(Revision: June 8th, 2022)

Fire/Explosion Hazard Scenario Identification Method Focusing
on the Three Elements of Combustion(Simple Hazard Scenario Identification Method)

Japan Organization of Occupational Health and Safety
National Institute of Occupational Safety and Health, Japan
If you have any question, comment, request, etc. concerning this document, let us know throughthe inquiry section of the official website of the National Institute of Occupational Safety and
Health, Japan (http://www.jniosh.johas.go.jp/rule/contact.html).

1.

Patterns of Causing Fire/Explosion (How Three Elements of Combustion Coexist)
To conduct risk assessments of chemical substances and to devise specific risk reduction measures, it isnecessary to comprehensively identify the hazards and the hazard scenarios of how they cause a fire or explosion(hereafter referred to as “identifying the hazard scenarios”). The basis for identifying the hazard scenarios of
causing a fire or explosion is to find the conditions under which the three elements of combustion1 coexist. Thismeans that a fire or explosion occurs when combustible or inflammable chemicals come into contact and mix withoxygen (air), forming an explosive atmosphere (an unsafe condition)2, and at the same time, an ignition source
occurs, so assuming work in an open area where oxygen (air) is always present, it is enough to focus on the twopoints of the formation of an explosive atmosphere and the occurrence of ignition sources. Based on whether risk
reduction measures are taken against these two points (whether measures are taken to prevent the formation of an
explosive atmosphere and the occurrence of ignition sources), hazard scenarios of causing a fire or explosion
when combustible chemical substances are handled in an open area can be classified into four patterns (by how
the three elements of combustion coexist) as shown in Table 1 below for identification.
Table 1

Identification Patterns for Hazard Scenarios of Causing Fire/Explosion during Work in an Open Area
(by How the Three Elements of Combustion Coexist)3
II. Formation of explosive atmosphere

I. Use of combustible chemicals(1) Measures are NOT taken to prevent (2) Measures are taken to prevent
formation of explosive atmosphere
formation of explosive atmosphere

III. Occurrence of ignition source

Pattern (a)(3) Measures are NOT taken
to prevent occurrence ofignition sources

Pattern (c)Three elements of combustion may becoexistingThree elements of combustion cancoexistExplosive atmosphere

Explosive atmosphere

There is always a high risk of fire andexplosion, so prompt measures are
required.

An explosive atmosphere can be formed
by a failure such as forgetting to closethe container lid (trigger event B).

Pattern (b)Pattern (d)Three elements of combustion cancoexistThree elements of combustion cancoexistExplosive atmosphere

Explosive atmosphere

Ignition sources can occur due to a
failure such as poor ground connection
caused by deterioration (trigger event A).

An explosive atmosphere can be formed
and ignition sources can occur due to thesimultaneous occurrence of trigger
events A and B.

* In Table 1 above, events that can occur at any time are enclosed with a solid line (trigger event are enclosed with a dashed line ().

), and those that are triggered by a(4) Measures are taken toprevent occurrence ofignition sources

1

Combustion is an oxidation reaction that involves the generation of heat and light, and it does not occur if even one of the three elements,“combustibles (combustible substances),” “oxygen supply sources (supporting materials),” and “ignition sources,” is missing. The key topreventing combustion is to eliminate at least one of these three elements.
2
During work that handles chemical substances but does not involve any reaction, such as coating, the chemical substances are always in contact
with oxygen (air) (assuming that an explosive atmosphere is always formed during work in an open area if no preventive measures are taken).
3
The “trigger events” mentioned in Table 1 are described in detail in Section 3.

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Pattern (a): Measures are taken neither to prevent the formation of an explosive atmosphere nor to preventthe occurrence of ignition sources.
(1) An explosive atmosphere can always be present(3) Ignition sources can occur at any timee.g. When working with paint in a container without a lid (without taking measures to prevent the formationof an explosive atmosphere), there is always a risk of the formation of an explosive atmosphere. If thishappens and an ignition source occurs due to electrostatic discharge, it could cause a fire or explosion.

Pattern (b): Measures are taken only to prevent the occurrence of ignition sources.
(1) An explosive atmosphere can always be present(4) Ignition sources can occur due to the occurrence of a trigger event A
e.g. When working with paint in a container without a lid (without taking measures to prevent the formationof an explosive atmosphere), there is always a risk of the formation of an explosive atmosphere. If thishappens and an ignition source occurs, for example, due to poor ground connection caused bydeterioration (trigger event A), it could cause a fire or explosion.

Pattern (c): Measures are taken only to prevent the formation of an explosive atmosphere.
(2) An explosive atmosphere can be formed due to the occurrence of a trigger event B(3) Ignition sources can occur at any timee.g. Even when measures are taken to prevent the formation of an explosive atmosphere, an explosive
atmosphere can be formed by forgetting to close the lid of the container (trigger event B), and if such an
explosive atmosphere flows into another work site where measures are not taken to prevent occurrenceof ignition sources (e.g., a place where fusion cutting is being performed), it could cause a fire or
explosion.

Pattern (d): Measures are taken both to prevent the formation of an explosive atmosphere and to prevent theoccurrence of ignition sources.
(2) An explosive atmosphere can be formed due to the occurrence of a trigger event B(4) Ignition sources can occur due to the occurrence of a trigger event A
e.g. Even when measures are taken to prevent the formation of an explosive atmosphere, an explosive
atmosphere can be formed by forgetting to close the lid of the container (trigger event B). If thishappens and an ignition source occurs, for example, due to poor ground connection caused bydeterioration (trigger event A), it could cause a fire or explosion.

The following is a summary of the hazard scenario identification method by checking in advance in which
pattern the work subject to risk assessment is performed (hereafter referred to as “simple hazard scenario
identification method”)4. Figure 1 shows the outline of the simple hazard scenario identification method. Various
hazard scenarios are identified by preparing three types of sheets in order.
(i) Prepare a “Working Condition Check Sheet” (Table 2).
Check in which pattern in Table 1 the work subject to risk assessment is performed (and if it is already in an
unsafe condition) by checking the characteristics of the handled chemical substances, working conditions,
measures already taken, and others.
(ii) Prepare a “Trigger Event Check Sheet” (Table 3).
Comprehensively identify trigger events that can cause an unsafe condition.
(iii) Prepare a “Hazard Scenario Identification Sheet” (Table 4).
Identify the hazard scenario of causing a fire, explosion, or effects on others (including industrial accidents) bychecking whether an explosive atmosphere will be formed and whether ignition sources will occur due to theoccurrence of an identified trigger event.
4

The “simple hazard scenario identification method” summarizes the minimum points to be checked to identify the hazard scenario of causing a fireor explosion as easily as possible when conducting risk assessment and risk reduction of chemical substances. Note that this does not necessarily
cover all risks (all fire and explosion hazard scenarios).

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Figure 1 How to Identify Hazard Scenarios of Causing Fire/Explosion Focusing on the Three Elements of Combustion
Table 2Working Condition Check Sheet (Form)[B] Handled chemical substances and facilities, equipment, and others[C] Confirmation of pattern of the three elements of combustion that can cause fire or explosion
used for work
InformationonHandling
conditions[A] Workhazards of(temperature,
Facilities,
Q-2. Are measures taken to
Q-3. Are measures taken toprocedure/details Handled
Q-1. Are the handled chemical
Patternchemicalchemicalprevent the formation of an
prevent the occurrence ofhumidity, amountequipment, andsubstances combustible?
(a) - (d)substances
substances
handled, storage
tools used for work
explosive atmosphere?
ignition sources?
concerned
conditions, etc.)

1
2
3
-

Table 3 Trigger Event Check Sheet (Form)[A] Workprocedure/details[D] Trigger[C] Confirmation of pattern of the events related to[B] Handled chemical substances and facilities,
three elements of combustion thatfacilities,
equipment, and others used for work
can cause fire or explosion
equipment, andtools[E] Trigger events related to work/operation(human errors)

Handling

Commission errors
Measures to
Measures toInformation
conditions
Handled on hazards of (temperature, Facilities,
prevent
prevent
Facility, equipment,
Omission
Patternequipment,
formation of occurrence ofand tool failures
humidity,
chemical chemical(a) - (d)and tools
errorsSelection Sequential Time Qualitative Quantitative
ignition(Failure mode)
substances substances amount handled, used for work explosive
atmospheresources
concerned
storageerrorserrorserrorserrorserrorsconditions, etc.)

Othererrors1
2
3-

Table 4

Hazard Scenario Identification Sheet (Form)[C] Confirmation of pattern of the three elements of
combustion that can cause fire or explosion[A] Work
Measures to
Measuresto prevent
procedure/details
prevent
Patternformation of
occurrence of(a) - (d)explosive atmosphere
ignition sources[F] Unsafe conditions[D] [E] Trigger events

1

2

3

-

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Formation of explosive
atmosphereOccurrence ofignition source[G] Accidents and disasters

Fire / explosion

Other effects

2. Checking Characteristics of Handled Chemical Substances, Working Conditions, Current Measures, etc.
(Preparation of “Working Condition Check Sheet”)(1) Preparation of “Working Condition Check Sheet”
Prepare a “Working Condition Check Sheet” (Table 2) to check which hazard scenario identification pattern ofcausing a fire or explosion (how the three elements of combustion coexist) in Table 1 is applicable to each work
subject to risk assessment. The method of filling in the form is described below.
[Column A]: Enter the work details/method described in the work procedure manual.
Enter work procedures and details referring to the latest version of the work procedure manual that reflects thedetails and methods of the work actually performed at the work site. At this time, clarifying the purpose (intent) of
the work will enable a more detailed analysis.
* If there is no work procedure manual, check the work actually being performed and prepare such a manual, even a
simple one, to clarify the work details.
* Even if there is a work procedure manual, check in advance that the contents of the manual match the actual work.
If there is any difference, clarify which is wrong, correct the wrong one to make both match, and then proceed withthe following analysis.
* If the results of the previous process performed in another place are expected to affect the process subject to risk
assessment, or if the results of that process affect subsequent processes, it is advisable to include these processes inthe same check sheet. If one process and another are analyzed separately because they are performed by different
workers in different places, the hazard scenario that “another failure occurs while a process is performed under anunsafe condition caused by a failure in the previous process, causing a fire or explosion” will be overlooked.
* By using a detailed work procedure manual, you can devise and take more specific risk reduction measures.

[Column B]: Enter the handled chemical substances and facilities, equipment, and tools used in the work.
b-1) Enter the name of the handled chemical substances. If multiple chemical substances are handled, enter thename of each one5.
* For chemical substances, you can enter their product names, but it is necessary to also enter chemical substancenames so that their SDSs can be referred to.

b-2) Obtain information on hazards and applicable laws and regulations by checking GHS labels, SDSs, and thelike. Enter the points that require special attention, such as physical property data (e.g., flash point andpossibility of dust explosion of powdered material), if any.
* If there are no GHS labels or SDSs, order the latest one as soon as possible.

b-3) Enter the conditions of use (temperature, humidity, amount handled, storage conditions, etc.) of the handledchemical substances, and how to dispose of them6.
* These will provide basic information for determining the possibility of formation of an explosive atmosphere.

b-4) List the facilities, equipment, and tools used in the work, and enter their names. Also check their purposes
of use and appropriate use.
[Column C]: Enter the confirmed identification pattern of the hazard scenario of causing a fire or explosion.
Enter the answers to Q-1 through Q-3 below in their corresponding columns, and check which of theidentification patterns of hazard scenarios of causing a fire or explosion in Table 1 applies.
5
6

If multiple chemical substances are handled in a single process, it is advisable to subdivide the process and analyze each subdivided work.
SDSs can contain notes on disposal, which you can refer to.

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I.

Check if the handled chemical substances are combustible.
Q-1. Are the handled chemical substances combustible?
Fires and explosions occur when combustible chemicals are handled. Check if the handled chemical substances

are combustible by referring to the GHS labels or SDSs7.
A-11 If combustible chemical substances are handled- Enter the product name and chemical substance name, and then go to Q-2 and Q-3.
A-12 If combustible chemical substances are NOT handled- Enter “No.”
II. Check whether measures are taken to prevent the formation of an explosive atmosphere.
Q-2. Are measures taken to prevent the formation of an explosive atmosphere?
In open work sites, oxygen is always present, and an explosive atmosphere is formed (the condition becomesunsafe) when combustible or inflammable chemicals come into contact and mix with oxygen8. Table 5 shows
examples of measures to prevent the formation of an explosive atmosphere9. Check whether these measures aretaken or not, and if they are taken, enter the details.
A-21 (1) If measures are NOT taken to prevent the formation of an explosive atmosphere- Enter “No measures taken.” An explosive atmosphere can always be present.
* Enter the reason(s) why it has not been considered necessary to take measures, if any.
A-22 (2) If measures are taken to prevent the formation of an explosive atmosphere- Enter the measures taken to prevent the formation of an explosive atmosphere, and also check their
purposes. Even when measures are taken to prevent the formation of an explosive atmosphere, themeasures can be invalidated and an explosive atmosphere can be formed by forgetting to close the lidof the container, failure of the local exhaust ventilation, forgetting to turn on the switch, or the like(trigger event B)10.

7

For chemical substances for which SDSs are not obliged to be prepared, you can determine if they are combustible or not based on your experienceor knowledge.
8
This document covers the handling of chemical substances during work in open areas, such as coating. For the use of chemical substances inclosed spaces, such as reactors in chemical plants, you can refer to “Hazardous Areas” defined in the following guidelines or the like:- Technical Recommendations of the National Institute of Occupational Safety and Health, Recommended Practices for Explosion-ProtectedElectrical Installations in General Industries, TR-46 (2018) (the latest version at the time of writing this document)- Guidelines on How to Precisely Define Hazardous Areas in Plants (Ministry of Economy, Trade and Industry, 2020)- JIS C 60079-10:2008, Electrical apparatus for explosive gas atmospheres - Part 10: Classification of hazardous areas
9
Some of the measures listed in Table 5 are taken in combination with abnormality detection means (e.g., sensors) in order to detect the formation ofan explosive atmosphere.
10
Even if there are existing risk reduction measures, the JNIOSH method identifies hazard scenarios assuming a case where these measures areinvalidated. In contrast, for simplification purposes, the simple hazard scenario identification method checks whether there are measures to preventthe formation of an explosive atmosphere and the occurrence of ignition sources, and also identifies cases where each of the said measures isinvalidated due to the occurrence of a trigger event.

-5-III. Check whether measures are taken to prevent the occurrence of ignition sources.
Q-3. Are measures taken to prevent the occurrence of ignition sources?
Possible ignition sources of fire or explosion and examples of countermeasures are shown in Table 6. Table 7
shows the basics and examples of measures to prevent the occurrence of electrostatic sparks11. For the eightfactors of (a) through (h) in Table 6, check whether measures are taken to prevent the occurrence of ignition
sources, and if they are taken, enter the details.
A-31 (3) If measures are NOT taken to prevent the occurrence of ignition sources- Enter “No measures taken.” Ignition sources can occur at any time.
* Enter the reason(s) why it has not been considered necessary to take measures, if any.
A-32 (4) If measures are taken to prevent the occurrence of ignition sources- Enter the measures taken to prevent the occurrence of ignition sources, and also check their purposes.
Even when measures are taken to prevent the occurrence of ignition sources, the measures can beinvalidated and ignition sources can occur, for example, due to poor ground connection caused bydeterioration (trigger event A)10.
IV. Check the identification pattern of the hazard scenario that the three elements of combustion coexist,
causing a fire or explosion.
Based on the answers to Q-1 through Q-3, check which of the identification patterns (a through d) of hazard
scenarios of causing a fire or explosion in Table 1 applies, and enter it. The following apply depending on thepattern.
Pattern (a): Fire or explosion could occur at any time.
You should take some risk reduction measures before conducting risk assessment and risk reduction. After that,check Q-1 through Q-3 again.
Patterns (b) - (d): A trigger event can cause a fire or explosion.
Some risk reduction measures have already been taken, and provided these measures work, the three elementsof combustion will not coexist, but the occurrence of a trigger event, such as an equipment failure and work error,
can invalidate them, as a result of which the three elements of combustion coexist, causing a fire or explosion.
(2) Purposes of preparing a “Working Condition Check Sheet”
The purposes of preparing a “Working Condition Check Sheet” are as follows:1)

to confirm that the contents of the work procedure manual match the work actually being performed,2)

to check the characteristics of the handled chemical substances, handling conditions, equipment used, etc., and3)

to check how risk reduction measures are currently taken, and classify them into patterns to ascertain if anunsafe condition has arisen.

11

Measures to prevent the occurrence of electrostatic sparks are centered on those to prevent ignitable electrostatic discharge. In addition, Articles
286-2 and 287 of the Ordinance on Industrial Safety and Health also stipulate measures against static electricity.

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Table 5 Examples of Measures to Prevent the Formation of an Explosive Atmosphere12
MeasureSuppressgas/vapor
explosive
atmospheres

Examples- Remove unwanted combustible gas and liquid residues.
- Prevent the leakage of combustible gas and liquid.
- Control the release of combustible gas and vapor.
- Ventilate to prevent the retention of combustible gas and vapor.
Examples of ventilation equipment: Downward suction hood (e.g., ventilation workbenches),side suction hood, push-pull ventilators, enclosure hood (e.g., draft chamber)

Suppressdust-explosive
atmospheres

Examples of abnormality detection means: Concentration meter, gas detector* Should be appropriately installed in a place where the formation of an explosive atmospherecan be reliably detected.
* The concentration should be controlled to be less than 1/4 of the lower explosive limit(LEL).
- Select an appropriate powder particle size.
- Prevent powder from being more refined.
- Prevent powder retention and accumulation (including accumulation in exhaust/ventilationequipment).
- Limit the scale of handling.
- Divide facilities into compartments.
- Remove unnecessary protrusions from facilities.
- Prevent leakage of combustible powder.
- Prevent scattering and accumulation of combustible powder.
Examples of ventilation equipment: Downward suction hood (e.g., ventilation workbenches),side suction hood, push-pull ventilators, enclosure hood (e.g., draft chamber)

12

Prepared on the basis of the Technical Recommendations of the National Institute of Occupational Safety and Health, Recommendations for
Requirements for Avoiding Electrostatic Hazards in Industry 2007 JNIOSH-TR-No.42 (2007).

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Table 6

Possible Ignition Sources of Fire or Explosion and Examples of Countermeasures13

Classification
Electrical ignition (a) Electric
sources
sparksPossible ignition sources

Examples of measures- Electric sparks emitted from relay contacts of heating - Use explosion protected equipment.
devices, automatic temperature controllers, etc.
- Arcs emitted when lighting equipment breaks- Arcs from electrical welding nozzles- Sparks from non-explosion protected equipment andleaking electrical equipment- Use of non-explosion-protected equipment (e.g.,mobile phones, smartphones)(Refer to Table 7 Basics of Measures to(b) Electrostatic  When an object is charged and the electric fieldstrength formed by the charge exceeds a certain
Prevent Occurrence of Electrostatic
sparkslevel, dielectric breakdown occurs, causing
Sparks.)electrostatic sparks (discharge)
 Electrostatic sparks can occur in the following cases:- when there is metal near a charged metal object- when a charged worker touches metal such as adoorknob- when taking off work clothes- when a poorly grounded metal ladle touches themetal part of the manhole of the reaction tankduring sampling of liquid samples- when there is metal near a poorly grounded metal
part of a strainer with a built-in filter during theliquid transportation process- when there is metal near an insulated metal
container being filled with charged liquid, powder,or the like
- Exposed hot surfaces of electric heaters, heating- Maintain and inspect high-temperature
High-temperature (c) Hot
conduits, hot metals, or the likeequipment, monitor overload (using
ignition sources
surfaces- Fire sparks scattered during welding, gas cutting, or
sensors).
the like- Monitor the presence or absence of hot- The back side of a steel plate being welded or cut, etc. sections due to mechanical friction inequipment and devices.
- Limit welding, gas-cutting, and othersimilar operations appropriately.
- Remove hot objects from the(d) Thermal - Near burning material
surroundings.
radiation - Near an electric heater or boiler- Focused sunlight, etc.
- Use heat shielding material.
- Collision/impact between metals (especially light- Prohibit the use of light metal alloy
Impact ignition (e) Impact/
metal alloys)
products.
sourcesfriction- Friction due to foreign matter entering a moving part, - Remove combustibles and foreignetc.
matter from equipment and devices.
- Fluid friction- Take measures against fluid friction,such as operating the valve slowly andremoving combustibles from thesystem (cleaning).
- Operate the valve slowly.
(f) Adiabatic - Adiabatic compression due to rapid inflow ofgas into a closed space such as a pipe, - Remove combustibles (cleaning).
compression high-pressure
etc.14- Kitchen stove- Limit the use of fire according to the
Physicochemical (g) Naked- Heating stove
work environment.
ignition sources
flame- Candle light- Adequately control brought-in fire.
- Match/lighter- Cigarette light- Oxyacetylene flame / blowtorch flame- Boiler- Fuel combustion flames in various furnaces- Small flames in analytical instruments, etc.
(h) Spontaneous - Substances that ignite immediately upon contact with - Prevent accumulation of heat by
air or watersubdivision
ignition- Ignition due to accumulation of chemical reaction- Appropriately control temperature
heat inside combustible substances(using sensors).
- Perform forced cooling.

13
14

Prepared on the basis of Analysis of Explosion Disasters (Kitagawa, Nikkan Kogyo Shimbun, 1980) (in Japanese).
Precautions for High Pressure Gas Accidents Caused by Adiabatic Compression of Oxygen and Frictional Heat (High Pressure Gas Safety Instituteof Japan) https://www.khk.or.jp/Portals/0/resources/activities/incident_investigation/hpg_incident/pdf/dannetu.pdf (in Japanese, confirmed on May
22, 2021)-8-

Table 7
MeasureGrounding all
conductors

Basics and Examples of Measures to Prevent Occurrence of Electrostatic Sparks15
Description and examples
All conductors and conductive materials must be grounded because charged conductors candischarge sparks, causing a fire or explosion accident.
Grounding is a measure to prevent electrification of a conductor by electrically connecting itto the ground. Bonding is to connect conductors electrically. This is used to ground a conductorthat is not easy to ground directly by connecting it to another grounded conductor. Bonded
conductors have the same potential.
- Ground equipment, facilities, and other installed conductive structures (B-c).
- Eliminate insulated metals: Ground metals on non-conductors (e.g., plastic pipes, container flanges,
metal drums on insulated floorings) (B-c).

Groundingworkers andpreventing themfrom becoming
chargedElimination of
non-conductors16

Since workers also cause electrostatic discharge, prevent workers from becoming charged(from accumulating of electric charge) by using antistatic work shoes and conductive flooring.
- Ground the human body (C-c) by using antistatic work shoes and conductive flooring (B-c).
- Wear antistatic work clothes (C-c)

The charge on a non-conductor is not easily dissipated even if it is grounded. The electriccharge generated on a non-conductor accumulates and may cause a fire or explosion accident.
You can reduce the static electricity-induced risk by improving electrical conductivity by using
conductors instead of non-conductors and grounding them or adding an antistatic agent tonon-conductors (e.g., insulating liquid).
You can reduce the effect of charged non-conductors, and consequently reduce the static
electricity-induced risk by covering non-conductors with grounded conductors or dividing
non-conductors into compartments with the use of grounded conductors. A grounding wirespirally wound around an insulated hose is an example.
- Use conductive containers, pipes, filters, and others (A-c), and ground them (B-c).
- Use electrostatic shields (B-c).
- Add an antistatic agent or conductive liquid to insulating liquid (B-c).

Suppressing
chargegeneration

In general, the amount of electric charge generated depends on the contact area and thefriction speed. You can suppress the generation of electric charge by reviewing the work
process, such as slowing down the speed.
- Limit the operation speed and flow rate of liquid/powder transportation (C-c).
- Avoid turbulence and ejection of liquids that are easily charged (C-c).

Removing static
electricity

Measurements
related to static
electricity17

This means to suppress electric charge using a static eliminator. The electric charge of thecharged object is neutralized by the ions generated by the static eliminator. This is equivalent toincreasing the conductivity of the medium around the charged object (to accelerate charge
dissipation), and is effective for eliminating static electricity from non-conductors. However, thestatic eliminator should not be used alone as a risk reduction measure, but should always be usedin combination with other measures (B-c).
Check the conductivity, charge electric potential, and leakage resistance, which are indicatorsof the above measures, through the following measurements. Even when an explosion-protected
measuring instrument is used, it can be an ignition source, so never make measurements when
combustible gas, solvent vapor, or dust is present in the work site (B-b).
- Check whether all conductors are grounded using a tester.
- Measure the electric potential of bags containing raw materials as well as workers with anelectrostatic potentiometer.
- Measure the leakage resistance of floorings, workbenches, carts, and others with an insulation
resistance tester.

15

Prepared on the basis of the Technical Recommendations of the National Institute of Occupational Safety and Health, Recommendations for
Requirements for Avoiding Electrostatic Hazards in Industry 2007, JNIOSH-TR-No.42 (2007) (in Japanese). In Table 7, A) through D) correspondto the priority of risk reduction measures, and a) through d), to the classification of measures based on the concept of multiple protection measure.
16
Regarding static electricity- and weather-induced changes in humidity, it is known that humidification decreases the surface resistance of
non-conductors and accelerates charge dissipation. Therefore, with low humidity, the charge will not dissipate and non-conductors will be charged,
increasing the possibility of generating electrostatic sparks. In other words, there is a risk that electrostatic sparks will be generated due to changes
in humidity (in weather conditions). For work sites susceptible to changes in weather conditions, you should identify the hazard scenario assumingthat no measures are taken to prevent the occurrence of ignition sources. On the other hand, even in workplaces where temperature and humidity
are controlled, such as in sterile rooms, if a trigger event occurs, such as a worker forgetting to turn on the switch, it could cause a failure in
humidity control (a lower humidity), and consequently the occurrence of electrostatic sparks, which you should consider when identifying thehazard scenario and devising risk reduction measures.
17
Prepared on the basis of the Measures against Static Electricity Accidents (in Paint Manufacturing Industry), Second Edition (Japan Paint
Manufacturers Association (November 2014) (in Japanese).

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3.

Identification of Trigger Events of Fire/Explosion (Preparation of “Trigger Event Check Sheet”)(1) What is a trigger event?
When conducting risk assessment and risk reduction of chemical substances, it is important to identify all thehazards hidden in the work and equipment used to handle chemical substances. The JNIOSH method
comprehensively identifies the events that can actualize hidden hazards (trigger events) for each work described in
the work procedure manual. The classification of trigger events is shown in Table 8. Trigger events are broadlyclassified into (i) facility, equipment, and tool failures, (ii) inappropriate work/operations, and (iii) external factors.
These trigger events can trigger the formation of an explosive atmosphere or the occurrence of ignition sources.
Table 8Classification(i) Facility, equipment,
and tool failures(ii) Inappropriate works(iii) External factors

Classification of Trigger Events

Description and examples of how to identify the hazard scenario- Machines can break.
E.g. What happens if the local exhaust ventilation does not work?
What happens if the container lid is damaged?

- People (workers) can make errors.
E.g. What happens if you forget to turn on the local exhaust ventilation?
What happens if you press the wrong switch?

- The equipment can stop due to a power outage. In addition, large-scaledisasters caused by natural disasters such as earthquakes, typhoons, andfloods occur frequently.
E.g. What happens if a large-scale power outage occurs?
What happens if a flood occurs and the factory is inundated?

(2) Preparation of a “Trigger Event Check Sheet”
When conducting risk assessment and risk reduction of chemical substances, you should comprehensively
identify trigger events and check if the formation of an explosive atmosphere or the occurrence of ignition sources
is triggered by these events in order to identify various hazard scenarios that are hard to imagine (or recognize)
only by checking work sites at normal times.
Identifying that the descriptions in the work procedure manual are followed, prepare a “Trigger Event Check
Sheet” (Table 3) to comprehensively identify (i) facility, equipment, and tool failures and (ii) inappropriate works(human errors)18. The method of filling in the form is described below19.
[Column A]: Transcribe the work details/method described in the work procedure manual.
Transcribe the matters entered in [Column A] of the “Working Condition Check Sheet.”[Column B]: Transcribe the handled chemical substances and facilities, equipment, and tools used in the work.
Transcribe the matters entered in [Column B] of the “Working Condition Check Sheet.”[Column C]: Transcribe the confirmed identification pattern of the hazard scenario of causing a fire or explosion.
Transcribe the matters entered in [Column C] of the “Working Condition Check Sheet.”18

In the simple hazard scenario identification method, fires and explosions caused by external factors such as large-scale power outages and natural
disasters are omitted from consideration, but it is desirable to identify them as events that can actualize hazards depending on the characteristics ofthe region where the work site is located.
19
Since this is intended to comprehensively identify possible trigger events in order to reduce unexpected accidents, you should try to fill in all thecolumns.

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[Column D]: Enter the trigger events related to facilities, equipment, and tools.
d-1) Check the purposes of use of facilities, equipment, and tools.
d-2) Based on the idea that “machines can break (can fail to operate as expected),” identify facility, equipment,
and tool failures as trigger events. For example, the following cases can be identified:- The equipment breaks down and does not work.
- The equipment operates differently from the intended purpose due to some kind of failure (malfunction)(however, if the malfunction is caused by a worker’s error, enter it in [Column E]).
* You should identify not only failures in the facilities and others described in [Column B] but also failures that caninvalidate the facilities and others provided as the measures taken to prevent the formation of an explosive
atmosphere or occurrence of ignition sources described in [Column C]20.
* At this point, all possible failures should be listed, since whether or not the identified failures in facilities,
equipment, and tools can cause unsafe conditions (leading to the formation of an explosive atmosphere or theoccurrence of ignition sources) or actually cause the formation of an explosive atmosphere or the occurrence ofignition sources is examined in the hazard scenario identification stage.
* It is also important to check according to the time axis of the work procedure on the basis of the Genba (actual
place), Genbutsu (actual part), and Genjitsu (actual situation) principle21. Even if some measures have already beentaken against near-misses, they should also be included in the analysis in order to recheck their effectiveness. Do
not think you do not have to consider near-misses because they have already been addressed.

[Column E]: Enter the trigger events related to works (human errors).
e-1) Check the purpose and method of work or operation.
e-2) Based on the idea that “people can make errors,” identify failures in work as trigger events22, classifying
them into the seven types of human errors23 shown in Table 9.
* If there is any work to be carried out to prevent the formation of an explosive atmosphere or the occurrence ofignition sources, even if it is not specified in [Column A], “Work procedure/details,” human errors that invalidate
such work should also be identified24.
* At this point, all human errors that could occur during the work should be listed, since whether or not the identified
human errors can cause unsafe conditions (leading to the formation of an explosive atmosphere or the occurrenceof ignition sources) or actually cause the formation of an explosive atmosphere or the occurrence of ignition
sources is examined in the hazard scenario identification stage.
* Human errors are broadly classified into (A) “Careless mistakes” and (B) “Intentional violations”25 by theirbackground factors. All possible human errors should be identified as the trigger events that can actualize potential
hazards. At this point, you do not have to classify human errors into (A) “Careless mistakes” and (B) “Intentional
violations.”26

20

Although failures in detectors (sensors) or alarms installed to detect abnormalities should also be identified as trigger events in principle, they areomitted here for simplification purposes. Since abnormality detection means are normally used in combination with risk reduction measures(contain and control, preventive safeguards, and detection means), failures in abnormality detection means can invalidate risk reduction measures.
It is advisable to take into consideration failures in abnormality detection means when examining specific risk reduction measures.
21
The idea of emphasizing the three Gens (actualities) of Genba (actual place), Genbutsu (actual part), and Genjitsu (actual situation) and trying tosolve the problem not at a desk but after observing the actual place and parts and recognizing the actual situation.
22
Prepared based on the classification of human errors by Swain et al. in the Handbook of Human Reliability Analysis with Emphasis on Nuclear
Power Plant Applications, Final Report (A. D. Swain, H. E. Guttmann, 1983). In Table 9, human errors are broadly classified into omission errors
and commission errors, and commission errors are further classified into six types.
23This method is basically the same as the guide word used in HAZOP for chemical plants.
24
Work specified as risk reduction measures in the work procedure manual can be classified into errors (1) through (6). Further, even if not explicitly
specified in the work procedure manual, failures experienced in daily work should also be classified as (7) “Other errors” as far as possible.
25
Changing the work method on site in order to improve production efficiency should also be regarded as a rule violation.
26
If you consider also the background factors at the hazard scenario identification stage, you should take into consideration combinations of morefactors, which makes it difficult to systematically identify hazard scenarios. At this stage, human errors should be considered only by theirconsequences, and what results they can lead to should be identified as hazard scenarios. Background factors should be identified and classified
when examining risk reduction measures against human errors.

- 11 -

Table 9 Classification of Human Errors
Classification(1) Omission errors
Commission errors(2) Selection errors(3) Sequential errors(4) Time errors

Description
Fail to carry out the required work.
E.g. Fail to activate the local exhaust ventilation.

Carry out the wrong work.
Select the wrong tool. Work on the wrong part.
Issue the wrong instruction or information (setting error).
E.g. Open Valve B by mistake.
E.g. Set the wrong amount of raw material. Set the temperature too high.

Work in the wrong order.
E.g. Open Valve B before opening Valve A.

Work at the wrong time (too early or too late).
E.g. Be late to activate the local exhaust ventilation.

Non-standard work intensity (quality).
(5) Qualitative errors(6) Quantitative errors(7) Other errors

E.g. Open/close a valve too fast/slow.
E.g. Insufficient cleaning
E.g. Failure to close the lid properly
E.g. Insufficient stirring (not uniform after stirring for the set time)Non-standard amount of work (filling rate, duration time, etc.).
E.g. Wrong filling rate (resulting in too much/little filling amount)E.g. Wrong heating time (resulting in overheating/underheating)Errors other than the above.
E.g. Drop tools, spill paint.
E.g. Disconnect the ground wire (invalidating measures against ignition sources).

(3) Purposes of Preparing a “Trigger Event Check Sheet”
The purposes of preparing a “Trigger Event Check Sheet” are as follows:1)

to understand the work details (procedure), characteristics (risks) of the handled chemical substances, andhow the chemical substances are handled, and to check the purposes of the facilities, equipment, and tools
and how they are used,2)

to check in advance whether measures are taken to prevent the formation of an explosive atmosphere and theoccurrence of ignition sources, to clarify the purposes of such measures, and also to be aware that suchmeasures can be invalidated,3)

to comprehensively identify facility, equipment, and tool failures and inappropriate works (human errors) as
events that can actualize the potential hazards of the handled chemical substances (trigger events),

4)

to detect inappropriate alteration of the work procedure manual (e.g. shortcuts and unfounded changes) andunsafe behavior that deviates from the rules, and5)

to identify more specific hazard scenarios of causing a fire or explosion by examining the cases where an
identified trigger event (e.g., the formation of an explosive atmosphere and the occurrence of ignition
sources) occurs.

- 12 -

4.

Identifying Hazard Scenarios of Causing Fire/Explosion by Checking the Three Elements of
Combustion (Preparation of “Hazard Scenario Identification Sheet”)(1) Fire/Explosion Caused by Coexistence of the Three Elements of Combustion and Resulting Industrial
Accidents and Spread of Damage to Surrounding Area
Figure 2 shows the flow of events from a trigger event to fire or explosion and the resulting industrial accident
and the spread of damage to the surrounding area. There are cases where the condition is already unsafe due toinsufficient measures ((1) and (3)) and cases where the condition becomes unsafe if a trigger event occurs ((2) and(4)). In either case, if both the formation of an explosive atmosphere and the occurrence of ignition sources occur,
it could cause a fire or explosion27. Furthermore, a fire or explosion can cause industrial accidents (5) and damage
to the area around the plant (e.g., spread of fire to neighboring houses) (6). Such a series of events that can lead todisasters should be identified as a hazard scenario.

(1) through (4) correspond to the numbers in parentheses in Table 1.
(5) If there is a worker near the place where fire or explosion occurs, it could cause an industrial accident.
(6) If the scale of the fire or explosion is large, it could cause damage to the area around the plant.

Figure 2

Flow of Events from Fire/Explosion to Industrial Accidents and Spread of Damage to Surrounding Area

(2) Preparation of “Hazard Scenario Identification Sheet”
In order to identify the hazard scenario of causing a fire or explosion, prepare a “Hazard Scenario
Identification Sheet” (Table 4) by checking whether the occurrence of the trigger event identified in the “Trigger
Event Check Sheet” can cause the formation of an explosive atmosphere and the occurrence of ignition sources,on the basis of the entry (which of patterns (a) through (d) applies) in the “Working Condition Check Sheet.” Themethod of filling in the form is described below.

27

According to the classification of accidents by the Ministry of Health, Labour and Welfare, ruptures caused by explosions are classified as“explosions.”- 13 -

[Column A]: Transcribe the work procedure/details.
Transcribe the work procedure/details described in [Column A] of the “Trigger Event Check Sheet.”[Column C]: Transcribe the confirmed identification pattern of the hazard scenario of causing a fire or explosion.
Transcribe the matters described in [Column C] of the “Trigger Event Check Sheet.”
Select one from the trigger events listed in [Column D] and [Column E].
Select one from the trigger events listed in [Column D] and [Column E] of the “Trigger Event Check Sheet”
and enter it.
[Column F]: Enter whether an explosive atmosphere can be formed and whether ignition sources can occur(possible unsafe conditions).
Based on the identification patterns (a) to (d) of the hazard scenario of causing a fire or explosion that is
described in [Column C], check whether an explosive atmosphere can be formed and whether ignition sources canoccur.
f-1) If pattern (a): Measures are taken neither to prevent the formation of an explosive atmosphere nor to preventthe occurrence of ignition sources.
Since it is in an unsafe condition where fire or explosion can occur at any time, the measures shown in
Tables 5 to 7 should be taken before conducting a risk assessment.
f-2) If patterns (b) to (d):Check whether an explosive atmosphere can be formed and whether ignition sources can occur when oneof the trigger events listed in [Column D] or [Column E] occurs.
If pattern (b): Measures are taken only to prevent the occurrence of ignition sources.
Check whether the occurrence of ignition sources can be caused by any of the identified trigger events A
under the unsafe condition that an explosive atmosphere can always be present.
If pattern (c): Measures are taken only to prevent the formation of an explosive atmosphere.
Check whether the formation of an explosive atmosphere can be caused by any of the identified trigger
events B under the unsafe condition that ignition sources can occur at any time.
If pattern (d): Measures are taken both to prevent the formation of an explosive atmosphere and to prevent theoccurrence of ignition sources.
Measures have been taken to prevent the formation of an explosive atmosphere and the occurrence of ignition
sources, and the three elements of combustion cannot coexist and no fire or explosion will occur provided thesemeasures work, but if a trigger event occurs, invalidating these measures, it could cause a fire or explosion28. The
following two types of processes should be examined:- Check whether the occurrence of ignition sources can be caused by any of the identified trigger events A
under the condition that the formation of an explosive atmosphere has been caused by one of the identified
trigger events B.
- Check whether the formation of an explosive atmosphere can be caused by any of the identified trigger events
B under the condition that the occurrence of an ignition source has been caused by one of the identified
trigger events A.
28

Risk assessment and risk reduction are normally conducted without assuming the case where multiple trigger events occur at the same time, but inreality, there were some cases where multiple errors (failures) occurred at the same time, causing a fire or explosion. Pattern (d) covers cases wheremultiple trigger events occur.

- 14 -

For pattern (d), combinations of multiple identified trigger events should be examined, which means that you
must examine a huge number of hazard scenarios. It is therefore advisable, for example, to identify the trigger
event by combining the following α) and β), and then identify the hazard scenario of causing a fire or explosion.
α) Consider the occurrence of the trigger events related to facilities, equipment, and tools in [Column D] andthe occurrence of those related to works in [Column E] separately. In other words, first take two of themultiple trigger events related to facilities, equipment, and tools in [Column D], and then identify thehazard scenario. Next, examine the multiple trigger events related to works in [Column E] in the same way.
β) Among the identified trigger events, first select the one that can cause the formation of an explosive
atmosphere, and then the one that can cause the occurrence of ignition sources, or vice versa. In this case,confirming in advance whether the identified trigger event can cause the formation of an explosive
atmosphere, the occurrence of ignition sources, or both at the same time will make the identification easier.
[Column G]: Enter accidents and disasters (fire/explosion, other effects).
Check the following based on whether an explosive atmosphere can be formed and whether ignition sources
can occur that are described in [Column F].
g-1) If an explosive atmosphere is formed and ignition sources occur (the three elements of combustion coexist)
There is a risk of fire or explosion. Describe that process in as much detail as possible. Further, considering
the number and placement of workers and work environment (e.g., implementation status of 5S activities,
equipment layout, evacuation routes, factory location), examine other effects (e.g., industrial accidents anddamage to the surrounding area) (Figure 2).
g-2) If no explosive atmospheres are formed or no ignition sources occur (the three elements of combustion do
not coexist)
Since fires and explosions cannot occur, enter “No effect.”29* Here, the simple method for identifying hazard scenarios of causing a fire or explosion by checking whether
the three elements of combustion coexist. On the other hand, fires and explosions can occur even when thethree elements of combustion do not coexist, which needs to be considered separately.
(3) Purposes of preparing a “Hazard Scenario Identification Sheet”
The purposes of preparing a “Hazard Scenario Identification Sheet” are as follows:
1) to comprehensively identify the hazard scenarios of causing a fire or explosion triggered by the occurrence ofa trigger event,2) to clarify the purposes of devising and taking risk reduction measures, such as preventing the occurrence ofignition sources and the formation of an explosive atmosphere, by checking the occurrence of each of thethree elements of combustion, and
3) to help perform the risk analysis of the identified hazard scenario and devise and take additional risk
reduction measures by describing the hazard scenario in the “Risk Assessment Implementation Sheet” which
is used for the JNIOSH method.

29

As the “Trigger Event Check Sheet” comprehensively identifies possible errors as trigger events, there may be some events that will not cause fires
or explosions, but even for such events, the results of checking the three elements of combustion should be recorded. These records will be usefulwhen conducting risk assessment and risk reduction again in the future when the equipment or work is changed.

- 15 -

5.

Example of Identification of Hazard Scenarios of Causing Fire/Explosion Focusing on the Three
Elements of Combustion(1) Description of work case
Here is an example of identifying a hazard scenario of causing fire or explosion focusing on the three elementsof combustion. In this section, the following work case is examined referring to “Coating with Air Spray Gun
Using Compressed Air” in “Human Resource Development Manual Using Practical Examination Tasks for Level
3 Technical Skill Test: Coating (Metal Coating Work),”30 which is available on “Waza no Tobira (Door to
Skills),” the portal site for the Ministry of Health, Labour and Welfare’s Skill Test System, etc.
1) Work process overview
The work case roughly consists of the following five processes (29 steps: refer to Table 10 for details). The
work is carried out at room temperature.
1. Degreasing:Remove oil and grease adhering to the object to be coated with lacquer thinner.

2. Primer coating: Apply a lacquer primer surfacer to the object to be coated so that the paint will adhere well.
3. Toning:

Mix paints of different colors to prepare the paint of the prescribed color.

4. Trial coating:

To check the color compatibility, dilute the toned paint with lacquer thinner and apply it toa sample for trial coating.

5. Top coating:

Apply the toned paint to the primed object.

2) Handled chemical substances and facilities, equipment, and others used for work
The handled chemical substances and the facilities, equipment, and others used for the work are identified asfollows.
- Handled chemical substancesWhite lacquer enamel, black lacquer enamel, lacquer thinner, and lacquer primer surfacer.
(See the next page (Reference Work Case) for the summaries of their SDSs (hazard information).)- Facilities, equipment, and others used for work
Spray coating equipment (air compressor, spraying pressure regulator, air spray gun, antistatic hose, spraying
workbench, spray booth [with local exhaust ventilation]), explosion protected equipment, conductive flooring,
plastic container, (wooden) stirring rod, filter paper, (cotton) waste cloth, funnel, brush, trash can (for waste cloth,
filter paper, stirring rod), and (metal) waste liquid container with lid- Clothes and equipment for work
Antistatic work clothes, antistatic work shoes, safety glasses, work cap, work gloves, solvent-resistant gloves,and respirator
3) Safety measures already taken
The safety measures already taken are identified as follows.
- Measures to prevent formation of explosive atmosphere
Local exhaust ventilation attached to spray booth, lid of paint cup on spray gun, and disposal of waste liquid in(metal) waste liquid container with lid

30

https://waza.mhlw.go.jp/shidousya/pdf/kinzokutosou.pdf (in Japanese, confirmed on May 22, 2021). Refer to the said manual for details on theoriginal work. Here, the work case is based on the original work with additional assumptions about the facilities and equipment used for the work,safety measures taken, and safety work procedures.

- 16 -

(Reference Work Case) Summaries of SDSs of Handled Chemical Substances in Work Case
(Information on Hazards)
Lacquer thinner- GHS classification
Flammable liquids, Category 2, etc.
- Composition and ingredient information
Toluene: 65–70%
Ethyl acetate: 10–15%
Butyl acetate: 10–15%, etc.
- Physical and chemical properties
Boiling point: 64.1–125°C
Flash point: 3.1°C
Explosion range: 1.2–36.5%
Autoignition temperature: 370°C- Applicable laws
Fire Service Act: Category IV hazardous material,class I petroleum (water-insoluble)
Industrial Safety and Health Act: Hazardous substancefor which name should be notified,
Inflammable substanceWhite lacquer enamel- GHS classification
Flammable liquids, Category 2, etc.
- Composition and ingredient information
Toluene: 30–35%
Titanium dioxide: 10–15%, etc.
- Physical and chemical properties
Boiling point: 77.2–144.4°C
Flash point: 4.5°C
Explosion range: 1.1–12%
Autoignition temperature: 399°C- Applicable laws
Fire Service Act: Category IV hazardous material,class I petroleum (water-insoluble)
Industrial Safety and Health Act: Hazardous substancefor which name should be notified,
Inflammable substance

Lacquer primer surfacer- GHS classification
Flammable liquids, Category 2, etc.
- Composition and ingredient information
Toluene: 20–25%, etc.
- Physical and chemical properties
Boiling point: 77.2–125°C
Flash point: −0.5°C
Explosion range: 1.2–15%
Autoignition temperature: 370°C- Applicable laws
Fire Service Act: Category IV hazardous material,class I petroleum (water-insoluble)
Industrial Safety and Health Act: Hazardous substancefor which name should be notified,
Inflammable substanceBlack lacquer enamel- GHS classification
Flammable liquids, Category 2, etc.
- Composition and ingredient information
Toluene: 25–30%
Nitrocellulose31: 10–15%
Ethyl acetate: 10–15%
Methyl isobutyl ketone: 10–15%, etc.
- Physical and chemical properties
Boiling point: 77.2–144.4°C
Flash point: 5.5°C
Explosion range: 1.1–12%
Autoignition temperature: 367°C- Applicable laws
Fire Service Act: Category IV hazardous material,class I petroleum (water-insoluble)
Industrial Safety and Health Act: Hazardous substancefor which name should be notified,
Inflammable substance- Measures to prevent occurrence of ignition sources(a) Against electrical sparks:
Use explosion-protected equipment, and prohibit bringing-in
non-explosion-protected equipment (e.g. smartphones).
(b) Against electrostatic sparks:
Use conductive flooring, ground metal products, use antistatic hoses, andwear antistatic work clothes and work shoes.
(c) Against hot surfaces:
No hot objects are used.
(d) Against thermal radiation:
There are no hot objects nearby.
(e) Against impact/friction:
No measures are taken.
(f) Against adiabatic compression: As compressed air is used, ignition due to adiabatic compression hardly
occurs.
(g) Against naked flame:
Control the use and bringing-in of fire.
(h) Against spontaneous combustion: Nothing generates heat.

31

A chemical substance classified as explosive grade 1.1. Attention should be paid to accumulation of dry enamel and scattering of powder enamel.

- 17 -

(2) Description of analysis example
The following is an example that applies the simple hazard scenario identification method to the metal coating
work described in (1).
1) Preparation of “Working Condition Check Sheet”
Table 10 shows an example of preparing a “Working Condition Check Sheet.”[Column A]: Enter the work details/method described in the work procedure manual.
The metal coating work consisting of five processes (29 steps) is entered in [Column A].
[Column B]: Enter the handled chemical substances and facilities, equipment, and tools used in the work.
The chemical substances to be handled in metal coating work, hazard information and handling conditions ofthese substances, and facilities, equipment, and others used for the work are checked and entered in [Column B].
[Column C]: Enter the confirmed identification pattern of the hazard scenario of causing a fire or explosion.
Questions Q1 to Q3 are answered for each process.
(Q1) All the handled chemical substances are combustible.
(Q2) Measures taken to prevent the formation of an explosive atmosphere (those entered in Table 5)- Local exhaust ventilation attached to the spray booth- Lid of the paint cup on the spray gun- Disposal of waste liquid in the (metal) waste liquid container with a lid(Q3) Measures taken to prevent the occurrence of ignition sources (those entered in Table 6)32
(a) Against electrical sparks:

Use explosion protected equipment, and prohibit bringing-in
non-explosion-protected equipment (e.g. smartphones).

(b) Against electrostatic sparks:

Use conductive flooring, ground metal products, use antistatic
hoses, and wear antistatic work clothes and work shoes.

(c) Against hot surfaces:

No hot objects are used.

(d) Against thermal radiation:

There are no hot objects nearby.

(e) Against impact/friction:

No measures are taken.

(f) Against adiabatic compression:

As compressed air is used, ignition due to adiabatic compression
hardly occurs.

(g) Against naked flame:

Control the use and bringing-in of fire.

(h) Against spontaneous combustion: Nothing generates heat.
From the above, the “degreasing process” and “toning process” are confirmed as pattern (b), and theothers as pattern (d).

32

In hazard scenario identification, the measures already taken to prevent the occurrence of ignition sources are classified into “Inherent safetymeasure (elimination/substitution),” “Engineering control,” “Signage/warning and/or administrative control,” “Personal protective equipment,”
and “Others (N/A, etc.).”- 18 -

2) Preparation of “Trigger Event Check Sheet”
Table 11 shows an example of preparing a “Trigger Event Check Sheet.” The entries in [Column A] to[Column C] are the same as those in the “Working Condition Check Sheet.” For the 29 steps subdivided from thefive processes, the facility, equipment, and tool failures in [Column D] and inappropriate works in [Column E] are
identified as trigger events33.
[Column D]: Enter the trigger events related to facilities, equipment, and tools.
In addition to the facility, equipment, and tool failures in [Column B], errors (failures) in the measures toprevent the formation of an explosive atmosphere and those to prevent the occurrence of ignition sources
confirmed in [Column C] are identified.
[Column E]: Enter the trigger events related to works (human errors).
Based on the information on working conditions in [Column A] to [Column C], the six types of human errors
from (1) omission errors to (6) quantitative errors in Table 9 are identified. For (7) other errors, human errors
experienced in ordinary work and those that can be noticed by observing the work site are identified34.
At this point, no distinction is made between “Careless mistakes” and “Intentional violations” (because bothfactors can work together).
3) Preparation of “Hazard Scenario Identification Sheet”
For the trigger events described in [Column D] and [Column E], hazard scenarios of causing fire or explosion
and subsequent effects on others are identified on the basis of the information on the work details/conditions,chemical substances to be handled, and others. Tables 12 (a) and (b) show the Hazard Scenario Identification
Sheets for Steps 1 and 2 of the degreasing process and Table 12 (c) shows that for Step 9 of the primer coatingprocess35. Both processes are carried out in an open area where oxygen (air) is present.
Degreasing Process (Steps 1 and 2) (Pattern (b)) (Tables 12 (a) and (b))
Step 1: Using a waste cloth moistened with lacquer thinner, wipe the object to be coated so that no greaseor oil stains remain, and then wipe it with a dry, clean waste cloth.
Step 2: Dispose of the used waste cloth in a trash can.
Although Steps 1 and 2 are classified as pattern (b) and measures are taken to prevent the occurrence of ignition
sources, an explosive atmosphere can always be present. Whether ignition sources can occur when one of thetrigger events listed in [Column D] or [Column E] occurs under this unsafe condition is checked. If an ignition
source can occur, how it can cause a fire or explosion is entered in [Column F] (e.g., “Fire caused by ignition ofvapor around thinner”), and effects on others are entered in [Column G] (e.g., “Burns caused by fire, spread of fireto surrounding combustibles, spread of fire to work clothes, etc.”), to identify the hazard scenario.

33

To comprehensively identify safety-related trigger events, it is desirable to specify in advance the work and operations being implemented as risk
reduction measures in the work procedure manual or others.
34
Although “(a) Prohibit bringing-in non-explosion-proof equipment (e.g., smartphones)” and “(g) Control the use and bringing-in of fire” have been
implemented, and trigger events that can invalidate these measures can be identified, they are omitted here.
35
Due to space limitations, only Steps 1 and 2, which are classified as pattern (b), and Step 9, which is classified as pattern (d), are shown.

- 19 -

(Reference Work Case) Hazard Scenario Identification for Step 1[Column F]
Conditions for formation of
explosive atmosphere[Column G]

Conditions for occurrence of ignition sources

Fire/explosion

Other effects

Ignition sources can occur due to the occurrence of the - Fire caused- Burns caused byfollowing trigger events:
by ignition offire, spread of fire
- Explosion-protected lighting failure
vapor aroundto surrounding- Deterioration of antistatic work clothes
thinner
combustibles,- Dirty soles of antistatic shoes
spread of fire to- Deterioration of ground wire of conductive
work clothes, etc.
flooring- Deterioration of ground wires of metal products- Bringing in non-explosion-protected lighting- Laying a stain-proof vinyl sheet on the floor- Wearing non-antistatic work clothes or work shoes

An explosive atmosphere isconsidered to be present
regardless of theoccurrence of the identified
trigger event.

* In Step 1, an explosive atmosphere has already been formed, and if an ignition source occurs due to the occurrence of a trigger
event, it will cause a fire or explosion.
* The following trigger events can cause the formation of an explosive atmosphere, but cannot trigger the occurrence of ignition
sources, and therefore cannot cause a fire or explosion:- Damage to plastic container- Damage to trash can- Wiping the object to be coated with a waste cloth moistened with lacquer thinner after wiping it with a dry, clean cloth- Wiping only a part of the object to be coated with lacquer thinner- Too few times of wiping (Too many times of wiping is no problem.)- Spilling the lacquer thinner(Reference Work Case) Hazard Scenario Identification for Step 2[Column F]
Conditions for formation of
explosive atmosphereAn explosive atmosphere isconsidered to be present
regardless of theoccurrence of the identified
trigger event.

[Column G]

Conditions for occurrence of ignition sources

Fire/explosion

Other effects

Ignition sources can occur due to the occurrence of the - Fire caused- Burns caused byfollowing trigger events:
by ignition offire, spread of fire
- Explosion-protected lighting failure
vapor aroundto surrounding- Deterioration of antistatic work clothes
thinner
combustibles,- Dirty soles of antistatic shoes
spread of fire to- Deterioration of ground wire of conductive
work clothes, etc.
flooring- Deterioration of ground wires of metal products- Bringing in non-explosion-protected lighting- Laying a stain-proof vinyl sheet on the floor- Wearing non-antistatic work clothes or work shoes* In Step 2, an explosive atmosphere has already been formed, and if an ignition source occurs due to the occurrence of a trigger
event, it will cause a fire or explosion.
* The following trigger events can cause the formation of an explosive atmosphere, but cannot trigger the occurrence of ignition
sources, and therefore cannot cause a fire or explosion:- Damage to plastic container- Damage to trash can with lid- Leaving used waste cloth as it is- Disposing of the plastic container in a container at hand other than a trash can with a lid- Not disposing of used waste cloth immediately, but leaving it for a while- Spilling the lacquer thinner

Primer Coating Process (Step 9) (Pattern (d)) (Table 12 (c))(Step 9) Prime using the spray gun.
Step 9 is classified as pattern (d), for which some measures are taken to prevent the formation of an explosive
atmosphere and the occurrence of ignition sources. The following is an example of a hazard scenario in whichthese measures are invalidated due to the occurrence of any of the trigger events in [Column D] and [Column E],
causing a fire or explosion.

- 20 -

By considering a combination of a trigger event A, which can cause the formation of an explosive atmosphere,
and a trigger event B, which can cause the occurrence of ignition sources, among the trigger events related tofacilities, equipment, and tools listed in [Column D], a hazard scenario that can cause a fire or explosion andsubsequent effects on others can be identified.
(Reference Work Case) Hazard Scenario Identification for Step 9(Trigger Events A and B Related to Facilities, Equipment, and Tools)[Column F]
Conditions for formation of explosive
atmosphereAn explosive atmosphere can beformed due to the occurrence of thefollowing trigger events A:- Local exhaust ventilation failure- Damage to lid of paint cup- Damage to waste liquid container
with lid[Column G]

Conditions for occurrence ofignition sources
Ignition sources can occur due to theoccurrence of the following trigger
events B:- Deterioration of antistatic hose
- Explosion-protected lighting
failure- Deterioration of antistatic work
clothes- Dirty soles of antistatic shoes- Deterioration of ground wire of
conductive flooring- Deterioration of ground wires ofmetal products

Fire/explosion

Other effects- Fire or
explosioncaused byignition ofvapor in thespray booth- Burns caused byfire, spread of fireto surrounding
combustibles,
spread of fire towork clothes, etc.

* In the above table, “” means to identify the hazard scenario by combining the left and right trigger events.
* The following trigger events cannot cause the formation of an explosive atmosphere, and are therefore omitted from thefollowing analysis results:- Clogging of or leakage from spray gun- Air compressor failure- Pressure regulator failure

By considering a combination of a trigger event C, which can cause the formation of an explosive atmosphere,
and a trigger event D, which can cause the occurrence of ignition sources, among the trigger events related toworks listed in [Column E], a hazard scenario that can cause a fire or explosion and subsequent effects on others
can be identified.
(Reference Work Case) Hazard Scenario Identification for Step 9(Trigger Events C and D Related to Work/Operations)[Column F]
Conditions for formation of explosive
atmosphereAn explosive atmosphere can beformed due to the occurrence of thefollowing trigger events C:- Leaving the paint cup uncovered- Working in a place other than thespray booth- Spilling the lacquer primer
surfacer- Dropping the spray gun[Column G]
Conditions for occurrence of ignition
Fire/explosion
Other effects
sources
Ignition sources can occur due to the- Fire or- Burns caused byoccurrence of the following trigger
explosion
fire, spread of fire
events D:
caused byto surrounding- Dropping the spray gun
ignition of
combustibles,- Bringing in non-explosion-protected
vapor in the
spread of fire tolighting
spray booth
work clothes, etc.
- Laying a stain-proof vinyl sheet on
the floor- Wearing non-antistatic work clothes
or work shoes* In the above table, “” means to identify the hazard scenario by combining the left and right trigger events.
* The trigger event “Dropping the spray gun” can cause both the formation of an explosive atmosphere and the occurrence ofignition sources, leading to a fire or explosion.
* The following trigger events cannot cause the formation of an explosive atmosphere, and are therefore omitted from thefollowing analysis results:- Priming only a part of a steel plate- Too thick/too thin coating film

- 21 -

Table 10 Working Condition Check Sheet (Example)[B] Chemical substances handled and facilities, equipment, and others used for work

[C] Confirmation of coexistence of three elements of combustion that could cause fire or explosion
Q-3. Are measures taken to prevent the occurrence of ignition sources?

1

Degreasing[A] Work procedure/details

Using a waste cloth moistened with lacquer thinner, wipe
the object to be coated so that no grease or oil stains
remain, and then wipe it with a dry, clean waste cloth.

Dispose of the used waste cloth in a trash can.

3

Activate the local exhaust ventilation for the spray coating
equipment.

4

Pour lacquer primer surfacer into the cup on the spray gun.

5

Dispose of the plastic container of the lacquer primer
surfacer in a trash can.

6

Adjust the air pressure to 0.2 to 0.3 MPa with the spraypressure regulator.

7

Primer coating

2

Adjust the discharge rate of the lacquer primer surfacer
emitted from the spray gun by spraying on a sample fortrial coating.
Pull the trigger of the spray gun one step to blow off thedust from the surface of the object to be coated.

9

Prime using the spray gun.

10

Dispose of the lacquer primer surfacer remaining in thecup in a waste liquid container with a lid.

11

Allow to air-dry at room temperature.

12

Pour white lacquer enamel into a plastic container.

13

Toning8

Add black lacquer enamel little by little to white lacquer
enamel and stir with the stirring rod until uniform.
Dispose of the used plastic container and stirring rod in a
trash can.

15

Place a small amount of the toned paint in a plastic
container, and dilute it with lacquer thinner at a dilution
ratio of 10:8.

16

Activate the local exhaust system for the spray coating
equipment.

17

18

Trial coating

14

20

Dispose of the mixed paint remaining in the cup in a waste
liquid container with a lid.

21

Activate the local exhaust system for the spray coating
equipment.

22

Pour the toned paint into the cup on the spray gun.

23

Dispose of the used plastic container in a trash can.

24

Adjust the air pressure to 0.2 to 0.3 MPa with the spraypressure regulator.

Top coating

Spray on a sample for trial coating using the spray gun.

Adjust the discharge rate of the paint emitted from thespray gun by performing trial spraying. Also, adjust thepattern adjustment knob appropriately.

26

Pull the trigger of the spray gun one step to blow off thedust from the surface of the object to be coated.

27

Apply a topcoat using the spray gun.

28

Dispose of the mixed paint remaining in the cup in a waste
liquid container with a lid.

29

Allow to air-dry at room temperature.

Information on hazards ofchemical substances
concerned

Lacquer thinner
Flammable liquids, Category 2(toluene, ethyl(Flash point: 3.1°C)
acetate, butyl acetate,(Explosive range: 1.2 to 36.5%)
etc.)

Lacquer primer
surfacer(e.g., toluene)

Lacquer enamel(white)(toluene, titanium
dioxide, etc.)
Lacquer enamel(black)(toluene, cellulose
nitrate, acetic ether,methyl isobutyl
ketone, etc.)

Flammable liquids, Category 2(Flash point: -0.5°C)(Explosive range: 1.2 to 15%)

Lacquer enamel (white)
Flammable liquids, Category 2(Flash point: 4.5°C)(Explosive range: 1.1 to 12%)Lacquer enamel (black)
Flammable liquids, Category 2(Flash point: 5.5°C)(Explosive range: 1.1 to 12%)Lacquer enamel (white)
Flammable liquids, Category 2(Flash point: 4.5°C)(Explosive range: 1.1 to 12%)Pour the resulting paint into the cup on the spray gun while
Lacquer enamelfiltering it using filter paper.
(toned paint)
Lacquer thinner
Dispose of the used plastic container, stirring rod, andfilter paper in a trash can.

19

25

Handledsubstances

Lacquer enamel (black)
Flammable liquids, Category 2(Flash point: 5.5°C)(Explosive range: 1.1 to 12%)Lacquer thinner
Flammable liquids, Category 2(Flash point: 3.1°C)(Explosive range: 1.2 to 36.5%)

Handling conditions(temperature, humidity, amounthandled, storage conditions, etc.)

Facilities, equipment,
and tools used forwork

Q-1. Are the chemical
substances handled
combustible?

Q-2. Are measures taken toprevent the formation of an Inherent safety
explosive atmosphere?
measure(elimination/su
bstitution)

Lacquer enamel (black)
Flammable liquids, Category 2(Flash point: 5.5°C)(Explosive range: 1.1 to 12%)Signage/warning and/or
administrative control

Personal
protective
equipment

Others (N/A, etc.)

Pattern(a) - (d)No measures taken(a) Prohibit bringing-in nonexplosion-protected equipment(a) Use explosion-protectedl(e.g., smartphones)
equipment(b) Ground metal products(b) Use a conductive(b) Wear antistatic work clothes
flooring
and antistatic shoes(b) Ground metal products(g) Control the use andbringing-in of fire(c) Avoid using hot objects(d) Remove hot objects from thesurroundings(e) No measures taken(f) As compressed air is used, ignition
due to adiabatic compression isunlikely to occur(h) There is nothing that generates
heat

(b)

- Local exhaust ventilation
attached to spray booth- Lid of paint cup on spray gun- Disposal of waste liquid in(metal) waste liquid container
with lid(a) Prohibit bringing-in non(a) Use explosion-protectedl explosion-protected equipment(e.g., smartphones)
equipment(b) Ground metal products(b) Use a conductive(b) Wear antistatic work clothes
flooring(b) Ground metal products and antistatic work shoes(g) Control the use and(b) Use antistatic hoses
bringing-in of fire(c) Avoid using hot objects(d) Remove hot objects from thesurroundings(e) No measures taken(f) As compressed air is used, ignition
due to adiabatic compression isunlikely to occur(h) There is nothing that generates
heat

(d)

No measures taken(a) Prohibit bringing-in nonexplosion-protected equipment(a) Use explosion-protectedl(e.g., smartphones)
equipment(b) Ground metal products(b) Use a conductive(b) Wear antistatic work clothes
flooring
and antistatic work shoes(b) Ground metal products(g) Control the use andbringing-in of fire(c) Avoid using hot objects(d) Remove hot objects from thesurroundings(e) No measures taken(f) As compressed air is used, ignition
due to adiabatic compression isunlikely to occur(h) There is nothing that generates
heat

(b)

- Spray coating equipment
Room temperature, 700 mL (total)
Dilute the toned paint with lacquer thinner in a - Workbench- Plastic container
plastic container.
- Stirring rod
Use the toned paint with a spray gun.
Yes (Lacquer enamel, lacquer
Dispose of the used plastic container, stirring - Filter paper
thinner)- Trash canrod, and filter paper in a trash can.
- (Metal) Waste liquid
Dispose of the remaining mixed paint in acontainer with lid
waste liquid container with a lid.

- Local exhaust ventilation
attached to spray booth- Lid of paint cup on spray gun- Disposal of waste liquid in(metal) waste liquid container
with lid(a) Prohibit bringing-in non(a) Use explosion-protectedl explosion-protected equipment
equipment(e.g., smartphones)(b) Use a conductive(b) Ground metal products
flooring(b) Wear antistatic work clothes(b) Ground metal products and antistatic work shoes(b) Use antistatic hoses(g) Control the use andbringing-in of fire(c) Avoid using hot objects(d) Remove hot objects from thesurroundings(e) No measures taken(f) As compressed air is used, ignition
due to adiabatic compression isunlikely to occur(h) There is nothing that generates
heat

(d)

- Spray coating equipment- Workbench- Plastic container
Yes (Lacquer enamel, lacquer- Trash canthinner)- (Metal) Waste liquidcontainer with lid- Local exhaust ventilation
attached to spray booth- Lid of paint cup on spray gun- Disposal of waste liquid in(metal) waste liquid container
with lid(a) Prohibit bringing-in non(a) Use explosion-protectedl explosion-protected equipment(e.g., smartphones)
equipment(b) Ground metal products(b) Use a conductive(b) Wear antistatic work clothes
flooring(b) Ground metal products and antistatic work shoes(g) Control the use and(b) Use antistatic hoses
bringing-in of fire(c) Avoid using hot objects(d) Remove hot objects from thesurroundings(e) No measures taken(f) As compressed air is used, ignition
due to adiabatic compression isunlikely to occur(h) There is nothing that generates
heat

(d)

Room temperature, 500 mL
Pour lacquer thinner into a plastic container,
moisten a waste cloth with lacquer thinnerfrom the container, and then use the cloth.
Dispose of the waste cloth in a trash can.

- Plastic container- Waste cloth (cotton)- Trash canYes (Lacquer thinner)- Spray coating equipment
Room temperature, 200 mL- Workbench
Use lacquer primer surfacer with a spray gun.
- Plastic container
Dispose of the waste cloth in a trash can.
Yes (Lacquer primer surfacer)- Trash can
Dispose of the waste liquid in a waste liquid- (Metal) Waste liquidcontainer with a lid.
container with lid

Room temperature, 200 mL (total)
Use in a plastic container.
Dispose of the used plastic container andstirring rod in a trash can.

- Plastic container- (Wooden) Stirring rod- Trash canYes (Lacquer enamel)

Lacquer enamel (white)
Flammable liquids, Category 2(Flash point: 4.5°C)(Explosive range: 1.1 to 12%)Lacquer enamel(toned paint)
Lacquer thinnerEngineering control

Room temperature, 200 mL
Use the toned paint with a spray gun.
Dispose of the used plastic container in a
trash can.
Dispose of the remaining mixed paint in a
waste liquid container with a lid.

Lacquer thinner
Flammable liquids, Category 2(Flash point: 3.1°C)(Explosive range: 1.2 to 36.5%)- 22 -

Table 11 Trigger Event Check Sheet (Example)[E] Trigger events related to work/operation(human errors)[D] Trigger events related[B] Chemical substances handled and facilities, equipment, and [C] Confirmation of coexistence of three elements of combustion that could cause fireto facilities, equipment,
others used for work
or explosion
and tools[A] Work procedure/details
Handledsubstances

Degreasing

1

Using a waste cloth moistened with lacquer
thinner, wipe the object to be coated sothat no grease or oil stains remain, andthen wipe it with a dry, clean waste cloth.
Lacquer thinner(toluene, ethyl
acetate, butyl
acetate, etc.)2

Dispose of the used waste cloth in a trash
can.

3

Activate the local exhaust ventilation forthe spray coating equipment.

Information on
hazards ofchemical
substances
concerned

Handling
conditions
Measures toFacilities,(temperature,
prevent formationequipment, andhumidity, amountof explosive
tools used for work
handled, storage
atmosphereconditions, etc.)

Room temperature,
500 mL
Pour lacquer thinner
into a plastic
Flammable liquids,
container, moisten a - Plastic container
Category 2
waste cloth with
- Waste cloth(Flash point: 3.1°C)
lacquer thinner from (cotton)(Explosive range:
the container, and - Trash can
1.2 to 36.5%)
then use the cloth.
Dispose of thewaste cloth in a
trash can.

Commission errors
Measures to prevent occurrence of ignition sources

Engineering control(a) Use explosion-protected
equipment
No measures taken(b) Use a conductive flooring(b) Ground metal products

Pattern(a) - (d)Facility, equipment, and tool
failures

Omission errors
Selection errors

Signage/warning and/or
administrative control(a) Prohibit bringing-in nonexplosion-protected equipment(e.g., smartphones)(b) Ground metal products(b) Wear antistatic work clothes
and antistatic work shoes(g) Control the use and bringing-inof fire(b)- Damage to plastic container- Damage to trash can- Explosion-protected lighting
failure- Deterioration of antistatic
work clothes- Dirty soles of antistatic work
shoes
- Deterioration of ground wireof conductive flooring- Deterioration of ground wires - Leave the used
waste cloth as it isof metal products

Sequential errors- After wiping theobject to be coatedwith a dry, clean
cloth, wipe it with awaste clothmoistened withlacquer thinner- Dispose of theplastic container in acontainer at hand
other than a trashcan- Forget to start the
local exhaust
ventilation- Activate the local
exhaust ventilation
after a trial blow

Pour lacquer primer surfacer into the cup
on the spray gun.

- Leave the paintcup uncovered

5

Dispose of the plastic container of thelacquer primer surfacer in a trash can.

- Leave the usedplastic container as
it is- Dispose of theplastic container in acontainer at hand
other than a trashcan6

Primer coating

4

Adjust the air pressure to 0.2 to 0.3 MPa
with the spray pressure regulator.

Lacquer primer
surfacer(e.g., toluene)

Room temperature,
200 mLUse lacquer primer
Flammable liquids, surfacer with aCategory 2
spray gun.
(Flash point: -0.5° Dispose of theC)
waste cloth in a
(Explosive range:
trash can.
1.2 to 15%)
Dispose of thewaste liquid in a
waste liquidcontainer with a lid.

- Local exhaust- Spray coating
ventilation attachedequipmentto spray booth(a) Use explosion-protected- Workbench- Lid of paint cup
equipment- Plastic containeron spray gun(b) Use a conductive flooring- Trash can- Disposal of waste (b) Ground metal products- (Metal) Waste liquid liquid in (metal)(b) Use antistatic hoses
container with lid
waste liquidcontainer with lid(a) Prohibit bringing-in nonexplosion-protected equipment(e.g., smartphones)(b) Ground metal products(b) Wear antistatic work clothes
and antistatic work shoes(g) Control the use and bringing-inof fire(d)Qualitative errors

Quantitative errors- Wipe only a part of- Too few times/too
the object to be
many times ofcoated with lacquer
wipingthinner- Do not dispose of
the used waste cloth
immediately, but
leave it for a while- Handle the lacquer- Work in a placeprimer surfacer
other than the spray before activating thebooth
local exhaust
ventilation- Local exhaust ventilation
failure- Clogging of or leakage fromspray gun- Air compressor failure- Pressure regulator failure- Deterioration of antistatichose- Damage to lid of paint cup- Explosion-protected lighting
failure- Deterioration of antistatic
work clothes- Dirty soles of antistatic work
shoes
- Deterioration of ground wireof conductive flooring- Deterioration of ground wiresof metal products- Damage to waste liquidcontainer with lid

Time errors

Other errors- Spill lacquer thinner- Bring in non-explosionprotected lighting- Lay a stain-proof vinyl sheet on
the floor- Wear non-antistatic work
clothes or work shoes

Same as above- Too early/too lateactivation of thelocal exhaust
ventilation- Let the lacquer
primer surfacer
overflow from thepaint cup

- Do not dispose of
the used plastic
container
immediately, but
leave it for a while- Spill the lacquer primer surfacer- Bring in non-explosionprotected lighting- Lay a stain-proof vinyl sheet on
the floor- Wear non-antistatic work
clothes or work shoes

Same as above- Forget to adjust the- Work in a place
air pressureother than the spray- Leave the paintbooth
cup uncovered- Too high/too low
air pressure- Spill the lacquer primer surfacer- Drop the spray gun- Bring in non-explosionprotected lighting- Lay a stain-proof vinyl sheet on
the floor- Wear non-antistatic work
clothes or work shoes- Forget to perform
trial spraying- Leave the paintcup uncovered

Same as above- Too high/too lowdischarge rate

Same as above

7

Adjust the discharge rate of the lacquer
primer surfacer emitted from the spray gun
by spraying on a sample for trial coating.

8

Pull the trigger of the spray gun one step toblow off the dust from the surface of theobject to be coated.

- Forget to blow off
the dust- Leave the paintcup uncovered

Same as above- Pull the trigger all
the waySame as above

9

Prime using the spray gun.

- Leave the paintcup uncovered

Same as above- Prime only a part of- Too thick/too thin
the object to becoating film
coatedSame as above

10

Dispose of the lacquer primer surfacer
remaining in the cup in a waste liquidcontainer with a lid.

- Leave the waste
liquid container
uncovered- Dispose of lacquer
primer surfacer in aplastic container at
hand

11

Allow to air-dry at room temperature.

Pour white lacquer enamel into a plastic
container.

13

14

Toning12

Add black lacquer enamel little by little towhite lacquer enamel and stir with thestirring rod until uniform.

Same as above- Take out of thespray booth before
drying completely- Dry in a place otherthan the spray booth- Pour black lacquer
enamel by mistake
Lacquer enamel
Lacquer enamel (white)(white)Flammable liquids,(toluene,
Category 2titanium dioxide, (Flash point: 4.5°C)
etc.)(Explosive range:
1.1 to 12%)Lacquer enamel(black)Lacquer enamel(toluene,(black)cellulose nitrate, Flammable liquids,
acetic ether,Category 2
methyl isobutyl (Flash point: 5.5°C)
ketone, etc.)(Explosive range:
1.1 to 12%)

Room temperature,
200 mL (total)
Use in a plastic- Plastic container
container.
- (Wooden) Stirring
Dispose of the used rod
plastic container- Trash canand stirring rod in a
trash can.

(a) Use explosion-protected
equipment
No measures taken(b) Use a conductive flooring(b) Ground metal products(a) Prohibit bringing-in nonexplosion-protected equipment(e.g., smartphones)(b) Ground metal products(b) Wear antistatic work clothes
and antistatic work shoes(g) Control the use and bringing-inof fireDispose of the used plastic container andstirring rod in a trash can.

- 23 -(b)- Damage to plastic container- Damage to trash can- Explosion-protected lighting
failure- Deterioration of antistatic
work clothes- Dirty soles of antistatic work
shoes
- Deterioration of ground wireof conductive flooring- Deterioration of ground wiresof metal products- Mistake whitelacquer enamel forblack lacquer- Pour black lacquer
enamelenamel after stirring- Use a metal rod at
hand as the stirringrod- Dispose of theused plastic- Leave the used
container andplastic container andstirring rod in a
stirring rod as they
container at handareother than a trash
can- Do not stir until
uniform- Do not dispose of
the used plastic
container or stirring
rod immediately, but
leave them for awhile- Too long/too shortdrying time

- Let the whitelacquer enamel
overflow from theplastic container- Spill the lacquer enamel- Bring in non-explosionprotected lighting- Lay a stain-proof vinyl sheet on
the floor- Wear non-antistatic work
clothes or work shoes- Let the black
lacquer enamel
overflow from theplastic container

Same as above

Same as above

Table 11 Trigger Event Check Sheet (Example) (Continued)[E] Trigger events related to work/operation(human errors)[D] Trigger events related[B] Chemical substances handled and facilities, equipment, and [C] Confirmation of coexistence of three elements of combustion that could cause fireto facilities, equipment,
others used for work
or explosion
and tools[A] Work procedure/details
Handledsubstances

Place a small amount of the toned paint in aplastic container, and dilute it with lacquer
thinner at a dilution ratio of 10:8.

16

Activate the local exhaust ventilation forthe spray coating equipment.

17

Trial coating

15

Information on
hazards ofchemical
substances
concerned

Handling
Measures toconditions
Facilities,
prevent formation(temperature,equipment, andof explosive
humidity, amounttools used for work
atmospherehandled, storage
conditions, etc.)

Commission errors
Measures to prevent occurrence of ignition sources

Engineering control

Pattern(a) - (d)Facility, equipment, and tool
failures

Omission errors
Selection errors

Signage/warning and/or
administrative control

Lacquer enamel(white)Flammable liquids,
Category 2(Flash point: 4.5°C)(Explosive range:
1.1 to 12%)Lacquer thinner
Flammable liquids,
Category 2(Flash point: 3.1°C)(Explosive range:
1.2 to 36.5%)

Room temperature,
700 mL (total)
Dilute the toned
paint with lacquer
thinner in a plastic- Spray coating- Local exhaustcontainer.
equipment
ventilation attached
Use the toned paint(a) Use explosion-protected- Workbench
to spray boothwith a spray gun.
equipment- Plastic container- Lid of paint cup
Dispose of the used(b) Use a conductive flooring- Stirring rod
on spray gun
plastic container,- Filter paper- Disposal of waste (b) Ground metal products
stirring rod, and(b) Use antistatic hoses- Trash canliquid in (metal)
filter paper in a
- (Metal) Waste liquid waste liquidtrash can.
container with lid
container with lid
Dispose of theremaining mixed
paint in a waste
liquid container witha lid.

(a) Prohibit bringing-in nonexplosion-protected equipment(e.g., smartphones)(b) Ground metal products(b) Wear antistatic work clothes
and antistatic work shoes(g) Control the use and bringing-inof fire(d)- Local exhaust ventilation
failure- Clogging of or leakage fromspray gun- Air compressor failure- Pressure regulator failure- Deterioration of antistatichose- Damage to plastic container- Damage to trash can- Damage to waste liquidcontainer with lid'- Rip filter paper- Damage to lid of paint cup- Explosion-protected lighting
failure- Deterioration of antistatic
work clothes- Dirty soles of antistatic work
shoes
- Deterioration of ground wireof conductive flooring- Deterioration of ground wiresof metal products- Activate the local
exhaust ventilation
during or after trial
coating- Forget to start the
local exhaust
ventilation- Pour the paint into
the cup without
filtering it- Leave the paintcup uncovered

19

Spray on a sample for trial coating using
the spray gun.

- Leave the paintcup uncovered- Work in a place
other than the spray
booth

20

Dispose of the mixed paint remaining in thecup in a waste liquid container with a lid.

- Leave the waste
liquid container
uncovered- Dispose of themixed paint in aplastic container at
hand

21

Activate the local exhaust ventilation forthe spray coating equipment.

- Forget to start the
local exhaust
ventilation

Dispose of the used plastic container in a
trash can.

24

Top coating

23

Adjust the air pressure to 0.2 to 0.3 MPa
with the spray pressure regulator.

Lacquer enamel(white)Flammable liquids,
Category 2(Flash point: 4.5°C)(Explosive range:
Room temperature,
1.1 to 12%)200 mL- Local exhaust
Use the toned paint- Spray coating
ventilation attached
Lacquer enamelwith a spray gun.
equipmentto spray booth(a) Use explosion-protected(black)Dispose of the used
Lacquer enamel- Workbench- Lid of paint cup
equipment
Flammable liquids, plastic container in(toned paint)- Plastic containeron spray gun(b) Use a conductive flooring
Category 2
a trash can.
Lacquer thinner- Trash can- Disposal of waste (b) Ground metal products(Flash point: 5.5°C) Dispose of the- (Metal) Waste liquid liquid in (metal)(b) Use antistatic hoses(Explosive range:
remaining mixed
container with lid
waste liquid
1.1 to 12%)
paint in a waste
container with lid
liquid container with
Lacquer thinnera lid.
Flammable liquids,
Category 2(Flash point: 3.1°C)(Explosive range:
1.2 to 36.5%)(a) Prohibit bringing-in nonexplosion-protected equipment(e.g., smartphones)(b) Ground metal products(b) Wear antistatic work clothes
and antistatic work shoes(g) Control the use and bringing-inof fire(d)- Local exhaust ventilation
failure- Clogging of or leakage fromspray gun- Air compressor failure- Pressure regulator failure- Deterioration of antistatichose- Damage to trash can- Damage to waste liquidcontainer with lid- Damage to lid of paint cup- Explosion-protected lighting
failure- Deterioration of antistatic
work clothes- Dirty soles of antistatic work
shoes
- Deterioration of ground wireof conductive flooring- Deterioration of ground wiresof metal products- Do not stir until
uniform- Let the toned paintoverflow from the- Spill the mixed paint
plastic container- Spill the lacquer thinner- Let the lacquer- Bring in non-explosionthinner overflow
protected lightingfrom the plastic- Lay a stain-proof vinyl sheet on
container
the floor- Mistake the ratio of - Wear non-antistatic work
lacquer thinner toclothes or work shoes
the paint- Let the resulting
paint overflow fromthe cup- Leave the paintcup uncovered- Leave the usedplastic container as
it is- Dispose of theplastic container in acontainer at hand
other than a trashcan- Spill the mixed paint- Spill the lacquer thinner- Drop the spray gun- Bring in non-explosionprotected lighting- Lay a stain-proof vinyl sheet on
the floor- Wear non-antistatic work
clothes or work shoes

Same as above- Coat only a part ofthe object to be- Too thick/too thincoatedcoating film
- Too high/too low
paint discharge rate

- Handle the paint- Work in a place
before activating theother than the spray
local exhaustboothventilation

Other errors

Same as above- Do not dispose of
the used plastic
container, stirringrod, or filter paper
immediately, but
leave them for a
while- Activate the local
exhaust ventilation
during or after trial
coating

Same as above- Too early/too lateactivation of thelocal exhaust
ventilation- Let the paintoverflow from thecup- Do not dispose of
the used plastic
container
immediately, but
leave it for a while- Spill the paint- Bring in non-explosionprotected lighting- Lay a stain-proof vinyl sheet on
the floor- Wear non-antistatic work
clothes or work shoes

Same as above- Forget to adjust the- Work in a place
air pressureother than the spray- Leave the paintbooth
cup uncovered- Too high/too low
air pressure- Spill the paint- Drop the spray gun- Bring in non-explosionprotected lighting- Lay a stain-proof vinyl sheet on
the floor- Wear non-antistatic work
clothes or work shoes- Forget to perform
trial spraying- Leave the paintcup uncovered

Same as above- Too high/too lowdischarge rate

Same as above- Forget to blow off
the dust- Leave the paintcup uncovered

Same as above- Pull the trigger all
the waySame as above- Prime only a part of- Too thick/too thin
the object to becoating film
coatedSame as above

25

Adjust the discharge rate of the paintemitted from the spray gun by performing
trial coating. Also, adjust the patternadjustment knob appropriately.

26

Pull the trigger of the spray gun one step toblow off the dust from the surface of theobject to be coated.

27

Apply a topcoat using the spray gun.

- Leave the paintcup uncovered

Same as above

28

Dispose of the mixed paint remaining in thecup in a waste liquid container with a lid.

- Leave the waste
liquid container
uncovered- Dispose of themixed paint in aplastic container at
hand

29

Allow to air-dry at room temperature.

- Dry in a place otherthan the spray booth- 24 -

Quantitative errors- Pour the resulting
paint too fast/tooslow into the cup- Dispose of theused plastic- Leave the used
container, stirring
plastic container,rod, and filter paper
stirring rod, and filter
in a container at
paper as they are
hand other than atrash canDispose of the used plastic container,
stirring rod, and filter paper in a trash can.

Qualitative errors- Too early/too lateactivation of thelocal exhaust
ventilation- Use filter paper ofa wrong size at hand
- Work in a place
other than the spray
booth

18

Pour the toned paint into the cup on thespray gun.

Time errors- Work in a place
other than the spray- Add the toned paintbooth
to subdivided- Use a metal rod at
lacquer thinnerhand as the stirringrod

Lacquer enamel
Pour the resulting paint into the cup on the(black)spray gun while filtering it using filter
Lacquer enamel
Flammable liquids,
paper.
(toned paint)
Category 2
Lacquer thinner(Flash point: 5.5°C)(Explosive range:
1.1 to 12%)22

Sequential errors

Same as above- Take out of thespray booth before
drying completely- Too long/too shortdrying time

Table 12 (a) Hazard Scenario Identification Sheet (Degreasing Process: Step 1)[C] Confirmation of coexistence of three elements of combustion that could
cause fire or explosion[A] Workprocedure/details

Measures toprevent
formation of
explosive
atmosphere

Measures to prevent occurrence of ignition
sourcesEngineering control

Signage/warning and/or
administrative control

Pattern(a) - (d)[F] Unsafe conditions[D] [E] Trigger events
Formation of explosive atmosphere- Damage to trash can

1

No measures
taken(a) Prohibit bringing-in non(a) Use explosionexplosion-protected equipment
protected electrical(e.g., smartphones)
equipment(b) Ground metal products(b) Use a conductive(b) Wear antistatic work clothes
flooring
and antistatic shoes(b) Ground metal products (g) Control the use and bringing-inof fire(b)

Occurrence of ignition source

Fire/explosion

Effects on others

N/A

No effect

No effect

Working in an open area can cause an explosive
atmosphere to be formed around thinner.

- Damage to plastic container

Using a waste clothmoistened with lacquer
thinner, wipe the object
to be coated so that no
grease or oil stains
remain, and then wipe itwith a dry, clean waste
cloth.

[G] Accidents and disasters

Same as above

N/A

No effect

No effect

Fire caused by ignition of vapor aroundthinner

Burns caused by fire, spread of fire to
surrounding combustibles, spread of fireto work clothes, etc.

- Explosion-protected lighting failure

Same as above

Poor lighting insulation can cause electric sparks.

- Deterioration of antistatic work clothes

Same as above

Workers can become charged, causing electrostatic
sparks.

Same as above

Same as above- Dirty soles of antistatic work shoes

Same as above

Same as above

Same as above

Same as above- Deterioration of ground wire of conductive
floorSame as above

Same as above

Same as above

Same as above- Deterioration of ground wires of metal
products

Same as above

Same as above

Same as above

N/A

No effect

No effect- After wiping the object to be coated with adry, clean cloth, wipe it with a waste clothmoistened with lacquer thinnerComing close to a conductive object can cause
electrostatic sparks.

Working in an open area can cause an explosive
atmosphere to be formed around thinner.

- Wipe only a part of the object to be coatedwith lacquer thinnerSame as above

N/A

No effect

No effect- Too few times/too many times of wiping

Same as above

N/A

No effect

No effect- Spill the lacquer thinnerSame as above

N/A

No effect

No effect- Bring in non-explosion-protected lighting

Same as above

Bringing in non-explosion-protected lighting can cause
electric sparks from the power source of the lighting.

Fire caused by ignition of vapor aroundthinner

Burns caused by fire, spread of fire to
surrounding combustibles, spread of fireto work clothes, etc.

- Lay a stain-proof vinyl sheet on the floor

Same as above

Workers can become charged, causing electrostatic
sparks.

Same as above

Same as above- Wear non-antistatic work clothes or work
shoes

Same as above

Same as above

Same as above

Same as above

Table 12 (b) Hazard Scenario Identification Sheet (Degreasing Process: Step 2)[C] Confirmation of coexistence of three elements of combustion that could
cause fire or explosion[A] Workprocedure/details

Measures toprevent
formation of
explosive
atmosphere

Measures to prevent occurrence of ignition
sourcesEngineering control

Signage/warning and/or
administrative control

Pattern(a) - (d)[F] Unsafe conditions[D] [E] Trigger events
Formation of explosive atmosphere

Working in an open area can cause an explosive
atmosphere to be formed around thinner.

- Damage to plastic container- Damage to trash can with lid

2

Dispose of the used
waste cloth in a trash
can.

No measures
taken(a) Prohibit bringing-in non(a) Use explosionexplosion-protected equipment
protected electrical(e.g., smartphones)
equipment(b) Ground metal products(b) Use a conductive(b) Wear antistatic work clothes
flooring
and antistatic shoes(b) Ground metal products (g) Control the use and bringing-inof fire(b)[G] Accidents and disasters

Same as above

Occurrence of ignition source

Fire/explosion

Effects on others

N/A

No effect

No effect

N/A

No effect

No effect

Fire caused by ignition of vapor aroundthinner

Burns caused by fire, spread of fire to
surrounding combustibles, spread of fireto work clothes, etc.

- Explosion-protected lighting failure

Same as above

Poor lighting insulation can cause electric sparks.

- Deterioration of antistatic work clothes

Same as above

Workers can become charged, causing electrostatic
sparks.

Same as above

Same as above- Dirty soles of antistatic work shoes

Same as above

Same as above

Same as above

Same as above- Deterioration of ground wire of conductive
floorSame as above

Same as above

Same as above

Same as above- Deterioration of ground wires of metal
products

Same as above

Same as above

Same as above

N/A

No effect

No effect

Working in an open area can cause an explosive
atmosphere to be formed around thinner.

- Leave the used waste cloth as it isComing close to a conductive object can cause
electrostatic sparks.

- Dispose of the plastic container in acontainer at hand other than a trash can witha lid

Same as above

N/A

No effect

No effect- Do not dispose of the used waste cloth
immediately, but leave it for a while

Same as above

N/A

No effect

No effect- Spill the lacquer thinnerSame as above

N/A

No effect

No effect- Bring in non-explosion-protected lighting

Same as above

Bringing in non-explosion-protected lighting can cause
electric sparks from the power source of the lighting.

Fire caused by ignition of vapor aroundthinner

Burns caused by fire, spread of fire to
surrounding combustibles, spread of fireto work clothes, etc.

- Lay a stain-proof vinyl sheet on the floor

Same as above

Workers can become charged, causing electrostatic
sparks.

Same as above

Same as above- Wear non-antistatic work clothes or work
shoes

Same as above

Same as above

Same as above- 25 -

Same as above

Table 12 (c) Hazard Scenario Identification Sheet (Primer Coating Process: Step 9)[F] Unsafe conditions[C] Confirmation of coexistence of three elements of combustion that could cause fire or explosion[A] Workprocedure/details

Measures toprevent formationof explosive
atmosphere

Measures to prevent occurrence of ignition
Signage/warning and/or
Engineering control
administrative control

Pattern(a) - (d)[D] [E] Trigger events- Local exhaust ventilation failure

Formation of explosive atmosphereAn explosive atmosphere can be formed in the spray booth duringcoating.

- Clogging of or leakage from spray gun- Air compressor failure- Pressure regulator failure[G] Accidents and disasters

Occurrence of ignition source

Fire/explosion

The spray gun can become charged due to deterioration of theantistatic hose, causing electrostatic sparks.
An explosion-protected lighting failure can result in electric sparks
due to poor lighting insulation.
Deterioration of antistatic work clothes can cause workers to becomecharged, causing electrostatic sparks.
Fire or explosion caused by ignition of
Deterioration of antistatic work shoes can cause workers to become vapor in the spray boothcharged, causing electrostatic sparks.
Deterioration of the ground wire of the conductive flooring can cause
workers to become charged, causing electrostatic sparks.
Deterioration of ground wires of metal products can cause workers to
become charged, causing electrostatic sparks.

N/A(Omitted)

N/A(Omitted)

N/A(Omitted)

Effects on others

Burns caused by fire, spread of fire to
surrounding combustibles, spread offire to work clothes, etc.

No effect
No effect
No effect

No effect
No effect
No effect

Fire or explosion caused by ignition ofvapor in the spray booth

Burns caused by fire, spread of fire to
surrounding combustibles, spread offire to work clothes, etc.

An explosive atmosphere can be formed in the spray booth duringcoating due to a local exhaust ventilation failure.

- Deterioration of antistatic hose

- Damage to lid of paint cup- Explosion-protected lighting failure9- Local exhaustsystem attached(a) Prohibit bringing-in nonto spray booth(a) Use explosionexplosion-protected equipment- Lid of paint cup protected lighting(e.g., smartphones)
Prime using the spray on spray gun(b) Use a conductive(b) Ground metal products
gun.
- Disposal offlooring(b) Wear antistatic work clothes
waste liquid in(b) Ground metal products and antistatic shoes(metal) waste(b) Use antistatic hoses(g) Control the use and bringingliquid container
in of firewith lid

If the lid of the paint cup is damaged, causing the added paint toevaporate and exceed the capacity of the local exhaust system, an
explosive atmosphere can be formed in the spray booth during
The spray gun can become charged, causing electrostatic sparks.
coating.

If the waste liquid container with a lid is damaged, causing the added
paint to evaporate and exceed the capacity of the local exhaust
ventilation, an explosive atmosphere can be formed in the spraybooth during coating.
The spray gun can become charged due to deterioration of theantistatic hose, causing electrostatic sparks.
An explosion-protected lighting failure can result in electric sparks
due to poor lighting insulation.
Deterioration of antistatic work clothes can cause workers to become
If the added paint evaporates and exceeds the capacity of the local
charged, causing electrostatic sparks.
exhaust ventilation, an explosive atmosphere can be formed in the
Deterioration of antistatic work shoes can cause workers to become
spray booth during coating.
charged, causing electrostatic sparks.
Deterioration of the ground wire of the conductive flooring can cause
workers to become charged, causing electrostatic sparks.
Deterioration of ground wires of metal products can cause workers to
become charged, causing electrostatic sparks.
An explosive atmosphere can be formed in the spray booth duringcoating due to a local exhaust ventilation failure.
If the lid of the paint cup is damaged, causing the added paint toevaporate and exceed the capacity of the local exhaust ventilation, an
explosive atmosphere can be formed in the spray booth during
Poor lighting insulation can cause electric sparks.
coating.

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

If the waste liquid container with a lid is damaged, causing the added
paint to evaporate and exceed the capacity of the local exhaust
ventilation, an explosive atmosphere can be formed in the spraybooth during coating.
An explosive atmosphere can be formed in the spray booth duringcoating due to a local exhaust ventilation failure.

(d)- Deterioration of antistatic work clothes

If the lid of the paint cup is damaged, causing the added paint toevaporate and exceed the capacity of the local exhaust ventilation, an
explosive atmosphere can be formed in the spray booth during
Workers can become charged, causing electrostatic sparks.
coating.
If the waste liquid container with a lid is damaged, causing the added
paint to evaporate and exceed the capacity of the local exhaust
ventilation, an explosive atmosphere can be formed in the spraybooth during coating.
An explosive atmosphere can be formed in the spray booth duringcoating due to a local exhaust ventilation failure.

- Dirty soles of antistatic work shoes

If the lid of the paint cup is damaged, causing the added paint toevaporate and exceed the capacity of the local exhaust ventilation, an
explosive atmosphere can be formed in the spray booth during
Workers can become charged, causing electrostatic sparks.
coating.
If the waste liquid container with a lid is damaged, causing the added
paint to evaporate and exceed the capacity of the local exhaust
ventilation, an explosive atmosphere can be formed in the spraybooth during coating.
An explosive atmosphere can be formed in the spray booth duringcoating due to a local exhaust ventilation failure.

- Deterioration of ground wire of conductive
flooring

If the lid of the paint cup is damaged, causing the added paint toevaporate and exceed the capacity of the local exhaust ventilation, an
explosive atmosphere can be formed in the spray booth during
Workers can become charged, causing electrostatic sparks.
coating.
If the waste liquid container with a lid is damaged, causing the added
paint to evaporate and exceed the capacity of the local exhaust
ventilation, an explosive atmosphere can be formed in the spraybooth during coating.
An explosive atmosphere can be formed in the spray booth duringcoating due to a local exhaust ventilation failure.

- Deterioration of ground wires of metal
products- Damage to waste liquid container with lid

If the lid of the paint cup is damaged, causing the added paint toevaporate and exceed the capacity of the local exhaust ventilation, an
explosive atmosphere can be formed in the spray booth during
Metal products can become charged, causing electrostatic sparks.
coating.
If the waste liquid container with a lid is damaged, causing the added
paint to evaporate and exceed the capacity of the local exhaust
ventilation, an explosive atmosphere can be formed in the spraybooth during coating.
The spray gun can become charged due to deterioration of theantistatic hose, causing electrostatic sparks.
An explosion-protected lighting failure can result in electric sparks
due to poor lighting insulation.
Deterioration of antistatic work clothes can cause workers to become
If the added paint evaporates and exceeds the capacity of the local
charged, causing electrostatic sparks.
exhaust ventilation, an explosive atmosphere can be formed in the
Deterioration of antistatic work shoes can cause workers to become
spray booth during coating.
charged, causing electrostatic sparks.
Deterioration of the ground wire of the conductive flooring can cause
workers to become charged, causing electrostatic sparks.
Deterioration of ground wires of metal products can cause workers to
become charged, causing electrostatic sparks.

- 26 -

Table 12 (c) Hazard Scenario Identification Sheet (Primer Coating Process: Step 9) (Continued)[F] Unsafe conditions[C] Confirmation of coexistence of three elements of combustion that could cause fire or explosion[A] Workprocedure/details

Measures toprevent formationof explosive
atmosphere

Measures to prevent occurrence of ignition
Signage/warning and/or
Engineering control
administrative control

Pattern(a) - (d)[D] [E] Trigger events

Formation of explosive atmosphere[G] Accidents and disasters

Occurrence of ignition source

Fire/explosion

Sparks can occur due to the impact of dropping thespray gun.
Bringing in non-explosion-protected lighting can cause
If the added paint evaporates and exceeds the capacity electric sparks from the power source of the lighting.
of the local exhaust ventilation, an explosive
Laying a stain-proof vinyl sheet on the floor can cause Fire or explosion caused by ignition of- Leave the paint cup uncovered
atmosphere can be formed in the spray booth during
vapor in the spray booth
workers to become charged, causing electrostatic
coating.
sparks.
Wearing non-antistatic work clothes or work shoes cancause workers to become charged, causing electrostatic
sparks.
Sparks can occur due to the impact of dropping thespray gun.
Bringing in non-explosion-protected lighting can cause
electric sparks from the power source of the lighting.
Working in an open area can cause an explosive
Laying a stain-proof vinyl sheet on the floor can cause- Work in a place other than the spray booth
Same as above
atmosphere to be formed in the work area.
workers to become charged, causing electrostatic
sparks.
Wearing non-antistatic work clothes or work shoes cancause workers to become charged, causing electrostatic
sparks.
- Prime only a part of the steel plate
N/A(Omitted)
No effect- Too thick/too thin coating film

N/A

(Omitted)

No effect

Effects on others

Burns caused by fire, spread of fire to
surrounding combustibles, spread offire to work clothes, etc.

Same as above

No effect
No effect

Sparks can occur due to the impact of dropping thespray gun.

9

- Local exhaustsystem attached(a) Prohibit bringing-in nonto spray booth(a) Use explosionexplosion-protected equipment- Lid of paint cup protected lighting(e.g., smartphones)
Prime using the spray on spray gun(b) Use a conductive(b) Ground metal products
gun.
- Disposal offlooring(b) Wear antistatic work clothes
waste liquid in(b) Ground metal products and antistatic shoes(metal) waste(b) Use antistatic hoses(g) Control the use and bringingliquid container
in of firewith lid- Spill the lacquer primer surfacer

If the added paint evaporates and exceeds the capacityof the local exhaust ventilation, an explosive
atmosphere can be formed in the spray booth duringcoating.

- Drop the spray gun

If the added paint spilled from the paint cup evaporates
and exceeds the capacity of the local exhaust
ventilation, an explosive atmosphere can be formed in
the spray booth during coating.

(d)- Bring in non-explosion-protected lighting- Lay a stain-proof vinyl sheet on the floor- Wear non-antistatic work clothes or work
shoes

Bringing in non-explosion-protected lighting can cause
electric sparks from the power source of the lighting.
Laying a stain-proof vinyl sheet on the floor can cause Fire or explosion caused by ignition ofvapor in the spray booth
workers to become charged, causing electrostatic
sparks.
Wearing non-antistatic work clothes or work shoes cancause workers to become charged, causing electrostatic
sparks.
Sparks can occur due to the impact of dropping thespray gun.
Bringing in non-explosion-protected lighting can cause
electric sparks from the power source of the lighting.
Laying a stain-proof vinyl sheet on the floor can cause
Same as above
workers to become charged, causing electrostatic
sparks.
Wearing non-antistatic work clothes or work shoes cancause workers to become charged, causing electrostatic
sparks.

If the paint cup is left uncovered, causing the added
paint to evaporate and exceed the capacity of the local
exhaust ventilation, an explosive atmosphere can beformed in the spray booth during coating.
Working in an open area other than the spray booth cancause an explosive atmosphere to be formed in thework area.
Electric sparks can be generated from the lighting power Fire or explosion caused by ignition of
If the lacquer primer surfacer is spilled and the added
supply.
vapor in the spray booth
paint evaporates and exceeds the capacity of the local
exhaust ventilation, an explosive atmosphere can beformed in the spray booth during coating.
If the spray gun is dropped and the added paint spilledfrom the paint cup evaporates and exceeds the capacityof the local exhaust ventilation, an explosive
atmosphere can be formed in the spray booth during
If the paint cup is left uncovered, causing the added
paint to evaporate and exceed the capacity of the local
exhaust ventilation, an explosive atmosphere can beformed in the spray booth during coating.
Working in an open area other than the spray booth cancause an explosive atmosphere to be formed in thework area.
Workers can become charged, causing electrostatic
Same as above
If the lacquer primer surfacer is spilled and the added
sparks.
paint evaporates and exceeds the capacity of the local
exhaust ventilation, an explosive atmosphere can beformed in the spray booth during coating.
If the spray gun is dropped and the added paint spilledfrom the paint cup evaporates and exceeds the capacityof the local exhaust ventilation, an explosive
atmosphere can be formed in the spray booth during
If the paint cup is left uncovered, causing the added
paint to evaporate and exceed the capacity of the local
exhaust ventilation, an explosive atmosphere can beformed in the spray booth during coating.
Working in an open area other than the spray booth cancause an explosive atmosphere to be formed in thework area.
If the lacquer primer surfacer is spilled and the added
Same as above
Same as above
paint evaporates and exceeds the capacity of the local
exhaust ventilation, an explosive atmosphere can beformed in the spray booth during coating.
If the spray gun is dropped and the added paint spilledfrom the paint cup evaporates and exceeds the capacityof the local exhaust ventilation, an explosive
atmosphere can be formed in the spray booth duringcoating.

- 27 -

Burns caused by fire, spread of fire to
surrounding combustibles, spread offire to work clothes, etc.

Same as above

Burns caused by fire, spread of fire to
surrounding combustibles, spread offire to work clothes, etc.

Same as above

Same as above

6.

Diversion of Hazard Scenario Information Obtained by Simple Hazard Scenario Identification Method
to JNIOSH Method
The information contained in the three types of sheets prepared by the simple hazard scenario identification
method can help prepare the Risk Assessment Implementation Sheet to be used in the JNIOSH method. Table 13
shows the correspondence between the entries in the Risk Assessment Implementation Sheet to be used in the
JNIOSH method and the hazard scenario information obtained by the simple hazard scenario identification
method. In Step 2 (1) “Identification of trigger event and hazard scenario” of the JNIOSH method, entries shall beclassified into “Trigger events (Initial events),” “Unsafe conditions (Intermediate events),” and “Process
accidents/disasters (Consequential events),” which you can transcribe from [Column D] or [Column E], [Column
F], and [Column G], respectively. In Step 2 (2), you can enter the measures to prevent the formation of an
explosive atmosphere and those to prevent the occurrence of ignition sources that are confirmed in [Column C] inthe “Confirmation of existing risk reduction measures” column. You can also enter the matters listed in [Column
A] and [Column B] in the “Understanding hazards related to handled chemical substances and processes” column
in Step 1, and in the “Results of understanding hazards related to handled chemical substances and processes”
column in Step 2. Based on the above entries, you can perform the risk analysis and risk evaluation of the hazard
scenario, and devise risk reduction measures and examine how to implement them. Tables 14 (a) and (b) show (apart of) the hazard scenario identification results diverted from Tables 10 through 12 to the Risk Assessment
Implementation Sheet to be used in the JNIOSH method. The risk analysis and risk evaluation results of thehazard scenario and examination results of additional risk reduction measures are included36.
Table 13

Correspondence between Entries in Risk Assessment Implementation Sheet Used in JNIOSH Method
and Information Obtained by Simple Hazard Scenario Identification Method(JNIOSH method)
Entries in Risk Assessment Implementation Sheet(Simple hazard scenario identification method)
Information obtained by preparing three types of sheets

Step 1: Understanding hazards related to handled chemical substances and processes
Response to questionnaires(Results of understanding hazards related to chemical
substances handled and processes)[Column B] Handled chemical substances and facilities, equipment,
and others used for work/operation- Handled chemical substances- Information on hazards of chemical substances concerned- Handling conditions

Step 2: Implementation of risk assessment and risk reduction
Purpose of objective work/operation& equipment and facilities
Initiating hazard(Trigger event)(1) Hazard
identification

Process maｌfunction(Unsafe Conditions)
Process accidents(Fire/explosion, Other effects)(2) Existing risk reduction measures

36[Column A] Work/operation procedure/details (purpose ofwork/operation)[Column B] Facilities, equipment, and tools used for work/operation[Column D] Trigger events related to facilities, equipment, and tools[Column E] Trigger events related to work/operation[Column F] Unsafe conditions- Formation of explosive atmosphere- Occurrence of ignition source[Column G] Accidents and disasters- Fire/explosion- Other effects[Column C] Confirmation of pattern of causing fire or explosion- Measures to prevent formation of explosive atmosphere- Measures to prevent occurrence of ignition sources

Risk analysis and risk evaluation in Table 14
Part 1: Assuming that there are no existing (functioning) risk reduction measures, both Steps 2 and 9 are classified as pattern (a), which always has
a risk of fire or explosion; therefore the hazard scenario occurrence frequency is evaluated as “Likely” (risk level III).
Part 2: Based on the implementation status of existing risk reduction measures, Step 2 is classified as pattern (b), and the hazard scenario
occurrence frequency is evaluated as “Possible” (risk level III), whereas Step 9 is classified as pattern (d), and the hazard scenario occurrence
frequency is evaluated as “Unlikely” (risk level II).
Part 3: Since the current risk level is III or II, considering the additional risk reduction measures, the hazard scenario occurrence frequency isevaluated as “Unlikely” (risk level II). Here, the risk level of Step 9 remains at II, which seems at a glance that the risk level does not change, but
this is because it is evaluated by the criteria for risk analysis and risk level determination (risk matrix), and does not mean that the additionallyproposed risk reduction measures are ineffective (the occurrence frequency is slightly lower, but is evaluated as “Unlikely” in light of the criteria).
To reduce the risk level to I, it is necessary to reduce the severity by devising and taking inherent safety measures (elimination/substitution), but
if this is not possible, you should always be aware of the possibility of fire or explosion as a residual risk, and record the importance of working
while maintaining the measures to prevent the formation of an explosive atmosphere and those to prevent the occurrence of ignition sources.

- 28 -

Table 14 (a) Diversion to Risk Assessment Implementation Sheet Used in JNIOSH Method (Step 2)

Risk Assessment Implementation Sheet
Date of implementation

XX XX, XXXX

Implemented by (Prepared by)

XXXXX

Step 1: Understanding hazards related to handled chemical substances and processes
Response to questionnaires(Results of understanding hazards
related to chemical substances handled
and processes)[Handled chemical substances] Lacquer thinner- Pour lacquer thinner into a plastic container, moisten a waste cloth with lacquer
thinner from the container, and then use the cloth- Room temperature, 500 mL- Flammable liquids, Category 2(Flash point: 3.1°C) (Explosion range: 1.2–36.5%)[Answers to Q1 through Q17] 1. Subject to risk assessment, 2. GHS,
3. Combustibility, inflammability

Items for which“Yes” is circled in
the questionnaire

Step 2: Implementation of risk assessment and risk reduction
Purpose of objective work/operation &equipment and facilities(1) Hazard
identification

Initiating hazard(Trigger event)
Process malfunction(Unsafe Conditions)
Process accidents(Fire/explosion,
Other effects)(2) Existing risk reduction measuresst(2) 1 step risk estimation andevaluation; Under assumption of no
existing risk reduction measures(2) 2nd step risk estimation andevaluation; Confirmation ofeffectiveness of existing risk reduction
measures(3) 3rd step risk estimation andevaluation; Confirmation ofeffectiveness of additional risk
reduction measures(3) Availability of additional risk
reduction measure(3) Message or instruction to field
workers and plant operator(3) Residual risk

[Work/operation] Step 2: Dispose of used waste cloth in trash can[Facilities, equipment, and tools] Plastic container, waste cloth, and trash can[Purpose] To organize the work environment[Trigger event] Explosion-protected lighting failure[Formation of explosive atmosphere] Working in an open area can cause an
explosive atmosphere to be formed around thinner.
[Occurrence of ignition sources] Poor lighting insulation can cause electric
sparks.
[Fire/explosion] Fire caused by ignition of vapor around thinner[Other effects] Burns caused by fire, spread of fire to surrounding combustibles,
spread of fire to work clothes, etc.
Pattern (b)(a) Use explosion-protected equipment (B-c)(a) Prohibit bringing-in non-explosion-protected equipment (e.g. smartphones)(C-c)(b) Use conductive flooring (B-c)(b) Ground metal products (B-c) (C-c)(b) Wear antistatic work clothes and antistatic shoes (C-c)(g) Control the use and bringing-in of fire (C-c)

Severity

Probability(Frequency)

Risk level

Major

LikelyIII

Severity

Probability(Frequency)

Risk level

Major

PossibleIIIa) Install gas concentration meter and local exhaust ventilation (B-a, b)b)c) Types of risk
reduction measuresconducted(implemented)
A) Inherent safetymeasure(elimination/
substitution)B) Engineering controlsC) Administrative
control,(Signage/warning)D) Personal protective
equipment Purposes of risk
reduction measuresa) Contain and controlb) Detection meansc) Preventive
safeguardsd) Mitigative
safeguards

S

P/F

R

Major

UnlikelyIIa) Availablea) Periodic operation check of gas concentration meter, operation check of local exhaust ventilation(Others) Make sure to implement measures to prevent static electricity.
Check for residual risk:
Yes
How to deal with residual risk: An explosive atmosphere can always be present, so be careful ofventilation.

Remark- 29 -

Table 14 (b) Diversion to Risk Assessment Implementation Sheet Used in JNIOSH Method (Step 9)

Risk Assessment Implementation Sheet
Date of implementation

XX XX, XXXX

Implemented by (Prepared by)

XXXXX

Step 1: Understanding hazards related to handled chemical substances and processes
Response to questionnaires(Results of understanding hazards
related to chemical substances handled
and processes)[Handled chemical substances] Lacquer primer surfacer- Pour lacquer primer surfacer into the cup on the spray gun,- Room temperature, 200 mL- Flammable liquids, Category 2(Flash point: 0°C) (Explosion range: 1–15%)[Answers to Q1 through Q17] 1. Subject to risk assessment, 2. GHS,
3. Combustibility, inflammability,
13. High pressure

Items for which“Yes” is circled in
the questionnaire

Step 2: Implementation of risk assessment and risk reduction
Purpose of objective work/operation &equipment and facilities(1) Hazard
identification

Initiating hazard(Trigger event)
Process maｌfunction(Unsafe Conditions)
Process accidents(Fire/explosion,
Other effects)(2) Existing risk reduction measures[Work/operation] Step 9: Prime using the spray gun.
[Facilities, equipment, and tools] Spray coating equipment, workbench, plastic
container, trash can, and (metal) waste liquid container with lid[Purpose] To improve adhesion of paint[Trigger event] The Local exhaust ventilation, and then the explosion-protected
lighting fail.
[Formation of explosive atmosphere] An explosive atmosphere can be formed in
the spray booth during coating.
[Occurrence of ignition sources] An explosion-protected lighting failure canresult in electric sparks due to poor lighting insulation.
[Fire/explosion] Fire or explosion caused by ignition of vapor in the spray booth[Other effects] Burns caused by fire, spread of fire to surrounding combustibles,
spread of fire to work clothes, etc.
Pattern (d)- Local exhaust ventilation attached to the spray booth (B-a)- Lid of the paint cup on the spray gun (B-a)- Disposal of waste liquid in the (metal) waste liquid container with a lid (C-a)(a) Use explosion-protected lighting (B-c)(a) Prohibit bringing-in non-explosion-protected equipment (e.g. smartphones)(C-c)(b) Use conductive flooring (B-c)(b) Ground metal products (B-c) (C-c)(b) Use antistatic hoses (B-c)(b) Wear antistatic work clothes and antistatic shoes (C-c)(g) Control the use and bringing-in of fire (C-c)

Probability(Frequency)

Risk level

Major

LikelyIII

Severity

Probability(Frequency)

Risk level

Major

UnlikelyII(2) 1st step risk estimation andevaluation; Under assumption of no
existing risk reduction measures

Severity(2) 2nd step risk estimation andevaluation; Confirmation ofeffectiveness of existing risk reduction
measures(3) 3rd step risk estimation andevaluation; Confirmation ofeffectiveness of additional risk
reduction measures(3) Availability of additional risk
reduction measure(3) Message or instruction to field
workers and plant operator(3) Residual riska) Oblige to measure the front wind speed of the local exhaust ventilation
before starting work and not to start work if there is no wind. (C-a)b) Oblige to conduct inspection and maintenance of explosion-protected
equipment about once every two years to maintain explosion-protected
performance. (C-c)

 Types of risk
reduction measuresconducted(implemented)
A) Inherent safetymeasure(elimination/
substitution)B) Engineering controlsC) Administrative
control,(Signage/warning)D) Personal protective
equipment Purposes of risk
reduction measuresa) Contain and controlb) Detection meansc) Preventive
safeguardsd) Mitigative
safeguards

S

P/F

R

Major

Unlikely

II

Major

UnlikelyIIa) b) Availablea) Periodic operation check of gas concentration meter, operation check of local exhaust ventilation(Others) Make sure to implement measures to prevent static electricity
Check for residual risk:
Yes
How to deal with residual risk: Give education once a year to notify that risk reduction measures are
implemented as measures to prevent the formation of an explosive
atmosphere and the occurrence of ignition sources, and subsequent fires
and explosions. In addition, patrol the work site to check theimplementation status and check the inspection records once a month.

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