Contributory Factors: PLANT/EQUIPMENT

At 2:09 p.m. on Friday, February 16, 2007, liquid propane under high pressure was released in the Propane De-Asphalting (PDA) unit of Valero’s McKee Refinery, 50 miles north of Amarillo in the Texas panhandle, near the town of Sunray. The resulting propane vapor cloud found an ignition source, and the subsequent fire injured workers, damaged unit piping and equipment, and collapsed a major piperack. The fire grew rapidly and threatened surrounding units, including a Liquefied Petroleum Gas (LPG) storage area. Fire-fighting efforts were hampered by high and shifting winds and the rapid spread of the fire. A refinery-wide evacuation was ordered approximately 15 minutes after the fire ignited.

Three of the four workers injured were seriously burned, including a contractor. The refinery was completely shut down for just under two months and operated at reduced capacity for nearly a year.

KEY ISSUES:
• FREEZE PROTECTION OF DEAD-LEGS
• EMERGENCY ISOLATION OF EQUIPMENT
• FIREPROOFING OF SUPPORT STEEL
• FIRE PROTECTION FOR HIGH PRESSURE LPG SERVICE
• CHLORINE RELEASE

ROOT CAUSES:
1. The McKee Refinery had no formal written program in place to identify, review, and freeze-protect dead-legs or infrequently used piping and equipment, such as the propane mix control station.
2. The McKee Refinery did not apply Valero’s mandatory Emergency Isolation Valve procedure when evaluating risks in the PDA unit to ensure that the large quantities of flammable materials in the unit could be rapidly isolated in an emergency.
3. API guidance and Valero’s corporate Fire Proofing Specifications standard do not specify sufficiently protective distances for fireproofing pipe rack support steel for processes handling high-pressure flammables, such as the LPG in the PDA unit.

Image credit: CSB

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.

Image Credit: CSB

At approximately 6:15 p.m. on March 4, 1998, a catastrophic vessel failure and fire occurred near Pitkin, Louisiana, at the Temple 22-1 Common Point Separation Facility owned by Sonat Exploration Co. Four workers who were near the vessel were killed, and the facility sustained significant damage.

The facility housed two petroleum separation trains and consisted of separation equipment, piping, storage vessels, and a gas distribution system. The separation trains were designed to produce crude oil and natural gas from well fluid, derived from two nearby wells. The vessel ruptured due to overpressurization, releasing flammable material which then ignited.

KEY ISSUES:
• DESIGN & HAZARD REVIEWS
• PRESSURE-RELIEF DEVICES
• OPERATING PROCEDURES

ROOT CAUSES:
1. Sonat management did not use a formal engineering design review process or require effective hazard analyses in the course of designing and building the facility.
2. Sonat engineering specifications did not ensure that equipment that could potentially be exposed to high-pressure hazards was adequately protected by pressure-relief devices.

Image Credit: CSB

Four reactors exploded after an initial fire in a warehouse in the plant. The toxic gas released due to the fire and explosion affected the local community. Electrical short circuit and improper shutdown was the reason that triggered the incident.

Proximate causes:
• Inadequate tools, equipment & vehicles (Electrical appliances shortcut)
• Failure in following procedure (improper shutdown)

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

On Sunday, March 17, 2019, at approximately 10:00 am, a large fire erupted at the Intercontinental Terminals Company, LLC (ITC) bulk liquid storage terminal located in Deer Park, Texas (Figure 1). The fire originated in the vicinity of Tank 80-8, an 80,000-barrel aboveground atmospheric storage tank that held naphtha, a flammable liquid, typically used as a feedstock or blend stock for production of gasoline. ITC was unable to isolate or stop the release of naphtha product from the tank, and the fire continued to burn, intensify, and progressively involved additional tanks in the tank farm. The fire was extinguished on the morning of March 20, 2019.

The incident did not result in any injuries to either ITC personnel or emergency responders. However, the local community experienced disruptions, including several shelter-in-place notifications, which prompted local schools and businesses either to close or operate under modified conditions.

KEY ISSUES:
• RELEASE DETECTION
• RELEASE ISOLATION
• PROLONGED EMERGENCY RESPONSE

Image credit: CSB

On March 21, 2011, during calcium carbide production at the Carbide Industries plant in Louisville, KY, an electric arc furnace exploded, ejecting solid and powdered debris, flammable gases, and molten calcium carbide at temperatures near 3800°F (2100°C). Two workers died and two others were injured.

KEY ISSUES:
• FACILITY SITING
• NORMALIZATION OF DEVIANCE
• CONSENSUS STANDARDS

ROOT CAUSES:
1. Despite past incidents, neither the previous owners nor Carbide Industries identified that the control room should be relocated and cameras installed to better protect workers while they remotely monitored the furnace.
2. Carbide Industries issued 26 work orders for leak repair for water leaks on the furnace cover in the five months prior to the March 2011 incident, but continued operating the furnace despite the hazard from ongoing water leaks.
3. The company did not adequately address past explosive incidents, which normalized blows as routine events.
4. The company did not have a process safety management program in place that required the elimination of overpressure incidents in the furnace.

Image credit: CSB

On April 2, 2010, the Tesoro Refining and Marketing Company LLC (‘Tesoro’) petroleum refinery in Anacortes, Washington (‘the Tesoro Anacortes Refinery’), experienced a catastrophic rupture of a heat exchanger in the Catalytic Reformer / Naphtha Hydrotreater unit (‘the NHT unit’). The heat exchanger, known as E-6600E (‘the E heat exchanger’), catastrophically ruptured because of High Temperature Hydrogen Attack (HTHA). Highly flammable hydrogen and naphtha at more than 500 degrees Fahrenheit (°F) were released from the ruptured heat exchanger and ignited, causing an explosion and an intense fire that burned for more than three hours. The rupture fatally injured seven Tesoro employees (one shift supervisor and six operators) who were working in the immediate vicinity of the heat exchanger at the time of the incident. To date this is the largest fatal incident at a US petroleum refinery since the BP Texas City accident in March 2005.

The NHT unit at the Tesoro Anacortes Refinery contained two parallel groups, or banks, of three heat exchangers (A/B/C and D/E/F) used to preheat process fluid before it entered a reactor, where impurities were treated for subsequent removal. The E heat exchanger was constructed of carbon steel.

At the time of the release, the Tesoro workers were in the final stages of a startup activity to put the A/B/C bank of heat exchangers back in service following cleaning. The D/E/F heat exchangers remained in service during this operation. Because of the refinery’s long history of frequent leaks and occasional fires during this startup activity, the CSB considers this work to be hazardous and nonroutine. While the operations staff was performing the startup operations, the E heat exchanger in the middle of the operating D/E/F bank catastrophically ruptured. .

KEY ISSUES:
• INHERENTLY SAFER DESIGN
• TESORO PROCESS SAFETY CULTURE
• CONTROL OF NONROUTINE WORK
• MECHANICAL INTEGRITY INDUSTRY STANDARD DEFICIENCIES
• REGULATORY OVERSIGHT OF PETROLEUM REFINERIES

ROOT CAUSES:
1. High Temperature Hydrogen Attack
2. NHT Heat Exchanger Flanges – A History of Leaking
3. Hazardous Nonroutine Work
4. Process Hazard Analyses Failed to Prevent or Reduce the Consequences

Image credit: CSB

On Tuesday, April 2, 2019, just before 10:46 am, a vapor cloud of isobutylene formed at the KMCO, LLC (‘KMCO’) facility in Crosby, Texas after a three-inch gray iron (a type of cast iron) y-strainer, a piping component, failed.

Shortly after 10:50 am, the vapor cloud found an ignition source and ignited, causing an explosion. The explosion killed one KMCO worker and seriously burned two others. On the day of the incident, more than 200 KMCO employees, contract workers, and visitors were onsite. The incident injured at least 30 workers (seven KMCO employees and 23 contract workers). A shelter-in-place was issued to community members within one mile of the KMCO facility.

KEY ISSUES:
• MECHANICAL INTEGRITY

Image credit: CSB

At approximately 7:20 a.m. on April 3, 2017, the bottom of a steam condensate (hot water) storage tank catastrophically failed at the Loy-Lange Box Company (LLBC), located at 222 Russell Boulevard in St. Louis, Missouri. The 1952-pound, 30-inch diameter by 17-½-feet long steel tank, called a Semi-Closed Receiver (SCR)4 contained about 510 gallons condensed steam (water at about 330 °F and 100 psig.) Condensate from the vertically-mounted SCR was normally sent to two associated steam generators.

As the pressure in the tank suddenly dropped due to the failure of the tank bottom, a portion of the water in the SCR instantaneously exploded into steam, resulting in an increase in volume of about 75 times the volume of the SCR. A steam explosion of this type is extremely hazardous. The energy released was equivalent to about 350 pounds of TNT. Some of that energy dissipated when the escaping steam condensed to water, but the surveillance video from a nearby custom work truck shop clearly shows the power of the explosion and the effect on the building, as does the damage evident after the event.

The force of the steam explosion exiting the bottom of the SCR destroyed a large portion of the LLBC facility, and launched the storage tank like a rocket through the roof. One LLBC employee was fatally injured, and a second was left in critical condition.

Even after pulling loose from all of the piping and floor attachments, and crashing up through the structure of the building and out through the roof, the 1952-pound SCR was still traveling at about 120 mph. It rose to about 425 feet above street level and traveled laterally across about 520 feet. It remained airborne for over 10 seconds. As it fell, the SCR crashed through the roof of Faultless Healthcare Linen’s property at 2030 S. Broadway, fatally injuring three individuals.

KEY ISSUES:
• CORROSION
• MECHANICAL INTEGRITY & INSPECTION

ROOT CAUSES:
1. Steam generator repairs.

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

Two employees accidently fell in an aerobic tank sewage treatment station. Two more employees fell into the aerobic tank in the subsequent rescue.

Proximate causes:
• Inadequate tools, equipment & vehicles (Aerobic tank no special ventilation equipment)

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

A crack occurred in a pipeline (diameter 200 mm) conveying oil and gas, and the following fire damaged three pumps and some instrumentation

Proximate causes:
• Inadequate tools, equipment & vehicles (Equipment failure: sealing failure and pipe leak)

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

An April 11, 2003, vessel explosion at the D.D. Williamson & Co., Inc. (DDW), plant in Louisville, Kentucky, killed one operator. The explosion damaged the western end of the facility and released 26,000 pounds of aqua ammonia (29.4 percent ammonia solution in water), forcing the evacuation of as many as 26 residents and requiring 1,500 people to shelter-in-place.

DDW used the vessel in the manufacture of food-grade caramel coloring. It functioned as a feed tank for a spray dryer that produced powdered colorants. The feed tank, which was heated with steam and pressurized with air, was operated manually. To ensure that the filling, heating, and material transfer processes stayed within operating limits, operators relied on their experience and on readouts from local temperature and pressure indicators.

The feed tank most likely failed as a result of overheating the caramel color liquid, which generated excessive pressure. .

KEY ISSUES:
• OVERPRESSURE PROTECTION
• HAZARD EVALUATION SYSTEMS
• LAYERS OF PROTECTION
• OPERATING PROCEDURES & TRAINING

ROOT CAUSES:
1. D.D. Williamson did not have effective programs in place to determine if equipment and processes met basic process and plant engineering requirements.
2. D.D. Williamson did not have adequate hazard analysis systems to identify feed tank hazards, nor did it effectively use contractors and consultants to evaluate and respond to associated risks.
3. D.D. Williamson did not have adequate operating procedures or adequate training programs to ensure that operators were aware of the risks of allowing the spray dryer feed tanks to overheat and knew how to respond appropriately.

Image Credit: CSB

On the night of April 12, 2004, during an attempt to make the first production batch of triallyl cyanurate (TAC) at MFG Chemical, Inc. (MFG) in Dalton, Georgia, a runaway chemical reaction released highly toxic and flammable allyl alcohol and toxic allyl chloride into the nearby community. The fire department ordered an evacuation of residents and businesses within a halfmile of the facility. The release forced more than 200 families from their homes. One MFG employee sustained minor chemical burns and 154 people received decontamination and treatment at the local hospital for chemical exposure, including 15 police and ambulance personnel assisting with the evacuation. Five residents required overnight hospitalization for breathing difficulties. The reactor continued venting toxic vapor for nearly eight hours and the evacuation order lasted more than nine hours.

KEY ISSUES:
• REACTIVE CHEMICALS PROCESS DESIGN
• PROCESS SCALE-UP
• EMERGENCY PLANNING & RESPONSE

ROOT CAUSES:
1. MFG did not understand or anticipate the reactive chemistry hazards. They did not make use of readily available literature on the hazards of reactive chemistry, or conduct a comprehensive literature search of the reactive chemistry specifically involved in manufacturing the product, which would have alerted them to the hazards involved in manufacturing TAC.
2. MFG did not perform a comprehensive process design and hazard review of the laboratory scale-up to full production before attempting the first production run.
3. MFG did not prepare and implement an adequate emergency response plan. They did not train or equip employees to conduct emergency mitigation actions.
4. MFG did not implement the EPA Risk Management Program or the OSHA Process Safety Management program prior to receiving the allyl alcohol. The regulations require comprehensive engineering analyses of the process, emergency planning, a pre-startup safety review, and coordination with the local community before receiving the covered chemical at the site and introducing the covered chemical into the process.

Image Credit: CSB

On April 17, 2013, a fire and explosion occurred at the West Fertilizer Company (WFC), a fertilizer blending, retail, and distribution facility in West, Texas. The violent detonation fatally injured 12 emergency responders and three members of the public. Local hospitals treated more than 260 injured victims, many of whom required hospital admission. The blast completely destroyed the WFC facility and caused widespread damage to more than 150 offsite buildings. The WFC explosion is one of the most destructive incidents ever investigated by the U.S. Chemical Safety and Hazard Investigation Board (CSB) as measured by the loss of life among emergency responders and civilians; the many injuries sustained by people both inside and outside the facility fenceline; and the extensive damage to residences, schools, and other structures. Following the explosion, WFC filed for bankruptcy.

The explosion happened at about 7:51 pm central daylight time (CDT), approximately 20 minutes after the first signs of a fire were reported to the local 911 emergency response dispatch center. Several local volunteer fire departments responded to the facility, which had a stockpile of between 40 and 60 tons (80,000 to 120,000 pounds) fertilizer grade ammonium nitrate (FGAN), not counting additional FGAN not yet offloaded from a railcar.

More than half of the structures damaged during the explosion were demolished to make way for reconstruction. The demolished buildings include an intermediate school (552 feet southwest of the facility), a high school (1,263 feet southeast), a two-story apartment complex with 22 units (450 feet west) where two members of the public were fatally injured, and a 145-bed nursing home (500 feet west) where many of the seriously injured civilians resided. A middle school (2,000 feet southwest) also sustained serious but reparable damage. Section 3 describes the incident and its consequences in detail.

KEY ISSUES:
• REGULATORY OVERSIGHT
• HAZARD AWARENESS
• EMERGENCY PLANNING & RESPONSE
• FERTILIZER GRADE AMMONIUM NITRATE STORAGE PRACTICES
• LAND USE PLANNING & ZONING

ROOT CAUSES:
1. The presence of combustible materials used for construction of the facility and the fertilizer grade ammonium nitrate (FGAN) storage bins, in addition to the West Fertilizer Company (WFC) practice of storing combustibles near the FGAN pile, contributed to the progression and intensity of the fire and likely resulted in the detonation.
2. The WFC facility did not have a fire detection system to alert emergency responders or an automatic sprinkler system to extinguish the fire at an earlier stage of the incident.
3. Regulatory, Insurance, Emergency Response, Emergency & Land Use Planning deficiencies.

Image credit: CSB

On April 20, 2010, a multiple-fatality incident occurred at the Macondo oil well approximately 50 miles off the coast of Louisiana in the Gulf of Mexico during temporary well-abandonment activities on the Deepwater Horizon (DWH) drilling rig. Control of the well was lost, resulting in a blowout—the uncontrolled release of oil and gas (hydrocarbons) from the well. On the rig, the hydrocarbons found an ignition source and ignited. The resulting explosions and fire led to the deaths of 11 individuals, serious physical injuries to 17 others, the evacuation of 115 individuals from the rig, the sinking of the Deepwater Horizon, and massive marine and coastal damage from a reported 4 million barrels of released hydrocarbons.

BP was the main operator/lease holder responsible for the well design, and Transocean was the drilling contractor that owned and operated the DWH. On the day of the incident, the crew was completing temporary abandonment of the well so that it could be left in a safe condition until a production facility could return later to extract oil and gas from it.

Abandonment activities would essentially plug the well. Earlier, a critical cement barrier intended to keep the hydrocarbons below the seafloor had not been effectively installed at the bottom of the well. BP and Transocean personnel misinterpreted a test to assess cement barrier integrity, leading them to erroneously believe that the hydrocarbon bearing zone at the bottom of the well had been sealed. When the crew removed drilling mud from the well in preparation to install an additional cement barrier, the open blowout preventer (BOP) was the only physical barrier that could have potentially prevented hydrocarbons from reaching the rig and surrounding environment. The ability of the BOP to act as this barrier was contingent primarily upon human detection of the kick and timely activation and closure of the BOP.

Removing drilling mud after the test allowed hydrocarbons to flow past the failed cement barrier toward the DWH. The hydrocarbons continued to flow from the reservoir for almost an hour without human detection or the activation of the automated controls to close the BOP. Eventually, oil and gas passed above the BOP and forcefully released onto the rig. In response, the well operations crew manually closed the BOP. Oil and gas that had already flowed past the BOP continued to gush onto the rig, igniting and exploding. The explosion likely activated an automatic emergency response system designed to shear drillpipe passing through the BOP and seal the well, but it was unsuccessful.

KEY ISSUES:
• BOP TECHNICAL FAILURE ANALYSIS
• BARRIER MANAGEMENT AT MACONDO
• SAFETY CRITICAL ELEMENTS
• HUMAN FACTORS
• ORGANIZATIONAL LEARNING
• SAFETY PERFORMANCE INDICATORS
• RISK MANAGEMENT PRACTICES
• CORPORATE GOVERNANCE
• SAFETY CULTURE

ROOT CAUSES:
1. Technical Factors
2. Human and Organizational Factors
3. Regulatory Factors

Image Credit: CSB

On May 3, 2019, a silicone manufacturing process generated a flammable gas inside an enclosed production building at the AB Specialty Silicones (‘AB Specialty’) facility in Waukegan, Illinois. At approximately 9:30 p.m., the flammable vapor cloud found an ignition source and ignited, causing an explosion and fire. The flammable vapor originated from the area where AB Specialty was making a silicon hydride emulsion.

The explosion fatally injured four AB Specialty employees and caused serious injury to another AB Specialty employee. At the time of the incident there were nine AB Specialty employees onsite. The explosion heavily damaged the AB Specialty’s production building. Additionally, the force from the explosion was felt up to 20 miles away in the surrounding communities, and some nearby businesses sustained damage from the blast. Post-incident, AB Specialty has resumed some of its operations at another location.

KEY ISSUES:
• FLAMMABLE GAS DETECTION
• FLAMMABLE GAS VENTILATION

Image credit: CSB

At about 12:07 a.m. on May 4, 2009, highly flammable vapor, released from a waste recycling process, ignited and violently exploded, severely injuring two employees and slightly injuring two others at Veolia ES Technical Solutions, LLC. Multiple explosions afterward significantly damaged every structure on the site. Residences and businesses in the surrounding community also sustained considerable damage. The fire was declared under control by 10:38 a.m. that day.

KEY ISSUES:
• UNSAFE BUILDING SITING
• ATMOSPHERIC RELIEF SYSTEMS
• PLANT EMERGENCY PROCEDURES

ROOT CAUSES:
1. The vent devices were not designed to contain or control hazardous and/or toxic vapor.
2. No record existed of a process hazard analysis (PHA) to evaluate the siting of the lab/operations building so close to the operating units.

Image credit: CSB

A leakage of Carbon disulfide cooling pipe occurred in Ruixing company. 8 killed and 6 injured in the following rescue process.

Proximate causes:
• Inadequate tools, equipment & vehicles (pipe leaking)

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

On May 24, 2017, an explosion occurred at the Midland Resource Recovery (MRR) facility in Philippi, West Virginia, killing two workers and severely injuring another worker. The founder and president of MRR was one of the victims. The CSB initiated an investigation of the incident and deployed an investigative team on May 28, 2017. While the CSB was investigating this incident, the MRR facility experienced a second explosion, on June 20, 2017. This explosion fatally injured a contractor employed by Specialized Professional Services, Inc. (SPSI). MRR had hired SPSI to perform investigation and mitigation work at its Philippi facility following the May 24, 2017, explosion.

The CSB determined that the probable cause of these incidents was reactive, unstable chemicals that exploded when workers tried to drain the uncharacterized, chemically treated liquid from natural gas odorizer equipment. The CSB investigation found that MRR lacked an effective safety management system to identify and control hazards from reactive chemicals. Among other things, MRR had no formal hazard identification process in place to analyze or characterize what chemicals were inside the odorizer vessels (and in what quantity) before decommissioning and chemically treating this equipment with sodium hypochlorite. The company also lacked effective safeguards to prevent unexpected or uncontrolled chemical reactions.

Following these catastrophic incidents, MRR asserts that it has stopped using reactive chemicals, including sodium hypochlorite, and the company now uses a proprietary process to remove the mercaptan smell from decommissioned odorization equipment.

KEY ISSUES:
• INEFFECTIVE MANAGEMENT OF REACTIVE CHEMICAL HAZARDS
• LACK OF A PROCESS SAFETY MANAGEMENT SYSTEM
• PERSISTING GAPS IN FEDERAL SAFETY REGULATIONS FOR REACTIVE CHEMICAL HAZARDS

ROOT CAUSES:
1. The company did not conduct a formal evaluation of the reactive chemistry, perform a hazard analysis, and ensure that sufficient safeguards are in place to prevent reactive chemical incidents.
2. The company did have a thorough and complete understanding of their reactive chemistry under design conditions and under all foreseeable abnormal conditions.

Image credit: CSB

A fire occurred in the terpene resin production line reactor overheating, and it damaged an area of 800-900 square meters

Proximate causes:
• Inadequate tools, equipment & vehicles (overheat from reactor of Terpene dilute resin leads the final pipeline explosion)

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

Fire and explosions occurred at the Miller Chemical and Fertilizer Complex, which blended raw materials to manufacture agricultural products

Damage to the facility: $20 million dollars/Shelter-inplace within a mile radius of the warehouse

Proximate causes:
• Defective equipment

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: 911 Photography

On the morning of June 14, 2006, an operator was mixing and heating a flammable mixture of heptane and mineral spirits in a 2,200-gallon open top tank equipped with steam coils. The finished product, ‘Super Clean and Tilt’ is a proprietary mixture, which is applied to cured concrete surfaces to prevent bonding with wet concrete.

As the operator was adding an ingredient to the batch, he observed a ‘dense fog’ accumulating on the floor below the tank. He immediately notified a senior operator who helped him shut down the operation. They both exited the building and advised workers in adjoining areas to leave.

As the vapor cloud spread throughout the mixing area and surrounding workspaces, other employees exited the building.

Within about 10 minutes after the operator first observed the vapor cloud, most employees who were working in the area had evacuated. A contracted delivery driver passed some of these employees as he walked into the building and into the spreading vapor cloud. The cloud ignited within seconds of him entering. The driver died several days later from the burns he received.

The pressure created by the ignition blew the doors open to an adjacent area, injuring a temporary employee. This employee suffered second-degree burns and was hospitalized for three days. .

KEY ISSUES:
• FLAMMABLE LIQUID PROCESS DESIGN
• ENGINEERING CONTROLS
• PLAN REVIEW & CODE ENFORCEMENT
• EMERGENCY PREPAREDNESS

ROOT CAUSES:
1. The process was not designed and constructed in accordance with fire safety codes and OSHA regulations.
2. The Fire Department did not require UFC to comply with critical safety requirements (local exhaust and floor level ventilation)
3. The facility was unprepared for an emergency release of this magnitude.

Image credit: CSB

At approximately 4 am on Friday June 21, 2019 there was a release of vapor in the PES refinery alkylation unit. The vapor found an ignition source, causing a fire and multiple explosions.

KEY ISSUES:
• MECHANICAL INTEGRITY
• HF CORROSION

Image credit: CSB

During the night of June 27, 2016, the two personnel on duty at PGP – a control board operator and an outside operator – were stopping production of natural gas liquids due to pipeline problems downstream of the facility. Although this was a non-routine activity, the control board operator had experience conducting the procedure. The operators initiated the necessary steps from the control room, when, at 11:22 p.m., a sudden explosion and fire occurred. No abnormal alarms or other indicators warned the two PGP personnel of any problems. Within a minute of the initial explosion, the operators activated the emergency shut down systems at the plant and sheltered in the control room.

Over the course of the incident, the site experienced 13 different ruptures of piping and equipment. The CSB concludes that the first loss of containment most likely originated at a BAHX when it lost core integrity due to accumulated thermal fatigue.

The BAHX of interest was part of A-Train, one of three process lines (A, B, and C) at PGP. The rupture released flammable hydrocarbon into the process area in and around a variety of potential ignition sources. After ignition, emergency systems depressurized the plant and sent much of the process fluids to a flare, but the rupture also caused a portion of A-Train’s contents to continue to feed the fire, which intensified several times over approximately the next 35 minutes as additional piping and equipment failed. Equipment, piping, and vessels in the A-Train process area were extensively damaged .

KEY ISSUES:
• EXCHANGER FAILURE DUE TO THERMAL FATIGUE
• SERVICE LIFE DETERMINATION OF BRAZED ALUMINUM HEAT EXCHANGERS
• SOCIAL MEDIA USE IN EMERGENCY RESPONSE

ROOT CAUSES:
1. The absence of a reliable process to ensure the mechanical integrity of the heat exchanger contributed to the catastrophic failure of the equipment.

Image credit: CSB