Annual Report on Liquefied Petroleum Gas (LPG)
Related Accidents(2012 version)

The High Pressure Gas Safety Institute of Japan (KHK)
Information Services & Research Department
International Affairs Office
Toranomon 4-3-13, Minato-ku, Tokyo 105-8447
TEL: +81-3-3436-2201 FAX: +81-3-3438-4163
Web: http://www.khk.or.jp/english/index.html
MAIL: oversea@khk.or.jp

1. Introduction
This Annual Report contains accidents that occurred in 2012 related to facilities for supplies and consumptions of
LPG at home or on business, which are regulated by the Act on the Securing of Safety and the Optimization ofTransaction of Liquefied Petroleum Gas (hereinafter, the “LPG Act”).

This report also contains analyze the dataof the accidents in 2012 by comparing with those in the last nine years (2003 to 2011).

2. Definitions
2.1 Definition of accidents(1) LPG accidents[1] Leakage

A case in which liquefied petroleum gas (hereinafter, “LPG”) leaked, but it did
not catch fire and cause human damages such as poisoning and asphyxiation.
However, in this report, leakage of a very little amount of LPG from joints aslittle as soap bubbles formed when those of threaded parts or rubber tubes are
soaked by soap water is excluded.

[2] Leakage andexplosion

Cases in which LPG leaked, and it resulted in an explosion or a fire caused by
the explosion, as follows.
A. Leakage and explosion, when the explosion resulted from leaked gas only.
B. Leakage, explosion and fire, when a fire broke out following explosion
caused by leaked gas.

[3] Leakage andfire

A case in which a fire that is not limited to that recognized as a fire by the fire
department resulted from leakage of LPG excluding those covered by [2]above. Here, a fire without leakage, which is caused by the overheating or the
failure of LPG appliances including their accessories or by spreading of flames
from a cooking oven, grill, etc., is not classified as a LPG accident.

[4] Poisoning andasphyxiation

A case in which human damages of CO poisoning and asphyxiation arecaused due to incomplete combustion, leakage of LPG, or leakage of exhaustgas from exhaust pipes, etc., at LPG consumption facilities.

(2) Other accidents (not classified as LPG accidents)[1] Accidents caused by suicide, damage by intention, mischief, theft, or other similar causes[2] Accidents resulting from a natural disaster
Example)Accidents caused by facilities’ damages resulting from collapse of houses due
to earthquake

Example)Accidents caused by facilities’ damages resulting from flood and landslide

Even if accidents are resulted from natural disasters, however, those caused by defects in toppling
prevention measures, fallen snow prevention measures (snow shelters, protective boards), or otherinsufficiencies in safety measures, are classified as LPG accidents.
[3] Accidents involving portable cooking stoves and gas cartridges[4] Other accidents not categorized in the LPG accidents of (1) above
2.2 Classification of human damages
Classified as follows according to the level of damage.
Death:

when a person was confirmed to have died within about five days from thetime of accident

Seriously injured: when a person suffered an injury at the time of accident that took 30 days ormore for full recovery
Slightly injured:

when a person suffered an injury at the time of accident that took less than 30days for full recovery

Copyright © The High Pressure Gas Safety Institute of Japan1

3. LPG accidents
3.1 Occurrences of accidents in the past
900

Number of accidents
800

Number of injuries
Number of deaths
700

It is noted a characteristic of accidents data inJapan that the number of leakage of gas,
which has not caught a fire and caused no
casualties due to poisoning or asphyxiation, iscounted as a LPG accident.

Number of accidents and casualties

600

500

400

300

200

100

0
1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

2011

Figure 1: Accident occurrences and casualties by year
Table 1: Change in the number of accidents and casualties by year
Year
Number ofaccidents
Rate to theprevious year

1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

167

112

170

217

217

299

368

540

497

581

638

570

793

761

570

559

545

496

82

88

101

68

75

79

78

87

90

120

105

105

219

34 ▲33

52

28

0

38

23

47 ▲8

17

10 ▲1128▲4 ▲6 ▲20

714

▲2

▲3

▲9

515

4 ▲22

401

▲3 ▲22 ▲14 ▲26 ▲25 ▲23 ▲27

390

306

262

194

146

112

7

15 ▲33

10

5

▲2

12

3

33 ▲13

0

109

239

33

38

69

44

33

52

59

74

40

65

56

72

63

60

50

43

51

36

35

42

29

37

36

27

13

31

7

3

12

14

6

9

5

8

2

4

7

2

1

0

4

271

146

236

283

301

398

389

679

543

523

684

640

825

758

723

650

645

529

550

477

381

336

327

233

171

162

135

83

80

109

64

82

66

73

69

64

86

88

58

78

98

234

185

204

227

258

▲21

10

11

12

4

4

5

1

1

79

148

83

88

85

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2

9 ▲2

Number of deaths
Number of
injuries

Figure 1 shows the number of accidents that occurred between 1962 and 2012 and the resulting
casualties. Looking at the data by decade, the number of accidents increased gradually during the 1960s
along with the increase in LPG consumption and diversification of users.
In the 1970s, the number of accidents continued increasing along with the number of households using
LPG and reached a peak in 1979 with 793 accidents, causing 63 casualties. This was the year thatmarked the highest number of casualties, at a level similar to that of 1974.
Soon after entering the 1980s, a large-scale city gas explosion took place that resulted in enormous
human damages marked by 15 deaths and 222 seriously and slightly injured persons. The number ofaccidents was 761 that year. The number of accidents peaked out this year and started showing adownward tendency, reducing greatly to 570 in 1982.
Thereafter, the number of accidents continued declining linearly from the late 1980s, falling below 100 in
1994, to 82.
The year 1997 saw the lowest number of accidents (68) since enactment of the LPG Act. In the 2000s,
the number of accidents remained above 100 until 2012, although the number of deaths has been on thedecrease.

3.2 Accident situations by phenomenon
The numbers of accidents by phenomenon in the past decade are shown below.
Table2: Number of accidents by phenomenon
2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

34

41

46

137

113

115

84

76

116

155

75

56

46

70

64

53

45

60

55

48

2

1

2

6

51

60

42

60

45

44

9

7

11

6

11

6

14

8

11

8

120

105

105

219

239

234

185

204

227

255

Leakage
Leakage andexplosion (Fire)
Leakage and fire
(Excluding explosion)
CO poisoning andasphyxiation
Total

Number of accidents by phenomenon
Looking at the accidents that occurred in 2012, the number of leakage-only accidents was 155,
showing an increase of 39 from the previous year. On the other hand, the number of leakage andexplosion (fire) accidents was 48, a drop of seven from the previous year. Furthermore, the numberof leakage and fire accidents (excluding explosion) and the number of CO poisoning andasphyxiation accidents have continued decreasing slightly.
Overall, the number of leakage accidents has increased in recent years while that of explosion
caused by leakage has declined.
However, the total number of accidents has increased, although slightly.
Table 3: Number of CO poisoning accidents (excluding asphyxiation) by year and casualties
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Number of Accidents

9

6

10

5

11

6

14

8

10

8

Of the above, the number ofClass B or highr class accidents

4

1

1

0

3

2

6

3

3

2

Number of deaths

4

0

1

0

2

2

3

3

1

1

Number of injuries

17

21

22

13

29

8

85

16

32

37

Of the above, the number ofClass B or highr class accidents

1

7

0

0

9

0

65

7

16

23

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Observing the change in the number of CO
poisoning accidents that occurred between
2003 and 2012 and the accompanying
casualties both remained at steady levels.
However, the number of casualties
increased to 88 in 2009.

100
88

90
Number of accidents
Catualties

80
70
60
50

37

40
32

31

30

The increase is attributed to the large
number of casualties per accident.

23
21

19

21
10

20

13

14
11

10

10
8

9

10

8

6
6

5

0
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Year

Figure 2: Number of CO poisoning accidents by
year and casualties
Table 4: Number of buried pipes accidents by year and casualties
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Number of Accidents

4

12

12

17

21

31

24

18

18

15

Of the above, the number ofClass B or highr class accidents

0

1

0

1

0

0

0

0

0

0

Number of deaths

0

1

0

0

0

0

0

0

0

0

Number of injuries

1

4

6

3

1

2

0

2

0

0

Of the above, the number ofClass B or highr class accidents

0

0

0

2

0

0

0

0

0

0

Catualties

Accidents
35

35
Distribution pipes

3030
Supply pipes
8
Number of catualties

25

25
5

23
1
20

20

20
19

2
5

5

13

13

15

15
15

4

2
3

10

10
11
10
9
6
5

5

5

1
3 1

3
2

2

1
0

0
2003

2004

2005

2006

2007

2008

2009

2010

0

0

2011

2012

0

Year

Figure 3: Number of buried pipes accidents by year and casualties
Observing changes in the both number of buried pipes accidents that occurred between 2003 and2012 and casualties, it is shown that there have been no casualties since 2011. On the other hand,the number of accidents peaked in 2008 and has continued decreasing just slightly since then.
A large number of supply pipes accidents have taken place each year, mainly resulting fromdamages and deterioration due to corrosion.

Copyright © The High Pressure Gas Safety Institute of Japan4

4. Analysis of accident situations
The following kinds of LPG accidents that have occurred frequently were analyzed.
(1) CO poisoning accidents
As shown in Table 3 and Figure 2, eight CO poisoning accidents occurred in 2012, showing adecrease of two from the previous year. Two of eight were Class B accidents, resulting one fewer
than in the previous year. The breakdown of eight accidents is shown below.
[1] Accident caused by use of compact water heater that is not equipped with an incomplete
combustion prevention device in an unventilated room[2] Accident caused by use of commercial floor mounted heater whose adjusted pressure wasabnormal due to clog in the equipment[3] Accident caused by inappropriate ventilation because the exhaust port of a noodle cooker wascovered by a pot*A noodle cooker is a device for boiling noodles[4] Accident caused by use of noodle cooker in an unventilated kitchen[5] Accident caused by use of commercial oven in an unventilated kitchen[6] Accident caused by use of commercial dish washing machine in an unventilated school kitchen[7] Accident caused by use of commercial oven in a kitchen with a ventilation port clogged by dirt
[8] Accident caused by inadequate ventilation due to a bird’s nest built inside a ventilation pipe of aforced exhaust (FE) instant gas water heater*FE refers to combustion devices that take in the air inside a room and discharge exhaust
outdoor by force. A typical example is an instant gas water heater.
(2) Buried pipes accidents
Table 4 and Figure 3 show that 15 accidents involving buried pipes took place in 2012, a drop of
three from the previous year. Eleven of fifteen accidents involved supply pipes, which was two fewer
than in the previous year, and four involved distribution pipes, one fewer than the previous year.
Accidents of Class B or higher classes did not occur. (Between 2003 and 2012, only two accidentsof Class B or higher classes occurred; see Table 4)
Causes of accidents include damages in nine accidents (supply pipes in seven accidents anddistribution pipes in two accidents) and deterioration due to corrosion in six accidents (supply pipes
in four accidents and distribution pipes in two accidents).
(3) Bulk supply accidents
In 2012, 13 accidents involving bulk supply (supply facilities only) occurred, showing an increase of
six from the previous year. The 13 accidents were as follows. All accidents were in the bulk storagetank side.
*Bulk supply refers to supply of liquefied petroleum gas into bulk storage tanks from portable LPG
generators (bulk tank trucks). (See Figure 4)[1] Gas leakage from liquid outlet valve (3 accidents)[2] Gas leakage from equalizing valve (1 accident)[3] Gas leakage caused by error in detachment of level gauge (1 accident)[4] Damage to safety valve caused by frozen water content (1 accident)[5] Gas leakage caused by damage to diaphragm of regulator (1 accident)[6] Accidents caused by actuation of safety valve of vaporizer (2 accidents)[7] Damages caused by snow (3 accidents)[8] Damage to supply facilities due to error by building demolition workers (1 accident)

Copyright © The High Pressure Gas Safety Institute of Japan5

Figure 4: Bulk supply system
Protector

Regulator
Release valve
Liquid inlet valve

Gas outlet

Safety valve

valve

Liquid outlet valve

Level gauge

Filling port

Figure 5: Bulk storage tank5.

Accident classification

When an accident occurs, it is classified as follows according to the degree of loss.
Contents of loss

Class A(1) Deaths

5 or more(2) Deaths plus serious injuries

10 or more

(3) Casualties (death plus injury) 30 or more
(4) Direct property damage

200 million yen or more

(5) Any accident affecting the public, or which could have developed into a large scale disaster(1) Deaths

Class B

1 to 4(2) Serious injuries

2 to 9(3) Casualties (injury)

6 to 29(4) Direct property damage

200 million yen or more

(5) Accidents repeatedly occurring at the same works(6) Any accident affecting the public, or which could have developed into a large scale of disaster.
Class C

Other than Classes A and B

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6. List of major accidents that occurred in 2012
Accident title

CO poisoning while using compact water
heaterCO poisoning while using noodle cooker

Leakage and explosion

Date

February 6

February 21

August 18

Death/ seriously injuries/
minor injuries

1/0/1

0/1/21

0/2/1

Overall toll

2

22

3

Substance nameCO gasCO gas

LPG

Scale

-

-

-

Primary phenomenon/
secondary phenomenon

CO poisoning/ -CO poisoning/ -Under investigation/ -Situations of handling

While being operated

While being operated

While in a halt

Accident causes (maincauses)/ (secondary causes)

Incomplete combustion of LPG appliance/ -Error in equipment handling/ -Under investigation/ -Two users were found collapsed on thefloor of a house attached to a mechanicalprocessing factory, and their relatives
alerted the fire department. At the hospitalwhere the two were taken, it was confirmedthat one of them died due to CO poisoning
and the other one was slightly affected.
At the site of the accident, heated water
was running from an open-type water
heater, and its burner and heat exchanger
fins were confirmed to be clogged by soot.
Under the circumstances, the cause of theaccident is believed to be the room fillingwith exhaust containing carbon monoxidecaused by incomplete combustion of thewater heater and non-use of a ventilating
fan.

Noodle cookers were being used during ahands-on learning class for Japanese
noodle-making, held at a community
facility. A total of 22 persons, including 16high school students, four teachers, andtwo instructors, complained that they had
headaches and felt sick. They werediagnosed with CO poisoning at thehospital where they were taken.
The cause of the accident is believed to be
the accumulation, in the room, of exhaustcontaining carbon monoxide, which
generated because of incomplete
combustion that resulted from blocking of
the exhaust port of the noodle cooker byanother pan.

Under investigation
An explosion took place at a restaurant
after closing, while employees were
working inside, causing serious injuries totwo persons and minor injuries to one.
The cause of the accident is underinvestigation.
It is noted that their gas meter (with3 amaximum working flow rate of 7 m /hour),whose valid period of verificationprescribed by the Measurement Act, has
expired.

Ignition source

Accident outline

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