways of exposure
H - Data sources
I - List of acronyms and contact addresses
J - Glossary
K - Bibliography and references
Preface
Chemical exposure has always been a feature of human society. Before
human beings started making new chemical substances, they were exposed
to poisonous plants, venomous animals, and chemicals of natural
origin, such as produced by fire. With the onset of mining and
smelting of minerals, workers were exposed to fumes and dusts.
Poisoning occurred in early civilizations through the use of lead and
mercury. However, the rapid industrialization of the last century, the
increasing numbers and volume of chemicals produced in this century,
and the growing global market in chemicals of the recent decades has
accelerated dramatically the range of chemicals and types of exposure
experienced by individuals and populations.
The public has become aware and increasingly concerned about exposure
to chemicals, particularly through major chemical incidents, such as
the Minimata mercury poisoning, the Itai-Itai disease caused by
cadmium, the Seveso and Bhopal incidents involving dioxin and methyl
isocyanate, respectively, and the Spanish toxic oil episode. Incidents
such as these cause fear, and sometimes panic, in populations. They
are frightening because they have the potential to cause large numbers
of deaths and disabilities and because they raise questions about the
fragility of technologies over which society, and the local community
in particular, may lose control. Expressions of concern have also been
increasing, not only by the public, but also by the scientific and
medical community, that there may be long-term effects on human
health, such as the development of cancers and congenital
malformations, resulting from these chemical incidents. Furthermore,
there is concern that exposure to chemicals may be giving rise to
diseases, not hitherto recognized, or exacerbating diseases of another
etiology.
Governmental authorities in many countries now recognize that these
concerns need to be faced, both to allay unnecessary fears and to take
timely, cost-effective action, where appropriate, to protect human
health and the environment, and to mitigate deleterious effects of
chemical incidents.
The International Programme on Chemical Safety (IPCS) was established
in 1980 by the World Health Organization (WHO), the International
Labour Organisation (ILO) and the United Nations Environment Programme
(UNEP) to provide, through chemical risk assessment, an
internationally-evaluated, scientific basis on which countries may
develop their own chemical safety measures, and to strengthen national
capabilities for prevention and treatment of harmful effects of
chemicals and for managing the health aspects of chemical emergencies.
Through an informal IPCS Consultation of Experts, held in February
1992, a number of scenarios of concern to governments were identified
where guidance was needed if health and environmental authorities were
to meet their responsibilities for protection of human health and
the environment. These scenarios included: chemical incidents
involving human exposure with or without immediate health effects;
where exposed persons needed to be followed-up for possible sequelae
or delayed effects; and observation of health effects of unknown
cause, but suspected chemical aetiology. As a result of this
consultation, and in pursuance of its mandate in the field of
chemical safety, the IPCS decided to prepare guidelines
for governments as to the roles of health and environmental
authorities in meeting their responsibilities in relation to these
scenarios. Further, to support the work of the WHO in the area of
chemical incidents, two WHO Collaborating Centres were established,
one on the "Health Aspects of Chemical Accidents" at the Utrecht
University Hospital, in the Netherlands, the other for an
"International Clearing House for Major Chemical Incidents", at the
University of Wales Institute, Cardiff, in the United Kingdom.
The United Nations Conference on Environment and Development (UNCED),
held in Rio de Janeiro, Brazil, in June 1992, defined an international
strategy for environmentally sound management of toxic chemicals
within the principles of sustainable development and the improvement
of quality of life for humankind. Promotion of effective international
cooperation with respect to prevention of, preparedness for and
response to emergencies and incidents involving chemicals, including
management of poisoned patients, follow-up of sequelae, and incident
site clean-up and rehabilitation, is one of the important aspects of
sound management of chemicals identified by UNCED. Following UNCED,
the IPCS has played a central role in establishing strengthened
cooperation among international organisations through the
Inter-Organization on Sound Management of Chemicals (IOMC), and in
setting up an Intergovernmental Forum on Chemical Safety (IFCS). In
relation to chemical incidents, the IPCS is dealing mainly with the
health and medical aspects.
A number of important international initiatives have already been
undertaken in relation to the health aspects of chemical incidents. In
1989, "Methods for Assessing and Reducing Injury from Chemical
Accidents" was published jointly by the IPCS and the Scientific
Committee on the Problems of the Environment (SCOPE) of the
International Council of Scientific Unions (ICSU). In 1994, the IPCS,
the Organisation for Economic Co-operation and Development (OECD), the
United Nations Environment Programme Industry and Environment
Programme Activity Centre (UNEP-IE/PAC) and the WHO European Centre
for Environment and Health (WHO-ECEH) published "Health Aspects of
Chemical Accidents", giving guidance on chemical incident awareness,
preparedness and response for health professionals and emergency
responders. In 1996, OECD issued guidance concerning the "Health
Aspects of Chemical Accidents", as a supplement to its "Guiding
Principals for Chemical Accident Prevention, Preparedness and
Response". In 1988, UNEP produced its APELL Handbook ("Awareness
and Preparedness for Emergencies at Local Level") which gives
a ten-step process of instituting or planning for, preparation
of, and response to incidents at local level through cooperation
between industry, local authorities and the public.
Following the consultation in 1992, the IPCS organised two
international conferences (Cardiff, UK, 1-3 April 1993, and Sao Paulo,
Brazil, 6-11 June 1994), at which a number of well-known chemical
incidents were examined with a view to identifying the lessons to be
learned by the health sector in dealing with such incidents. In
consultation with an editorial panel (see Appendix A), guidance
material on the public health sector role in chemical incident
preparedness, response and follow-up was then drafted, based on the
conclusions and recommendations of the two conferences. This draft
material was examined at a number of IPCS workshops held in Wales, UK
between 1995 and 1998 (see Appendices B and C) and subsequently
assembled into a guideline document, which enabled the general
principles for this policy document to be identified.
The IPCS gratefully acknowledges the financial support of the UK
Department of Health, through its annual contributions to the
Programme, throughout the period during which this activity was being
undertaken. The lead role of the WHO Collaborating Centre for an
International Clearing House for Major Chemical Incidents, UWIC, in
the preparation of this document is also greatly appreciated.
John Haines
INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
Structure of this document
This document describes how countries can improve the public health
response to acute chemical incidents, and ensure a better outcome for
the health of their populations.
Part 1 is a succinct summary for the policy maker at government and
regional level, and describes the major public health problems posed
by chemical incidents and the actions that need to be taken by policy
makers.
Part 2 gives more details of the public health response to an
incident. It has two purposes. Firstly, it is provided to give the
interested policy maker greater insight into the technicalities of the
public health approach. More importantly, though, this section is
offered as a template for all the public health functions that will
need to be introduced into every country to ensure an adequate public
health response.
Part 3 takes the functions as described in Part 2 and offers a
suggested model, or structural framework, into which these functions
can be built. It is intended purely as a model. There will be many
possible ways of ensuring the provision of a comprehensive public
health response - from wholly self-contained to wholly contracted in.
There are some international structures already in place and these are
described.
Part 4 contains the appendices, covering for example individuals
contributing to the document, examples of major chemical incidents,
and a bibliography and the references.
Guidance for public health policy makers
Introduction
emergency services deal with acute
chemical incidents
This policy document has been written primarily to give
policy makers at national and regional level a broad understanding
of the problems posed to the health of people and populations, as well
as the environment, when a chemical incident occurs and chemicals are
released into the environment. Often, the release will have occurred
at a specific site - the incident scene. For this sort of release,
the emergency services become involved and, by and large throughout
the world, are well prepared, trained, and organised to cope with the
release itself. They put out any fires, try to contain any liquid
chemicals and rescue casualties. The chemicals, however, are often
dispersed, into the air, onto the soil, or into the water etc.
In other sorts of incidents, the chemical is released into food or
water. Occasionally, the release is silent and is only announced by an
increase in symptoms or illness. In these cases, there is no scene,
the emergency services are not involved, and it is other services,
such as water authorities that become involved.
the impact on the public's health is
usually not considered
What is rarely addressed, though, is the impact that the release of
the chemical (and any containment or clean-up processes) has on the
health- both the short term and the long term - of individuals
and the public, and what difference there might have been to the
health of the people if different courses of action had been taken by
the emergency responders.
public health professionals are trained to do this
Addressing the impact on populations and advising on the best course
of action to minimise the health impact is the role of the public
health services. Public health is also concerned with the study of
the distribution and determinants of diseases in populations. Public
health / environmental health professionals are trained in
epidemiological techniques and in the application of management skills
to achieve change. These techniques and skills have typically been
applied to the control of infectious diseases and food poisoning
outbreaks. To be able to apply these techniques and skills to acute
chemical incidents, some additional training will often be required.
However, once this knowledge and expertise has been gained, it should
be possible for public health / environmental health professionals, as
full members of the emergency response team, to advise on the best
course of action for the emergency responders to take.
The public health response in an acute chemical incident is
therefore:
* the assessment of the likely impact on the health of the
first responders exposed people and the population
* the provision of evidence-based advice on appropriate
measures to be taken to minimise the loss of health, both
mortality and morbidity, and
* the follow-up of exposed people.
public health capability needs developing
Generally throughout the world, this public health response is poorly
developed. Often, it will require considerable development to
provide sufficient public health / environmental health professionals
with the proper training and experience at the national and regional
level. This development can often usefully be conducted in parallel
with the development of other public health functions, such as
infectious disease control or food poisoning outbreak control. Once
developed, a strong and vital public health response can only be
achieved if public health/environmental health professionals are full
members of the planning teams and emergency response teams.
The Public Health Problems of Chemical Incidents
unpredictable nature of incidents
Chemical incidents can happen any where, and at any time. This is true
even if there are no chemical installations in the area. Lorries can
spill their contents, rail tankers can overturn, and clouds of
chemical vapour can drift over in the wind or be deposited in the
rain. The vast majority of chemical incidents are not the
media-grabbing type, such as Bhopal (see page 12). They are smaller,
and involve less people; but they are none-the-less just as serious in
terms of illness, death and anxiety to people, the public, the
emergency services and employees.
problems if public health professionals are
not involved in planning
Experience has shown that preparedness is the crucial factor for the
successful management of chemical incidents. The most important areas
for preparedness are incident combat (plugging the leak, extinguishing
the fire etc), medical treatment, clean-up, and, most importantly from
the point of view of the affected public and the emergency services,
dealing with the questions and uncertainties about the health effects.
Sadly, the sector with the expertise and knowledge to deal with this
aspect public health / environmental health specialists - is often
left out of the planning and management of chemical incidents. Below
are a couple of examples of chemical incidents that had a public
health outcome, including one where public health involvement was
lacking and where a different outcome might have been achieved if it
had been present.
Water-based contamination - Camelford UK
On 6th July 1988, a relief driver mistakenly emptied 20 tonnes of
aluminium sulfate solution from his tanker into the contact chlorine
reservoir of a small, unmanned drinking water treatment plant in the
UK. Because there had been a technical problem at the site a few hours
earlier, the resulting increase in levels of aluminium were not
recognised until several days later. Aluminium levels of 620,000mg/l,
sulfate levels of 4,500,000mg/l and pH values of 3.9 - 5.0 were
recorded. Some 12,000 local residents and a further 8,000 holiday
makers were put at risk.
aluminium sulfate emptied into water supply
Once a problem had been identified, the water authority installed
bowsers, but did not reveal publicly the cause of the incident.
Neither was an immediate rapid epidemiological assessment carried out.
An inquiry was ordered in mid July, which reported in August, by which
time much public anxiety and media interest about the long-term health
consequences had been raised.
Considerable public anxiety could have been avoided
Two further public inquiries and several epidemiological studies were
initiated over the next two years, which found an increased incidence
in a wide range of symptoms in the people who were exposed. However,
the researchers were unable to exclude the possibility that the
associations could have been due to anxiety and the publicity
associated with the incident.
Considerable public anxiety and unrest continued for a number of
years.
Air-borne contamination from a fixed site - Bhopal, India
poor land-use planning led to many people dying
Union Carbide Corporation had a number of tanks storing methyl
isocyanate (MIC) within its plant at Bhopal. On the night of 2nd/3rd
December 1984, tank 610, containing 42 tonnes of MIC, started leaking
following a rise in pressure. The gaseous cloud caused immediate lung
and eye problems, and killed, ultimately, 2800 people, injured and
debilitated between 50,000 and 150,000 people, hospitalised
immediately 1400 people and caused widespread panic in the 5 million
local residents. A second, neighbouring tank 611 threatened to leak,
causing many people to leave the area until it was made safe. It is
the worst chemical disaster in the world to date.
Considerable controversy surrounds the question of the chemical
composition of the chemical cloud. The tank appears to have suffered a
considerable rise in temperature, which would likely have given rise
to a number of byproducts. These remain unknown.
Many clinical and epidemiological studies were started following the
disaster, looking in particular at toxicological, immunological,
neurological, psychological and genetic aspects. The principal long
term effects have been on the lungs and the eyes.
Frequency of public health chemical incidents
Public health chemical incidents are surprisingly common. There are a
number of databases in the world that have collected comprehensive
public health surveillance data about chemical incidents in their
countries. The Agency for Toxic Substances and Disease Register
(ATSDR), in the USA, has the largest current one - the Hazardous
Substances Emergency Events Surveillance System (HSEES). The National
Focus for Work on Response to Chemical Incidents (National Focus), in
the UK, started a national surveillance system in 1998. A pilot
surveillance system collected data from Wales during 1993 to 1995
- the All-Wales Environmental Health Surveillance Project (AWEHSP).
Data from the HSEES and the AWEHSP are produced in Table 1.
Table 1
frequency and outcome of all public health chemical incidents
in the USA and Wales: UK
Database Period Area / pop Number Died Affected Evacuated
covered of incidents
HSEES 1993-7 Part of USA 24,573 111 9652 23,851
80m. pop
AWEHSP 1993-5 Wales 330 5 473 0
3m. pop
chemical incidents involving the public are common
There is no international database that collects data on public health
chemical incidents down to the level of these national databases.
However, the United Nations Environment Programme (UNEP) does produce
a list of all the large incidents that have involved a hazardous
substance -large being where 25 or more people have been killed, or
125 or more people have been injured or 10,000 or more people have
been evacuated.
In the 28 years between 1970 and 1998, the data were as follows:
Table 2
Frequency and outcome of large scale public health chemical
incidents, 1970 - 1998
Geographical area Number of large Died Affected Evacuated
scale incidents
USA 87 372 14,356 517,000
UK 9 167 489 133,000
Worldwide 350 13,000 100,000 3 million
incidents that threaten the public
It can be seen that, in the USA and UK, the ratio of the annual number
of large scale incidents to all incidents (about 1:1600 and 1:400
respectively) is low. Thus, if the same ratios were applied to the
worldwide number of large scale incidents, the estimated number of all
incidents could range from 100,000 to 500,000 per year. (These figures
are broadly indicative only, and must be taken with caution) A list of
these large scale incidents is provided in Appendix E.
What is a public health chemical incident?
Many chemical incidents occur which do not threaten the safety of the
public. This document is concerned with those incidents that do - that
is, incidents that threaten to expose, or actually expose, two or more
members of the public (ie: people who are not employees or first
respondents) to a chemical hazard. These incidents are usually sudden
and acute, although they tan include chronic incidents where the
public has just become aware of the release and the potential threat
to health. Deciding that an incident is a threat to the public health,
and who should make that decision, may not always be easy matters to
determine. Chemical incidents may be accidental or intentional (ie
malicious or caused by terrorists).
Outcomes of chemical incidents
public concern is rising rapidly
Analysis and experience of these has shown that the range of outcomes
from incidents that affect the public health are:
Public Health Outcomes
of Chemical Incidents
*
Public anxiety
*
Deaths and illness
*
Delayed health effects
*
Damage to local economy
*
Opportunity costs
*
Legal costs
*
Rehabilitation costs
Public anxiety The public's perception of the risk to their health
from chemical incidents has changed dramatically over the last twenty
years. Communities, pressure groups and the media are becoming
increasingly interested in chemical incidents. Governments are coming
under rising pressure to demonstrate that there are policies,
personnel and other resources in place to effectively deal with
incidents, that the management of any incident will be in competent
hands, and that the harm to the public is minimised.
During an incident, this public anxiety leads to pressure on
politicians and policy makers, as well as health professionals, to
provide information about the short, medium and long term risks to the
health of the people exposed. Because of the lack of public health
involvement in the assessment of the health effects of chemical
incidents, these questions are often difficult to answer. This has led
in many countries to a loss of confidence by the public in the ability
of national and local government, and particularly the public health
services, to protect them.
large number of people have been affected
Deaths and illness Large incidents, with extensive media coverage,
are thankfully rare, but in all, the reported incidents, both large
and small have caused in the order of 13,000 dead, 100,000 injured or
ill and nearly 3 million people to be evacuated over the last 28 years
worldwide (see Table 2). Evidence from ATSDR (the Agency for Toxic
Substances and Disease Registry, USA (Jones et al 1993)) and from a
survey in Wales, UK (The All-Wales Environmental Health Surveillance
Project 1993 - 1995 (Bowen 1999)) has also shown that there are very
many small chemical incidents that are unreported but which put the
public at risk, raise considerable anxiety and often cause fatalities
or injuries requiring hospital admission.
Delayed health effects Chemicals do not necessarily produce an
immediate effect. Depending on the level of chemicals taken into the
body (the dose), there may be long term chronic effects, or effects
that appear only years later. Examples of long term effects are skin
scarring and disfigurement from burns, respiratory difficulties from
damage to the lining of the lungs, and so on. Delayed effects occur
mainly as cancers, or teratogenic effects - problems appearing in the
offspring during fetal development.
Economy The local and national economy can be affected. Livelihoods
and productivity can be interrupted, often for long periods of time.
Community anxiety can be raised, affecting inward investment.
environmental impacts are considerable
Opportunity costs Whenever a chemical incident occurs, opportunity
costs are encountered. Examples of these are the closure of
contaminated health facilities, the costs of monitoring the
pollution, and the costs of decontaminating the waterways, soil or
food stuffs.
Litigation and compensation When people have been injured or their
livelihoods interrupted, they frequently look for compensation. The
time taken to apportion blame and the legal processes all add
considerably to the final costs of any incident.
Costs of rehabilitation The environment may have been extensively
damaged by the incident, or may require extensive remediation to
return it back to its previous state. Frequently, the clean-up
operation of large spills requires large amounts of top soil or beach
sand to be removed and disposed of safely. The costs of
decontamination and the resulting effects on the environment and
wildlife can be considerable.
The polluter rarely pays The evidence from around the world is that
the polluter rarely pays. Often the polluter is unidentified, and
considerable resources have to be expended to identify the chemical
and the source. Even when the polluter has been identified and is
clearly at fault, the legal process of bringing an action can take
many years. It is usual, therefore, for national or local governments
to pay for the majority of the costs of chemical incidents that affect
the public and public areas.
The problems caused by lack of involvement by public
health professionals
the population effect is not considered
The problem with many incidents is that there is no person or
organisation present to take an objective, detached and holistic
public health view of the incident. Each government agency is
committed to fulfilling its own objectives and functions. There is
often no person or organisation with the time or expertise to consider
the impact of an action or decision on the health and well-being of
the local population. This means that the best courses of action are
not considered or researched, people are not registered to be followed
up, and the long term health effects are not investigated.
Public health personnel are specifically trained to take this view, to
consider the long-term effects, and to balance the different overall
effects on the public. They are trained in appropriate research
methods, in epidemiological approaches and in methods of multi-agency
working and public relations.
The roles at government level
The roles for government are:
ensure high quality public health services
1. At the LOCAL level, to ensure that the public health management of
chemical incidents is comprehensively, effectively and efficiently
conducted, so as to achieve the best outcome in terms of the health of
the public whenever a chemical incident occurs. Additional national
specialist support may be necessary for this.
assume overall responsibility
2. At the NATIONAL level, to take responsibility and to be accountable
to the public for their protection and the overall management of
public health chemical incidents.
Recommended actions at government level
To ensure that these roles are met, government will need to carry out
the following actions:
Recommended Actions
NATIONAL
*
Identify responsible individual
*
Establish inter-departmental
collaboration
*
Draw up national plan
*
Review legislation
*
Set up national
surveillance systems
*
Ensure sufficient specialist
health care facilities
*
Ensure sufficient resources for
epidemiological surveillance
and assessments
1. Identify a responsible government individual or department An
individual or department needs to be identified who will be
responsible for ensuring that the national public health plan for
dealing with chemical incidents is implemented.
2. Establish interdepartmental collaboration There will be a number
of separate departments within government each of which may have
statutory responsibilities for areas covering chemical incidents. The
public health response at a government level to a chemical incident is
to balance the requirements and actions of the various departments to
achieve the best public health outcome. This requires coordination and
collaboration across the departments in advance of, and most
particularly during any incident.
3. Develop a national plan for dealing with chemical incidents A
national plan needs to be developed, which makes explicit the
policies of the government, identifies the gaps in the service and
any needed, sets targets and minimum standards at the national and
local level, enacts the necessary legislation and enables a
political and administrative response in the event of a significant
incident.
4. Improve the legislative context Legislation will usually be
required for:
* the establishment of a hazardous sites register
* the control of hazardous sites
* building regulations
* land use planning
* the control of chemical transportation
* the control of waste disposal sites
* the control of contaminated crops, foodstuffs and drinking water
* formal command and control of the incident site and incident
management.
5. Fulfill other national requirements The government will also need
to establish:
* an efficient public relations system
* a national surveillance and data collection and collation
system
* a system of simulation exercises at government level
* an audit / evaluation system of the effectiveness and
efficiency of local exercises and responses,
* that there are sufficient specialist health service facilities
and staff nationally.
The government should also be aware of, and plan for the fact that
terrorist attacks are an increasing possibility. These attacks may
use chemicals or biological agents, or may target chemical sites.
6. Establish a comprehensive national public health function and
structure. Chemical incident management is only one of a number of
functions that can be performed by public health staff. These can
include the control and management of outbreaks of infectious
diseases, food poisoning, various aspects of major emergencies and
disasters, the collection and interpretation of population health
status data and various methods of controlling the demand, supply and
effectiveness of the health care system.
A comprehensive public health function requires consideration of the
recruitment, training and job market for the specialty; regulation and
continuing professional education; the provision of epidemiological
and other specialist skills; and the relationship with other health
related agencies, such as housing, social services and education.
7. Contribute to international collaboration. Co-operation and
collaboration at the international level are effective and efficient
ways to ensure that:
* research is conducted that underpins the scientific basis of
the public health response
* that lessons are learned about the public health responses to
chemical incidents and that these lessons are promulgated to
all countries of the world.
Recommended Actions
INTERNATIONAL
*
Establish links with
WHO Collaborating Centres
*
Contribute to the International Chemical
Incident Register
To these ends, governments can help by contributing to the
international development and standardisation of:
* guidelines for the public health management of chemical incidents
* chains of command: national - regional - local
* registration of chemical incidents
* data sets for the register
* training.
Many of these functions are conducted by the IPCS and the
International Clearing House, UWIC, in Cardiff, which runs the
International Chemical Incident Register.
The roles at the local level
Governments will also need to ensure that, at the local level, there
are appropriate and efficient systems to enable the following
functions to be carried out to ensure the effective public health
management of chemical incidents.
1. Advice on the best actions to achieve the best public health
outcome of a current incident. During an incident, the principle
public health role is to assess the overall likely impact of the
incident on the health of the public, the first responders, the health
care workers and the environment and to advise the first responders
on the best actions. This assessment should take into account not only
the chemical released during the incident, but also any consequences
of the actions that might be taken by the emergency services to deal
with it (the emergency response options), such as burning off,
cleaning-up with other chemicals, flushing into the sewage system etc.
Ideally, the assessment should consider the short, medium and long
term health effects of the possible options. The principle role
breaks down into the following sub-roles:
Recommended Actions
LOCAL
*
Review the public health structures and
links with emergency services
and health services
*
Ensure sufficient training
*
Ensure high quality audits
* Hazard identification -identifying the nature and quantity of
the chemical and its potential effects on health as it disperses
into the environment
* Risk assessment - assessing whether the release of the
pollutant actually poses a health risk to the emergency
personnel, employees and the public
* Advice to the first responders - on their own protection, and
on matters such as personal protective equipment, casualty and
personnel decontamination, evacuation and safe return
* Assessing the (likely) impact of the emergency response and any
environmental decontamination or clean-up on the health of the
public
* Recommending the courses of action that produce the best
public health outcome.
2. Advising the public the media and the politicians. Information
and advice about the health consequences of a chemical incident are
usually required rapidly and in an authoritative and credible way. In
particular, public health professionals are often asked to provide
information about the short, medium and long term health effects of
the current contamination. They may also be called upon to be the
focal point for the issuing of such statements, or to bear
responsibility for health-related sections of the general
communication with the public.
3. Measuring the actual health impact of the incident. Pollutants
can have an immediate effect, a long term effect or a delayed effect.
Public health professionals need to organise for the immediate
measurement of the health of exposed and potentially exposed people,
and to organise to have them followed-up as part of a proper
epidemiological study.
4. Contributing to the rehabilitation of the community. Once the
incident is over, the local community may need to rebuild the economy
and lifestyle, and to regain its confidence in the chemical industry
and public services. Public health professionals can contribute to
this process.
Recommended actions at the local level
To ensure that these roles can be fulfilled, government will need to
ensure that:
1. Competent public health services are comprehensively established
at the local level. This maybe acheived by extending the range of
current services (such as the control of infectious disease outbreaks)
or by developing new services. It may require a plan and resources to
be identified. Where services are poorly developed, the less frequent
but more dramatic nature of chemical incidents can be a useful
incentive to the establishment of the full range of public health
functions.
2. Local public health professionals have access to skills,
expertise, and resources in the following areas:
* chemical and medical toxicology
* poisons information - on a 24 hour per day, 365 day per year,
service
* environmental toxicology
* environmental epidemiology
* environmental risk assessment
* environmental sampling
* environmental monitoring and modelling
* biological monitoring
* medical epidemiology
* surveillance
* risk assessment and hazard analysis
* risk perception and risk communication
* risk management
* media skills
* rehabilitation
* accident and emergency services
* audit
3. There is a comprehensive training, simulation and exercise
function working at the local level and reporting to the national,
central level.
4. Public health services are fully involved in the planning
processes and part of the off-site command team during an incident.
Functions
The public health environmental health functions in the management of
an acute chemical incident
Part 2 The chronological flow of functions
Background information
This section describes the principle features of chemical incidents
and how they affect the health of individuals, the population and
society in general.
Planning and Preparedness
These functions include the baseline / one-off / set up functions and
activities, such as producing the chemical incident plan and community
risk assessment.
|
v
Routine Activities
These are the activities that have to be done on a regular basis, to
ensure an efficient response during an incident. They include updating
the plan, conducting routine surveillance, and training.
|
v
Helping to Deal with Incidents
These are the functions that the public health services need to carry
out during the acute stages of an incident.
|
v
Assessing the Impact on the Health of the Public
This section describes how to investigate the health effects of an
incident.
|
v
Remediation, restitution and rehabilitation
This section describes how the public health services can contribute
to the restoration of the local community once an incident is over.
Guidelines and Legislation Required
The work of the emergency response team can be greatly enhanced with
proper regulatory back-up. This section describes useful legislation.
Background information
Chemicals worldwide
Chemicals have played a major role in the development of human
societies - in agriculture and food; in industry and transport; in
housing, and in health. Extraordinary advances in chemical technology
have been made throughout the world in the last fifty years (United
Nations Environment Programme 1992). Manufacturing has become far more
complex and on a larger scale, and an ever increasing number of new
chemicals is entering the market each year. Over 11 million chemical
substances are known and some 60,000 to 70,000 are in regular
use. Between 200 and 1000 chemicals are produced in excess of one
tonne annually. Currently new chemicals are entering the market
at the rate of about 600 each month (or over 7000 per year)
(Lillibridge 1997).
there is a large and ever-increasing number of
chemicals worldwide
Dealing with chemicals involves manufacturing, processing,
transportation, storage, distribution, use and waste disposal. More
than 4 billion tonnes of hazardous chemicals are moved each year
around the world by motorway, rail, and pipeline systems. Fertilisers,
weedkillers and insecticides are spread in huge quantities on
agricultural land. Thus, even if a community does not have any fixed
chemical sites, hazards may be passing through, or being used locally,
putting that population at risk.
Given the increases in the production and use of chemicals, it is
therefore not surprising that the potential for inadvertent chemical
releases has increased, giving rise to a greater risk to human health
and the environment.
Types of chemical incident
Essentially, and for the purposes of this document, a chemical
incident is an unexpected, uncontrolled release of a chemical from
its containment. A public health chemical incident is one where two
or more members of the public are exposed (or threatened to be
exposed) to a chemical.
In the majority of cases, this is an acute release. An acute release
is a release where the exposure dose is rising, or is likely to rise
to rapidly.
chemicals are released...
Sometimes, however, the release is chronic. This is where the
exposure dose is not rising rapidly and public health measures do not
have to be taken so rapidly. It may be, however, that the public
health concern emerges suddenly and acutely. This document is
concerned with the acute releases.
... and travel through media...
Chemicals in all their states can be involved in incidents, from
gases - heavier or lighter than air; liquids - volatile and
non-volatile; solids - powders, dusts, the effluent from volcanic
eruptions; natural toxins, such as from algal blooms; and
increasingly important these days, biological toxins and chemicals
used in terrorist attacks. They may or may not be visible or
odourous. What are not included in this document are releases of
radio-active materials such as leaks from power stations, or the
detonation of nuclear warheads.
... to the human body
The released chemical usually enters an environmental medium (the
contaminated medium) - air, water, soil, sediment or food. In the
air, it may form a gas or vapour cloud or plume, and may rise up and
drift away. It may disperse completely or it may fall to earth some
distance away, contaminating whatever it lands on. Releases into
water may seep into the soil and then into the aquifer, into rivers
or reservoirs and thus into drinking water. Releases onto the soil
may be washed by rain or containment water into the aquifer or rivers,
or be taken up by crops, grazing animals or passing people. The
chemical may also be released onto ready-to-eat food, or onto crops.
Sometimes the chemical releases directly onto an object - such as a
piece of equipment, or the floor. Very occasionally, the chemical is
released directly onto the person or animal. Indeed, it is when the
chemical comes into contact with humans or animals, or threatens to do
so, that the incident becomes a public health matter. The route that
the chemical takes from its release to the human body is known as the
pathway of exposure (see Appendix G). It enters the body through a
portal of entry, for example, skin, lungs or digestive tract.
the chemicals, often unknown, cause
considerable public anxiety
At the time of the release or during the control procedures, chemicals
may react to produce thermal or aqueous degradation or reaction
products which may themselves present greater hazards than the
original chemicals. There is often considerable difficulty in
identifying the chemicals or the toxic products. There is also
limited scientific knowledge of the acute and long-term health effects
of these products. These uncertainties can become significant
psychological and social stressors to the exposed and the general
public over a substantial period of time. Experience has shown that
these stressors may then emerge as problems that are more difficult
to manage than the original potential danger from the chemical.
Chemical incidents can occur in fixed sites, such as chemical
manufacturing sites, storage tanks or laboratories. They may also
occur during transportation, on roads, rail, pipeline, waterways,
sea or air.
there are many types of releases...
The release itself may be caused by a leak or spill from a
container, the container may break or explode1, or the chemical may
catch fire. Chemicals may also be released naturally from volcanoes.
The factors leading up to the incident, the contributory factors,
include such things as poor maintenance of manufacturing and storage
equipment, road traffic accidents, human error, poor weather
conditions or terrorism.
...affecting a few, to thousands of people
The release itself may be detected or silent. Even if the release
is known about, the identity of the chemical may be known or
unknown. Different release states and identities have profound
effects on the planning and management of incidents. Chemical
incidents range from small releases, for example a chemical drum
being washed ashore to full-scale major emergencies, (see Appendix H
for examples).
From 1993 to 1997, more than 24,000 chemical incidents were reported
to the surveillance system in the United States (ATSDR - which covers
14 of the 54 states of the country). Eighty-five percent involved a
single chemical agent, most often a volatile hydrocarbon. In addition,
evidence from the UK surveillance system showed that the majority of
these incidents actually presented a threat to the public health
(National Focus Annual Report - 1999).
Toxic versus physical effects of a chemical incident
Chemical incidents, by the very nature of the way many of them occur,
will affect people in a number of ways.
* Effects of explosion. People may be subjected to blast injuries,
mechanical trauma, the effects from building and structural
damage and collapse, and from loss of housing and shelter.
* Effects of fire. People may be burnt or exposed to smoke and heat
inhalation, or suffer from the longer term sequelae.
* Effects of natural disasters. People may be subjected to the
suffocating effects of ash, to mudslides and loss of housing and
amenities.
1 a particularly dangerous example is the BLEVE (Boiling-Liquid
Expanding-Vapour Explosion), when a sealed liquid canister is
heated, ruptures and then explodes.
These physical effects are often seen in major trauma incidents; and
other emergency planning systems have usually already been developed
to cope with these. However, it should not be forgotten that during a
chemical incident these effects may in fact present more of a health
problem than the chemical itself.
* Socio/psychological effects.
* Effects of the toxic nature of chemicals.
This document is concerned with these two aspects.
What happens at the scene of a typical chemical incident site
there will usually be a command and control structure
When an incident occurs, site employees and some or all of the
emergency services usually attend the scene (the first responders).
If formal co-ordination is required, an on-site (operational)
command is initiated; this is usually controlled by the fire brigade.
If the incident gets larger, or there is threat to life or property or
public order, additional levels of command are initiated, usually
with the police (or military) taking overall control of the management
of the incident, at the off-site tactical or strategic command
centre. As many services and agencies as are necessary should be
present in the off-site command centre.
the site is usually divided into areas of increasing risk
Chemical incidents will present the first responders with health
risks. These risks may be toxic (from the chemical or its
by-products) or physical (such as explosion or building collapse).
When the risk of contamination or physical injury is sufficient,
protective equipment (personal protective equipment (PPE) and
shields etc.) is used. Depending on the level of risk, risk zones are
usually established around the incident. The hot zone, bounded by a
hot line, is the area where first responders must use protective
equipment to prevent primary contamination or physical injury. The
warm zone, which surrounds the hot zone, is the area where
appropriate personal protective equipment must be worn to prevent
secondary contamination. The decontamination line separates the warm
zone from the cold zone. Decontamination should be performed across
this line. Treatment, support and command facilities are located in
the cold zone. (see Appendix F for a diagram)
It may also be necessary to control access to the scene of the
incident. Public, press, sightseers and residents may try to gain
access, putting themselves and others at risk. The first access
control line is usually the outer boundary of the cold zone, the cold
line. Various degrees of access may be imposed the nearer one gets to
the incident site.
Some other terms used to describe the various zones are:
hot zone: exclusion zone, red zone
warm zone: contamination reduction zone, yellow zone
cold zone: support zone, green zone.
Primary and secondary contamination are important problems
Casualties in the hot zone are usually collected by the fire service
personnel and transferred across the hot line, through designated
access control points, to ambulance personnel in the warm zone. Care
must be taken to avoid contaminating the ambulance personnel during
the transfer. Contaminated casualties should be decontaminated before
removal from the warm zone, ideally in specially-designed
decontamination units. There should be two decontamination sites, one
for casualties, and one for first responders in protective suits.
Casualties are often "triaged" before transfer to health care
facilities, to identify those casualties that have the most serious
injuries and who would benefit most from rapid transfer and treatment.
A vulnerable zone (in effect a potential hot zone) can be declared,
which is the area likely to be contaminated if the emergency response
actions are not successful.
IPCS definition
The IPCS, following an international meeting of experts, has agreed a
definition of an acute chemical incident requiring public health
involvement, and four levels. These are:
Chemical An occurrence of public health concern caused by an
Incident acute release of a toxic or potentially toxic agent
Level 1 An acute release with no human exposure
Level 2 An acute release with suspected or actual exposure
Level 3 An acute release where the suspected / actual release
is related to ill-health
Level 4 An acute release giving rise to a civil defence or
equivalent major emergency.
Effects on the health of the individual
The effect that a chemical can have on the human body and on the
health of the person (the morbidity), is determined by a number of
factors. These factors are described below, starting with the actual
release and working forward to the human body. A brief description of
the actual effects is then given.
a chemical can be affected by many factors on its journey
from the release to the tissues of the body
Factors affecting toxic outcome
Pathway of exposure Once a chemical has been released from its
containment, it has to reach the body to have an effect. The route to
the body can be varied, and will depend upon the nature of the
release, the nature of the chemical, the types of media that are
contaminated and their movement, and any preventive or protective
measures that might be taken. These factors may well determine the
portal of entry. (see Appendix G for a diagram)
At the portal of entry The actual route into the body will affect
the dose. Chemicals will enter the body through the skin, eyes,
lungs or digestive tract. The rate of absorption through each of
these barriers will be different for different chemicals. Absorption
will also be affected by the concentration of the chemical at the
portal of entry, which may change over time, and the exposure
duration - the length of time that the chemical is in contact with
the body, and air temperature, humidity and the person's age
(particularly children).
In the body Within the body itself, the effect will depend upon the
actual toxicity of the chemical and the biologically effective dose
- the quantity of chemical taken into the target tissue. The way the
dose is accumulated in the target tissue can make a difference to its
impact. Even if the exposure is short, the peak level might be high
enough to cause toxic effects. Where the exposure is prolonged and the
dose rate low, it may be the total cumulative dose that causes
toxicity. Other factors that may have a bearing on the effect of the
chemical are age, gender, immune state, concomitant exposures and
general fitness of the person.
Toxicological effects
Presentation of the effects When a chemical has a toxic effect on
the body, the signs and symptoms may present themselves differently.
Every chemical has a particular pattern of injury, with adverse
effects concentrated in certain target organs or tissues. Effects
can be local, for example burning or blistering of the skin, eyes or
respiratory tract. The effects can also be systemic, once the
chemical has got into the body fluids. All organs and fluids in the
body can be affected.
The time elapsing between exposure and the onset of the signs and
symptoms can vary. Some effects, for example eye and respiratory
irritation or central nervous system depression, can occur rapidly,
within minutes or hours of the exposure (acute effects). Other
effects, for example congenital malformations or cancers, may take
months or years to appear (delayed effects).
The duration of the symptoms can also vary, from short term, to
long term or chronic.
Effects on the health of the public
chemical incidents cause considerable public anxiety,
Stress and anxiety The occurrence of major chemical incidents has
shaped the way members of the public perceive exposure to chemical
substances. Reports of incidents elsewhere, such as those listed in
Appendix E, may cause fear and anxiety in populations living close to
chemical industries. Such incidents are fear-inducing because they
have the potential to cause large numbers of deaths and illness and
because they raise questions about the fragilities of technologies
over which society and the local community, let alone the individual,
have little or no control. Concern is also increasingly being
expressed not only by the public, but also by the scientific and
medical community, and by pressure groups, that chemical incidents may
lead to long-term effects on human health, such as cancers and
congenital malformations, and that exposure to chemicals may be giving
rise to diseases not hitherto recognised, or exacerbate diseases of
another aetiology.
As a result of these concerns, the public are becoming increasingly
aware of all potential environmental hazards. With the inability of
the chemical industry or the public health authorities to provide
adequate information, the media are starting to quickly and loudly
articulate those concerns. Public health authorities are increasingly
being faced with problematic assessments of the risk to health and, in
the absence of appropriate advice and expertise, are frequently being
criticised for their inability to address community concerns.
In most countries, no surveillance systems exist for gathering data on
these incidents or for bringing their effects to the attention of
governments and thus to policy decision makers. Only a few reports on
the management of minor incidents have been published (the selection
mechanism often being the amount of media exposure). These have shown
that during a chemical incident, the emergency personnel and the
public are commonly exposed to chemicals because they are inadequately
trained, equipped, or informed.
... morbidity and death
During an incident, lack of information because of the wish for
secrecy, or differing professional opinions may raise public anxiety
levels. Occasionally, public anxiety may lead to the mimicking of
symptoms.
Deaths and illness Data gathered so far around the world have
indicated that chemical incidents exact a high price in terms of
deaths and illness. Large incidents are thankfully rare, but they have
caused considerable numbers of deaths. Evidence from ATSDR (Jones et
al 1993) and from the Welsh survey (Bowen 1999) has also shown that
there are very many small chemical incidents that will remain
unreported unless a specifically designed and targeted reporting
system is in place. The particular concern here is that whilst many
people assume that there are little or no public health concerns with
these small incidents, the evidence is very much to the contrary. The
public is often put at risk from these events, with injuries and
deaths occurring, and considerable anxieties raised.
The costs to society and the economy
There may be significant other effects of the incident upon society.
These relate to the:
* Economy - livelihoods, and inward investments
* Opportunity costs - e.g., closures of health care facilities,
schools, factories, etc
* Litigation and compensation - the costs of pursuing settlements
* Costs of rehabilitation - return the affected components of the
community back to their original states.
Planning and preparedness
having plans ready and rehearsed has
been shown to make a major difference
to the management and the outcome
Careful planning and thorough preparedness are prerequisites for an
effective response to a chemical incident. At the national level,
government needs to set up the procedures and organisations necessary
to ensure the effective and comprehensive public health management of
any chemical incident. A national plan should be produced, circulated
and discussed widely until general agreement has been reached.
Resources will need to be found to correct deficits in the national
provision. At the local level, public health authorities need to
identify the potential situations where chemical incidents could
occur, and to assess the likely health risks to exposed people,
property and the environment if such incidents were to occur. The
public health sector needs to be fully involved in the planning and
preparedness process, including emergency plan development and
implementation.
Planning and preparedness at the National Level
Essential steps in planning and preparedness
National Level
*
One person
*
Draw up plan
*
Set up inventory of hazard sites
*
Audit and monitor training and responses
The following steps are required to ensure a comprehensive response to
any chemical incident:
* Identify a person / government department to take
responsibility for the national co-ordination of the public
health management of chemical incidents.
* Identify all the government departments, national bodies and
experts with a responsibility and/or interest in chemical
incidents.
* Make an assessment of the impact of previous chemical incidents
on the health of the public and the environment.
* Assess the risk of, and likely public health impact of new
chemical incidents
* Draw up a national plan that
- sets out the national structures required to ensure an
effective local public health response
- lays down national policies for the public health management
of chemical incidents
- ensures government inter-departmental collaboration and
co-ordination
- ensures cross-border liaison, collaboration and
co-ordination with neighbouring countries
- links to international bodies such as the WHO.
* Establish a national major hazard site inventory and enact the
legislation required.
* Conduct exercises at the national level.
* Allocate the resources necessary.
* Set up systems to monitor
- the production of local plans and the efficiency of local
exercises
- the effectiveness of the local response to actual incidents.
Planning and preparedness at the Local Level
There are a number of procedures and activities that need to be
actioned and pursued by local public health / environmental health
officials, and these are described below:
1. set up multi-disciplinary public health working arrangements
2. start networking with all interested parties
3. conduct a community risk assessment
4. conduct a baseline health assessment
5. if necessary, conduct a baseline environmental assessment
6. start liaising with the local community
7. draw up a public health chemical incident plan
8. establish access to the variety of information sources, databases
and people with expertise
9. assess the comprehensiveness of the local health care facilities
10. pursue measures to reduce the probability of incidents
11. pursue measures to reduce the health effects of incidents.
1. Set up multi-disciplinary public health working arrangements
multidisciplinary team working (and practice) are
essential for good public health management
The public health response to a chemical incident should be a
multi-disciplinary one, as a wide range of skills and expertise is
required (see Table 3). A multi-disciplinary team is usually the best
way of achieving the various tasks that are necessary, both in the
planning phase and during an incident. In addition, if the team has
been meeting during the planning phase, then the resulting teamwork
during an incident is likely to be greatly enhanced. A team therefore
needs to be set up, taking into account the available staff and their
skills and training. The team will fulfill all of the functions
described below.
The team, and preferably a coordinating centre, should be
established and if possible resourced. The geographical area covered
by the team will need to be decided upon, and will depend on the
terrain, the population, the types and distribution of chemical
industries, the extent of chemical risk, the availability of expertise
and resources and the arrangement of other public health chemical
incident teams.
Public health services will also be required to respond to other types
of incidents, such as infectious disease outbreaks and major disasters
such as train crashes. Usually a team structure, with resources, is
employed in these circumstances. Where existing structures are in
place, it may be efficient to combine or link the several functions.
Where these structures are not in place, the need to set up public
health chemical incident teams can be a useful spur to the formation
of these other structures.
2. Start networking
Many people and organisations will be involved in the planning and
management phases of chemical incidents (see Table 3). Some will be
local, but many will be further afield, and usually only contactable
by phone, fax or e-mail. The public health team will need knowledge of
these people and organisations, and to have built up good
relationships with them, so that during an incident, the maximum help
and assistance is speedily obtained. The public health team will
therefore need to establish a network of necessary contacts. These
contacts will need to cover all aspects of chemical incidents, from
planning and preparedness, through incident management and long-term
follow-up, to audit and evaluation.
Table 3
People and groups in the public health chemical incident network
other public health / environmental central government
health departments and institutes
major local chemical industries
medical and environmental environmental groups, pressure
toxicologists groups and watchdogs
poisons centres public and community groups
toxicology laboratories emergency services
clinical medical specialists * fire
local hospitals * police
specialist hospitals * ambulance
occupational health services * transport
environmental investigation * emergency medical responders
and control
environmental monitoring and specialist environment agencies
modelling
biological monitoring * rivers
health surveillance * wildlife
medical and environmental * transport
epidemiologists
risk assessment, perception * ocean / sea
and communication
* agricultural
food safety organisations * air quality
health planners pollution control agencies
emergency planners * factories inspectorates
local government weather services
3. Conduct a community risk assessment
A community risk assessment is an assessment of the severity of the
potential effects of a chemical incident in the local area. It is
comprised of four steps:
* the identification of hazardous chemical sites, pipelines and
transport routes
* the identification of possible incident scenarios and their
exposure pathways
* the identification of vulnerable populations, facilities and
environments, and
* an estimation of the health impact of potential chemical
incidents and the requirements for health care facilities.
It is an important early task for the public health multi-disciplinary
team.
The community risk assessment is conducted by the public health /
environmental health specialists. It is a complex process, and
involves a wide range of expertise and agencies. As much of the data
required by each agency will overlap with others, a coordinated
approach to data requests and collection will produce more valid and
complete data returns. In addition, the process can be greatly
improved by involving members of the public. They will help not only
by providing local knowledge, but will also increase understanding and
allay anxiety by relaying the methods and findings back to the
community. Conducting a community risk assessment develops and
strengthens the relationships between the emergency services, the
chemical industry, the general public and the public health services.
It will also help to identify training requirements.
identify high risk sites
Hazardous Sites Assessments The identification of hazardous sites in
the local community is an important means of recognising possible
emergency situations. Once identified, it may be possible to check the
availability of appropriate expertise, site emergency plans,
materials, decontamination equipment, antidotes, and site evacuation
procedures. There are however, no generally accepted guidelines for
doing this, and it will be best to pool ideas and experience from all
members of the team.
Ideally a local inventory should be collated. However, this will need
to be kept up-to-date, and mechanisms need to be introduced to enable
reporting of changes and to administer the register. Chemicals may
change quite frequently, for example seasonal chemicals such as
fertilizers, swimming pool disinfectants and fireworks.
Essential steps in planning and preparedness
Local level
*
Conduct baseline assessments
*
Conduct community risk assessments
*
Liaise with the community
*
Draw up local plan
There are a number of ways in which hazardous sites can be
identified:
* National hazard inventory. If a national hazard inventory already
exists (such as that based on the European Seveso II Directive), it
should be searched for hazardous chemicals or hazardous sites in the
local community. Depending upon the number of hazardous sites, the
team may wish to prioritise the local list in order to cope rationally
with the workload.
* Direct local enquiry. The people with the greatest amount of
information about the types of chemicals present are the site
operators themselves; and it would seem perfectly reasonable to
request information about stored chemicals from them. Experience in
many countries is that this is regarded as commercially confidential
information, and is not given out. However, it is to hoped that a more
ethical and community sensitive attitude may develop which would
enable the release of this information.
* Planning enquiries. Typically, local planning regulations in many
countries will require companies to draw up plans for buildings and
sites that describe their use. Frequently they are put into the public
domain, and are sometimes presented for formal public consultation.
Depending on local arrangements, it may be possible for the local
authority to search their records to provide details of chemical
sites, or even of the chemicals to be manufactured.
* Local incident surveillance and environmental monitoring.
Monitoring systems set up to detect the occurrence of incidents or
changes in the background environmental level of chemicals may
indicate the types of chemicals being stored or used at sites.
It should also be remembered that sites include not only fixed sites
but also transport routes including pipelines, and waste disposal
sites. Chemical sites may be in danger from terrorist attack on
the site itself, as well as from being near to other terrorist
strategic sites, such as armed forced bases or significant civil
buildings.
Develop likely / possible incident scenarios For each site
identified, it will be necessary to identify the chemicals present
(current and planned) and to develop scenarios of possible releases
for each one.
Map out the exposure pathways For each site and substance, the
vulnerable zone - the area to which the contaminants might be
transported through air or water - is estimated. This can often be
done using computer models. It requires a thorough knowledge of the
topography of the area, the waterways, reservoirs and prevailing
climate. A map can then be produced of the vulnerable zones.
predict where released chemicals might travel to,
and identify vulnerable sites
Community vulnerability assessments The populations within the
vulnerable zone that could be affected are then identified, with an
emphasis on any especially vulnerable groups (children in schools,
the elderly in residential facilities, hospital patients etc). It
should be remembered that the population includes the resident
population as well as the working population (in the plant and in
the area), and other populations in the area at certain times, such as
motorists, tourists and visitors to entertainment facilities.
Factors that affect the vulnerability include the amount and quality
of shelter, the access into and out of the site and the amount of
training provided.
Facilities and structures in and around the vulnerable zone that
provide essential services (e.g. hospitals) and which could be
disabled by an incident are also identified. Areas where contamination
would have significant effects such as farmland, water for leisure
activities or wildlife support, areas for special conservation or with
endangered species should be considered.
Assessing the vulnerability around chemical transport routes will
present greater difficulties. However, it should be remembered that
highly toxic chemicals are often transported by rail, which by its
nature, passes through densely populated areas, and by inland
waterways.
determine the ability of the local health care
facilities to cope
Health impact assessment This brings together the evidence from the
exposure pathway and vulnerability stages to calculate the
casualties - the number and distribution, the type and severity of
the injuries; any evacuation and sheltering required, the delayed
effects of acute exposure: the effects of secondary contamination.
Air dispersion modelling programmes may be used during this process
(e.g. the ALOHA programme).
Resource requirements Given the quantity and quality of the health
effects, it will then be necessary to translate these health effects
into health care resources required. These requirements are then
compared against the health care resources available. The team
evaluates the capabilities of the health care sector, the emergency
services and the public to respond to (or prevent) potential incidents
based on current resources, legal safeguards, and existing plans,
training, and procedures.
Steps in community risk assessment
Resources
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An important point to determine is the 'saturation point' of the local
health care facilities, so as to determine when to call in additional
help, or refer patients to facilities out of the area. There are two
ways of doing this: calculate the type and number of casualties that
the local health care services could cope with, and apply this to the
various scenarios to ascertain those that would breach them and those
that would not. The second way is to work forwards from each scenario,
and calculate the exact numbers of casualties. Total requirements can
then be estimated, and links established with services in other areas.
These estimates are by their nature imprecise.
The health impact assessment brings all these assessments together to
make a final estimate of the impact of a release of the chemical on
the health of the population, wildlife, environment and facilities.
More quantitative methods can be used if resources are available (Risk
Analysis, Emergency Management Institute, National Emergency Training
Centre Student Manual SM 305.3, Washington DC USA, September 1990).
Initiatives to reduce both the risk of an incident occurring, and the
vulnerability of the population are then undertaken.
4. Conduct baseline health assessment
To measure the impact on health (morbidity and mortality) that a
chemical release has caused, it is necessary to know the background
levels of illness in the community before the release. Of course,
levels of morbidity and mortality can change overtime. The purpose of
the baseline measure is to set up the systems, and to check
whether the levels are normal or indicate that there are already
chemical-related health effects. There are two sorts of background
levels that can be measured.
General health statistics With the huge number of chemicals being
produced, the range of potential symptoms that could be produced is
very wide. Therefore as wide a range of morbidity and mortality
statistics should be accessed and reproduced as possible. The data
should include process data, such as general practioner visits and
hospital admissions, morbidity data such as condition specific
hospital admission rates, congenital malformation rates, and cancer
registration rates, and mortality data.
it is very helpful if the background levels
of illness are measured regularly
In most countries, the health statistics will cover populations
greater than that likely to be affected by a chemical incident, or
with different geographical boundaries. This can make it more
difficult to identify any changes in the health of the affected
population. To increase the power of any epidemiological study to
detect changes in the health of affected people, routine data should
ideally be collected from populations around the chemical sites.
However, this can very expensive, and is usually impractical.
Nevertheless, for very high risk sites, it may be worthwhile.
changes following a chemical incident
are more easily identified
If routine statistics are not available to produce a baseline measure,
consideration should be given to conducting a one-off survey. Again,
the resources required to do this will need to be found.
In addition, it would be very valuable if baseline measurements of
chemical biomarkers can be taken from the first responders. This is
because they are the group of people at most long-term risk of
exposure. Ideally, these measures should be conducted by the
occupational health services. It is reasonable to freeze the samples
and only analyse them after an incident, together with a post-incident
sample. This improves the accuracy.
Sentinel health events A sentinel health event is a preventable
disease, disability, or untimely death whose occurrence serves as a
warning signal that a hazardous environmental exposure may have
occurred.
A sentinel health event system uses many of the same datasets as the
more general surveillance systems described above, but focuses more
specifically on a limited number of priority diseases and conditions.
All these diseases and conditions are sufficiently rare and
sufficiently specific that they suggest exposure to hazardous levels
of a contaminant and a need for control or further study. Because they
are based on the International Classification of Diseases (ICD) codes,
the conditions can be monitored using death certificates or hospital
discharge data.
it can be helpful to collect data about
certain chemical-related illnesses
Sentinel health events include both acute conditions reported for
individuals (Type 1), and unusual health patterns seen in
populations (Type 2). For the second category, individual case
reports are not considered to be sentinel events because the
conditions are insufficiently specific. However, statistically
significant excesses of cases in populations over defined periods of
time, or space-time clusters, suggest the possibility of an
environmental aetiology. In addition, unusual patterns in particular
populations, such as the young, population unexposed to other known
risks, or genetically unrelated individuals living in the same place,
may suggest a need for further examination of the data.
Type 1 sentinel health events: conditions reported for individual
patients
* poisoning with metals, pesticides, lead, and carbon monoxide.
Clinical poisoning reports, and biomarkers of exposure (bone or
blood leads above certain levels) or effect (cholinesterase
inhibition)
* cancers specific to physical or chemical agents, such as
mesothelioma, clear cell cancer of the vagina, and angiosarcoma
of the liver
* precocious puberty - a rare event warranting inquiring into
oestrogen exposure possibly associated with pesticides,
industrial chemicals, or food additives
* certain blood disorders - methaemaglobinaemia
* certain neurological disorders-toxic neuropathies.
Type 2 sentinel health events: unusual health patterns in a
population
* Bladder cancer in the young, in non-smokers, in humans and their
pets, in a spatial cluster
* Lung cancer in non-smokers
* Primary liver cancer in non-drinkers without known exposure to
hepatitis B
* Multiple, excess occurrences of other rare cancers
(rhabdomyosarcoma, myelogenous leukaemia, acute leukaemia in
children, acute granulocytic leukaemia in adults)
* New asthma in low-risk, non-allergic children in non-smoking
households (but specificity is low)
* New diseases.
5. Conduct baseline environmental assessment
collecting regular samples from targetted areas
for background measurement can be very helpful
It is just as important to know the baseline levels of chemicals in
the environment before an incident occurs. Air, water, soil, sediment
and food in the vicinity of chemical plants should be sampled for the
full range of chemicals, or their by-products, being manufactured,
used or stored. Priority areas may need to be selected from the
community risk assessment, and those areas targeted. It may be
helpful, for a complete environmental assessment, to predict the
levels of environmental contamination from a variety of likely release
scenarios. There are various computer dispersion models available for
this purpose; although many of the models are unable to adequately to
take account of all the relevant variables.
6. Start liaising with the local community
bringing the public and local community
into the planning systems has many benefits
The local community is comprised of people who live and work in the
area that could be affected by a chemical release. It is for their
protection that all these measures are being taken. It is proper
therefore that the local community is not only informed about the
preparations, but is also involved in drawing them up. Community
members who do help with these preparations must be seen to be truly
representing their local community. Once an incident has occurred,
there need to be robust public warning systems for informing the
public of the incident and any protective measures that they should be
taking.
Liaison itself should not be seen as a one-way process into the local
community. It should be seen as a three-way exchange, - between the
local community, the public services and the local chemical industry.
Some of the methods used to liaise with the public are described
below. It will be appropriate for some of these meetings with the
public to be with the chemical industry alone, with the public
services alone, or with both parties.
there are many ways of doing this
Large public meetings These are the commonest and most familiar way
of initiating face-to-face discussions with the public. Whilst this
may be one of the most expedient ways of interacting with the largest
possible number of concerned people at one time, it is often one of
the least effective ways to institute a dialogue. However, public
meetings can be beneficial if the hosting officials are skilled in
risk communication and work to avoid negative outcomes.
Public availability sessions Informal, one-on-one communication has
been shown to be perhaps the most effective way to discuss health risk
issues. Although very time consuming and resource intensive, a
personal and confidential discussion between a concerned individual or
family and a public health / environmental health professional seems
to reduce many of the barriers to communication described above.
One way to facilitate such one-on-one communications is through public
availability sessions. These sessions are hosted by public health
agencies in the local community; experts are available to talk with
all interested individuals either by appointment or on a first-come,
first-served basis. The sessions need to be well publicised in advance
and staffed by health professionals skilled in risk communication and
knowledgeable about the local risks. The health professional should be
conversant with the health effects of the chemical(s) and able to
assess the potential harm.
Liaising with the community
*
Large public meetings
*
Public availability sessions
*
Community Advisory Panels
*
Mass mailing
*
The media
Community Advisory Panels There is a growing recognition in many
countries that to achieve an effective, long-term solution to the
public health impact of chemical incidents, residents must be an
integral part of the decision-making. Experience has shown that a good
compromise between one-on-one communication and large public meetings
is the establishment of Community Advisory Panels (CAPS). These panels
provide the opportunity for an effective dialogue between community
representatives and environmental / health officials and chemical
industry representatives. The panels also help ensure continuity over
a period of months or years, and the opportunity for mutual education.
In the United States, CAPS have proved to be an effective mechanism
for government agencies to:
* obtain information about the health concerns of the community
* establish open and ongoing communication
* convey information about government-sponsored health activities
as they occur
* educate the community about the scientific process and educate
government health officials about the site in question
* reach agreement on the measures to be implemented.
CAPS typically comprise 12 to 15 community representatives, chosen
either by self nomination or by community organisations. The panels,
whose members represent the widest possible spectrum of community
interests, usually meet every 3 months in a public forum. Rules
regarding the conduct of meetings and issues to be covered are agreed
upon at the outset and enforced throughout the process.
Public Warning Systems Some countries and towns have set up a public
warning system where, for example, a siren is sounded and the public
listen in to the radio for information and instructions. The public
will need training and updating in the process. However, it can be
very effective in high priority areas.
Other Mechanisms for Public Interaction There is a variety of other
ways for government officials and the chemical industry to interact
with people living in environmentally threatened communities
threatened by chemical incidents.
Site visits can help the community to appreciate the measures taken by
the industry to protect the workers and the public. This can help
reduce anxiety and build trust and confidence.
Mass mailings are an efficient way to notify residents of a
concerned community about new scientific findings, planned activities,
or upcoming meetings. Mailings are most effective when they are done
in a one-page, "fact sheet" format with bulleted information.
Information sheets will also be helpful in providing information about
the priority sites and their chemicals, warning formats and protective
actions to be taken.
Other mechanisms These include telephone help-lines, drop-in
centres, and public training sessions. Radio and television can be
very important and effective mechanisms, depending on local
availability. However, it is essential that before any incident
occurs, a policy is developed and followed, and that relationships
with the media are developed and well maintained; and that during an
incident, appearances on radio and television are restricted to a few,
trained and experienced people.
7. Draw up a public health chemical incident plan
a well developed plan needs all the
relevant parties to come together
The management of a major incident is a complex affair which requires
the input from a wide variety of organisations and agencies. These
inputs should be timely and correct. If not, the outcome can become
considerably worse. Planning (and rehearsals) help to ensure that
people have developed, understood and learned their roles before any
incident. Plans are an up-dateable record of those roles - a
'living' document.
The planning for major incidents and disasters has been
comprehensively developed throughout much of the world. In most
places, there will be a general plan covering major incidents and
disasters. In addition, there will often be a general plan covering
the roles of the emergency services in chemical incidents. There will
also usually be major incident plans in the hospitals, covering most
types of incidents. However, public health plans to deal with chemical
incidents are usually non-existent or poorly developed.
Before starting the process of producing a public health chemical
incident plan, a decision needs to be taken as to where the plan will
'sit':
- stand alone
- integrated into a public health outbreak plan, covering food
poisoning and infectious diseases
- integrated into the emergency services chemical incident plan
- integrated into the emergency services major incident plan.
Whichever is chosen, care must be taken to ensure that the plan is
co-ordinated with the other relevant but un-integrated plans.
The public health chemical incident plan will need to cope with four
different scenarios:
The four planning scenarios
1
Detected release, known chemical, fixed site
2
Detected release, known chemical, moving site
3
Detected release, unknown chemical
4
Silent release, but suspected.
* a detected release of a known chemical from a fixed site -
this will usually be from a registered hazardous site
* a detected release of a known chemical from a non-fixed site -
such as from a well-labelled road tanker
* a detected release of an unknown chemical typically, this will
occur in releases from sites not on the hazardous site inventory,
or with unknown combustion products from a chemical fire
* a silent release, where the release is unknown or was thought to
be harmless, but is now suspected from other routes.
Plans should be developed in close co-operation with and with input
from all the agencies, specialists, communities, commercial sectors
and other authorities that the public health / environmental health
professionals will need to interact with during an incident. The plans
will also be significantly improved if relevant members of the local
community are involve throughout the process. Templates of plans which
have been developed and tested are readily available via the Internet.
Extensive evaluation of the plan and its implementation should be
carried out after every incident or training exercise.
8. Establish access to information, databases and expertise
ways of getting hold of
information need to be set up
At the time of an incident, it is vital to have rapid access to data
about the chemical. It is important therefore that the chemical
databases are purchased and installed, or 24 hour electronic access
established well before. The data needed will include information
about:
* the physical characteristics of the chemical (this influences the
way it disperses in the environment and how it enters the body)
* the biological tests available to detect exposure and/or adverse
health effects
* environmental sampling techniques and equipment needed
* lists of antidotes and decontamination procedures
* medical signs and symptoms and methods of treatment.
People with expertise in these aspects may well be needed to
supplement the information from the databases. Poisons centres are an
excellent source of information. Contact is much better made before
the incident, and this has been described above.
9. Assess the comprehensiveness of health care facilities
The availability of adequate local health care facilities, including
toxiological laboratories, and adequately trained health care staff
are very important for the successful care and treatment of casualties
following an incident. Facilities need to be assessed for their
numbers, medical equipment, decontamination equipment, drugs and
antidotes, and training.
the adequacy of the local health
care facilities needs checking
Where the injuries involve burns or severe toxic symptoms, the local
health care facilities can rapidly be overwhelmed by even a small
number of casualties. Access to facilities in neighbouring districts
or further afield will then be necessary. Identifying where those
facilities are is an important step in the planning and preparedness
phase.
An alerting mechanism (to the occurrence of an incident) needs to be
developed and regularly tested.
10. Pursue measures to reduce the probability of incidents
The community risk assessment may have identified sites and procedures
where improvements might lessen the probability of an incident
occurring. Often, some of these improvements can only be done by the
company producing, storing or transporting the chemical, and it may
require a multi-agency team to negotiate these changes.
preventive and protective measures
should be put in place
Examples of common improvements are:
* an onsite chemical emergency plan coordinated with the local
chemical incident plans
* clear procedures for off-site personnel making deliveries to a
site
* additional training for workers in onsite hazards and routine
safety procedures
* backup systems for evenings / weekends / holidays
* regular monitoring of contaminant levels from planned processing
or releases
* regular surveillance and standardised reporting of incidents
* improved procedures for product or waste release, or waste
product containment
* improved specifications for vehicles carrying hazardous
substances.
11. Pursue measures to reduce the health effects of incidents
As well as measures to reduce the probability of an incident
occurring, there are other preventive measures that can be put in
place that will reduce the impact of the chemical on the people and
the environment, should a chemical actually be released. Examples of
common improvements are:
* locating chemical sites away from centres of population
* registration of all chemicals in commercial establishments with
the hazard inventory to ensure rapid identification of the
released chemical
* regular evaluation of plans and their implementation
* storage of lesser amounts of chemicals
* smaller batch processing
* good quality labelling of all chemicals in transit
* rapid notification of the chemical incident emergency services in
the event of an incident
* regular surveillance and standardised reporting of incidents,
including the small "routine" ones
* measures to decontaminate land or water already contaminated by
waste disposal, and to protect the public by education and other
means
* measures to prevent or contain fire-water run-off
* introduction of separate drainage ditches or holding tanks to
contain leaked liquid chemicals.
Routine activities
Once the plans and assessments have been completed and put in place,
there are certain routine procedures that need to be gone through on a
regular or continuous basis.
These are:
* Recognising chemical incidents
* Conducting population health surveillance
* Conducting environmental monitoring
* Conducting exercises and training
* Conducting national incident surveillance and contributing to
international incident surveillance
Recognising chemical incidents
releases occur in different ways
and can be difficult to detect
Although a few chemical incidents are major ones, and the event is
self-evident, most acute chemical incidents are small-to-medium
events, that only the polluter, and anyone directly involved,
initially knows about. The polluter may not inform the emergency or
public health services. This will most likely be because the polluter
feels that the incident can be handled without outside assistance, and
that the incident is not believed to pose any (appreciable) risks
outside the facility (on the basis of a rapid initial assessment).
Other reasons may include the polluter's wish not to be identified, or
because they do not appreciate (or care about) the personal or public
health implications. Indeed, the emergency services do not always
appreciate the possible public health implications.
various alerting mechanisms need to be set up
Therefore, and in order for the public health / environmental health
professionals to be able to help reduce the public health consequences
of all acute chemical incidents, they need to set up systems that
will detect the release of the chemicals. Once detected, the public
health / environmental health professionals will need to rapidly
assess, judge or estimate whether there is then a risk to the public's
health.
Detection can occur in seven ways -
1. the polluter informs the emergency services who inform the
public health services. In some cities, a mandatory notification
system (of all releases) has been established
2. observation of a release itself - often as a major event, such
as an explosion or oil tanker disaster
3. information from the public about an environmental change eg
colour, smell, eye irritation
4. ad hoc observation of a rise in an environmental contaminant
5. observation of a rise in an environmental contaminant using
routine monitoring environmental data
6. hunches from clinicians and others (e.g. poisons information
centres) who are presented with a sudden rise in an unusual
health problem
7. observation of a rise in a sentinel health event or other health
measure, using routine monitoring health data
Seven detection methods
1
polluter informs
2
direct observation
3
*non-specific changes -colour, smell
4
*rise in environmental pollutant level
5
*rise in routine environmental monitoring levels
6
*clinical hunches
7
*rise in routine health monitoring levels
*requires public health activity
to setup alerting systems
Toxicovigilance
Most of these methods require members of the community to become more
aware of the possibility of a chemical incident and then to know what
to do if their suspicions are raised. This 'toxicovigilance' has to be
developed and encouraged in a wide variety of people and
organisations, such as accident and emergency staff, primary care
doctors and nurses, infectious diseases doctors and community
investigators (because chemical incidents can mimic outbreaks of
infectious diseases), poisons information centres, epidemiologists and
public health / environmental health institutions, and other groups
receiving reports of potentially toxic events. Members of the chemical
industry need to be encouraged to report all acute chemical incidents,
however small.
Once a suspicion has been raised, the person needs a quick and easy
route to alert the emergency services and the public health chemical
incident management team. A toxicovigilance programme therefore
requires:
* The public, local institutions and organisations, and all members
of the emergency, environmental and health services to be
regularly encouraged to be alert to the possibility of chemical
incidents, and to be educated on the means of communicating
rapidly with the emergency services and the public health
chemical incident management team
* A well-publicised, twenty four hour incident telephone line,
and a network co-ordinator always available
* A surveillance and monitoring system.
Conducting population health surveillance
Once the baseline health assessment has been completed, routine
surveillance needs to be established. Routine population health
surveillance is the ongoing and systematic collection, analysis and
interpretation of health data in order to:
* identify a health event that may be related to an unknown,
acute release of a chemical
* monitor trends in the different types of health status
* stimulate epidemiological research likely to lead to control
or prevention
* permit assessment of the effects of control measures
routine collection of health data helps in
identifying trends and incidents, stimulating
research, and auditing control measures
The same set-up for health surveillance will be required as for the
baseline health assessment, that is access to regularly updated
general health statistics and to regularly updated sentinel health
events. There are certain attributes that any surveillance system
should fulfill:
* Simplicity
* Flexibility
* Acceptability
* Sensitivity
* Predictive Positive Value
* Representativeness
* Timeliness.
The essential features of each system are described below.
General health statistics
Data from a wide variety of routine sources need to be collected,
collated and presented in a way that allows trends and comparisons