Impact: HUMAN (On Site Injuries)

A release of hexane created a vapor cloud which was ignited on an electric motor, causing an explosion. This resulted in damage to a process unit and injured 20 people. The plant was eventually replaced.

[ Property Damage $200 Million. Estimated Current Value $280 Million ]

Image credit: Gaulke

At approximately 2:00 pm on December 11, 2002, a maintenance employee entered the wastewater treatment (WWT) room at Environmental Enterprises, Inc. (EEI), in Cincinnati, Ohio, to retrieve a tool. His path brought him directly alongside the WWT clarifier, an open-top tank with a conical bottom for settling solids (Figure 1).

As the mechanic approached the clarifier, he noticed a “rotten egg” odor that became stronger as he moved forward. He suddenly felt pressure in his lungs and was unable to breathe. He attempted to flee the area but was overcome by hydrogen sulfide (H2S) gas and collapsed.

Fortunately, fellow employees found the victim a few moments later and pulled him to safety. He recovered, and there were no other injuries. .

KEY ISSUES:
• HAZARD COMMUNICATION
• OPERATING PROCEDURES
• MANAGEMENT OVERSIGHT
• MECHANICAL INTEGRITY

ROOT CAUSES:
1. The facility had no written procedures for operating the WWT area.
2. The operator responsible for the WWT area had no formal training in waste treatment or chemistry.
3. This incident may have been avoided if the operator had been aware of the possible reactions that can produce H2S gas.
4. EEI did not have a formal system for investigating incidents and communicating findings to employees.
5. The facility did not implement procedures or assign responsibilities for calibrating, inspecting, and maintaining the H2S detector.
6. Management oversight could have ensured that then proper treatment methods were used.

Image Credit: CSB

An explosion and fire occurred at a gas-to-liquids (GTL) plant in Bintulu, Sarawak. The fire was brought under control on the next day. The plant was one of only two commercially successful GTL plants in the world at the time, with a capacity to produce 12,500 bbl-per-day of middle distillates and waxes from natural gas feedstocks. The explosion occurred in the air separation unit (ASU) which supplied oxygen for the production of synthesis gas feedstock. The investigation into the incident pointed to an initial combustion event in the ASU as the most probable cause. This combustion event is thought to have initiated explosive burning of the aluminium heat exchanger elements in the presence of liquid oxygen, such that the elements ruptured explosively. Twelve people were injured, none seriously, and the plant was shut down for several months for repairs.

[ Property Damage $275 Million. Estimated Current Value $510 Million ]

Image credit: Shell

A benzoyl peroxide (BPO) explosion and fire that occurred at the Catalyst Systems, Inc., production facility in Gnadenhutten, Ohio. At 11:55 am on January 2, 2003, a vacuum dryer holding nearly 200 pounds of BPO exploded. Employees were drying granular 75 percent BPO to make 98 percent BPO when the material explosively decomposed. One employee was slightly injured, and the BPO processing building was significantly damaged.

KEY ISSUES:
• HAZARDS OF BENZOYL PEROXIDE
• REACTIVE CHEMICAL HAZARDS
• PROCESS SAFETY MANAGEMENT SYSTEMS

ROOT CAUSES:
1. Industry standards and guidance documents not reviewed and followed.
2. Good engineering practices to manage the hazards not implemented.

Image Credit: CSB

This incident occurred at an oil sands facility, specifically with minor explosions occurring in the froth treatment plant. Damage appeared to be mainly limited to electrical cables in the solvent recovery area. The cause of the fire appears to have been a hydrocarbon leak in piping. The plant’s emergency response team was assisted by the local fire brigade and the fire was extinguished in two hours. Only one minor injury was reported. The incident occurred eight days after the new facility began operating.

[ Property Damage $120 Million. Estimated Current Value $189 Million ]

Image credit: Jason Woodhead

An explosion occurred on this oil sands upgrader site north of Fort McMurray, Alberta. Five workers were injured in the blast, including one who received third-degree burns. A subsequent fire occurred at the top of one of the site’s four coke drums and burned for nearly four hours. As a result, two of the coke drums were disabled. Workers returned to normal shifts the following morning. The majority of the damage was sustained above the cutting deck and derrick infrastructure of the coke drum. At the time of the incident, the plant was operating on bypass conditions due to process upsets. An internal investigation team determined that the fire resulted from the opening of the top unheading valve on an active low-pressure coke drum. This allowed hot hydrocarbons to be released within the coker cutting deck building and was followed by ignition, leading to the explosion and fire. Exceptionally cold weather following the incident hampered efforts to gain access to the coker unit’s cutting deck, due to the deluge protection in this area. Firefighting in freezing conditions caused additional damage.

[ Property Damage $385 Million. Estimated Current Value $425 Million ]

Image credit: CBC

An explosion severely injured a graduate student at Texas Tech University in Lubbock, Texas, in the chemistry department during the handling of a high-energy metal compound, which suddenly detonated. Texas Tech had entered into an agreement with Northeastern University, which holds a contract from the U.S. Department of Homeland Security to study the high-energy materials.

KEY ISSUES:
• LABORATORY SAFETY MANAGEMENT FOR PHYSICAL HAZARDS
• HAZARD EVALUATION OF EXPERIMENTAL WORK IN RESEARCH LABORATORIES
• ORGANIZATIONAL ACCOUNTABILITY & OVERSIGHT OF SAFETY

Image & AcciMap Credit: CSB

On the evening of January 12, 2009, 2 refinery operators and 2 contractors suffered serious burns resulting from a flash fire at the Silver Eagle Refinery in Woods Cross, Utah. The accident occurred when a large flammable vapor cloud was released from an atmospheric storage tank, known as tank 105, which contained an estimated 440,000 gallons of light naphtha. The vapor cloud found an ignition source and the ensuing flash fire spread up to 230 feet west of the tank farm.

On November 4, 2009, a second accident occurred at the Silver Eagle Refinery in Woods Cross, Utah, when a powerful blast wave – caused by the failure of a 10 inch pipe – damaged nearby homes.

KEY ISSUES:
• MECHANICAL INTEGRITY

ROOT CAUSES:
1. Sulfidation corrosion

Image credit: CSB

Heavy storm conditions in the North Sea caused four of this floating production, storage, and offloading’s (FPSO) 10 anchor chains to break resulting in the vessel moving off its position. It is estimated that the FPSO was subject to 53-knot winds and nine meter waves. Normally, a complex piping system runs from the wells on the seabed up to the FPSO, however, this infrastructure was damaged in the incident. Following the vessel moving off its position, all of the wells were immediately shut in. Subsequent surveys showed that no oil had been lost. The 74 non-essential crew were evacuated to near-by platforms and 43 essential crew members remained onboard. Two members of crew received minor injuries. The facility was projected to be producing an average of 18,400 bbl-per-day of oil prior to the loss.

[ Property Damage $450 Million. Estimated Current Value $497 Million ]

Image credit: Maersk

A tank ruptured in Warsaw Chemical company, it contained hazardous chemical that caused a fire followed by an explosion. After the fire some chemicals spilled into Winona lake.

50 homes were evacuated

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: 1480 News Now

A February 7, 2003, explosion and fire inside a vent collection system (VCS) at Technic Inc., in Cranston, Rhode Island, critically injured one employee, who suffered permanent eye damage and chemical burns to his face and upper body. Eighteen other employees were sent to the hospital for medical evaluations, and the fire department evacuated the surrounding community. Facility operations were interrupted for several weeks.

The explosion and fire were caused by a violent chemical reaction inside the vent collection system, which was likely initiated when the employee tapped on a duct with a small hammer. The building where the incident occurred housed several chemical processes that were connected to the ventilation system.

KEY ISSUES:
• INCOMPATIBLE CHEMICAL MIXING
• PROCESS SAFETY REVIEW
• MANAGEMENT OF CHANGE
• PREVENTIVE MAINTENANCE
• EMERGENCY PLANNING & RESPONSE

ROOT CAUSES:
1. Technic did not conduct a process safety review as a part of the engineering process to identify and evaluate the hazards associated with installing a vent collection system to handle the exhausts from multiple processes.
2. Technic did not identify and evaluate the hazards created by changes to facility processes and equipment (i.e., management of change).

Image Credit: CSB

On the 11 February 1980 a fire and a series of explosions occurred at a warehouse in a factory at Trubshaw Cross, Longport, Stoke-on-Trent. On the morning of the fire the warehouse contained some 49 tonnes of liquefied petroleum gas (LPG) in cartridges and aerosol containers as well as about 1 tonne of petroleum mixtures in small containers, raw materials, and packaging materials. It is almost certain that the source of ignition was the electrical system of a battery operated fork lift truck.

LPG is a well known fire and explosion hazard; the circumstances of the fire emphasise the need for occupiers of premises containing LPG to be adequately informed, by obtaining information and advice from authoritative sources, on the hazards of LPG and the precautions to be observed in its storage.

Report: https://www.icheme.org/media/13695/the-fire-and-explosions-at-permaflex-trubshaw-cross-stoke.pdf

Image Credit: Stoke Sentinel

On February 12, 2014, a mechanical integrity failure released sulfuric acid in the alkylation unit, which burned two Tesoro Martinez refinery employees. Approximately 84,000 pounds of sulfuric acid were released during the incident.

On March 10, 2014, sulfuric acid sprayed and burned two contract workers while they removed piping in the same alkylation unit. The CSB found that this second incident shared similar causation with a 1999 incident at the same refinery, then called the Avon refinery, owned by the Tosco Corporation, that resulted in four fatalities. Similarities between the two incidents suggest that the Tesoro Martinez refinery did not effectively continue to implement or communicate important safety lessons from the 1999 Tosco incident.

KEY ISSUES:
• PROCESS SAFETY CULTURE
• PROCESS SAFETY INDICATORS

ROOT CAUSES:
1. The safety culture at the Tesoro Martinez refinery created conditions conducive to the occurrence and recurrence of process safety incidents that caused worker injuries at the refinery over several years.
2. Prior sulfuric acid exposure incidents at the Tesoro Martinez refinery could have properly been considered leading indicators of an impending serious chemical accident and then triggered preventive inspections and review of the refinery’s safety systems and equipment.

Image & AcciMap Credit: CSB

Image credit: CSB

Overheating and explosion of a reactor occurred, likely as a result of a runaway reaction. The cause was suspected to be the addition of the incorrect component. A neighboring building also was destroyed.

[ Property Damage $63 Million. Estimated Current Value $141 Million ]

Image credit: Currenta

An explosion at this 70,000 bbl-per-day oil refinery caused damage to the FCC, utilities, storage tanks, and asphalt unit. One employee was hospitalized for burns. Another person was injured when her car was struck by debris from the explosion on the nearby highway. There was a total of four injuries. A skeleton crew of just 40 people were on site because the blast occurred on a public holiday. There would typically have been about four times as many people on duty at the time of the explosion. The fire was brought under control the same day by the site’s fire brigade, supported by local fire departments. The release is believed to have occurred during a start-up on the propylene splitter unit, as a result of the catastrophic failure of a pump. Some processing resumed about two months later, and the FCC was re-commissioned eight months after the incident.

[ Property Damage $380 Million. Estimated Current Value $454 Million ]

Image credit: Delek

On Wednesday, February 18, 2015, an explosion occurred in the ExxonMobil Torrance, California refinery’s Electrostatic Precipitator (ESP), a pollution control device in the fluid catalytic cracking (FCC) unit that removes catalyst particles using charged plates that produce sparks (potential ignition sources) during normal operation. The incident occurred when ExxonMobil was attempting to isolate equipment for maintenance while the unit was in an idled mode of operation; preparations for the maintenance activity caused a pressure deviation that allowed hydrocarbons to backflow through the process and ignite in the ESP.

The CSB found that this incident occurred due to weaknesses in the ExxonMobil Torrance refinery’s process safety management system. These weaknesses led to operation of the FCC unit without pre-established safe operating limits and criteria for unit shutdown, reliance on safeguards that could not be verified, the degradation of a safety-critical safeguard, and the re-use of a previous procedure deviation without a sufficient hazard analysis that confirmed that the assumed process conditions were still valid. .

KEY ISSUES:
• LACK OF SAFE OPERATING LIMITS & OPERATING PROCEDURE
• SAFEGUARD EFFECTIVENESS
• OPERATING EQUIPMENT BEYOND SAFE OPERATING LIFE
• RE-USE OF PREVIOUS PROCEDURE VARIANCE WITHOUT SUFFICIENT HAZARD ANALYSIS

ROOT CAUSES:
1. ExxonMobil did not establish the safe operating limits for operating the FCC unit in Safe Park (a standby mode of operation) or determine process conditions that required unit shutdown.
2. ExxonMobil did not perform a sufficient hazard analysis to determine if the unit conditions specified in the 2012 procedure were valid for the 2015 operation.
3. ExxonMobil operated FCC unit equipment beyond its predicted safe operating life.
4. ExxonMobil lacked safety instrumentation to detect flammable hydrocarbons flowing through the equipment and into the ESP.
5. ExxonMobil refinery management permitted opening process equipment without conforming to refinery standards.

Image credit: CSB

A fire occurred on one of the two hydrotreaters on an oil sands upgrader facility. The fire was reported to be as a result of the failure of a pipe, resulting in a releaser of naphtha. One worker was seriously injured as a result of the fire, which was extinguished after two days.

[ Property Damage $220 Million. Estimated Current Value $220 Million ]

Image credit: CBC

On April 8, 2004, four workers were seriously injured when highly flammable gasoline components were released and ignited at the Giant Industries Ciniza refinery, east of Gallup, New Mexico. The release occurred as maintenance workers were removing a malfunctioning pump from the refinery’s hydrofluoric acid (HF) alkylation unit. Unknown to personnel, a shut-off valve connecting the pump to a distillation column was apparently in the open position, leading to the release and subsequent explosions.

KEY ISSUES:
• MECHANICAL INTEGRITY
• CORROSION & SCALE FORMATION
• VALVE DESIGN
• HUMAN FACTORS CONSIDERATION
• MANAGEMENT OF CHANGE
• LOCKOUT/TAGOUT & ISOLATION

ROOT CAUSES:
1. An MOC hazard analysis was not conducted.
2. the facility lacked procedures to verify that the pump had been isolated, depressurized and drained.
3. Instead of determining the cause of frequent pump malfunctions and then implementing a program that would prevent problems before they occurred, Giant used breakdown maintenance by making repeated repairs to the pump seals after failure.

Image Credit: CSB

On April 8, 1998, an explosion and fire occurred during the production of Automate Yellow 96 Dye at the Morton International Inc. plant in Paterson, New Jersey. The explosion and fire were the consequence of a runaway reaction, which overpressurized a 2000-gallon chemical vessel and released flammable material that ignited. Nine employees were injured.

KEY ISSUES:
• INTERNAL HAZARD COMMUNICATION & PROCESS SAFETY INFORMATION
• REACTIVE HAZARD MANAGEMENT
• PROCESS SAFETY MANAGEMENT

ROOT CAUSES:
1. Neither the preliminary hazard assessment conducted by Morton in Paterson during the design phase in 1990 nor the process hazard analysis conducted in 1995 addressed the reactive hazards of the Yellow 96 process.
2. Process safety information provided to plant operations personnel and the process hazard analysis team did not warn them of the potential for a dangerous runaway chemical reaction.

Image Credit: CSB

A two-inch-diameter line carrying hydrogen gas at 3,000 psi failed at a weld, resulting in a high pressure hydrogen fire. The fire resulted in flame impingement on the calcium silicate insulation of the skirt for a 100-feet-high reactor in a hydrocracker unit. The steel skirt for this reactor, which was between 10 and 12 feet in diameter and had a wall thickness of seven inches, subsequently failed. The falling reactor damaged air coolers and other process equipment, greatly increasing the size of the loss. At the time of the incident, the hydrocracker unit was being shut down for maintenance and the reactor was in a hydrogen purge cycle. The initial hydrogen leak is believed to have resulted from the failure of an elbow to reducer weld in the two-inch-diameter hydrogen preheat exchanger by-pass line.

[ Property Damage $90 Million. Estimated Current Value $202 Million ]

Image credit: San Francisco Chronicle

The incident took place on Easter Monday the 16th April 2001. During the morning the SGP was operating normally and the Central Control Room (CCR) reported a quiet shift, with no alarms showing for the SGP. In the early afternoon there were only 185 people on site, rather than a normal weekday figure of about 800. Most of the staff were inside buildings preparing for the shift handover, which was due to occur at 3pm. A number of people were working in the open air.

At approximately 14.20 hrs a catastrophic failure of a section of pipework on the SGP plant occurred at an elbow just downstream of a water-into-gas injection point. The six inch diameter pipe P4363, (the overhead line carrying flammable gas under high pressure),ruptured releasing a huge cloud containing around 90% ethane/propane/butane. About 20-30 seconds later the gas cloud ignited. As a result a massive explosion and fire followed.

KEY LESSONS:

Management of Pipework Inspection
• Effective pipework inspection systems are a vital major accident prevention measure for high hazard pipework.
• Such systems should at least meet current industry good practice standard.
• Decisions on inspection intervals should be informed by suitable and sufficient information on process conditions and previous inspection findings.

Management of Change
• Effective management of change systems, which consider both plant and process modifications, are essential to prevent major accidents.
• Particular care is needed to ensure that ‘quick fix’ modifications, during the commissioning and early operation phases of new plant, are covered.

Management of Corrosion
• Systematic and thorough arrangements are necessary for the effective management of corrosion on major hazard installations.
• Such arrangements should ensure that any available information on relevant corrosion degradation mechanisms is identified and acted on.
• Adequate resource, including relevant expertise, should be applied to ensure that adequate standards are achieved and maintained.

Communication
• Effective communication is an important element of any safety management system. In the context of major hazard establishments the accurate recording and effective sharing of information and data relevant to plant corrosion is essential for major accident prevention.
• Communication systems should aim to actively involve the workforce in the prevention of major accidents as part of an adequately resourced process safety management system.

Image Credit: HSE

During the transfer of acetal from one vessel to another a fire and explosion occurred due a chemical reaction, which caused the rupture of one of the vessels.

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: Unidentified

An explosion occurred in a glycol unit refining tower of a petrochemical plant

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: CCTV

A fire occurred in a company producing ammonia, and other chemical products. The facility was severely damaged in the catastrophic fire.

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)

Two firefighters were injured tackling a blaze at a refinery. The incident occurred when crude oil leaked from a pipe supplying the refinery from bulk storage tanks.

[ Property Damage $110 Million. Estimated Current Value $147 Million ]

Image credit: ISAB