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Workplace Assessment: Determination of Hazards Profile Using a Flexible Risk Assessment Method. Töökeskkonna hindamine: ohtude profiili määramine paindliku riskianalüüsi meetodi abil

by Reinhold, Karin, PhD

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MODEL 2, the only permitted risk without special attention is trivial risk (I), which
falls to the green zone. The risk levels have the following coloration:
I, green zone – permitted risk;
II and III, yellow zone – permitted risk, with caution: the safety guidance has to be
closely followed and the worker’s individual peculiarities have to be considered;
IV and V, red zone – inadmissible risk, which requires mitigation/elimination or
additional safety measures in order to continue the work procedures.

Table 1.1 MODEL 1 risk estimation

Likelihood Slightly dangerous
(no injury


(injur with sub-sequent
complete recovery)

Extremely dangerous
(permanent severe
Almost Trivial risk I Acceptable risk II Moderate risk III
Considerably Acceptable risk II Moderate risk III Substantial risk IV
but possible

Probable Moderate risk III Substantial risk IV Intolerable risk V

Table 1.2 MODEL 2 A simple risk level estimator
Severity of harm

Likelihood of Slightly harmful Harmful Extremely harmful
Improbable I Trivial risk II Tolerable risk III Harmful risk

Unlikely II Tolerable risk III Harmful risk IV Dangerous risk

Probable III Harmful risk IV Dangerous risk V Intolerable risk

MODEL 2 was used as a starting point to develop the NLI method “Risk
analysis in the work environment and the arrangement of internal audit” (Kruus et
al., 2001). A similar approach is also applied in the document “Five steps of risk
assessment“ (1998, in Estonian), which was compiled on the basis of Health &
Safety Executive (HSE, 1994).

The following model (MODEL 3) was worked out by the labour inspector
Laurik (Table 1.3) (Tint, 1998). In MODEL 3, the multiplication of probability and
severity is determined as a numerical risk level, which has six distinguishable
levels: trivial (I), small (II), acceptable (III), medium (IV), substantial (VI) and
intolerable (IX). The peculiarities in this model are the significantly greater number
to intolerable risks compared to substantial risk and equalization of acceptable and
tolerable risk (level III).


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Table 1.3 MODEL 3 Risk matrix developed by Laurik (Tint, 1998)
The risk level is estimated by dependence R = S × T, where S is the probability and
T – the severity of the occasion.
Consequence (T)


Trivial injury
(microinjury), some

shortlasting illfeelings

Slight injury or
disease due to the
dangerous, harmful
work conditions

Severe injury or


(death, disability,
occupational disease)

(very seldom),
occupational injury
or disease appears
once in 10…20
occupational injury
or disease happens
in some years
(often), one or
some accidents
happen a year

Trivial risk

Small risk

Acceptable, tolerable
risk (eliminated in

3-5 months)

Small risk

Medium risk,
(eliminated with

measures in
3-5 months)

Substantial risk
(eliminated in
1-3 months)

Acceptable, tolerable
with measurements

Substantial risk
(eliminated in 1-3


Intolerable risk
(stop the activities

at once)

The final improved matrix, MODEL 4 (Table 1.4), uses the colour scheme from
MODEL 1 and MODEL 2, and the principle for calculation of risk levels from
MODEL 3. The severity of the consequences is determined as follows: (i) slight
(overcoming disease or trauma that does not cause permanent damage); (ii) harmful
(dangerous or permanent health damages such as burnings, concussions, hearing
loss, asthma, etc); (iii) very dangerous (permanent and irreversible damages such
as limb loss, poisonings, fatal accidents, accidents causing health damages for
several workers, etc).

Table 1.4 MODEL 4 Risk matrix with six risk levels (Kruus et al., 2001)
Probability Consequences
(or harmful) (2)
Very dangerous
(or impossible)

Trivial risk
Small risk
(or tolerable)
Permissible risk
(or hazardous)

Unlikely (or
slightly probable)


Small risk
(or tolerable)

Permitted risk
(or hazardous)


Permissible risk
(or hazardous)

Permitted with control

(or harmful)

Permitted with
control (or harmful)
Unpermitted risk
(endangering life)


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The last method is considered to have the highest value in assessing risks at
workplace and has been created in co-operation of several Estonian risk assessment
specialists; however, it has not achieved the expected popularity among
practitioners. The reasons for it are not studied in depth.

Despite several theoretical risk assessment models available, the primary
shortages in risk assessment reports include, as mentioned before, the absence of a
specific method and confusion with principles for risk level estimation (Labour
Inspectorate, 2008). This indicates the necessity to offer a fresh approach to
assessing risks at workplaces.

1.4 Chemical exposure and risk assessment at workplaces

People are continuously exposed to different chemical hazards in everyday worklife
and during their leisure time continuously. According to the data gathered by
the National Board for Health Protection of Estonia in 1996 (Tint, 1998), at least
25,000 workers were exposed to different types of chemicals (petroleum products,
nitric and lead compounds, benzene and its derivates, manganese, nickel, phenols
etc.) and 22,000 workers were exposed to different types of aerosols (organic dust,
welding aerosols, oil-shale dust, mineral fibres, dust of abrasive materials, etc.)

Exposure to a chemical agent is typically the contact of that agent with the outer
boundary of a subject, such as the respiratory system, skin, or digestive system
(Harper, 2004). In occupational settings, the main concern is towards exposure
through the respiratory system, although increasingly results of dermal exposures
are a problem as well.

Currently, workplace chemical safety information is communicated primarily
by means of classification listings, labels and Material Safety Data Sheets (MSDS)
provided by the chemical manufacturer or supplier, while the toxicological data are
rarely consulted (Fairhurst, 2003). The lack of information is expected to be
overcome by new European chemicals policy. The new EC Regulation No
907/2006 on the Registration, Evaluation, and Authorisation of Chemicals
(REACH) came into force on 1 June, 2007 (EC, 2006). REACH aims at improving
the protection of human health and the environment through a more inclusive and
focused system for the identification and assessment of the properties and uses of
chemical substances produced in or imported to Europe. The detailed testing
requirements under REACH have not yet been harmonized with the requirements
for substance classification under the currently developed Globally Harmonized
System (GHS) (Foth and Hayes, 2008).

The number of occupational diseases is a specific indicator of the influence of
existing hazards and risk factors in the work environment. Exposure to chemicals
may initiate various occupational diseases such as skin diseases, airway and lung
diseases, neurological diseases, or exacerbate noise induced-hearing loss (Bardana,
2008; Morata et al., 1993; Sliwinska-Kowalska et al., 2005; Timbrell, 2002). To
diminish the mutagenic, carcinogenic, teratogenic and other harmful effects of
chemicals, the health damages have to be diagnosed in the early stage of the illness.


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Therefore, tracing linkage from disease to possible causative agents by screening
for the presence of specific chemicals is crucial.

Within the framework of European risk assessment of chemical substances, the
occupational risks have to be assessed (EC, 1998). This risk assessment is
performed considering the toxic properties of a substance on the one hand and the
extent of exposure at the workplace on the other. The principles of risk assessment
are described in the Technical Guidance Documents (EC, 1996), where it is
recommended that the risks of workers should be determined on the basis of
measured exposure levels or in the absence of measurement data by means of
models. In order to perform an accurate risk assessment of chemical exposure, a
health and safety expert is usually needed. However, there are often cases where an
expert is not readily available, especially among SMEs. The conclusions of a
scientific investigation held in the UK (Topping et al., 1998) suggest that
companies lack the appropriate tools to make a thorough evaluation of chemical
risks. Thus, a simplified risk assessment method that provides assessment results
without expert involvement is required.

1.4.1 Existing assessment methods

In general, the methods that aim at making the analysis of chemical risks more
accessible to companies can be grouped into four categories (Balsat, 2003). These
methods claim to be simple and the majority of them use the R-phrases (EC, 2001)
for identification of hazards. The last two groups can be interpreted as risk
assessment methods since they either evaluate the acceptability of the risk (third
level) or make the semi-quantitative risk assessment possible (fourth level). The
use of R-phrases as the basis of a generic approach to the development of exposure
control levels is not novel. For example, Gardner and Oldershaw (1991) proposed a
generic approach to the development of appropriate exposure-control levels for
volatile organic substances, based on R-phrases for single exposure toxicity. The
most relevant shortcoming of the schemes that are built up using R-phrases as the
main danger parameter is the fact that they are highly dependant on the good use
by suppliers of the R-phrase classification system.

According to literature (Topping et al., 1998), there are strong indications that
occupational exposure limits (OELs) could also, with additional information (for
example on physical properties and use), be used to identify appropriate control
measures that can be recommended to users of chemicals. Approaches that use
OELs were developed by Brooke (1998) and Russell et al. (1998). The method by
Brooke shows how established OELs, for which there is well documented
information on the basis of the limit, can be used to validate the control strategies
recommended by the scheme. The scheme identifies best-case, worst-case and
midpoint margins between target airborne concentrations for chemical hazards,
based on exposure limit values and toxicological data (example in Table 1.5, for
vapours with the R-phrase R48 (Harmful case)), defines four main risk levels


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(hazard bands) + skin hazard, but does not make specific connections between the
health hazards and risk levels.

Table 1.5 Margins between target airborne concentrations for hazard band B (R48
Harmful) and repeated exposure classification for cut-off values according to
Brooke (1998), for vapours
Target airborne concentration for hazard
band B, ppm
Lower Upper Midpoint
50 Upper
Harmful R48 classification cutoff
values, equated to TWA
(8 h) concentration, ppm

100 Upper
150 Upper



(Abbreviations: (1)-best-case; (2)-worst-case; (3)-midpoint)

5 50 28







The scheme proposed by Russell et al. (1998) is dependant on the availability of
robust OELs for a range of substances. It takes for its hazard base the R-phrases
assigned to chemicals by suppliers as part of their classification, labelling and
packaging duties. From its R-phrases, a chemical is assigned to one of five hazard
bands that will determine the level of exposure the scheme seeks to help the
employer achieve (Figure 1.9).

allocated to a
hazard band,
using R-phrases
allocated to a
Combination of

+ dustiness or
volatility band
and a band for
the scale of use

health hazard
and exposure
potential factors
desired level of

Type of approach
needed to
achieve adequate

Figure 1.9 Factors used in the core model by Russell et al. (1998)

Development of various schemes for evaluating and controlling chemical risks
has continued in the 21st century as well, with several schemes established and
some of them implemented, including COSHH Essentials (Control of Substances
Hazardous to Health), Chemical Control Toolkit, EASE model (Estimation and
Assessment of Substance Exposure) and Risk-EASE model, which are designed for
assessing chemical risks in working firms (Bredendiek-Kämper, 2001; HSE, 2003;


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ILO, 2005; Jones and Nicas, 2006; Mäkinen et al., 2002; Rantanen and Pääkkönen,
1999; Russel et al., 1998, Tickner et al., 2005) and PRHI (Process Route
Healthiness Index) developed for analysing new processes that have not yet been
implemented (Hassim and Edwards, 2006).

COSHH Essentials provides a basis for categorizing the hazard of chemical
substances, the estimation of likely exposures and a comprehensive approach for
integrating the two to provide practical guidance for common industrial activities.
This semi-quantitative risk assessment method (often referred to as the control
banding method (Jones and Nicas, 2006)) is mainly used in the UK and has been
verified as being valued by and useful for SMEs (Wiseman and Gilbert, 2002). The
COSHH Essentials method has been found to overestimate the danger in certain
cases such as mixtures of solvents or aqueous solutions (Brooke, 1998), which
demonstrates that the method tends to provide a safe-sided judgement. On the other
hand, Jones and Nicas (2006) compared exposure bands to measured exposures
with regard to solvent vapour degreasing and powder bag filling operations and
identified several “under-controlled” cases. Thus, it can be summarized that the
evidence verifying the appropriateness of the COSHH model is limited. As for the
proper use of COSHH the employers need information from MSDS, then the
evaluation is dependant on the quality of the safety sheets compiled by suppliers or

Chemical Control Toolkit (CCT) is based on COSHH Essentials and uses a 5-
step risk assessment scheme to perform the assessment (see Table 1.6). The
indicators of toxic endpoint and potency used by CCT are either R-phrases or GHS
of Classification and Labelling of Chemicals (United Nations, 2003). An exposure
band is a range of target 8-hour time-weighed average airborne concentrations
applicable to all chemical substances assigned to the given hazard band.

Table 1.6 The five steps of the Chemical Control Toolkit
Step Description
1. Hazard classification R-phrases or GSH classification are used to assign
the substance to hazard band A (low hazard), B, C, D
(high hazard) and/or S (skin hazard)

2. Scale of use Volume of substance used: small, medium, large
3. Ability to become airborne Defined as the volatility of liquids (based on the
boiling point and process temperature) and the
dustiness of solids – low, medium, high

4. Control approach Answers from Steps 1-3 are used with a matrix to
identify the appropriate control approach

5. Task-specific guidance The control approach level from Step 4 is used to
identify the guidance sheet for the specific task in
which the substance is used

The EASE model is often applied to assess inhalative exposure at workplaces. It
was developed on the basis of measured exposure levels classified according to
typical exposure scenarios in the 1990s by Health and Safety Executive (UK)


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(Tickner et al., 2005). These exposure scenarios were defined according to the use
patterns and control patterns as well as the physiochemical properties of
substances. A software tool has been developed (version 2.0 is currently used) and
some researchers (Bredendiek-Kämper, 2001; Mäkinen et al., 2002) have
conducted studies of comparison of EASE estimates relating to inhalative exposure
and appropriate workplace measurements to show if single EASE scenarios
correspond with measurement data representing “workplace reality”. Two studies
(Bredendiek-Kämper, 2001; Mäkinen et al., 2002) concluded that EASE
overestimates exposure in several cases, e.g for workplaces where low amounts of
powdery substances are handled or where medium-volatile solvents are present,
etc; and underestimates exposure in a few cases as well, for instance in the paint
factory where liquid substances were used. This circumstance leads to a high
degree of uncertainty of some EASE scenarios and thus of the corresponding risk
assessments as well.

Risk-EASE is a combination of two models (EASE and risk assessment model
used in BS 8800 (BSI, 1996)), developed by Finnish researchers (Rantanen and
Pääkkönen, 1999). It is based on a cross tabulation of the effect of the chemical
(most severe risk phrase) and the probability of consequent adverse health hazard.
The model is presented in Table 1.7, where probability is classified into three
groups as the percentage of OEL (<10%, 10–50%, 50–100%) and consequences
are divided into three groups as well (minor, harmful and severe effects). Cross
tabulation divides the risk into five categories according to the amount of risk
involved (low risk to unbearable risk). Mäkinen et al. (2002) conducted a study in
19 Finnish SMEs where the Risk-EASE model was used. It showed that the risk for
chemical exposure with Risk-EASE model was categorized higher than when the
original BS 8800 model was used alone. However, it was concluded that the cross
tabulation methods seem to work adequately when used for their intended purposes
by an experienced person. It was noted that in 19 Finnish SMEs workplaces lack
information about chemicals, work processes and health effects, and the
occupational healthcare units do not always have the skills required to make
adequate exposure and risk assessment decisions.

PRHI has been developed to quantify the health hazards that might arise from
chemical processes: the higher the index, the higher the hazards. It is influenced by
the health impacts due to potential chemical releases and the concentration of
airborne chemicals inhaled by workers. The PRHI index is calculated step by step
using the following formula (Hassim and Edwards, 2006):

PRHI = ICPHI × MHI × HHI × WECmax/OELmin [4]

First, ICPHI (Inherent Chemical and Process Hazard Index) is estimated where
work activities and conditionals that are potentially harmful to health are identified
and penalized (the sum of these gives ICPHI). Second, HHI (Health Hazard Index)
is calculated considering chemicals that may cause typical occupational diseases.
Third, materials at each stage of the process by healthiness are ranked, based on the


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NFPA Ranking for Health (NFPA, 2007), which gives MHI (Material Harm
Index). Fourth, WEC (Worker Exposure Concentration), which is the likely
concentration of chemicals in the workers’ immediate environment, is estimated.
Fifth, the OEL (Occupational Exposure Limit) is obtained and the PRHI is
calculated. The index has been implemented only in the early project stages of
factories and there no attempt has been made to correlate it with measurable
indicators of occupational health and safety of a working company.

Table 1.7 The Risk-EASE model according to Rantanen and Pääkkönen (1999)
Severe effects
Harmful effects (poisonings, cancer,
(burns, dermatitis, asthma, severe
Minor effects severe long-term permanent effects,
(discomfort, effects, moderate life-shortening
irritation, temporary permanent harm) illnesses)
moderate illness) R23, 24, 25, 33, 34, R26, 27, 28, 35, 39, 41,
R20, 21,22, 36, 37, 38 40, 43, 48, 62, 63, 64 42, 45, 46, 60, 61, 65

Improbable (severe
effects: <10% of
OEL; others 10%-

50% of OEL)
Possible (severe
effects: 10-50% of
OEL, others 50%-
100% of OEL)
Probable (severe
effects: 50%-100%
of OEL; others over

No action needed
(negligible risk)

(low risk)

Actions needed
(moderate risk)
(low risk)

Actions needed
(moderate risk)

Necessary actions

(moderate risk)
Actions needed
(moderate risk)

Necessary actions

(moderate risk)

Immediate actions

(unbearable risk)

To conclude, it has to be underlined that various concepts have been applied to
assess the risks arising from the workplace use of chemicals. From simple risk
matrices, based in part upon the limited opportunities for exposure control in a
defined setting, some approaches have been developed into forms where their
application is widespread. Some of the recent developments also provide
opportunities for targeting information to help SME users of chemicals manage
risks and track performance more effectively. Each of the method has its own
advantages and disadvantages. The overall disadvantage lies in the fact that some
of the schemes appear to have undergone limited validation, either during their
development or immediately after their implementation.

1.5 Aims of the present study

The importance of the thesis is closely connected with the policy of the EU in the
field of OHS. During the years 2008–2009 a campaign for risk assessment is to be
launched in each member state. The campaign seeks to demystify the risk


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assessment process and emphasizes the importance of workforce involvement in
the risk assessment to ensure that hazards are identified not only from principles of
knowledge but also by knowledge of working conditions and patterns of adverse
effects upon workers.

The basis of investigation is worldwide experience, which has shown that risk
assessment is a powerful tool for solving diverse problems in the work
environment and promoting safety in industries and to prevent occupational
accidents and diseases.

The aims of the study are:
o to analyse the existing risk assessment models and work out an original,

flexible method for employers to control the hazards at workplaces;


to provide the basis for the assessment of chemical risks at workplaces;
to offer an overview of the hazards profile (chemicals, dust, noise,
microclimate, lighting) in selected industries using the measurements of
work environment hazards as well as the flexible risk assessment method;
to implement the flexible risk assessment method in practice for solving
the problems of work conditions.

The novelty of the flexible risk assessment method for manufacturing and office
rooms consists in a unique approach which considers the measurements in the work
environment, analyse them on the basis of the legislation requirements and
scientific deliverables on exposure limits and the determination of risk levels in the
work environment. The flexible risk assessment method tries to combine health and
safety in one model. Health differs from safety in terms of the time for the effect to
appear. Safety deals with acute, that is serious short-term events. Whereas health is
a chronic matter, because it takes some time before the effects on people’s health
can be identified and the impact might persist over a long time.

The practical importance of the thesis involves the application of the proposed
method in safety engineering. The flexible risk assessment method can be used for
different purposes and at different levels: as a basis for decision-making when
selecting among different remedial actions for a mined out area within time and
financial restraints; a tool for deciding the acceptability of risk for the industrial
activities; a basis to decide over the appropriate personal protective equipment as
well as the need for health inspection by occupational physicians. The flexible risk
assessment method is applicable in various fields of manufacturing and office

Limitations of the study
In the current thesis, the investigation of occupational hazards is limited to
measurable hazards only. Attempts to integrate other hazards, such as psychosocial
and physiological hazards, to the same model have been made, but for this, further
investigation is needed and it is not covered in the current study.

The method, in the current stage, identifies the risk level of a hazard, but does
not offer direct advice on the selection of adequate or suitable control measures.
The general hierarchy of control measures is recommended, but detailed advice on
the controls remains for future research.


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The present study provides an in-depth analysis of work environment based on data
of measurements of occupational hazards and risk assessment performed in plastic,
clothing, wood, mechanical and printing industries towards progressive
improvements in OHS.

The examined physical and chemical hazards were selected considering the
most common and obvious occupational hazards present in the industrial sector in

To perform the measurements of occupational hazards, standard methods were

ISO 7726:1998 “Thermal environments – Instruments and methods for

measuring physical quantities” (for indoor climate)
DIN 5035-6:1990 “Artificial lighting. Measurement and evaluation” (for

ISO 9612:1997 “Acoustics – Guidance for the measurement and

assessment of exposure to noise in a working environment” (for noise)
EVS-EN 1231:1999 “Workplace atmospheres – Short term detector tube

measurement systems – Requirements and test methods” (for chemicals)
EN 482:1994 “Workplace atmospheres – General requirements for the

performance of procedures for the measurement of chemical agents” (for
ISO 10882-1:2001 “Health and safety in welding and allied processes–

Sampling of airborne particles and gases in the operator’s breathing zone –
Part 1: Sampling of airborne particles” (for chemicals)
EN 481:1993 “Workplace atmospheres – Size fraction definitions for

measurement of airborne particles” (for chemicals)
EN 689:1996 “Workplace atmospheres – Guidance for the assessment of

exposure by inhalation to chemical agents for comparison with limit values
and measurement strategy” (for chemicals)

WCB method 1150:1998 “Particulate (total) in air” (for dust).
The details of measurement procedures and apparatus used are described in Papers
II, IV and VI.

The criteria for risk levels of occupational hazards were obtained from
regulative norms, standards, directives and scientific literature. The literature scan
focused on the impact of the main occupational hazards on workers’ health.

Data from 18 enterprises were used for the assessment of the adequacy of the
method as well as to examine the hazards profile in manufacturing. All investigated
companies were assessed as SMEs. The enterprises were located in different parts
of Estonia; however the majority of them were in or around the capital and western
part of the country. The summary of the companies is presented in Table 2.1.

In each company, the management attitude towards health and safety was
assessed on the basis of the interest in the results of outcomes of the research, the


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