March 27, 2011

The importance of correct measurement in Process Safety

In February 2008, a stealth bomber of the US airforce crashed soon after take off. The pilots ejected safely but the loss was USD 1.4 billion. Wikepedia mentions the following about the cause for the crash...
"The findings of the investigation stated that the B-2 crashed after "heavy, lashing rains" caused water to enter skin-flush air-data sensors, which feed data to the computerized flight-control system. The water distorted preflight readings in three of the plane's 24 sensors, causing the flight-control system to send an erroneous correction to the B-2 on takeoff. The B-2 quickly stalled, became unrecoverable, and crashed. The sensors in question measure numerous environmental factors, including air pressure and density, for data to calculate airspeed, altitude and attitude. Because of the faulty readings, the flight computers determined inaccurate airspeed readings and incorrectly indicated a downward angle for the aircraft, which contributed to an early rotation and an un-commanded 30-degree pitch up and left yaw, resulting in the stall"
Whatever advanced process control systems you may have, it ultimately depends on the measurement reading that the system receives. Focus on the integrity of your primary measuring devices.
Read the article about the crash in this link.

March 26, 2011

Bayer stops MIC production

A news article mentions the following:
"In a surprise move in U.S. District Court in Charleston, attorneys for Bayer CropScience announced they were dropping plans to resume production of the chemical, commonly called MIC, and would begin dismantling the unit.
That ends the key part of the latest lawsuit in a nearly three-decade battle.But Bayer's decision erases a threat that loomed over the people of Institute for a generation.
The company will no doubt replace MIC, which is used to make a pesticide, with some other chemical, but nothing could be as bad, said Oden, a retired biology professor at West Virginia State University who still lives next to the plant."Chemicals don't have to kill," she said.
"There were so many questions that weren't answered," she said. "And I know there' no such thing as foolproof, because look at the situation in Japan. There's no safe, foolproof ways for doing most of what we do."
A 2008 accident that killed two workers and sent projectiles dangerously close to an aboveground MIC storage tank brought new scrutiny from Congress and the U.S. Chemical Safety Board.
The explosion also showed larger, more affluent communities in the Kanawha Valley that they too could be in danger — towns that the folks in Institute can't help but notice are whiter. In all, some 300,000 people live in the 25-mile MIC "vulnerability zone," which includes the state capital.
MIC is a colorless chemical used to make pesticides, polyurethane foam and plastics. It attacks the respiratory system, and at low levels, can irritate the eyes and throat. High concentrations can cause serious lung damage, hemorrhaging and death.
Several companies manufacture it, but the Institute plant is the only one in the nation that still stores it in large quantities.
Bayer has said it spent $36 million to improve safety and upgrade equipment, and that it slashed its MIC stockpile by 80 percent and eliminated all aboveground storage. How long it will take to exhaust the remaining supply and rid Institute of MIC entirely was not immediately clear.
Less than two years after Bhopal, Congress passed the federal Right-to-Know Act, to help the thousands of people around the country who live in the shadow of industry know what chemicals are made and stored in their neighborhoods. But that openness began to diminish after the terrorist attacks of 2001. Chemical plants became viewed as potential targets. Reports on the toxic inventory of industries were no longer as readily available to the public.

Read the full article in this link

March 25, 2011

"A Fail safe fails"

A news item in the The Wall street Journal reports the following:
"BP PLC came within 1.4 inches or less of preventing the worst offshore oil spill in U.S. history, say engineers studying the safety device that failed in last year's Gulf of Mexico disaster.
The device, known as a blowout preventer, was a massive set of valves that sat on the sea floor nearly a mile beneath the Deepwater Horizon drilling rig, which floated on the surface. It was equipped with powerful shears designed to cut through pipe and seal off the well in an emergency. Why the device failed has been one of the central mysteries of last year's disaster.
In a report released Wednesday, engineers hired by U.S. investigators say they have solved it: The force of the blowout bent the drill pipe, knocking it off-center and jamming the shears. Rather than seal the well, the blades got stuck 1.4 inches or less apart, leaving plenty of space for 4.9 million barrels of oil to leak out.
The investigators concluded the blowout preventer failed as a result of a design flaw, not because of misuse by BP or any of the other companies involved, and not because of poor maintenance. The fail-safe device, the last line of defense against a disaster, wasn't designed to handle a real-world blowout, according to investigators, who called for further study of the devices.
The report doesn't address what caused the blowout itself. That has been the subject of several other major inquiries, which all have found that a series of decisions by BP and its contractors set the disaster in motion.
Even if the device had worked, it wouldn't have saved the lives of the 11 rig workers killed in the accident. That's because no one even tried to activate the shears until after massive explosions killed the men and crippled the rig. But the device could have mostly prevented the oil spill that began when the Deepwater Horizon sank two days after the initial explosion".
How sure are you that your fail safe devices will work as intended? Today there are systems available to conduct a online partial stroke test of critical valves. But the test is done during normal operating conditions. In the case of a major upset or incident, conditions may prevent the fail safe devices from working. 
Read the article in this link.

March 23, 2011

Explosion in carbide plant

The CSB is planning to investigate an explosion in a carbide plant in the US, that occurred on Tuesday. Two employees were killed in the incident. A news report mentions that
"Located along the Ohio River in West Louisville, the plant is part of a petrochemical complex dubbed Rubbertown. It makes calcium carbide products, which are used in metal fabrication and construction.
The initial explosion occurred around 5:40 p.m. Monday and involved calcium-carbide — a flammable compound that combined with water produces unstable acetylene gas, Hamilton said. The second explosion happened when one of three transformers that contained mineral oil above the original blast caught fire, officials said."
The workers who died were longtime employees who worked in the furnace department where the explosion occurred, said plant general manager John Gant. Jorge Medina, 56, of Louisville, died at University Hospital early Tuesday morning with third-degree burns over 90 percent of his body. An autopsy is planned for Steven Nicholas, 59, of Charlestown, Ind., who died Monday".
Read the article in this link.

See video and pictures of the accident in this link

March 22, 2011

Fire in lift kills two persons

Thanks to Mr Sreedharan for sending information about a fire accident in a plant when two workers died in a fire in a lift when they were carrying combustible material. According to the news item, "the workers were carrying improperly packed medicine ‘CBS' which released a vapour which is combustible in nature. The vapour released was in large quantity leading to fire in the lift burning them alive. By the time the other workers in the factory arrived and tried to out the fire, both the casual workers were burnt alive". 
Read the article in this link
I had earlier posted an incident where a lab technician in a plant (the Lab was located in the control room building) was taking a bottle of solvent and using the lift (elevator) when he accidentally dropped the bottle. The solvent went down the elevators floor and collected in the well. A spark ignited the solvent and the person had to be rescued from the elevator.

How do we make PSM work in India?

PSM is an administrative control over process safety. The elements may vary from 14 to 30 and above but finally it is an administrative control. Human beings take decisions that can have an effect on PSM. For example, the CSB has released the safety video of the Bayer Crop science explosion where it mentions an interlock was bypassed by operators with the knowledge of the manager. Whatever systems you have, there will be a time, when under pressure for production, mistakes can happen and the administrative control fails. Behaviour based safety, developing process safety culture, operational discipline all are dependent on the Human Being. Especially the ones at the top…
Why do the same mistakes keep happening over and over again? It’s because of a basic human trait ….. if   nothing has happened for so many years, one does not expect to see anything bad in the future, too.
What you do not see may cost you terribly!! Whose job is it to see that the human being at the operational level does not deviate from set procedures? It’s the job of the top management. But it’s a chicken and egg situation. Today’s top management in Chemical Plants are under severe pressure themselves and often loose sight of what is going on at the ground level. Whenever a new system that brings in top management involvement is implemented, I often see, that initially, everything is working all right and top management are focused on process safety. As time gets by, and people (including top management) and priorities change, the effectiveness of PSM changes, too. I feel that the only way to make PSM work is through effective legal enforcement. In this connection, I am happy to see in the CSB video that the Costa County officials have been able to bring down incidents by effective auditing of PSM systems.
I do not see this happening in India where PSM is not even Mandatory! Let’s not wait for another Bhopal to occur. Do write in your comments.

March 21, 2011

Cost - Benefit trade off and risk

An editorial in Las Vegas Review Journal highlights the need for facility siting, inherent safer design and cost benefit trade off Vs Risk. The article mentions the following:
"It's not too early to start asking the billion-dollar questions: Is it possible to build nuclear reactors that can be relied on to safely shut themselves down, using passive cooling systems dependent on gravity rather than electric pumps, during an earthquake of such magnitude? Of the 442 nuclear reactors in operation around the world today, the World Nuclear Association estimates 20 percent are located in areas of "significant seismic activity." Siting will be re-examined. Better designs do appear possible.
One hundred percent passive cooling systems are not yet commercially available. But had even a partial passive system been in place at the Fukushima Dai-ichi plant, Japan's current nuclear crisis could have been averted, argues John McGaha, a board member of the American Nuclear Society.
"The thing that got Japan in trouble was not the earthquake, but the tsunami that took out power supplies," Mr. McGaha says. "Passive reactors would have been part of the answer to what happened."
In General Electric's design for the Fukushima reactors, the cooling tanks for storage of spent fuel rods sit atop the containment buildings. Some of these tanks appear to have gone dry, leaving the spent rods to spew radiation. If the tanks sat at or below ground level, they could be refilled by simply opening a spigot from backup water tanks, or through gravity-fed pipelines.
Meantime, the backup diesel generators that might have averted the disaster were positioned in a basement, where they were overwhelmed by the tsunami. In the end, cost-benefit trade-offs will still be made. But a valid cost-benefit analysis requires data as to what the true "costs" are when systems fail."
Read the editorial in this link..

March 20, 2011

Description of some damages to the Nigata Nuclear plant in 2007 - Courtesy TEPCO

The earthquake at Nigata, Japan in 2007 was 6.9 on the Richter scale. The one that hit Fukushima was 8.9.(The Richter scale is Logarithmic!!!) See the damages caused by the Nigata earthquake...

"Displacement of the ducts connected to the main exhaust stack (units 1 to 5)'. Courtesy of The Tokyo Electric Power Company, Inc

Courtesy of The Tokyo Electric Power Company, Inc
"Leakage of water containing a trace of radioactivity into the sea via the non-controlled area of unit 6.
The seismic motion caused the overflow of water from the spent fuel pools in units 1 to 7. At unit 6, the overflowed water leaked into the non-controlled area via the electric cable conduit of the refueling machine and flowed into the sump. It was confirmed that water in the drainage sump had been discharged into the sea by the sump pump when the water level increased. (Refer to the figure below".)

Courtesy of The Tokyo Electric Power Company, Inc

Courtesy of The Tokyo Electric Power Company, Inc
Iodine and radioactive particulate materials were detected at the main exhaust stack of unit 7.
"When the earthquake occurred, unit 7 was automatically shut down. However, it was confirmed that since the gland steam ventilator continued to operate for a while, the steam sealing the shaft was exhausted, and subsequently radioactive steam left in the turbine had flowed out to through the gland steam ventilator. (This event was reported on July 16th.)
During normal operation, the turbine shaft is covered with the gland steam (containing no radioactive material) so that the steam containing radioactive materials sent from the reactor to the turbine does not flow out from the turbine through the gland steam ventilator.
Impact to the Environment
The radioactivity of radioactive iodine and radioactive particulate materials released to the environment through the main exhaust stack was about 4 × 108 becquerels and 2 × 106 becquerels, respectively. The dose by this radioactivity was 2 × 10-7 millisieverts, an equivalent to about one 10 millionth of the dose (2.4 millisieverts) an average person is exposed to from natural sources annually.
No radioactive material has been detected since the gland steam ventilator was stopped on July 19th".
For more details visit the TEPCO site in this link

March 19, 2011

Process Safety and Proposed changes to Indian Factories act

A news article in the Business Standard mentions the proposed changes to the Indian Factories Act. There are two proposed modifications, which I think may have an effect on process safety:
"The proposed changes to Section 64 and 65 of the Act, which deal with overtime working hours in factories, says the hours will be increased to 100 from the existing 50.
The proposals also seek to shift the blame for industrial accidents from the proprietor to the manager of a factory provided it is government-owned, by changing the definition of “occupier” of the factory in Section 2 (n) from the “person who has ultimate control over affairs of a factory” to the “person appointed to manage the factory”.
Workers who are working more hours of overtime are prone to making mistakes. There is a growing shortage of experienced qualified chemical plant operators in India and the proposed increase in overtime hours may affect process safety. The second proposed change of transferring accountability for Government owned companies to the person appointed to manage the factory may lead to a situation where the unit head in a government owned factory may resign when he or she finds things are not going his/her way with regard to process safety. This will lead to a discontinuity in managing process safety.
Read the article in this link.

March 16, 2011

Changes to my blog

Based on feedback from readers, I have added categories in my blog where u can browse the following postings:

Incidents (99)
Safe work practices (28)
BP Oil Rig Disaster (19)
Incident Investigation (19)
Organisational Culture (19)
Bhopal (17)
Emergency planning and response (15)
Mechanical integrity (15)
PSM (13)
Process design (10)
Human factors (9)
Audits (7)
Fire and explosion (7)
Runaway reactions (7)
Process safety and security (6)
Instrumentation (5)
Siting (5)
Transportation accidents (5)
LOPA (4)
Process Safety and Aviation (4)
Risk management (4)
Training (3)
Behaviour based safety (2)
Indian Regulatory (2)
Managing change (2)
Shutdown systems (2)
Vacuum hazards (2)
Alarm management (1)
Backup systems (1)
CSB Safety videos (1)
MSDS (1)

Where there is a human, there will be an error!

A report in the Hindustan Times about the investigation of a fire in Air India flight on September 4,2009 points out the following:
"A probe by the aviation regulator has found several safety lapses by Air India staff while evacuating 213 passengers from a Mumbai-Riyadh flight after a fire broke out in the aircraft on September 4, 2009. The Directorate General of Civil Aviation (DGCA) concluded that the AI's aircraft maintenance engineer failed to notice a fuel leak from the left side of aircraft before clearing it for take-off. "The engineer had left the bay without giving the final take-off clearance because it was raining," the report said.
Second, the airline ground staff were unable to report the fire to the pilots because the cockpit crew had switched off the radio communication equipment, violating the airline's operation manual. Worse, both the pilots left the aircraft before the evacuation process was complete and not a single cabin crew member was deployed at the end of the inflated emergency slides to assist passengers.
The report also blamed the airline engineers for failing to check the aircraft's fuel channel during routine inspection. "Constant wear and tear caused massive fuel leakage and fire," said the report.
An airport follow-me vehicle informed the air traffic controller on duty about the fuel leak but he wasted significant time in alerting the pilots, the report stated. "As per rules, the controller should have called the aircraft crew by its registration number but it kept calling the flight number," read the report.
The cockpit crew switched off the aircraft engine but was late to start the evacuation process. The cabin crew also overlooked hand signals about the fire from the ground staff."

It always takes a series of human errors to trigger an incident. In the chemical industry also, a similar situation exists. Pressure on production, lack of rest, overloading of equipment, communication gaps and top management disconnects are often common cause reasons for incidents.

Read the news report in this link.

March 15, 2011

Chemical Reactor Safety

The UK Health and Safety Executive has a write up on test methods for exothermicity for chemical reactors. Quoting from the article,
“The main types of test are:
1) basic screening tests;
2) isothermal calorimetry, aimed at quantifying reaction kinetics, heats of reaction, etc for particular reaction systems;
3) adiabatic calorimetry, used mainly for examining the runaway potential of reactions and individual compounds; and
4) combination instruments intended not only to give thermal data but also to calculate appropriate reactor vent sizes.
These tests tend not to give absolute results, in that the experimental conditions may affect the data obtained. Factors such as sample size, container material, heating rate, thermal inertia and endothermic effects (eg evaporation, gas evolution and phase changes) can all affect the result. The work, therefore, needs to be carried out by persons who are adequately trained and experienced in this type of investigation, to ensure that in each case suitable techniques are employed and adequate account is taken of experimental variables”.

Read the write up in this link.

Nuclear and process safety - Part 2

For those of who saw the videos of the explosion in the nuclear reactor in Japan, you must have observed the blast wave destroying the wall panels but the metal structure stayed intact. I believe the design worked as intended. But the news that sea water is being used for cooling indicates the seriousness of the situation. In a chemical plant emergency, we do not have to deal with radiation leaks but imagine the plight of the emergency responders in the Japan nuclear plant. They must wear protective clothing for the radiation and tackle the emergency also. For those of you who want to know a little more about the nuclear reactor incident, see this link
Another good article is in this link.
Read an explanation about the second reactor explosion in this link.

March 12, 2011

Earthquakes and nuclear /process safety

Our prayers are with the victims of the Japan earthquake. A BBC news article mentions the following:

"Japan's prime minister has declared a "nuclear emergency" after a number of reactors shut down in the wake of a massive earthquake hitting the country.Eleven reactors at four nuclear power stations automatically shut down, but officials said one reactor's cooling system failed to operate correctly.
Under Japanese law, an emergency must be declared if a cooling system fails.
In total, the country has 55 reactors providing about one-third of the nation's electricity.
In a statement, the Japan Atomic Industrial Forum released a statement that said Prime Minister Naoto Kan had declared the emergency "in case prompt action" had to be taken, but added that "no release of radioactive material" had been detected.
"Since emergency diesel generators at the Fukushima-1 and -2 NPPs are out of order, (energy company) TEPCO sent the emergency report to Nisa. There is no report that radiation was detected out of the site."
The reactor at the Fukushima Daiichi power station that triggered the emergency alert was the 40-year-old Reactor 1, one of six on the site.Reactors 1, 2 and 3 automatically shut down when the Magnitude 8.9 quake shook the plant, while reactors 4, 5 and 6 were not in operation as they were undergoing scheduled inspections.
It is understood that the earthquake cut electricity supplies to the power station, and the back-up generators did not come into operation when the outage occurred. As a result, not all of the cooling systems were available".
Obviously something happened to the back up generators and they could not come in line. We have to wait for the investigation report to come out.
Read the BBC article in this link.
Read an article about the seismic zoning in India in this link.

March 11, 2011

Making Process Safety Management Work

I am quoting excerpts from a recent speech by Mr Bob Dudley (Group CEO, BP) that is on the BP website
“We have created a powerful, central safety and operational risk organization headed by Mark Bly, who led our internal investigation of the accident. Mark reports directly to me and sits on our executive team.
His organization has the resources and the mandate to drive safe, reliable, and compliant operations, including intervention rights, in BP’s exploration and production operations anywhere in the world.
The new organization is now in action across BP in four main areas:
First, it is strengthening and clarifying requirements for safe, compliant and reliable operations.
Second, it is deploying around 500 specialist personnel within our businesses to guide, advise, and if necessary, intervene.
Third, it is providing deep technical expertise to our operating businesses.
And fourth, it is intervening where needed to stop operations and bring about corrective actions.
We are already seeing results.
For example, we have shut in one production platform to repair the fire water pumps. Another platform was shut down after the discovery of incorrect specifications for some fasteners. And a producing field was shut down to enable pipeline integrity work to be carried out. Further, we have decided we will not take rigs that do not conform to our standards and there are a number of cases where we have either turned away rigs or are negotiating for modifications which could bring the rig up to our standards.
We are conducting a major review of our risk management systems to ensure we have consistent standards that are applied in a disciplined way across BP.
And in support of all of this, we are linking our performance management and reward system directly to safety and risk management - as well as to key behaviours – teamwork, capability-building, listening and compliance with standards.
We will focus on the critical inputs that drive delivery, namely safety, capability, technology and relationships, rather than focussing primarily on outputs such as production barrels. If we get these right, then the outputs, including dollars, will follow. So we are emphasizing quality over quantity and value over volume.
We also learned a lot about what crisis management means in a world of 24 hour communications with massive social media coverage as well as conventional press and cable broadcasting. I saw how much pressure there is on everyone to take up polarized positions and over-simplify the issues”. 

The above points mentioned by the CEO has tremendous significance on Process Safety. I am postulating some simple rules if you want process safety to work:
1. You must be prepared to walk the talk if you want process safety to succeed.
2. Technical expertise is the key to maintaining process safety. Just having standards and a system is not enough. You must have technically competent people who understand the implications of the standards.
3. The board of directors must have direct access to technically competent people who can translate risks and their implications to them. 

4.Your organizational framework must institutionalize process safety management
5. If process safety is taken care of, profits will automatically follow. This lesson is most important for the people who control the purse strings!

Read the complete speech in this link.

Process safety - "simple" is getting lost

"I have always wished that my computer would be as easy to use as my telephone. My wish has come true. I no longer know how to use my telephone."--Bjarne Stroustrup, Danish computer scientist

I have the same feeling as the scientist when I see the modern advanced control systems. Ask any operation personnel about the meaning of all the jargon used in the current day instrumentation field - human engineered, wireless protocols, fieldbus, etc.. and I am sure he will blink at you. Today's control systems are so advanced that I suspect we are barely using 10 % of their capabilities. Does anyone think about the end user - namely the plant operating personnel? Did anyone really analyse whether we did need all the capabilities or we could have done it in a simpler way? A good example is alarm overload - today vendors sell alarm management software!! Why do we need so many alarms in the first place? When you do in house modifications, do not go overboard and suggest all the latest instrumentation. Study what is needed for you and implement only those that are needed.

March 10, 2011

Bromine leak affects many

An incident where bromine leaking from glass bottles has been reported at a chemical unit in South India. Many people were reported to be affected. Apparently the bromine leaked from glass bottles kept in the stores. If you are handling large quantities of Bromine it is always safer to use ISO containers instead of bottles. Of course this will involve costs but it is worth it. The European Bromine transportation safety forum has good details on how to handle emergencies with bromine including ISO containers. See this link for details.
Read more about the accident in these links:
Link 1
Link 2
News video
MSDS of bromine

March 7, 2011

importance of maintaining dyke / bund walls

Thanks to Abhay Gujar for sending information on a 300 MT hydrochloric acid leak at a facility in Singapore last month. The acid was contained within the bund and was later transferred safely. There were no injuries. This incident emphasizes the need to maintain your secondary and tertiary containment systems in proper condition. Read the article in this link.

March 5, 2011

New pipeline safety legislation in USA - Also needed in India?

An article mentions the following:
"Two US senators have introduced legislation to enhance pipeline safety.
The US has approximately 2.5 million miles of pipelines that transport oil, natural gas and hazardous liquids.  These pipelines are an integral component of the US economy and energy supply, and are generally considered a safer mode of transportation than other options for moving gas and liquids. 
Since 2006, there have been approximately 40 pipeline incidents each year that resulted in a fatality or injury.  Last September, a natural gas pipeline exploded in San Bruno, Calif., and quickly engulfed nearby homes in fire. The explosion, and subsequent fire, led to the death of eight people, and destroyed or damaged over 150 residences.
 The legislation introduced by Senators Lautenberg and Rockefeller would help mitigate pipeline risks through a number of measures.  The legislation would reauthorize and strengthen the authority of the Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) through fiscal year 2014. 
Specifically, the “Pipeline Transportation Safety Improvement Act of 2011” includes provisions that would:

  • Increase civil penalties for violators of pipeline regulations and add civil penalties for obstructing investigations;
  • Expand excess flow valve requirements to include multi-family buildings and small commercial facilities;
  • Eliminate exemptions and require all local and state government agencies, and their contractors, to notify “One-Call” notification centers before digging;
  • Require the installation of automatic or remote-controlled shut-off valves on new transmission pipelines;Require the Secretary of Transportation to establish time limits on accident and leak notification by pipeline operators to local and state government officials and emergency responders;
  • Require the Secretary of Transportation to evaluate whether integrity management system requirements should be expanded beyond currently defined high consequence areas and establish regulations as appropriate;
  • Make pipeline information, inspections, and standards available to the public on the PHMSA’s web site
  • Authorize additional pipeline inspectors and pipeline safety support employees, through a phased-in increase over the next four years;
  • Allow PHMSA to recover costs for oversight of major pipeline design and construction projects; and
  • Authorize appropriations for PHMSA for fiscal years 2011 through 2014."
With the natural gas pipeline network in India expanding in a big way, we should keep the above in mind.

Read the article in this link.

March 3, 2011

Learn Lessons from Incidents

The Directorate General, Factory Advice Services and Labour Insitutes (DGFASLI) has published a number of incidents on their website. I have separated the process incidents and given them below. Learn lessons from them.

Incident 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 :

  • 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
  • Pressure was not monitored by the pressure gauge installed in the furnace
  • No safety valve with the proper scrubber arrangement was not installed in the furnace".
Incident 2: "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-I continued to function, producing Chlorine as it was being operated on EB 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 with 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. No casualty. Causes:
  • Emergency power supply was not provided to the Chlorine absorption system to meet out any problem of power interruption during emergency of chlorine leak
  • 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".

Incident 3: "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:
  • The FRP tank was not maintained with a adequate strength and stability
  • The FRP tank was not tested and certified by the Competent person every year"

Incident 4:"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. Cause: Un-reacted ammonia in the granulator came out from the discharge end in the form of heavy puffing and injured the workers"

Incident 5:"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 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 and 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 DMSO explosive mixture. Causes:
  • DMSO is a flammable liquid. It has a flash point of 80°C and flammable range from 2.6% (volume) LFL to 63% (volume) UFL. Hence when the still, T-302 is at 136°C, 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.
  • 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"

Incident 6: "In a fine chemicals manufacturing industry, chemicals like 2 – amino Di-bromo-benzly alcohol, manganese dioxide and toluene were loaded into the 4 KL 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. Cause: HDPE barrel which was not provided with proper earthing or bonding to dissipate the static electric charges and hence fire broke out".

Incident 7: "A chemical factory had erected three MS cylindrical storage vessels with a capacity of 24 KL - 2 nos. and 30 KL - 1 no. At the time of incident, a tanker lorry with 24 KL 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 KL capacity) by using the rubber hose, one end of the rubber hose was connected to the outlet valve of the lorry and the other end of the rubber hose was connected to the 30 KL 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 outlet 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 onlookers and nearby factory workers.Causes :
  • 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.
  • 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".
The above information has been obtained from this link.