Annual Report on Liquefied Petroleum Gas(LPG) Related Accidents(2021 version)

The High Pressure Gas Safety Institute of Japan (KHK)1. Introduction
This Annual Report describes accidents that occurred in 2021 related to facilities for supplies andconsumptions of Liquified Petroleum Gas (hereinafter, “LPG”) at home or on business, which areregulated by the Act on the Securing of Safety and the Optimization of Transaction of Liquefied Petroleum
Gas (hereinafter, the “LPG Act”). This report also describes analyses of the data of the accidents in 2021
by comparing with the past.

2. Definitions
2.1 Definition of accidents(1) LPG accidents[1] Leakage
Cases in which LPG leaked, but it did not catch fire and cause human damages ofpoisoning and asphyxiation. However, leakage of a very little amount of LPG
from joints as little as soap bubbles formed when those of threaded parts or rubber
tubes are soaked by soap water is excluded.
[2] Leakage andCases in which LPG leaked, and it resulted in an explosion or a fire caused by theexplosion
explosion, as follows.
A. Leakage and explosion, when the leaked gas resulted to explosion only.
B. Leakage, explosion and fire, when a fire broke out following explosion causedby leaked gas.
[3] Leakage andCases in which a fire resulted from leakage of LPG excluding those covered byfire[2] above. This is not limited to that recognized as a fire by the fire department.
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 acooking oven, grill, etc., is not classified as a LPG accident.
[4] Poisoning andCases in which human damages of CO poisoning and asphyxiation are caused due
asphyxiation
to incomplete combustion, leakage of LPG, or leakage of exhaust gas fromexhaust 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 toearthquake
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 five days (120 hours) 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

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3. LPG accidents
3.1 Occurrences of accidents in the past

It is noted a characteristic of accidents datain Japan that the number of leakage of gas,
which has not caught a fire and caused nocasualties due to poisoning or asphyxiation,is also counted as an LPG accident.

Figure 1: Accident occurrences and casualties by year
Table 1: Change in the number of accidents and casualties by yearYear
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
Number of accidents
299 368 540 497 581 638 570 793 761 714 570 559 545 496 515 401 390 306 262 194 146 112 82 88 101
Rate to the previous year (%)
38 23 47 ▲8 17 10 ▲11 39 ▲4 ▲6 ▲20 ▲2 ▲3 ▲94 ▲22 ▲3 ▲22 ▲14 ▲26 ▲25 ▲23 ▲277 15
Number of deaths
52 59 74 40 65 56 72 63 60 50 43 51 36 35 42 29 37 36 27 13 31
73 12 14
Number of injuries
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
Year1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
Number of accidents
68 75 79 78 87 90 120 105 105 219 239 234 185 204 227 260 210 187 182 140 195 212 203 198 212
Rate to the previous year (%) ▲33 105 ▲1 123 33 ▲130 109
9 ▲2 ▲2110 11 15 ▲19 ▲11 ▲3 ▲23 394 ▲4 ▲22
Number of deaths
6958247210444511312001011
Number of injuries
64 82 66 73 69 64 86 88 58 78 98 79 148 83 88 85 52 76 60 52 50 46 32 29 20Copyright © The High Pressure Gas Safety Institute of Japan 2

Figure 1 shows the number of accidents that occurred between 1972 and 2021 and the resulting casualties.
Looking at the data, the number of accidents increased gradually during the 1970s along with the number ofhouseholds using LPG and reached a peak in 1979 with 793 accidents, causing 63 casualties. This was theyear that marked the highest number of accidents and casualties. In July 1978, a part of the LPG Act wasrevised : measures such as dealer's obligation to general consumers, the establishment of a certified research
institution system, etc. were implemented.
In August 1980, 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. In February 1981, Ministerial Ordinance Reform
was carried out : safety standards of the basement were established, installation of gas leak alarm equipmentfor LPG for the basement and business facilities was obliged, and odor concentration of LPG wasstrengthened.
Thereafter, the number of accidents continued declining linearly from the late 1980s, falling below 100 in
1994, to 82. Meanwhile, amendments to Act and Ministerial Ordinances were implemented several times. For
example, in July 1985, the Ministerial Ordinance amendment was implemented to strengthen the installationin restaurants of end gas faucets (fuse gas stoppers) with excess overflow safety mechanisms and theconnection method of rubber tubes.
After that, initiatives for eradicating accidents, such as promoting the deployment of safety devices inconjunction with the public and private sectors, have been promoted.
3.2 Accident situations by phenomenon
Table 2 shows the number of accidents by phenomenon that occurred between 2012 and 2021. Looking atthat of 2021, the number of leakage-only accidents that did not start fire or explosion was more than 75% oftotal accidents. Compared to the previous year, the number of leakage-only accidents increased by 12, leakage
and explosion (fire) accidents increased by 6.
Table 2: Number of accidents by phenomenon
2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
Leakage
Leakage andexplosion(Fire)
Leakage and fire(Excluding explosion)
CO poisoning andasphyxiation
Total

160

113

98

102

85

114

148

148

148

160

48

48

59

43

27

43

33

26

1925

44

43

27

31

1935

24

29

31

27

8

63

6

93

7000

260

210

187

182

140

195

212

203

198

212

4. Analysis of accident situations
The following kinds of LPG accidents that have occurred frequently were analyzed.
(1) CO poisoning accidents
As shown Figure 2, there was no CO poisoning accident in 2021, as well as the previous year.

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Figure 2: Number of CO poisoning accidents by year and casualties(2) Buried pipes accidents
In Japan, the pipes that are installed between LPG cylinders and a gas meter are called supply pipes, andare installed between a gas meter and consumption devices like heaters are called distribution pipes.
Pipes are installed on the ground or underground. The number of supply pipe accidents is greater thandistribution pipe accidents.
Figure 3 shows that 55 accidents involving buried pipes took place in 2021, a decrease of 3 from theprevious year.
Causes of accidents include damages to the pipes in 50 accidents (supply pipes in 35 accidents anddistribution pipes in 15 accidents) and deterioration due to corrosion in 4 accidents (supply pipes in 1
accident and distribution pipes in 3 accidents). In many cases, damages are caused by a construction
company erroneously cutting or breaking in a construction unrelated to gas facilities, causing gas
leakage. In such a case, since people are involved directly and treatment such as gas stoppage is taken
relatively quickly, most of them have not reached a large-scale accident.

Figure 3: Number of buried pipes accidents by year and casualties

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(3) Bulk supply accidents
In 2021, 12 accidents involving bulk supply (supply facilities only) occurred, showing an increase of 5
from the previous year.
*Bulk supply refers to supply of liquefied petroleum gas into bulk storage tanks from portable LPG
generators (bulk tank trucks). See Figure 4.
Causes of accidents are as follows:[1] Damages or corrosions (5 cases)[2] Incomplete closing or forgetting to close valves, stoppers, etc.(1 case)[3] Bad connection (1 case)[4] Failure or malfunction (1case)[5] Others or Unknown (4 cases)

Figure 4: Bulk supply system
Protector
Pressure Relief Device
Regulator

Liquid Inlet ValveGas Outlet Valve
Liquid outlet valve

Level Gauge

Filling PortFigure 5: Bulk Storage TankCopyright © The High Pressure Gas Safety Institute of Japan 5

5. Number of accidents that resulted in deaths or injures
Table 3 and Figure 6 show the number of accidents that resulted in deaths or injuries by phernomenon.
Table 3: Number of accidents, etc. that resulted in deaths or injuries by phenomenon

Leakage

Leakage and explosion(Fire)
Leakage and fire
(Excluding Explosion)

CO poisoning andasphyxiation

Total

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

Number of accidents

1011110011

Number of deaths

0000000000

Number of injuries

2011110011

Number of accidents

2724382116251615613

Nnumber of deaths

00010000

11

Number of injuries

333050372129232424

12

Number of accidents

1015

981

11

764

7

Number of deaths

0000000000

Number of injuries

131721

8115

784

7

Number of accidents

863

693

7000

Number of deaths

13

1

100

1000

Number of injuries

37541429

516000

Number of accidents

46455136274030211121

Number of deaths

1312001011

Number of injuries

85527660525046322920Figure 6: Number of accidents that resulted in deaths or injureis by phenomenon

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Contact for inquiries related to this document

The High Pressure Gas Safety Institute of Japan (KHK)
General Affairs and Planning Department
General Planning and International Affairs Group
4-3-13 Toranomon, Minato-ku, Tokyo 105-8447
TEL: +81-3-3436-1704 FAX: +81-3-3436-5704
Web: http://www.khk.or.jp/english/index.html
MAIL: oversea@khk.or.jp

Copyright © The High Pressure Gas Safety Institute of Japan