Impact: HUMAN (Offsite Fatalities)

In the early hours of 3 December 1984 a relief valve on a storage tank containing highly toxic methyl isocyanate (MIC) lifted. A cloud of MIC gas was released which drifted onto nearby housing.

Prior to this, at 23.00 hrs on 2 December, an operator noticed the pressure inside the storage tank to be higher than normal but not outside the working pressure of the tank. At the same time a MIC leak was reported near the vent gas scrubber (VGS). At 00.15hrs a MIC release in the process area was reported. The pressure inside the storage tank was rising rapidly so the operator went outside to the tank. Rumbling sounds were heard from the tank and a screeching noise from the safety valve. Radiated heat could also be felt from the tank.
Attempts were made to switch on the VGS but this was not in operational mode.

Approximately 2,000 people died within a short period and tens of thousands were injured, overwhelming the emergency services. This was further compounded by the fact that the hospitals were unaware as to which gas was involved or what its effects were. The exact numbers of dead and injured are uncertain, as people have continued to die of the effects over a period of years.

The severity of this accident makes it the worst recorded within the chemical industry.

KEY ISSUES:
• PLANT MODIFICATION / CHANGE PROCEDURES
• REACTION / PRODUCT TESTING
• DESIGN CODES – PLANT
• MAINTENANCE PROCEDURES
• EMERGENCY RESPONSE / SPILL CONTROL

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The Halifax Explosion was a maritime disaster in Halifax, Nova Scotia, Canada, which happened on the morning of 6 December 1917. The Norwegian vessel SS Imo collided with SS Mont-Blanc, a French cargo ship laden with high explosives, in the Narrows, a strait connecting the upper Halifax Harbour to Bedford Basin, causing a large explosion on the French freighter, devastating the Richmond district of Halifax.

Approximately 2,000 people were killed by the blast, debris, fires or collapsed buildings, and an estimated 9,000 others were injured. The blast was the largest man-made explosion at the time, releasing the equivalent energy of roughly 2.9 kilotons of TNT (12,000 GJ).

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On December 7, 2009, at approximately 2:30 pm, State Special Vessel No. 2, under an operating pressure of 29,000 psig, suddenly and violently ruptured, 120 days into a 150-day operating cycle. A white cloud of steam and debris rapidly expanded outward from the facility, traveled onto the interstate, and dissipated within seconds.

The sudden release of superheated liquid caused an eight-foot tall by four-foot wide vessel fragment, weighing approximately 8,600 pounds, to travel through two concrete walls and finally land about 435 feet from the NDK building. The fragment skipped across a neighboring facility parking lot and slammed into the wall of an adjacent business office. The force of the impact pushed the wall inward causing furniture to shift and ceiling tiles to fall. One person working near the wall was injured.

The thrust from the escaping liquid caused the base of the vessel to violently shear away from its foundation and blew pieces of structural steel out of the building into the parking lot of a nearby rest stop gas station, known as the Illinois Tollway (I-90) Oasis. One piece of structural steel struck and killed a truck driver at the rest stop. After shearing from its base and throwing shrapnel out of the facility, the vessel swung from the building and landed on the ground outside.

KEY ISSUES:
• PRESSURE VESSEL DESIGN & MATERIAL SELECTION REQUIREMENTS
• LEARNING FROM PREVIOUS INCIDENTS
• INSPECTIONS

ROOT CAUSES:
1. Stress corrosion cracking.
2. Testing & inspection deficiencies.

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A huge boil-over occurred on a fuel oil tank, killing at least 160 people in a huge fire ball. The explosion occurred on the fuel oil tank while it was being gauged, blowing the roof off the tank and setting it on fire. Eight hours after the tank fire started a violent boil-over occurred. Burning oil flowed down the hill where the tank was located and surrounded a second tank.

[ Property Damage $70 Million. Estimated Current Value $193 Million ]

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In a chemical plant that produces fertilizer, carbon dioxide and dry ice, a pipeline explosion occurred.

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
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On 10 January 1985 an explosion destroyed the central section of a three-storey block of luxury flats in South London, killing eight of the residents. Preliminary investigations indicated a gas leak as a probable cause.

It was found that the explosion was caused by gas leaking into the building from a crack in the gas main, a 150mm (6 inch) diameter cast iron pipe buried at the rear of the building, which carried gas at low pressure. The crack was primarily due to loading on the pipe caused by differential settlement. The loading could not be evenly distributed along the pipe, as it was held rigidly near the point of failure by the concrete encasement of a drain, which acted as a fulcrum.

Report: https://www.icheme.org/media/13699/the-putney-explosion.pdf

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On January 30, 2007, a propane explosion at the Little General Store in Ghent, West Virginia, killed two emergency responders and two propane service technicians, and injured six others. The explosion leveled the store, destroyed a responding ambulance, and damaged other nearby vehicles.

On the day of the incident, a junior propane service technician employed by Appalachian Heating was preparing to transfer liquid propane from an existing tank, owned by Ferrellgas, to a newly installed replacement tank. The existing tank was installed in 1994 directly next to the store’s exterior back wall in violation of West Virginia and U.S. Occupational Safety and Health Administration regulations.

When the technician removed a plug from the existing tank’s liquid withdrawal valve, liquid propane unexpectedly released. For guidance, he called his supervisor, a lead technician, who was offsite delivering propane. During this time propane continued releasing, forming a vapor cloud behind the store. The tank’s placement next to the exterior wall and beneath the open roof overhang provided a direct path for the propane to enter the store.

About 15 minutes after the release began, the junior technician called 911. A captain from the Ghent Volunteer Fire Department subsequently arrived and ordered the business to close. Little General employees closed the store but remained inside. Additional emergency responders and the lead technician also arrived at the scene. Witnesses reported seeing two responders and the two technicians in the area of the tank, likely inside the propane vapor cloud, minutes before the explosion.

Minutes after the emergency responders and lead technician arrived, the propane inside the building ignited. The resulting explosion killed the propane service technicians and two emergency responders who were near the tank. The blast also injured four store employees inside the building as well as two other emergency responders outside the store.

KEY ISSUES:
• EMERGENCY EVACUATION
• HAZARDOUS MATERIALS INCIDENT TRAINING FOR FIREFIGHTERS
• 911 CALL CENTER RESOURCES
• PROPANE COMPANY PROCEDURES
• PROPANE SERVICE TECHNICIAN TRAINING

ROOT CAUSES:
1. The Ferrellgas inspection and audit program did not identify the tank location as a hazard. Consequently, the tank remained against the building for more than 10 years.
2. Appalachian Heating did not formally train the junior technician, and on the day of incident he was working alone.
3. Emergency responders were not trained to recognize the need for immediate evacuation during liquid propane releases.

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On February 19, 1999, a process vessel containing several hundred pounds of hydroxylamine exploded at the Concept Sciences Inc. production facility near Allentown, Pennsylvania. Employees were distilling an aqueous solution of hydroxylamine and potassium sulfate, the first commercial batch to be processed at the facility. After the distillation process was shut down, the HA in the process tank and associated piping explosively decomposed, most likely due to high concentration and temperature. Four CSI employees and a manager of an adjacent business were killed. Two CSI employees survived the blast with moderate-to-serious injuries. Four people in nearby buildings were injured. The explosion also caused significant damage to other buildings in the Lehigh Valley Industrial Park and shattered windows in several nearby homes.

KEY ISSUES:
• HAZARDS OF PROCESSING HYDROXYLAMINE
• PROCESS HAZARDS EVALUATION
• CHEMICAL FACILITY SITING

ROOT CAUSES:
1. CSI’s process safety management systems were insufficient to properly address the hazards inherent in its HA manufacturing process and to determine whether these hazards presented substantial risks.
2. Inadequate collection and analysis of process safety information contributed to CSI’s failure to recognize specific explosion hazards.
3. Basic process safety and chemical engineering practices – such as process design reviews, hazard analyses, corrective actions, and reviews by appropriate technical experts – were not adequately implemented.
4. The existing system of siting approval by local authorities allowed a highly hazardous facility to be inappropriately located in a light industrial park.

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On 21 March 2019, a major explosion occurred at a chemical plant in Chenjiagang Chemical Industry Park, Chenjiagang, Xiangshui County, Yancheng, Jiangsu, China. According to reports published on March 25, 78 people were killed and 617 injured.

The State Council of China officially recognized the severity of the accident, often referred to as “3.21 Explosive Accident”.

The explosion occurred at a local time of 14:48 (06:48 GMT). 78 people were killed, and at least 94 were severely injured, 32 of whom were critically injured. Around 640 people required hospital treatment and were taken to 16 hospitals. The injured included children at a local kindergarten. CENC detected an ML2.2 artificial earthquake whose epicenter is at 34.331°N 119.724°E.

The force of the blast started numerous fires in Yancheng, knocked down several buildings, and reportedly destroyed windows several kilometers away. The fire was reported to have been controlled by 03:00 local time. Considerable damage was caused to nearby factories and offices; the roof of Henglida Chemical Factory, 3 km from the explosion, fell in. At least one of the people killed was in another building destroyed by the blast. Windows are reported to have been blown out up to 6 km away from the explosion, and houses and other buildings were damaged in the nearby village-level administrative divisions including Hai’an Town (Haianju) (海安社区) and Shadang (沙荡社区). This explosion was strong enough that it registered on earthquake sensors and could be seen by satellites. The blast created a crater resulting in a magnitude 2.2 seismic shock that took over 900 firefighters to get the fire under control.

Ref: https://en.wikipedia.org/wiki/2019_Xiangshui_chemical_plant_explosion
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At 09.45 on 22 March 1989 a vehicle carrying approximately 800 kg of mixed explosives exploded at the premises of Vibroplant Ltd on the Fengate Industrial Estate, Peterborough. The explosion caused the death of a fireman and injuries to at least 107 other people, 84 of whom received hospital treatment. Two of the injured were admitted to intensive care.

The vehicle was a standard commercial model specially modified to carry explosives, operated by Nobels Explosives Company (NEC), a subsidiary of ICI. It had entered the Vibroplant yard, in order to turn round off the road, when a minor explosion occurred inside the load compartment, causing a fire. The fire brigade was called and took up position. The fire increased and after approximately 12 minutes the entire load, apart from a small number of detonators, detonated en masse.

The vehicle did not carry any external placarding to tell emergency services that it contained explosives, but this did not contravene the legislation in force at the time. The fire brigade was told that the vehicle was carrying commercial explosives before firemen arrived on the scene.

Report: https://www.icheme.org/media/13701/the-peterborough-explosion.pdf

Image Credit: HSE