7/21/2019 Fires, Explosions and Related Incidents at Work 1992 1993 http://slidepdf.com/reader/full/fires-explosions-and-related-incidents-at-work-1992-1993 1/7 0950-4230(95)00035-6 J. Loss Prev. Proress Ind. Vol. 8. No. 5. pp. 291-297, 1995 Elsevier Science Ltd Printed in Great Britain 09504230/9 5 S IO.00 0.00 Fires explosions and related incidents at work in 1992-1993 K A Owens and J A Hazeldean Technical and Health Sciences Division, Health and Safety Executive, Magdalen House, Bootle, Merseyside, L20 3QZ Incidents in Great Britain reported to the Health and Safety Exec utive during 1992-1993 involv - ing fires, explosions, runaway chemical reactions and unignited releases of flammable materials are reviewed. Statistical comparisons are made against prev ious years based on the materials involved , and a number of common themes and causes are identified. Keywords: fires; explosions; unignited releases; exothermic reactions; carriage This paper summarizes fires, explosions and related inci- dents reported to the Health and Safety Executive (HSE) in 1992-1993. It originally formed part of a review sub- mitted to the Advisory Committee on Dangerous Sub- stances by the Explosives and Flammables Unit of HSE’s Technology and Health Sciences Division. The information was compiled from an analysis of accidents and dangerous occurrences reported to the HSE under Regulation 3 of the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1985 (RIDDOR). An HSE booklet’ describes the types of accidents and injuries reportable under RJD DO R. This paper also includes information on incidents that involved the manufacture, keeping and carriage of explosives. These incidents were reported to the HSE under Section 63 of the Explosives Act 1875 and Regu- lation 12(2) of the Road Traffic (Carriage of Explosives) Regulations 1989. The HSE investigates accidents and seeks to ensure that any safety lessons are learned by the company con- cerned to prevent similar accidents from occurring again. Additionally, the HSE communicates findings from acci- dent reports and investigations more widely in guidance booklets and other forms of advice. The information col- lected may also be used to identify the need for new guidance and research, and to support national and inter- national standards. The purpose o f publishing this report is to draw further attention to the hazards of flammable materials and common accident scenarios in the hope that readers may recognize particular situations and take action before an accident occurs. Overall statistics The accidents reported in this review occurred in the period 1 April 1992 to 31 March 1993 and involved fires, explosions, runaway chemical reactions and unignited releases of flammable materials. They occurred during work activities at premises and sites where the Field Operations Division (Factory, Agriculture and Quarry Inspectorates) and the Explosives Inspectorate of the HSE enforce the Health and Safety at Work, etc. Act 1974. The 675 injuries (including 2 1 fatalities) that resulted from fires or explosions are a subset of 147 374 injuries (including 405 fatalities) suffered in all types of accidents reported to the HSE. There are an estimated 700000 fixed premises and an additional unquantifiable number of transient sites where the Field Operations Division has enforcement responsibility. An estimated 15 million people are employed at these locations, and, of these, around 4.5 million are employed in manufacturing industries. Explosives are manufactured in about 124 licensed explosives factories, varying in size from those employing one or two people to those employing over 1000 people. In addition, explosives are held in 98 magazines licensed by the Explosives Inspectorate, and around 200 companies are involved in carrying explos- ives by road. Some of the main types of accidents, and those that caused or had the potential to cause serious conse- quences, have been broken down into the main categor- ies reported below and the overall ranking is shown in Table 1 Categories of accidents Category of total incidents Fatalities Flammable liquids 32 7 Flammable gases 23 1 Flammable solids 18 5 Liquefied petroleum gas 6 0 Exothermic reactions 3 5 Explosives 5 1 291
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7/21/2019 Fires, Explosions and Related Incidents at Work 1992 1993
2 9 2 F i r es e x p l o s i o n s a n d r e la t e d i n c i d e n t s a t w o r k i n 1 9 9 2 -1 9 9 3: K . A . Ow e n s a n d J . A . H a z e /d e a n
Table 1 The overall num bers of repo rted incidents in
these categories are presented in Table 2 for the last
five years.
Flamm able solids and dusts
The repor ted incidents (n = 200) in this cate gory
occurred across a wide range of work activities.
The largest nu mber of incidents relates to drying or
heating processes that go wrong. The range of materials
involved is wide, and includes clothing in a comm ercial
tumble drier, paper dust in a paper-mak ing machine, bis-
cuits and bread in large ovens, an adhesive coating in
a shoe factor y, foam backing in an oven at a carpet-
manufacturing plant, and soya and linseed grain pro-
ducts. M any of these incidents cause no injuries but may
cause extensive damage to the plant and prolonged shut-
down.
Seven incidents involved aluminium or magnesium
metals, and of these six involved the metal d ust. This
appears to be a disproportionate number considering the
relatively small number of premises that handle the se
dusts, and highlights the significant risks in processing
these substances. Metal dust fires are characterized by
intense heat and rapid fire grow th, and it is extremely
difficult to extinguish large tires before the pow der has
burnt out. Often the fire damage is so severe that there
is little prosp ect of confidently identifying the ignition
source. A recurring theme is that dust builds u p around
the process area or in extraction ducts. The H SE has
recently published guidance2 on the safe handling of
combustible dusts, which highlights the need for good
housekeep ing, including the frequent emptying of dust
extraction equipment and the regular inspection and cle-
aning of ducts.
Nine incidents involved substan ces described as
chemicals. The most no table led to the loss of 820 tonnes
of molten sulfur from a 900 tonne sto rage vessel. It was
suspected that corrosion under the lagging resulted in a
small hole a t the base of the tank. The sulfur did not
ignite but the leak continued for seven hou rs.
The only incident that caused offsite risk s was a
fire at a plant that was making chlorinated rubber. The
contents of a hot air drier caugh t fire, and a large p lume
of smoke drifted offsite. There were reports of nose and
throat irritation caused by the fumes.
Spontaneous combustion was identified as the cause
of a number of incidents even wh ere the hazard was well
understoo d in advance. One examp le involved a fire dur-
ing the unloading of a bulk ship’s cargo of raw cotton.
Three incidents occurr ed in carbon bed absorbe rs,
due to spontaneous combustion. Such absorbers are
likely to becom e more comm on due to environmental
controls requiring a reduction in the emission of organic
solvents. Fires in these units can be difficult to
extinguish because they may start deep within the carbon
bed, but instrumentation is available that allows fires to
be detected at an early stage and appropriate action to
be taken. As a result, although fires in these units are
repor ted every y ear, there is no significant record of
associated injuries.
Although not strictly a hazard derived from work
activities, arson remains a serious risk to many busi-
nesses. A notable incident involved a fire that started in
an outside storag e a rea for garden furniture and boxes.
Hundreds of tonnes of polypropylene goods and a large
factory were destroyed, but fortunately no-one was
injured.
Flammable liquids
The reported incidents (n = 359) involving flammable
liquids resulted in 172 injuries, including seven fatalities.
These figures continue to show a down ward trend in line
with the overall trend fo r all types o f accidents repor ted
to the HSE . The high number and wide variety of inci-
dents within this category reflect the extensive and
diverse uses that are found fo r flammable liquids w ithin
Table2 Accident statistics for fires and explosions from 1987/1988 to 1992/1993 (see text for the source and scope of accidents
F i re s e x p l o s i o n s a n d r e la t e d i n c i d e n t s a t w o r k in 1 99 2 -1 9 9 3: K . A . Ow e n s a n d J . A . H a z e ld e a n 2 9 5
The next largest group of accidents occurred during
battery charging, jump starting, and connection and dis-
connection of battery leads. Battery explosions usually
occur when hydroge n, evolved during charging, is
ignited by a spark. T he explosion usually results in injur-
ies from acid burns and fragments of the battery casing.
Most of the accidents could be avoided by following the
guidance contained in a HS E leaflet” on electric storage
batteries. The leaflet was produced in 1993 which w as
too late to have h ad any impact on the accident statistics
for 1992/1993.
Four incidents occurre d during the operation of
valves on oxygen cylinders. Ignition is usually caused
by adiabatic com pression, contamination with grease or
particle impact. Regular maintenance and prevention of
contamination are important to minimize such accidents.
The vulnerability of gas cylinders to fire engulfment
continues to be demonstrated. In 1992/1993, two fires
resulted in the bursting of oxygen cylinders and one
resulted in the bursting of an acetylene cylinder. In one
of these incidents, a fire in the engine of a rescue vehicle
spread rapidly to involve oxygen cylinders that were
carried on the vehicle.
One incident, which involved hydroge n, illustrates
that hazar ds can arise in unexpec ted situations. A wet
pick-up vacuum cleaner explo ded while it was being
used to clean u p aluminium swarf . It is though t that the
aluminium reacted with the cleaning fluid, which con-
tained hydrochloric acid, to produce hydrogen which
ignited The use of the cleaning fluid was subsequently
proh:>tted on the site and the matter was taken up with
th,: supplier.
Several incidents involved the release of significant
quantities of flammable gases during bulk storage , trans-
port and use. There is a need for adequ ate maintenance
of equipment and for prop er systems to ensure that main-
tenance and modifications are carried o ut safely and
without threatening the integrity of the plant or equip-
ment. The following incidents illustrate the conse-
quences when defects occur.
A leak occurred on a ship that was being loaded with
1100 tonnes o f propylene. The leak occurred when a
valve assembly blew out and left a 20 mm hole. It
took 11 hours to stop the leak, and 7-l 0 tonnes of
propylene wer e lost during this time. Fortunately the
gas did not ignite and there were no injuries.
Approximately 25 kg of ethylene exploded in a
high-pre ssure polyethylene plant. The investigation
showed that there had been a leak through holes at
the base of the reactor that had not been plugged fol-
lowing modification work. Two operators suffered
shock, and there was onsite damage to lightweight
structures and cladding and some breakage of glass
offsite.
In another incident, 14 tonnes of butadiene escape d
through a pressure relief valve on a cryogenic storage
vessel following the failure of a pressure switch
which allow ed excess nitrogen into the vessel. The
gas did not ignite but the incident was exacerbate d
because the control room wa s unmanned and the leak
was undetected for one hour.
4. During maintenance of a storag e sp here, air leaked
into the pneumatic supply line to a valve and caused
the valve to open. It was estimated that 1-2.5 tonnes
of vinyl chloride monom er wer e released. No injuries
were sustained.
Exothermic chemical reactions and
energetic substances
Incidents in this categor y include runaw ay chemical
reactions and unintended chemical interactions and
decomp ositions. They generally involve the release of
dangerou s chemicals but are not necessarily associated
with fires or explosions. The total number of incidents
n = 37) showed a decrease on the previous year’s fig-
ures. How ever, two of these incidents clearly fulfilled
the potential of certain chem ical reactions and decom po-
sitions to have serious consequenc es, in terms of both
human life (five fatalities) and environmental dama ge.
The five fatalities and one major injury all occurr ed
in one major incident at a large chemical company dur-
ing the cleaning out of a still. The still residues wer e
being heated , to aid removal, using a steam coil. The
temperature of the coil was not adequately controlled
and this lead to the violent decomp osition of the still
residues, which consisted of unstable nitro-compoun ds.
The incident was attributed to a change from the original
proce ss and the failure to plan and implement a safe sys-
tem of work. The process change lead to an increase in
the rate of deposition of thermally unstable materials. A
flame, in excess of 55 m long, issued from an access
hatch on the still, burnt throug h a control cabin in its
path, and impinged on an office block. Four people in
the control cabin wer e killed and one in the office block.
As a result o f this incident, compan ies are being advised
to review the design and location of control and other
buildings near chemical plants which process significant
quantities of flammable or toxic substances. The review
should be based on an assessment of the potential for
fire and explosion or toxic releases. The HSE have pub-
lished a report4 on this incident and the repor t high lights
further importan t lessons to prevent similar incidents.
Another major incident in this category occurre d at
a top-tier ‘major hazar d’ site. In this incident, the
decomp osition of a self-reactive substance led to an
intense fire in a storeroo m in the raw materials ware-
house. The fire spread rapidly to the remainder of the
warehouse and outdoor chemical drum storage area and
destroyed about 2500 tonnes of various chemicals.
Although none of the company employees were injured,
33 people , including three residents and 30 emergenc y
services personnel, were taken to hospital, where they
were primarily treated for smok e inhalation. This inci-
dent has been reported as a major accident to the Euro-
pean Comm ission, as required by the ‘Seveso D irective’,
and is the subject of a published HSE reporP. The HSE
report emphasizes the need to include storage areas in
the assessment of safety-related matters.
The need to carry out a risk assessment when
departing from accepted techniques for the synthesis of
chemicals is well illustrated by an incident that resulted
in laceration injuries to a postgra duate researc h student.
The student was synthesizing tertiary-butyl peroxyn itrate
by reacting tertiary-butyl hydro peroxid e with dinitrogen
7/21/2019 Fires, Explosions and Related Incidents at Work 1992 1993