On October 29, 2009, a massive explosion occurred at an oil terminal in Jaipur, India. The explosion was caused by a leak from a valve at the bottom of a tank containing motor spirit, which rapidly generated vapours that made the operator lose consciousness. The shift officer and a second operator also lost consciousness while attempting to respond to the leak.

The leak remained uncontrolled for 75 minutes, during which time the vapours ignited, causing a massive explosion and a fire that burned for 11 days and consumed all the petroleum products stored at the terminal. The explosion caused widespread damage and resulted in the deaths of 11 people, six from the terminal and five from outside.

The root causes of the accident were found to be the lack of written operating procedures specific to the site, the absence of remotely operated shutdown valves, and a lack of understanding of the hazards, risks, and consequences of the operation.

The Incident:
On October 29, 2009, during the evening shift at a terminal, the crew was preparing to transfer a type of fuel called motor spirit to a neighbouring terminal operated by Bharat Petroleum Corporation Limited. Four employees were scheduled to be working during this shift, and they began preparing the motor spirit tank for the transfer.

At around 6:10 pm, while the crew was preparing the motor spirit tank for transfer, a leak occurred from a valve at the bottom of the tank. The leak caused a jet of motor spirit to be released and rapidly generated vapoursthat made the operator lose consciousness. Because this critical activity was occurring outside of normal working hours, there was a delay in responding to the situation.

The shift officer tried to help the operator, but was also affected by the vapours and barely managed to escape. The second operator, who was in the canteen and was contacted by the shift officer, rushed to the tank but also lost consciousness. The third operator on the shift had already left for the day and was not present to initiate any rescue or mitigating efforts. As a result, the leak remained uncontrolled for 75 minutes. Eventually, the vapours ignited, causing a massive explosion and a fire that covered the entire facility.

It is worth noting that in this incident, the vapours were not visible. People at the site were aware of the vapours' presence because of their strong smell. Some people were able to escape the site, while others were either incapacitated by the vapours or were caught in the vapours when they ignited.

The fire that resulted from the explosion spread to all the other tanks and burned for 11 days. All the petroleum products stored at the terminal at the time of the accident, approximately 60 million litters, were consumed in the fire and the facility was completely destroyed.

Buildings in the immediate area were heavily damaged, and there was minor damage and broken windows within a radius of 2 km from the site. Eleven people lost their lives in the accident, six from the terminal and five from outside, and several others were injured. There were factories and industrial complexes located nearby.

Cause Of Incident:
The immediate causes of the accident were the failure to follow normal safety procedures, which involves a sequence of valve operations during the line-up activity, and an engineering design that allowed for the use of a valve called a "hammer blind valve." These valves have a large open area at the top that remains fully open whenever the valve position needs to be changed.

It was through this open area that the motor spirit leaked when the tank was being prepared for pumping to the neighbouring terminal because another valve connected to the tank was also open when the hammer blind valve was in the changeover position.

The root causes of the accident were the lack of written operating procedures specific to the site, the absence of remotely operated shutdown valves, and a lack of understanding of the hazards, risks, and consequences of the operation.

When the leak and subsequent explosion occurred, the weather was calm with low wind speeds. This, combined with the nature of the release (an upward jet of motor spirit), likely contributed to the production of vapours. After the incident, analysis showed that a flammable vapor cloud covered much of the terminal site, contained within the perimeter wall. The cloud had a diameter of approximately 1000 m, which was almost four times the size of the vapor cloud in the Bunce field accident in 2005.

The explosion caused widespread severe pressure damage across almost the entire site. The evidence suggests that the vapor cloud explosion generated overpressures of more than 200kPa over most of the terminal site. The damage was similar to that observed in the Bunce field accident in 2005, with crushing of oil drums above the liquid level, severe damage to buildings and vehicles, and severe damage to vehicles.

Areas with high overpressures included many open regions without trees, bushes, or pipes. In these areas, a deflagration would not be sustained and the overpressures would have dissipated. The overpressure damage evidence therefore does not support the theory that the vapor cloud explosion involved only a deflagration.

The directional indicators also did not support the theory that the explosion was caused by a deflagration only. The directional indicators suggest that the source of the detonation was in the Pipeline Division area in the northeast corner of the site. Unlike the Bunce field accident, it does not seem consistent with the evidence to suggest that the detonation occurred as a result of flame acceleration in trees.

The most likely cause of the detonation is flame entering the Pipeline Area control room or the pipeline pump house, causing a confined or partially confined explosion that then initiated a detonation as it vented from the building.

In reaching this conclusion, it appears necessary to consider the possibility that some of the directional evidence may have been affected by asymmetry in the vapor cloud. The exact source of the transition to detonation cannot be determined due to the limited evidence from the Pipeline Division area.

Measures Taken:
Immediate:

1. The ability to take emergency action from remote locations.
2. The introduction and enforcement of site operating procedures to reduce human error, improve operating discipline, improve site communications, and ensure the availability and proper use of personal protective equipment.
3. The use of dual level gauges and alarms, detectors, and CCTV systems.
4. The requirement to conduct a Quantitative Risk Assessment on larger sites.

Long Term:

1. Design and layout improvements to prevent the loss of hydrocarbon containment.
2. Improvements to firefighting capabilities.
3. Improved training, performance evaluation criteria, and safety-oriented corporate policies.
4. Making the safety function independent and autonomous, reporting directly to the company CEO.
5. Strengthening the internal safety auditing functions and providing professional safety auditing training
6. Using Quantitative Risk Assessment to inform siting criteria.
7. Reviewing land use legislation in the vicinity of major hazard facilities and the role of local and state governments in such matters./
8. Conducting a country-wide review of major hazard facilities from a security standpoint.

Problems In Handling Such Situations:

1. The lack of critical equipment and resources to tackle the situation and the lack of expertise in the country to handle well blowouts/well fires
2. The loss of crucial time in planning and arranging resources to address the situation, which exacerbated the situation.
3. Improper evaluation/analysis and response to the incident.
4. The failure of the site-in-charge and others to respond promptly to the incident.
5. The absence or non-adherence to standard operating procedures.
6. The dissemination of negative messages through the media due to the selection of an incompetent spokesperson.

MB Lal Committee Recommendation:
In April 2010, in response to the recommendations of the MB Lal Committee after the Jaipur fire in 2009, the Ministry of Petroleum and Natural Gas ordered all oil companies to upgrade their firefighting systems in accordance with revised OISD Standards 116 and 117. This was done in a time-bound manner for various locations including refineries, marketing installations, central tank farms, pipelines, crude oil tank farms, gas gathering stations, gas processing plants, and tank farms at Duliajan, Tengakhat, Moran, and Jorhat.

High Volume Long Range Monitors (HVLR) were installed at refineries and processing plants (1,424), marketing installations (1,142), and pipelines and central tank farms (460). Major upgrades to firefighting arrangements were also made in accordance with the recommendations of the MB Lal Committee.

These upgrades included the installation of 1,312 auto-actuated rim seal fire detection and extinguisher systems for all external floating roof class A tanks, based on linear heat hollow metallic tubes at refineries and processing plants (540), marketing installations (683), and pipelines and central tank farms (89). Hydrocarbon detection and alarm systems were also installed as needed.

Firewater systems and pumps were upgraded to handle double fire contingencies at installations with storage capacity greater than 30,000 KL. Medium Expansion Foam Generators (MEFG: 450 LPM) were also arranged for all necessary cases. All tank body valves were converted to Remote Operated Shut Off Valves (ROSOV) and mass flow meters were installed for all necessary pipeline transfers. Hammer blinds were also replaced as necessary, and CCTV cameras were installed at all necessary locations. Emergency kits were also arranged according to the specifications given in the recommendations of the MB Lal Committee.

Actions To Set Up Emergency Response Centre (ERC) In India:
In response to the recommendations made by the MB Lal Committee after the Jaipur fire in 2009, the Ministry of Petroleum and Natural Gas in India set up the Emergency Response Centre (ERC) equipped with state-of-the-art firefighting equipment and modern gadgets to handle catastrophic fire incidents in refineries, process plants, tank farms, and terminals.

In November 2014, a team from the OISD visited the Refinery Terminal Fire Company in Texas, USA, and the RTFC visited different Indian refineries and terminals.

In March 2015, the RTFC submitted a final report with recommendations to set up 22 ERCs across India, taking into consideration a 2-hour response time and an estimated cost of INR 1000 crore.

In a meeting in May 2016, the Indian Oil Corporation Limited (IOCL) informed the Ministry of Petroleum and Natural Gas that they did not have land available at the Hazira plant. In the same meeting, IOCL, Bharat Petroleum Corporation Limited, Hindustan Petroleum Corporation Limited, GAIL, and Oil and Natural Gas Corporation were advised to identify a location with 4-5 acres of land to build five ERCs.

In September 2016, a meeting was organized by the Ministry involving all stakeholders, and a committee was formed under the OISD to oversee the execution of the ERC project. It was decided that the first pilot project would be implemented at the IOCL Hazira plant in Gujarat, followed by five more ERCs after necessary surveys. The cost would be shared equally by the participating oil companies.

Again, In September 2016, Engineers India Limited (EIL) gave a presentation to the Ministry of Petroleum and Natural Gas and it was decided to engage EIL as the EPC Consultant for the ERC project.

In January 2019, the Chairman's report on the Standing Committee on Petroleum and Natural Gas stated that the IOCL would set up an ERC in Jaipur, HPCL in Vizag, BPCL in Manmad, ONGC in Hazira, and GAIL in Dibiyapur. A global pre-bid meeting was held to engage an EPC Consultant for the ERC project, but no responses were received to the global tender that was published. The committee advised revising the BEC and BRC and re-floating the global tender.

The proposed ERCs are designed to meet the requirements of refineries, process plants, tank farms, and terminals, but not well blowouts or well fires. There are no plans to set up ERCs in the northeast region, where most of the oil blocks are located. It may be difficult to transport the necessary equipment to the northeast due to inadequate infrastructure such as roads, bridges, and culverts.

Learning:

1. Facilities and installations with inherently high hazards should have redundant safety systems in place and ensure that they are always well-maintained
2. Management should have reliable systems in place to provide timely feedback on current practices and readiness at different facilities.
3. Management must ensure that identified actions are being carried out.
4. A strong focus on safety from top management will ensure that safety is prioritized throughout the organization.
5. A high level of operational competence should be maintained at all times by leveraging the combined knowledge and experience of all professional groups.
6. The lessons learned from major incidents should be shared widely within the industry, preferably through a dedicated website.

Suggestions:
India is currently not fully equipped to handle well blowouts and well fires due to a lack of both expertise and necessary facilities. It is necessary to bring in experts from abroad to implement the specialized techniques needed to address these situations.

The "Big Wind" vehicle is a specialized piece of equipment used to extinguish well fires. It works by using a gas turbine to blast a large volume of water at high velocity at the fire. In 1991, the Big Wind was used to extinguish nine fires in 43 days in Kuwait. It is a powerful tool for combating well fires, but it may not be suitable for every situation.

The first is the use of dynamite, which forces the burning fuel and oxygen away from the fuel source, and was first used in California in 1913.

The second is the "Devil's Cigarette Lighter" technology, which uses explosives to deprive the flame of oxygen and was used to extinguish a natural gas well fire in Algeria that had been burning for six months. The technique involved using a modified bulldozer to position a metal drum containing a nitro-glycerine charge near the well, and then running to a trench a safe distance away while the explosion extinguished the fire by displacing the oxygen. Water was then used to cool the well and drilling mud was pumped in to control the flow of gas before the well was capped. 

"Athey wagons" are special vehicles that are used to extinguish oil well fires. They are equipped with corrugated steel sheeting to protect against the intense heat and flames. These vehicles, along with typical bulldozers, are used in well fire situations to help contain and control the fire.

To raise the plume, a metal casing is placed over the well head, which is about 30 to 40 feet above the ground. This helps to lift the flame off the ground. To extinguish the fire, liquid nitrogen or water is injected at the bottom of the well to reduce the oxygen supply and extinguish the flame.

The LeRoy Corporation, a company based in Houston that specializes in fighting oil well fires, developed three machines that could extinguish flames by placing a cap over the burning pipe. These machines, named Shadrach, Meshach, and Abednego after the Biblical characters who survived being thrown into a fiery furnace, had an arm that could be positioned over the burning pipe. The walls of the machines were hollow, allowing water to circulate and keep the interior control room cool while fighting the fire.

There are several methods that have been used to extinguish oil well fires. One method is to use underground nuclear explosions, which generate high heat that can melt and seal the rock around the previously drilled hole, effectively extinguishing the fire. This method was first successfully used in the former Soviet Union.

Another method is to drill relief wells into the production zone and redirect some of the oil to make the fire smaller, by pumping heavy mud and cement deep into the well. This method was first successfully used in Texas in the mid 1930s. Another method is to use mechanical jaws to clamp off the pipe below the fire, and another method is to douse the fire with copious amounts of water.

Summary:
Vapour cloud explosions are dangerous events that can cause significant damage, depending on factors such as the amount of flammable material involved, how the cloud is dispersed, and the reactivity of the gas mixture. The concentration, size, and location of the vapour cloud can also play important roles. A case study of the IOCL Plant explosion in Jaipur, India, was used to understand the overpressure caused by the explosion and the resulting damage.

The results showed that high pressure, up to 1.0 bar, was only present in the immediate area of the plant. However, the explosion was still able to cause glass breakage up to 2 km away. The severity of the explosion at the Jaipur plant was surprising given that the site was not densely populated. However, analysis of vapour cloud formation and dispersion helped to explain the extent of the damage.

To prevent similar accidents in the future, it is important to have measures in place such as improved inventory management and protection against overfilling or leakage. There is also a need for better design of liquid containment and systems for detecting and responding to leaks.

Further research and analysis of major chemical accidents can help to improve our understanding of vapour cloud explosions and improve hazard identification and risk assessments. The publication and dissemination of information about these types of accidents can also be helpful in this regard.