REPORT OF CASE STUDIES IN THE STATE OF TAMIL NADU

 

Case Study on Accidents I Dangerous Occurrence for the year 2002

 

1.            In a fire works manufacturing factory, while one of the worker tried to cut the fuses with a Iron knife, sparks were generated and fell on the waste stored nearby and resulted 1n a fire accident. "Due to this accident, one worker died.

 

Causes:

 

1. Iron knives were used for fuse cutting

2. Wastes were stored in the fuse cutting area.

 

2.            In a coal based power generation factory, the workers were removing the choke In the ash hopper. They opened the hopper gate and found a very huge block in it and hence started hitting the block with a iron rod. Suddently it gave way and the whole slag at a temperature of 250C - 300C stagnating above it started flowing and splashed over the body of the workers. One worker died and one worker received bum injuries.

 

Causes:

 

There was no provision to contain or hold the slag from splashing when the choke was removed

 

3. In a semi-mechanized safety matches manufacturing unit there was a frame filling cum dipping machine in the factory. Dipped splints (Match sticks) were received from this machine in a poly woven sack and weighed. This sack was then transferred to the dipped splints room manually. While a worker was dragging the bag and storing the above sack by the side of the wall in the Dipped Splints Racks (DSR) room he noticed sparks of fire from the sack. This fire spread to the other sacks containing the match sticks and it developed Into a major fire. This in turn within a short while spread to the adjacent box filling hall through the door. Due to this fire accident, 13 workers died and 41 workers received bum injury.

 

Causes:

 

Synthetic bag contained dipped splints was dragged on the floor. Floor friction ignited the match stick.

 

4. In a Match factory. in the Box Filling Section. filling the match sticks in the match box was carried out with the help of box filling machine. Around 20 workers were engaged in box filling section./\> ..,

 

Dipped splints which were kept In the Aluminium tray were filled in the empty match, boxes with the help of filling machine. While doing so, due to friction of match stick heads with the friction composition of the empty match boxes, Fire broke out and spread over the match sticks kept in the Aluminium tray and further the fire spread to the adjacent room where 300 trays of dried match sticks were stored. Due to this fire accident, 4 workers died and 14 workers received burn injured

 

Causes:

 

Due to friction between the head composition and the friction composition of the empty match boxes fire broke out.

 

5. In a textile industry a worker was engaged In the work of transferring the bobbins in a trolley from 2nd floor to 3rd floor. He kept the collapsible gates of both the lift cage and the landing platform open. He was pushing a trolley towards the lift. Meanwhile someone operated the lift to third floor. The worker thinking that the lift ca~ was available went pushing the trolley unwarily. As the lift cage was not available he plummeted into the hollow lift way along with the trolley and grievously hit at the base of the lift pit after traversing a depth of 33 ft resulting in his death.

 

Causes:

 

Interlocking the device that will prevent the lift cage from being operated unless both gates of the lift cage and landing platform re In closed position was not fitted to the lift.

 

6. In a Fertilizer manufacturing factory urea manufactured in prill tower passes through a grizzly (a stainless steel selve) and falls on a conveyor. To facilitate repairing works to be carried out to a grizzly bar, two mental rods were placed above the grizzly bar and this was covered by a tarpaulin sheet right below this arrangement welding of grizzly bar was carried out.

 

When the welding process was being carried out heavy lumps of urea started falling down from the prill tower and fell on the iron plates placed over the grizzly bar. The iron plates along with heavy lumps of urea fell on the workers working right below the covered tarpaulin sheet and they sustained head Injuries and died.

 

Causes :

 

The temporary arrangements made above the grizzly bar to facilitate welding work was not of a strong and rigid construction to withstand falling of heavy lumps of urea from prill tower.

 

7. In a cement factory. the Coal Mill which was a horizontal, rotary unit of 4 m. dial consisted of two chambers divided by a diaphragm the first chamber Is called "Drying Chamber" and the second one was called the "Grinding Chamber". The accident took place in the Drying Chamber of the coal mill. Lumps of coal were carried to the Drying chamber by the hot gas comprising of carbon dioxide, Nitrogen and Oxygen from the pre-heater. Drying takes place as the coal mill rotates. As the maintenance crew wanted to tighten the "felt packing" In the inlet seal ring of the drying chamber, they tried to open the "seal ring" by unscrewing the bolts. While doing so, some three bolts got jammed; hence a contract worker (welder) and a company employee (Helper) were assigned the job of cutting the jammed bolts by means of Oxy-Acetylene gas flame.

 

These two workers entered the inside of coal mill through the manhole opening using a ladder and were then given the oxygen and Acetylene Cylinder hoses. The Cylinders were kept outside the coal mill. At that time, two other contract workers were already inside the coal mill and were working on the Diaphragm side of the chamber.

 

Actually these two contract workers were chiseling out the worn-out ball sticking to the holes in the diaphragm. The welder and the Helper meanwhile started cutting the jammed bolt using Oxy Acetylene Flame and finished cutting the first one. When they started cutting the second bolt, there was a big bang followed by a flash-fire. Flame and smoke came out of the manhole. All the four workers who were working inside the coal mill came rushing out of the coal mill with burnt skin and fire injuries.

 

Inspite of hospitalization and medical treatment, all the four victims died later due to burn injuries.

 

Causes :

 

1. In the drying chamber of the coal mill, there was a residual coal dust formed at the bottom. Due to the shuffling and movement of the workers inside the coal mill, the dormant coal dust got disturbed and started getting dispersed inside. As soon as the Oxy Acetylene torch was lit for cutting the second bolt, the coal dust got exploded followed by a flash of fire. The rapid release of heat from the explosion caused severe burn injuries to the workers.

 

2. There was no "work permit system" followed in the factory .

 

 

Case Study on Accidents/Dangerous Occurrence for the year 2003

 

 

1.            In a textile industry, in the warping section, a worker tried to check the warp tension with his hand. His hand had got caught in- between the warp yarns on the beam which was rotating at a speed of about 1000 rpm. Because of the high speed rotation of the beam he was pulled in and his body was caught in between the warp yarns resulting in death of the worker.

 

Causes:

 

1.                  Pull cord, to the warping machine with limit switch arrangement was not provided.

2.                  Electronic sensor was not provided to the warping machine to sense and switch off the machine if anybody enters into the beaming zone of the warping machine.

 

2. In a match work factory, manual mixing of chemicals like potassium chlorate, sulphur, red manganese/black manganese. glass powder. potassium bi-chromate, rosin, Ammonia solution with water has been done In a bucket made of iron.

 

While mixing the chemicals with a wooden stick due to friction developed from the iron bucket a spark emanated from the bucket and caught fire. Suddenly the worker kicked the bucket thereby the fire got spread to the sticks of the chemical dipped match sticks, which were stacked in Gunny bags. Due to this fire, huge smoke developed and four woman workers rushed into the toilet and locked themselves up inside. Due to this accident 7 workers died and 9 workers were injured.

 

Causes:

 

Mixing was done in a container made of iron.

 

3. In a foundry, worker was operating the die casting machine along with a apprentice. The apprentice in an attempt to remove the component which has fallen down in between the dies earlier, bent down and inserted his head between the dies and the operator did not notice this and operated the die casting machine. The dies closed and the head of worker got crushed in between the dies and the worked died.

 

Causes:

 

Doors covering the 2 dies (fixed and movable) with an interlock arrangement which will prevent the machine from being operated when the doors are open was not provided.

 

4.            A chemical factory. has erected three MS cylinderical storage vessels with a capacity of 24 KI. - 2 nos. and 30 KI. - 1 no. At the time of incident, a tanker lorry with 24 KI. petroleum product was brought to the premises for the purpose of unloading into the installed storage tanks.

 

The workers tried to unload the petroleum product into the left extreme vessel of the 3 vessels (30 KI. capacity) by using the rubber hose, one end of the rubber hose was connected to the out-let valve of the lorry and the other end of the rubber hose was connected to the 30 KI. horizontal tank valve.

 

While transferring the material, there was some leakage at the point of outlet valve connected to the rubber hose. In order to control the leakage, the workers decided to move the lorry to correct position. The driver started the tanker lorry and immediately there was a sudden fire noticed at the out let valve leakage area. The workers tried to put out the fire but they could not do so. Fire spread out to the other area and consequently the storage vessel got suddenly burst out and thrown out from its foundation.

 

Because of this explosion, the petroleum material became a fire ball, causing minor burn injury to about 23 on-Iookers and nearby factory workers.

 

Causes :

 

1.                  The petroleum product which is very highly flammable in nature was unloaded from the road tanker to the M.S. tanks without providing proper bonding to the road tanker and the storage tank; also earthing to avoid the risk of static electricity was not done.

 

2.                  While the petroleum product was leaking through the rubber hose, the driver started the tanker lorry. The small sparks released from the exhaust pipe, ignited the petroleum product vapour, resulting in fire and tank explosion.

 

5. In a Cement factory, lubrication oil pipeline of vertical Roller Mill II of Raw Meal Section was rinsed with kerosene using centrifugal circulating pump, to remove the sludge. The total length of the pipeline was 70 metres. The inlet of the pipeline was located near the control panel; the kerosene so pumped into the VRM-II pipeline was collected in a carboy.

 

At about 10.45 am, the pump was stopped. In order to remove the residual kerosene from the pipeline, the Assistant Foreman used a Nitrogen gas cylinder at one end of the pipeline; he asked a khalasi to connect a hose to the other end of the pipeline and hold the hose to a 200 litres barrel. By opening the Nitrogen gas cylinder and due to the Nitrogen Gas pressure, about 20 litres of residual kerosene was flushed from the pipeline and collected in the barrel. As the Nitrogen gas in the cylinder was exhausted, the Assistant Foreman brought an Oxygen Cylinder from the nearby area and by using a regulator he connected the oxygen cylinder to the inlet of the pipeline. At the other end, the khalasi was asked to insert the hose from the pipeline outlet into the 2 inch opening of the 200 litres barrel and hold it. At about 11.15 a.m., the Assistant Foreman, using the Regulator, reduced the Oxygen pressure to 4 kgf/sq.cm. (g) and let in the Oxygen gas into the Lube oil pipeline with the intention of flushing out the entire residual kerosene from the pipeline. In a few seconds, the barrel got exploded causing fire burn injuries to the khalasi who was holding the delivery end hose to the 200 litres barrel as well as to a Fitter/Welder and two contract workmen who were working closeby.

 

Causes :

 

1.                  Instead of using steam or an inert gas, like Nitrogen, the Assistant Foreman used Oxygen gas for flushing out the Kerosene from the pipeline. As kerosene is a flammable liquid, using the Oxygen gas for flushing out the kerosene will certainly cause explosion.

 

2.                  The khalasi was holding the delivery end hose into the 2 inch opening of the barrel which was already having about 20 litres of kerosene.

 

Insufficient vent in the barrel had caused pressure build-up, resulting in explosion. (In fact, the 2 Inch vent opening of the kerosene barrel was completely covered with the hose).

 

 

Case Study On Accidents/Dangerous Occurrence For The Year 2004

 

1. In a chemical factory yellow phosphorous was converted into red phosphorous in a rotary furnace. When the yellow phosphorous was cooked in the rotary furnace for its conversion to red phosphorous at 244oc, water which was surrounding the yellow phosphorous, became steam. When steam was vented, it carried away certain amount of phosphorous and this caused the vent line choke. This ultimately Increased the temperature and pressure of the vessel. Temperature shot up to 300oC and pressure was not being monitored. Suddenly the furnace exploded and the stored up hot gases caused flash fire injury on the worker and subsequently he died.

 

Causes :

 

1.                  The outlet for the generated steam and system pressure was chocked by the phosphorous and there was a pressure and there was a pressure temperature built up in the vessel

2.                  Pressure was not monitored by the pressure gauge installed in the furnace

3.                  No safety valve with the proper scrubber arrangement was not installed in the furnace.

 

2. In a cashewnut processing factory, 23 workers were working in a shed which formed a part of the factory. The size of the shed was 20' x 60'. The truss of the tiled roof in the shed was made up of logs of coconut tree. The height of the wall of the shed was 4 & above the wall 1.5' x 1.5' pillars made up of bricks were constructed without cement plastering.

 

Due to continuous rainfall & gusty wind the brick wall lost its stability and the pillars supporting the roof collapsed. The entire structure fell on the workers who were working and 3 workers died and 11 workers were injured.

 

Causes :

 

1.            The truss of the roof was constructed with logs of coconut tree.

2.            Pillars were constructed with poor cement bonding and also without cement plastering.

3.            In a Chlor-Alkali Plant, there were two Cell Houses, (viz.) Cell House-! & Cell House-II. Cell House-I was being operated on Tamil Nadu Electricity Board Power Supply and Cell House II on Captive Power.

 

On 18-07-2004 at 06.02 P,M.. the Captive Power Plant feeding electrical supply to Cell House - II got tripped due to a flashover (earth fault). This resulted in the tripping of load in Cell House - II and a few motor drives in other sections. But the Cell House-! continued to function, producing Chlorine as it was being operated on TNEB Power. There was a Chlorine Scrubber system which was a packed column and whose function was to absorb the chlorine gas by means of the circulating lime slurry, in the event of any operational upsets in the process and chlorine free air was vented to the atmosphere. There is a chlorine gas compressor in the chlorine liquefaction section, the compressor sucks the chlorine which is evolved in the cell during electrolysis and compresses it for chlorine liquefaction.

 

Since both the Chlorine scrubber blower and the Chlorine Compressor also got tripped along wlth the Cell House - II, the Chlorine gas which evolved from the Cells of Cell House II came out freely and drifted along with the wind toward the adjoining villages, namely Mettur and Katturvalavu and caused suffocation to about 24 villagers. They were admitted in the Mettur Government Hospital and were treated for chlorine inhalation. No casualty.

 

Cause :

 

1.            Emergency power supply was not provided to the Chlorine absorption system to meet out any problem of power interruption during emergency of chlorine leak

2.            Cell House I and Cell house - II were not provided with interlock arrangements in such a manner that if one cell house trips due to operational problem, the other cell house also gets tripped instantaneously.

 

4. In a textile mill there was a dangerous occurrence caused due to the collapse of partition wall separating the third & the fourth compartments of the Cotton Mixing area. The said wall was 17' long 11' high and ' thick. It was just constructed above the floor without any foundation. Huge quantity of cotton were stored in the fourth compartment whereas the third compartment was empty. The partition wall separating the 2 compartments suddenly collapsed clue to the stress developed by huge quantity "of cotton stored In the 4th compartment & fell on the workers in the 3rd compartment. Due to this 1 worker died and 3 were injured.

 

Cause :

 

Partition wall was constructed without proper foundation

 

 

5. In a textile mill large quantities of cotton dust were deposited on the roof and over surface of the tube lights provided for illumination.

 

Due to voltage fluctuation, spark was generated from the choke of one of the tube lights and cotton dust deposited over the tube light caught fire and fell on the sliver cans containing silver. As a result of this fire spread to the other machines in that hall and caused damage to the machinery and no worker affected.

 

Cause :

 

Flame proof electrical fittings were not provided

 

6. In a fire works factory, lighting arresters were provided only In crackers store room and not provided in any of the manufacturing sheds. Lightning struck one of the manufacturing sheds and the rockets, and other crackers stored in the sheds got exploded. As a result of this 7 sheds were totally damaged and 3 sheds were partially damaged. No worker was affected in this accident

 

Cause :

Lighting arrestors were not provided In the manufacturing shed.

 

 

Case Study On Accidents/Dangerous Occurrence For The Year 2005

 

1. In a factory, Steel Ingots are manufactured from iron scrap through induction furnace. Due to the cracks in the ramming mass, lining the furnace, the hot metal in the furnace penetrated through the cracks and punctured the S.S.. coil and a hole of about 5 mm. diameter developed in the SS ring due to this puncture. Hence, water from the above S.S. coil leaked into the furnace which on contact with the hot molten metal at 1550C, inside the furnace resulted in formation of steam below the furnace top. Due to high pressure developed in the furnace, the hot molten metal from the top opening of the furnace splashed on the workers, working on the platform as well as the side of the platform. Out of 15 injured workers 4 of them died.

 

Causes :

 

1.            The ramming mass lining was not packed properly without any cracks.

2.            The work of segregation of the iron was carried on the furnace platform

3.            Splash arrestors are not provided all around and above the top opening of the induction furnace.

 

2. In a factory, where 10 MT weak sulphuric acid was stored, suddenly the suction line valve tank nozzle assembly got broken and through this opening sulphuric acid drained out from the tank and this resulted in vacuum formation in the tank. This FRP tank hit against the supporting channel legs due to the formation of vacuum

 

Causes :

 

1.            The FRP tank was not maintained with a adequate strength and stability

2.            The FRP tank was not tested and certified by the Competent person every year

 

3. In a fire works factory during the process of manufacturing flower pots, in order to load the Aluminium power mixture into the paper cone, the paper cones were placed over a wooden tray and after loading they were beaten with a wooden stick. The wooden tray used for this purpose had iron nails in the joints and small quantity of aluminium powder had already spilled over the tray. Due to friction between the iron nails and chemical mixture, spark emanated and the chemical mixture kept nearby caught fire and resulted n explosion. Due to this explosion 2 workers died.

 

Cause :

 

Due to friction between the iron nails and chemical mixture, spark emanated and the chemical mixture kept nearby caught fire and resulted in explosion.

 

4. In an ingots manufacturing factory, a contractor was assigned the job of cutting one old metal gas cylinder. While doing so, a small hole was cut by means of gas cutting operation. Without informing the pungent smell of some gas. he left the factory. Through the hole, the chlorine gas emanated from the liquefied chlorine, escaped and vapourised with air and this affected the residents of the village.

 

Cause :

 

Gas detector to indicate the leakage of gas was not provided

 

5. In a fire works manufacturing factory, rockets which was manufactured using aluminium power, potassium nitrate, sulphur & charcoal were not properly dried on the drying platform. In the wet stage, the rockets were kept in the working shed. Due to moisture content, aluminium powder had undergone exothermic reaction and with the evolution of heat, the rockets got exploded. As a result of this explosion 10 workers died and 3 working sheds completely collapsed.

Cause :

Lighting arrestors were not provided In the manufacturing shed.

 

1.                   Rockets, which were not properly dried had undergone exothermic reaction due to moisture content and with the evolution of heat, got exploded.

2.                   Mixing and manufacturing sheds were not provided with rubber mats on the floor

 

 

6. In a factory, extraction of oil from rice bran was being carried on using hexane as a solvent. On a day of accident, repair works to the gadder frames of the extractor meant for transferring the rice bran was being carried on. A 40W electrical hand bulb was used for providing lighting. When the worker was holding the electrical hand bulb near the view glass opening, the hand bulb hit against the view glass opening. Spark emanated due to this, ignited the hexane vapour which was present in the extractor, a big fire consequently.

 

Causes :

 

1.            Oil extractor was not purged with inert gas - nitrogen before being taken up for maintenance activity.

 

2.            Electrical bulb and its electrical wirings are not of flameproof construction.

 

7. In a fire works industry, the unfinished and incompleted tubes containing the chemical mixtures of sulphur, aluminium powder, barium nitrate, strontium nitrate, charcoal, dextrin & salt petre were kept in the wooden box in the transit shed. Due to decomposition of the chemical mixture the tubes exploded.

 

Causes :

 

1. Chemical mixture used for the manufacture of fire works were kept in the decomposition stage in the transit shed.

 

8. In a fertilizer factory, as the granulator discharge chute got chocked the plant was stopped and the workers cleaned the choked discharge chute by means of poking. After cleaning, the plant was, started without feeding the raw materials namely phosphoric acid, sulphuric acid and ammonia; the granulator was put on dry run. Meanwhile, the heavy lump which caused the block in exhaust ducting fell down and consequently the unreacted ammonia, came out from the discharge end in the form of heavy puffing and injured 5 contract workers. They were given medical treatment in Government hospital and were discharged later

 

Causes :

 

1. Un-reacted ammonia in the granulator came out from the discharge end in the form of heavy puffing and injured the workers

 

9. In a textile industry, when a cotton lap was being processed in a carding machine, iron particles which were present in the lap created sparks and this ignited the cotton waste materials in carding cellar, blow room cellar and blow room MBO machine, resulting in big fire.

 

Causes :

 

1. Iron particles present in the cotton lap created spark, when it was processed in the carding machine

 

10. In a pharmaceuticals manufacturing industry, after the bulk drug is produced the solvents are recovered by distillation in solvent recovery plant. In this instance, a flash distillation still, T-302 was used for the recovery of solvent, Dimethly Sulfoxide (DMSO) in the Solvent Recovery Plant. A batch quantity of 5 KI. of 75% concentration DMSO was charged into the still T-302 in which 700 mm. of Hg vacuum using a piston vacuum pump and a temperature of 136~ were maintained. When this batch was going on and 2.5 KI. of DMSO was inside T-302, there was a hissing sound and immediately after the hissing sound was heard by the worker the still T-302 got exploded with a fire ball, killing a chemist and another chemical engineer. The control room which was located very close to the Solvent Recovery Plant was heavily damaged in the explosion. There were so many joints, flanges a gaskets in the pipe line along the DMSO vapour route on the vacuum pump side. Hence failure of such parts might have led to leakage of air in the circuit and could have caused air DM50 explosive mixture.

 

Causes :

 

1.           DMS0 is a flammable liquid. It has a flash point of 80C and flammable range from 2.6% (voIume) LFL to 63% (volume) UFL. Hence when the still, T-302 is at 136C, vacuum is absolutely necessary to rule out air entry and to prevent fire. Before the explosion, a hissing sound was heard by a witness; this indicates that vacuum still, T-302 could have failed due to development of hole (s) through which air entered and formed an explosion.

 

2.           As air ingressed the still T-302, static charges could have been generated due to mixing with the DMSO. The static charges generated could have ignited the explosive mixture, leading to explosion and fire ball

 

11. In a factory, the waste wood material was accumulated on the floor below the expansion tank and was not removed atleast once in a day. The temperature of the thermic fluid inside the expansion tank could have been higher than the designed value. Due to high temperature there could be rise In pressure, which could have caused the spillage. The flash point of thermic fluid was 220 degree celsius. The required temperature at the hot press area was around 210 degree celsius. The thermic fluid was not tested for suitability by a competent person once in every three months period. Variation in specifications (acidity, flash point, suspended matter, viscosity and ash content) of the thermic fluid could have necessitated overheating and the flash point of the fluid could have been reached. At flash point the thermic fluid spilled and ignited the waste wood materials and caused this fire accident.

 

Causes :

 

1.            Variation in specification (acidity, flash point, suspended matter, viscosity and ash content) of the thermic fluid, could have necessitated overheating and the flash point of the fluid could have been reached. At flash point the thermic fluid spilled and ignited the waste wood materials and caused this fire accident.

 

12. In a fine chemicals manufacturing industry, chemicals like 2 amino Di-bromo-benzly alcohol, manganese dioxide and toluene were loaded into the 4 KI. stainless steel reactor (SSR5) and heated upto 65-70 degree centigrade and agitated in the above process. The resultant product layer was settled and filtered in SS nutsche filter by transferring through a HDPE hose. The remaining layer containing toluene was unloaded in a 200 litre HDPE barrel which was not provided with proper earthing or bonding to dissipate the static electric charges and hence fire broke out and spread to the nearby nutsche filter and SSR 6 reactor.

 

Causes :

 

1. HDPE barrel which was not provided with proper earthing or bonding to dissipate the static electric charges and hence fire broke out.