Lessons Learned from Accident Investigations
Integrated Qualitative and Quantitative Approaches to
Effective Risk Management
Henn Tosso, Piia Tint
Tallinn University of Technology
Kopli 101
11712 Tallinn, Estonia
Kai Aava
Energo Management Ltd
Kapi 8-6
10136 Tallinn, Estonia
Abstact
The aim of our paper is to present the chemical hazards risk assessment
methodological questions that give the adequate description of the workplace
situation; to minimise the health risks from dangerous substances in the workplace;
the integrated qualitative and quantitative approaches model implementation.
The mistakes and difficulties derived from the implementation in practice of the
theoretical base model are discussed.
Keywords: risk, risk management, integrated risk management, qualitative and
quantitative risk assessment
1. Risk Management
The aim of the effective risk management is to move towards the targets fixed in the
European Union strategic documents – to gain the qualitative worklife and work
environment. It is difficult to overestimate the necessity of worklife quality estimates
the quality as it is a part of all life quality in the country. The duty of the employers is
to guarantee healthy and safe work conditions to the workers.
The risk management model have to take into consideration demands from the
practical situations, in the same time they have to consider the general rules from the
European Union base documents.
The risk management system consists of the following elements being in logical
connection between them [1]:
1.
2.
3.
4.
Context
Risk Analysis
Treatment
Monitoring
The fifth element is Strategy, that binds all the previous four elements through the
higher hierarchy level.
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Proceedings of the 36th ESReDA Seminar, Coimbra, Portugal, June 02-03, 2009
RISK
MANAGEMENT
M1
M2
M3
M4
M5
M1
R1,1
R1,2
R1,3
R1,4
R1,5
M2
R2,1
R2,2
R2,3
R2,4
R2,5
M3
R3,1
R3,2
R3,3
R3,4
R3,5
M4
R4,1
R4,2
R4,3
R4,4
R4,5
M5
R5,1
R5,2
R5,3
R5,4
R5,5
1.
CONTEXT
M1
R1,4
R2,1
R5,1
R4,1
R1,5
4.
MONITORING
R4,5
5.
STRATEGY
M4
R5,4
R1,2
R5,2
2.
RISK ANALYSIS
R2,5
M2
M5
R3,4
R5,3
R3,5
R4,3
R2,3
R3,2
3.
TREATMENT
M3
European Union
Figure 1.1. Framework for Risk Management
Figure 1.2. The binary relations matrix (1)
The system could be determined as a collection of elements closely related between
each other, that forms a whole to fulfill a function or task [2].
The main aim of the risk management system is to assure healthy and safe work
conditions. Each individual element has its own function, but it has to be related with
the other elements. The system as a whole does not function to reach its goal if even
one element in the system does not fulfill its target put to it or the relationship
between the elements does not work.
The elements of the risk management system are (Figure 1.1.):
M1 – context, M2 –
risk analysis, M3 – treatment, M4 – monitoring, M5 – strategy. The binary relations
between the elements of the system could be presented as the Cartesian product:
R  M1 x M2 x M3 x M4 x M5
The binary relations between the five elements from M1 to M5 could be presented as
a matrix (Figure 1.2). In reality there has to be at least 25 binary relations on the basis
of that matrix (5 x 5).
The relations R1,1, R2,2, R3,3, R4,4, R5,5 deal with the internal structure of the elements
M1 to M5 of the observable system and they could be observable as autonomic subsystems.
According the EU model (Figure 1.1), 16 relationships are observed: R1,2, R2,1, R2,3,
R3,2, R3,4, R4,3, R4,5, R5,4, R1,5, R5,1, R2,5, R5,2, R3,5, R5,3, R4,5, R5,4.
The next step is to present the risk management system analytically. We do not
observe the internal structure of the elements, so we define the system as follows:
S:=M1,M2,M3,M4,M5;R1,2,R2,1,R2,3,R3,2,R3,4,R4,3,R4,5,R5,4,R1,5,R5,1,R2,5,R5,2,R3,5,R5,3,
R4,5,R5,4
On the enterprise level, the risk management is observed, as a rule, via input, output
and process [4,5].
X (Input)  F (Process)  Y (Output)
2
Lessons Learned from Accident Investigation
The current system has a shape: “input-output”. The elements and the number of
relations in the predicted system create relations between the input-amounts X and
output-amounts Y as follows:
R  M1 x ... x Mn  R  X x Y
The system is determined with the relationship R (X and Y is a Cartesian product).
Cartesian product X x Y gives us a corrected vector  x, y in the conditions where x
is an element of the amount X and y belongs to the amount Y, and the joint part of X
and Y is an empty amount.
X is defined as input variable cortege and variable X could be interpreted as
resources- for example: material, energetic, finace or informative resources derived
from the external environment. Further we assume that the resources X are
transformed in the system in some way changing internal qualities and they are
transferred into external environment. The output of the system Y is presented
through the output cortege that represents a system result or product.
The Cartesian products X = X1 x...x Xr and Y = Y1 x...x Ys determine the input and
output variables change-space.
The input X and the output Y n the variables change-space is determined through the
relationship xRy   x, y , that is a part of R  X x Y.
So the system “input-output” model with the relationship R presents a cortege of
three elements:
S =  X, Y, R 
Relation R could be presented through the function:
F:XY
The model „input-output“ where the relationship is manifested as a function is named
the functional model. Functional model represents a cortege that consists of three
elements:
S =  X, Y, F 
In the current situation we determine the input X in the case of chemical risk factors
in the work environment, process F is the total risk analysis derived from the
quantitative data of the measurements of occupational chemical hazards and their risk
assessment (output Y).
2. Context
The study case is carried out in an Estonian enterprise, where wood furniture is
produced. The problem setting was connected with the assessment of chemical risk
factors in the work environment, where lacquering of furniture details took place.
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Proceedings of the 36th ESReDA Seminar, Coimbra, Portugal, June 02-03, 2009
The short description of the process is as follows:
a female worker Tiina has worked over 10 years in the refinement department of this
enterprise and had the connection with hazardous solvents. She has got an
occupational health damage. Working for a long time in hazardous to health work
conditions, she has to have right to get the disability allowance connected with work.
Problem aroused with the State Social Insurance Board that refused to give the
allowance as the risk analysis made by the enterprise itself gave the result that the risk
in the mentioned department was acceptable. That gave the possibility to interpret
that the worker Tiina did not work in the hazardous, health damaging conditions.
The risk analysis had been carried out on the basis of quantitative indicators. For
example, the measured concentrations for toluene in the workplace air were from 1.0
to 975.0 mg/m3, for xylene from 1.0 to 494.0 mg/m3. These numbers show in which
frames the measurement results were noted down, but the real situation has to be
adequately assessed as the co-influence of quantitative and qualitative indicators.
On the basis of the safety cards of used substances, it turned out that in every-day
work process during the whole work-day, the worker was exposed to several
hazardous solvents:
Table I: The exposure of the worker to hazardous substances on the basis of chemical safety cards of
the technological process
Nr
The name of the substance
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Acetone
n-butanol
Butyl acetate
Butyl glycol
2-propylen glycol 1-metyl ether
2-propylen glycol 2-bensonate
Ethanol
Ethyl acetate
Formaldehyde
Isobutanol
Isopropyl alcohol
Xylene
Methyl ethyl keton
Nitro thinner P-646
Opaque ink DH1390-5001
Styrene
Toluene
p-toluene sulphuric acid
p-toluene suflon acid
Sulphuric acid
1-metoksy-2-propyl acetate
2-propanol
Mark
Measurement
results, mg/m3
CAS 67-64-1
CAS 71-36-3
CAS 123-86-4
CAS 111-76-2
CAS 34590-94-8
CAS 27138-31-4
CAS 64-17-5
CAS 141-78-6
Not measured
Not measured
Not measured
Not measured
Not measured
Not measured
Not measured
Not measured
Not measured
0,5 - 285
Not measured
1,0 - 494
Not measured
Not measured
Not measured
5,0 - 208
1,0 - 975
Not measured
Not measured
Not measured
Not measured
Not measured
CAS 67-63-0
CAS 78-93-3
CAS 108-88-3
CAS 104-15-4
CAS 7664-93-9
Exposure
limit,
mg/m3
45
221
90
192
The influence of the substances on the worker ( in Table 1) could be from allergic
reaction to loosing consciousness or permanent brain and nervous-system damages,
kidney- and liver damages depending on the exposure time, amount, co-influence,
concentration and individual characteristics.
4
Lessons Learned from Accident Investigation
The health risks are connected with the direct contact with refinement materials, as
the refinement is not isolated from the work environment.
The dangerous influence of chemicals on workers’ health has to be looked at
complexly [7]:
1.
If there is more that one hazardous substance in the air of work environment,
then the complex influence of substances has to be considered. The influence of
chemicals cocktail might be stronger than that the individual one. There is the
dependence that says: if the concentrations of the individual substances are C1,
C2, ... , Cn and their exposure limits are PN1, PN2, ... , PNn, then the sum of the
relations: C1/PN1 + C2/PN2 + ... + Cn/PNn has to be ≤ 1;
2. The toxicity of the chemical depends on the physical properties of the
substances. The substance may be in the solid (also dust), liquid or gaseous
(odours) form. The hazardousness of the dust depends on the dispersity of the
particles;
3. The influence of the hazardous substances might be increased by other indoor
microclimate factors as the temperature and humidity of the air, the overall
pressure of the air;
4. The individual characteristics of the worker have also to be considered;
5. The toxical influence of the substances is possible to divide into two big groups:
5.1. Subjective reasons: age, sex, ethnical group, genetic basis, endocrine state, diet
habits, fatigue, previous unhealthy situations and their treatment etc.;
5.2. The reasons deriving from the toxic substances and work, the work environment
or objective reasons (the character of the work, the work environment factors,
the structure of the substance, the amount of the substance, the physicalchemical properties of the substance, the way of influence of the substance, time
of exposure, the synergism and antagonism of substances).
3. Risk analysis
Risk analysis is based on basic reasons analysis method: Root Case Analysis (RCA)
[14]. Using the RCA, we found that the data presented by the enterprise and the real
situation are not in accordance. Good methods were used, but the methods were
different and different parts of these methods were taken and put together, so the
result was incorrect.
Based on the quantitative numerical factors the risk on worker’s health was assessed
as acceptable (II level of risk).
The main reason is the circumstance that the real problem (the working in the
unhealthy work conditions) does not achieve the strategic level, where the decisions
are made to improve the work conditions. As the risk level was determined as
acceptable, and then the practical steps for improvement of work conditions were not
taken. On the level of strategic management the aims are formulated with the
qualitative indicators.
To assess the work conditions of a finisher in the wood furniture factory’s workplace
the chemical risk factors were assessed by five different risk assessment methods.
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Proceedings of the 36th ESReDA Seminar, Coimbra, Portugal, June 02-03, 2009
The determination of the risk level is carried out on the basis of the following
scheme: the hazardous factor is determined, the probability factor is assessed, the
severity of consequences of the influence of the factor is assessed and the risk level is
determined (generally I-V).
1.
The Labour Inspectorate of Estonia has worked out the methodical instruction
„The risk analysis at workplace and the internal surveillance“, on the basis of
BS 8800 [9]. Using this method, the risk level of the finisher’s work is assessed
high (IV level of risk). The work has to be carried out using the precaution
measures and personal protective equipment (Method 1).
2.
European Agency for Occupational Safety and Health has worked out the new
risk assessment guidance [10] that assesses the possibility for health damages in
the finisher’s workplace as high risk (IV level). The work has to be carried out
using the precaution measures and personal protective equipment (Method 2).
3.
Tallinn University of Technology has worked out a simple/flexible risk
assessment method [11] that determines the work of the finisher health
damaging and the work is carried out on high risk level (IV). The work has to be
carried out using the precaution measures and personal protective equipment
(Method 3).
4.
Using the methodical instruction of the Estonian Centre of Occupational Health
„Chemical safety in construction“ [12], the risk level is high risk level (V), the
work has to be carried out using the precaution measures and personal
protective equipment, the possibility to health damages is very high (Method 4).
5.
Basing on the European Commission recommended instruction according to the
Directive 98/24 „A simplified method for risk analysis for chemical hazardous
factors getting into the body through skin or inhalation“ [13], the work in the
workplace is on high risk level (V level of risk), the use of the precaution
measures and personal protective equipment is necessary, the possibility to
health damages is very high (Method 5).
Table II: Risk Assessment matrix
s
e
R v
i e
s r
k i
t
y
3
High
3
2
Medium
2
Low
1
6
9
IV
Methods 1 and 3
V
Methods 4 and 5
4
6
II
III
1
RISK MATRIX
y
III
2
1
II
Method of the
enterprise
2
Low
Medium
I
Risk
6
probability
IV
Method 2
3
III
3
High
Lessons Learned from Accident Investigation
4. Implementation and monitoring
Enterprises have been recommended a basic model for quality management in
occupational health is as follows: „Input – Process – Output - Effect” [3].
X (Input)  F (Process)  Y (Output)  E (Effect)
The here presented model gives a better picture of hazards and their influences on the
worker, as it embraces the quantitative and qualitative aspects as a complex. The
influence of hazardous factors on the worker (E) is described as a whole state of the
work environment, which includes the influence on workers’ health, safety and
wellbeing. These three areas are assessable only with the qualitative parameters.
A simplified method of the presented model is spread in practice: „Input – Process –
Output”
X (Input)  F (Process)  Y (Output)
It is tried to manage the presented one-dimension model using the straight way, stepby-step, concentrating on the output (O), not assessing the influence of effect (E). The
system for feedback has to be considered. Cartesian product gives the possibility to
specify also the system’s state. The state of the work environment has to be assessed
considering all the hazardous factors and their co-influence as described in the
paragraph 2.
Looking at the system’s state environment in the context „human – machine –
environment“.
Z  Z1 x Z2 x Z3
Where: Z1 – the state of the worker;
Z2 – the state of the technical systems;
Z3 – the state of the work environment: Z3 = z3,1, z3,2, z3,3, z3,4, z3,5,
z3,1 – physical hazardous factors;
z3,2 – chemical hazardous factors;
z3,3 – biological hazardous factors;
z3,4 – psychological hazardous factors;
z3,5 – physiological hazardous factors.
The state of the environment influences on worker in the above mentioned system
and the results of the change of the worker’s state are seen as smaller or bigger health
damages. The continuous change of the state causes the permanent change in the
state- output (the severe health damage, occupational disease or death).
The state of the system Z´ in a certain time moment is depending on the input X and
pre-state Z that could be functionally described as follows:
F1 : X x Z  Z´
F1 – the function of states’ change-over.
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Proceedings of the 36th ESReDA Seminar, Coimbra, Portugal, June 02-03, 2009
The output of the system is determined by the binary connection of the input-state and
output:
F2 : X x Z  Y
Model „input-output-state“ could be described as follows:
S =  X; Z; Y; F1; F2 
The described system that considers the change-over functions F1 and F2 and time T,
including time moments t1 ... ti is the functional model that considers the change of
the system’s state in time. In the work process, the parameters of the work conditions
change in time and could be described only with the following model:
S(t) =  T; X; Z; Y; F1; F2 
The system is functioning in time, is connected with outdoor environment – that is the
system is changeable with out-door resources and information. The system is
influenced by inputs X(t), that are coming from the outdoor environment and the
system influences the outdoor environment through the output Y(t). At every time
moment, the system is in a certain state Z(t) and changes its state’s value or not,
depending its previous state. Output-influence Y(t) at every time-moment depends
totally on the values of X(t) and Z(t).
According to the assessment, Y decides the influence on E in different aspects.
The greatest attention as an input to X system „Human-Machine-Environment“ was
on the worker state, as process F working process and output Y again the system
„Human-Machine-Environment“ state from the human aspect.
In the investigated enterprise, the output Y was the risk matrix that was compiled on
the basis of the quantitative indicators and it gave the influence to E so that the Social
Insurance Board considered the worker’s work not health-damaging and did not give
the possibility for disability allowance.
X  F  Y  E
and
X´  F´  Y´  E´
We carried out the risk analysis F´ considering as quantitative and qualitative
indicators and got the result as the output Y´ risk matrix that reflected the real
situation in the enterprise and as a result, the influence E´ gave the possibility to the
Social Insurance Board to acknowledge the worker’s work environment as health
damaging and she was allowed to get the disability allowance.
It is recommendable that the connections for all elements and the strategy are given as
in Figure 1.2. It is needed that all the connections function on the basis of certain
priorities and over a certain time intervals, and then the process is manageable. At
first the most essential relations at the moment have to be considered. On the basis of
the essential dataflow, the strategic decisions have to be taken.
Output Y was defined with qualitative indicators, formally things were in order, but
the influence on E was not considered. The substances used in the enterprise, were
toxic, but the measurements in the work environment corresponded to the norms, but
the long-time influence on the worker’s health was forgotten.
8
Lessons Learned from Accident Investigation
In reality, the quantitative and qualitative indicators have to be looked at. The profile
has to be transformed where unbalanced situation can be found.
In practice, the above given European Union model versions are used.
1. The risk management is nowadays carried out without strong strategy. This
means that we are dealing with the results not with the preventive measures.
About risk management in this case we can speak only conditionally. The
scheme for this type of risk management is as follows:
RISK
MANAGEMENT
M1
1.
CONTEXT
M1
M2
M3
M4
M5
R1,2
M1
R1,2
R2,3
M2
4.
MONITORING
2.
RISK ANALYSIS
M4
M2
R3,4
R3,4
M3
M4
R2,3
3.
TREATMENT
M5
M3
European Union
Figure 3. Framework for Risk Management and the binary relations matrix (2)
The trajectory is realized: M1  M2 M3 M4
Only one chain is considered – the plan is good, but it is not enough, it enables to
move, but not to manage effectively and the result is not that was desired.
2.
The strategy for risk management is worked out, but it is not connected with the
other elements of risk management. Derived from this, the system as a whole
does not work.
M1
RISK
MANAGEMENT
M2
M3
M4
M5
1.
CONTEXT
M1
M1
R1,2
M2
4.
MONITORING
M2
M5
R3,4
R2,3
2.
RISK ANALYSIS
5.
STRATEGY
M4
R1,2
M3
R3,4
R2,3
M4
3.
TREATMENT
M5
M3
R5,5
European Union
Figure 4. Framework for Risk Management and the binary relations matrix (3)
The trajectory is realized: M1  M2 M3 M4 and as individual element M5.
The strategy exists, but is not relational.
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Proceedings of the 36th ESReDA Seminar, Coimbra, Portugal, June 02-03, 2009
3.
The risk management system as the whole structure exists, but does not function
as a dynamic system. For the really working risk management system it is
necessary and only possible S(t) – the system that changes in time and assesses
the situation. This is possible only in the case of feedback system.
RISK
MANAGEMENT
1.
CONTEXT
R2,3
M2
M1
R4,1
4.
MONITORING
R5,1
5.
STRATEGY
R5,4
M4
R3,4
R5,2
R3,4
M3
R1,2
2.
RISK ANALYSIS
M4
R4,1
M5
R5,1
M2
M5
R2,3
R5,3
R5,2
R5,3
R5,4
R5,5
3.
TREATMENT
M3
European Union
M1
M1
M2
M3
M4
M5
R1,2
Figure 5. Framework for Risk Management and the binary relations matrix (4)
The trajectory is realized: M1  M2 M3 M4 M1 and directive management
with inflexible programme M5 M1; M5 M2; M5 M3; M5 M4, that does not
consider the adequate state and changes. The main basis of the managementfeedback is not considered.
5. Strategic management
The management is carried out as a result of the info-change and includes
information I, decision D and realization R. Sequence of these operations visualize
the cortege  I, D, R  that is an elementary management cycle [3].
The strategic management expects the feedback p and l. Generally it means the
information I and on the basis of decision D calculation mechanism that determines
the manageable aim at the predicted time moment to gain the needed input parameter
value X.
Input X is transformed as the state of the system Z and/or on the basis of the output Y
and is the parameter that operates and influences the whole system.
The feedback principle includes the rule that the management is calculated by the
system state.
p: T x Z  X
l: TxYX
10
Lessons Learned from Accident Investigation
RISK
MANAGEMENT
1.
CONTEXT
M2
R2,1
R2,5
M1
R1,4
M3
R2,1
R1,5
4.
MONITORING
R4,5
M4
5.
STRATEGY
2.
RISK ANALYSIS
R2,5
M4
R3,2
R3,5
R4,3
M5
R3,5
R4,3
R4,5
M2
M5
R5,4
R3,2
3.
TREATMENT
M3
European Union
M1
M2
M1
M3
M4
M5
R1,5
Figure 6. Framework for Risk Management and the binary relations matrix (5)
The trajectory is realized: M1  M4 M3 M2 M1 and feedback to management
M1 M5, M2 M5, M3 M5, M4M5.
In order to operate the system, it is needed to know the connection between the
operated system output at every moment, depending on the inputs and transformed
system out-put mechanisms for signals to system inputs. The feedback might be
positive and negative. Positive feedback empowers the effect of the input signal, the
negative feedback debilitates but enables to restore the balance in the system if the
external disturbances function.
The problem is that the feedback for management is desired to be formed in
quantitative way- numerically. Neither the aim nor both the state and transfer
functions can be formulated only numerically. In this case the quality of management
would decrease. The leader on the strategic level does not need continuous
quantitative information; they need to see the risk profile – what is the state of things
actually like. This knowledge has to include both quantitative and qualitative
information [6,8].
The strategy for occupational health and safety for the years of 2007-2012 has been
compiled; also the strategic document on the European Union level for strategic risk
management model exists. There is no strategic management document for the
occupational health and safety for the year of 2009 in the Estonian Republic.
Conclusions
In the investigation, the risk management system model worked out on the European
level has been implemented on the example of an Estonian enterprise. We saw that
the model has not been dealt with as the whole, but only individual components are
taken into consideration. Making decisions is usually based only on quantitative
information and the importance of qualitative information and analyse have been
11
Proceedings of the 36th ESReDA Seminar, Coimbra, Portugal, June 02-03, 2009
underestimated. The quality of making strategic decisions on the hierarchical level
suffers as a result.
The conclusion is: it should be considered that both quantitative and qualitative
indicators must be used in strategic management, that means integrated qualitative
and quantitative approach to effective risk management.
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