Country: NORTH AMERICA

An explosion and fire that occurred in a polyethylene wax processing facility operated by Marcus Oil and Chemical on the southwest side of Houston, Texas. On Friday, December 3, 2004, at about 5:50 pm, employees heard a loud “pop” then saw light from a fire reflecting off a shiny tanker truck parked near the process equipment. About 45 seconds later, a violent explosion occurred and a fire fueled by molten wax erupted near the main warehouse. The warehouse and nearby equipment were quickly involved in the fire.

The Houston Fire Department arrived approximately five minutes after the explosion. Firefighters extinguished the three-alarm blaze by midnight, approximately seven hours after the explosion.

Three firefighters were slightly injured while fighting the fire, and local residents sustained minor injuries from flying glass. The explosion shattered windows in buildings and vehicles and caused structural damage as far as one-quarter mile away. Significant interior damage resulted when suspended ceilings and light fixtures were blown down in the onsite buildings, nearby businesses, and a church. Tank 7, a 12-foot diameter, 50-foot long, 50,000-pound pressure vessel was propelled 150 feet where it impacted a warehouse belonging to another business..

KEY ISSUES:
• PRESSURE VESSEL REPAIRS & ALTERATIONS
• NITROGEN INERTING SYSTEM DESIGN & OPERATION

ROOT CAUSES:
1. Poor welding severely weakened Tank 7 and led to its catastrophic failure.
2. The connection between the nitrogen and the compressed air systems increased the oxygen concentration in the inerting gas to an unsafe level.
3. Pressure vessels had operating pressures in excess of 100 psig, yet none was equipped with a pressure relief device.

Image Credit: CSB

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).

Image Credit: Library of Congress

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.

Image credit: CSB

An explosion ripped through the New Cumberland A.L. Solutions titanium plant in West Virginia on December 9, 2010, fatally injuring three workers. The workers were processing titanium powder, which is highly flammable, at the time of the explosion.

KEY ISSUES:
• FEDERAL COMBUSTIBLE DUST OVERSIGHT
• HAZARD RECOGNITION & TRAINING
• LEARNING FROM PREVIOUS INCIDENTS

ROOT CAUSES:
1. AL Solutions did not mitigate the hazards of metal dust explosions through engineering controls, such as a dust collection system. Specifically, AL Solutions did not adhere to the practices recommended in NFPA 484 for controlling combustible metal dust hazards.

Image credit: CSB

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 occurred in the ammonium nitrate process area of this plant. As a result of the explosion, the seven-story main process building was completely destroyed and a 30-foot-diameter crater was created. Metal fragments from the explosion punctured one of the plant’s two 15,000-metric-ton refrigerated ammonia storage tanks. The punctured tank released an estimated 5,700 metric tons of ammonia, causing the evacuation of approximately 2,500 people from the surrounding area. Metal fragments also punctured a nitric acid tank, resulting in the release of approximately 100 metric tons of this acid. The explosion tore metal siding from adjacent buildings, damaged three third-party electric generating stations, broke windows of buildings 16 miles away in Sioux City, and was felt more than 30 miles away.

[ Property Damage $203 Million. Estimated Current Value $404 Million ]

Image credit: EPA
Ref: https://en.wikipedia.org/wiki/Port_Neal_fertilizer_plant_explosion

At 1:33 pm on December 19, 2007, a powerful explosion and subsequent chemical fire killed four employees and destroyed T2 Laboratories, Inc. (T2), a chemical manufacturer in Jacksonville, Florida. It injured 32, including four employees and 28 members of the public who were working in surrounding businesses. Debris from the reactor was found up to one mile away, and the explosion damaged buildings within one quarter mile of the facility.

On December 19, T2 was producing its 175th batch of methylcyclopentadienyl manganese tricarbonyl (MCMT). At 1:23 pm, the process operator had an outside operator call the owners to report a cooling problem and request they return to the site. Upon their return, one of the two owners went to the control room to assist. A few minutes later, at 1:33 pm, the reactor burst and its contents exploded, killing the owner and process operator who were in the control room and two outside operators who were exiting the reactor area.

KEY ISSUES:
• REACTIVE HAZARD RECOGNITION
• HAZARD EDUCATION
• EMERGENCY PREPAREDNESS
• PROCESS DESIGN & SCALE-UP

ROOT CAUSES:
• T2 did not recognize the runaway reaction hazard associated with the MCMT it was producing.

Image credit: CSB

An eight-inch-diameter pipeline operating at approximately 700-pounds-per-square-inch ruptured, releasing a mix of ethane and propane. The record low temperature of 10°F for the region is believed to have contributed to the rupture. After a few minutes, the resulting release was ignited, causing a vapor cloud explosion. The explosion shattered windows up to six miles away and could be felt as far as 15 miles away. Seventeen additional pipelines, in a pipe rack containing 70 lines, were ruptured by the explosion.

The resulting fire involved two large storage tanks holding 3.6 million gallons of diesel, 12 small tanks containing a total of 882,000 gallons of lube oil, and two separator units. The explosion resulted in the partial loss of electricity, steam, and fire water for the refinery, since two power lines, two steam lines and a 12-inch diameter fire water line were located in this pipe rack. Upon the initial explosion, the lines for the dock fire pumps were damaged. Therefore, the water for fire fighting had to be supplied with the remaining plant fire pumps and municipal fire trucks taking draught from alternate sources. Approximately 48,000 gallons of aqueous film-forming foam (AFFF) concentrate, 200 fire brigade members, and 13 pumper units were used during the fire fighting effort, which was successful in extinguishing the fire approximately 14 hours after the initial explosion. Because of this incident, the refinery was completely shut down for three days and operated at reduced capacity for an additional three weeks.

[ Property Damage $69 Million. Estimated Current Value $155 Million ]

Image credit: Sam Kittner

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

A fire broke out at the oil sands refinery in Upgrader 2, an area of the plant that converts bitumen into crude oil products. Approximately 250 people were evacuated from the plant, but no injuries were reported. The fire burned for nine hours before being extinguished. Witnesses reported two explosions minutes apart which sent a fireball six stories high into the air. The plant also suffered ice damage from water used to fight the fire as temperatures in the area fell below -35 C. On February 3, 2005, the company announced that a ruptured cycle line was the most likely cause of the fire. Oil production was reduced from 225,000 bbl-per-day to about 110,000 bbl-per-day for about nine months.

[ Property Damage $120 Million. Estimated Current Value $168 Million ]

Image credit: Suncor

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

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

One worker died after hazardous chemical vapors released from an over-pressurized reactor burned his respiratory system. The worker charged chemicals inside a reactor vessel and a reaction started before he could close it.

OSHA’s proposed penalties total $87,780

Proximate causes:
• Inadequate management/supervision

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

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 January 7, 1998, two explosions in rapid succession destroyed the Sierra Chemical Company Kean Canyon plant near Mustang, Nevada, killing four workers and injuring six others.

The Kean Canyon plant manufactured explosive boosters for the mining industry. When initiated by a blasting cap or detonation cord, boosters provide the added energy necessary to detonate less sensitive blasting agents or other high explosives. The boosters manufactured at the Kean Canyon plant consisted of a base mix and a second explosive mix, called Pentolite, both of which were poured into cardboard cylinders. The primary explosives used in the base mix were TNT (2,4,6-trinitrotoluene), PETN (pentaerythritol tetranitrate), and Comp-B, a mixture of TNT and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine). The Pentolite is a mix of TNT and PETN.

KEY ISSUES:
• PROCESS SAFETY MANAGEMENT
• WORKER TRAINING
• PROCESS HAZARD ANALYSIS
• LANGUAGE BARRIERS

ROOT CAUSES:
1. Process hazard analysis (PHA) conducted by the facility was inadequate.
2. Training programs for facility personnel were inadequate.
3. Written operating procedures were inadequate or not available to workers.
4. The facility was built with insufficient separation distances between different operations and the design and construction of buildings was inadequate.
5. There was no systematic safety inspection or auditing program.
6. The employee participation program was inadequate.

Image Credit: CSB

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)
Image Credit: Creston News Advertiser

On January 9, 2014, West Virginia Department of Environmental Protection (WVDEP) inspectors arrived at the Freedom Industries (Freedom) chemical storage and distribution facility in Charleston, West Virginia, in response to complaints from the public about a chemical odor. Upon arrival, WVDEP inspectors discovered a chemical leaking from tank 396, an aboveground storage tank (AST). The leaking tank contents were originally reported as crude methylcychohexanemethanol (MCHM), but 13 days later Freedom reported it was a mixture of Crude MCHM and polyglycol ethers (PPH, stripped) called Shurflot 944.5 The chemical mixture escaped tank 396 through two small holes on the tank floor and traveled down a descending bank into the adjacent Elk River. The holes were caused by pitting corrosion that initiated on the internal surface of the tank floor. The tank contents drained into the gravel and soil surrounding tank 396 and found multiple pathways into the river. The secondary containment or dike wall, originally designed to control leaks, had cracks and holes from disrepair that allowed the mixture, containing Crude MCHM and PPH, stripped, to escape the containment. The leak also found a pathway to the river through a subsurface culvert, located under adjacent ASTs.

After prompting by WVDEP, Freedom took action to stop the leak and prevent further contamination by deploying services to recover the spill and vacuum the remaining tank contents. However, nearly 11,000 gallons of a mixture containing Crude MCHM and PPH, stripped had already entered into the surrounding soil and Elk River. Once in the river, it flowed downstream to the intake of the West Virginia American Water (WVAW) water treatment facility, about 1.5 miles downriver from Freedom. WVAW’s water treatment and filtration methods were unable to treat and remove all of the chemical mixture in its water treatment process and as a result, it contaminated the drinking water within WVAW’s distribution system. That evening, WVAW issued a Do Not Use (DNU) order for 93,000 customer accounts (approximately 300,000 residents) across portions of nine counties.

KEY ISSUES:
• TANK INSPECTIONS & MAINTENANCE
• RISK COMMUNICATION
• PUBLIC WATER SYSTEMS SAFETY & RISK ASSESSMENT
• TOXICOLOGICAL INFORMATION

ROOT CAUSES:
1. Corrosion of primary containment
2. Deteriorated secondary containment

Image credit: CSB

The entire refinery was shut down for three months after being struck by Hurricane Georges. The hurricane left the entire plant submerged under more than four feet of salt water from the Gulf of Mexico. Although the hurricane was only a Category 2 storm, its slow movement subjected the refinery to 17 hours of high wind and rain. The storm surge overtopped the dikes built to protect the refinery. In all, some 2,100 motors, 1,900 pumps, 8,000 instrument components, 280 turbines, and 200 miscellaneous machinery items required replacement or extensive rebuilding. Newer control buildings and electrical substations sustained little or no damage, as they had been built with their ground floors elevated approximately five feet above grade.

[ Property Damage $190 Million. Estimated Current Value $349 Million ]

Image credit: Chevron

On Wednesday, January 11, 2006, three workers continued the roof removal. About 11:15 a.m., the lead mechanic and the third worker were cutting the metal roof directly above the methanol tank vent. Sparks, showering down from the cutting torch, ignited methanol vapors coming from the vent, creating a fireball on top of the tank. The fire flashed through a flame arrester on the vent, igniting methanol vapors and air inside the tank, causing a explosion inside the steel tank.

The explosion inside the methanol storage tank
• rounded the tank’s flat bottom, permanently deforming the tank and raising the side wall about onefoot;
• ripped the nuts from six bolts used to anchor the tank to a concrete foundation;
• blew the flame arrester off the tank vent pipe;
• blew a level sensor off a 4-inch flange on the tank top;
• separated two 1-inch pipes, valves, and an attached level switch from flanges on the side of the tank;
• separated a 4-inch tank outlet pipe from the tank outlet valve; and
• separated a 4-inch tank fill pipe near the top the tank.

Methanol discharged from the separated pipes ignited and burned, spreading the fire. Methanol also flowed into the containment around the tank and through a drain to the WWTP where it was diluted and harmlessly processed. The lead mechanic and the third worker were in the man-lift basket over the methanol tank when the ignition occurred. They were likely burned from the initial fireball and burning methanol vapors discharging from the tank vent under pressure from the explosion. The lead mechanic, fully engulfed in fire, likely jumped or fell from the man-lift. Emergency responders found his body within the concrete containment next to the tank.

The third worker stated that he had been partially out of the man-lift basket leaning over the roof when the fire ignited. On fire, he climbed onto the roof to escape. Co-workers, unable to reach him with a ladder, told him to jump to an adjacent lower roof and then to the ground. He sustained second and third degree burns over most of his body, and was hospitalized for 4 months before being released to a medical rehabilitation facility. Methanol sprayed from separated pipes onto the crane, burning the crane cab with the mechanic inside. On fire, he exited the cab and was assisted by co-workers. He died in the hospital the following day.

KEY ISSUES:
• HAZARD COMMUNICATION
• HOT WORK CONTROL
• PLASTIC PIPE IN FLAMMABLE SERVICE
• FLAME ARRESTER MAINTENANCE
• FLORIDA PUBLIC EMPLOYEE SAFETY PROGRAMS

ROOT CAUSES:
1. The City of Daytona Beach did not implement adequate controls for hot work at the Bethune Point WWTP.
2. The City of Daytona Beach had a hazard communication program that did not effectively communicate the hazards associated with methanol at the Bethune Point WWTP.

Image 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

On January 13, 2003, at approximately 4:30 pm, a vapor cloud deflagration and pool fire erupted at the BLSR Operating, Ltd. (BLSR), facility located 5 miles north of Rosharon, Texas. Two BLSR employees were killed, and three were seriously burned. Two T&L Environmental Services, Inc. (T&L), truck drivers, who had just delivered gas condensate storage tank basic sediment and water (BS&W) to BLSR, were seriously burned; one of these men died on March 2.

The fire was caused by the release of hydrocarbon vapor during the unloading of BS&W from two vacuum trucks into an open area collection pit. BS&W is an oil/gas exploration and production (E&P) waste liquid. The fire destroyed two 50-barrel (2,100-gallon) vacuum trucks and seriously damaged waste liquid offloading equipment and structures at BLSR. One of the vacuum truck diesel engines was the most likely source of ignition..

KEY ISSUES:
• RECOGNIZING FLAMMABILITY HAZARDS OF EXPLORATION & PRODUCTION WASTE LIQUIDS
• SAFE HANDLING OF FLAMMABLE LIQUIDS

ROOT CAUSES:
1. Noble Energy, Inc., the shipper, failed to identify the flammability hazard of BS&W generated at its gas well production facility, and also failed to communicate the hazard to employees and contractors who were required to handle the flammable liquid.
2. T&L management did not require Noble Energy to provide vacuum truck drivers with a material safety data sheet or other document listing the potential flammability hazard of BS&W, nor did it identify the flammability hazard of the mixture in the vacuum truck tank.
3. BLSR management did not have effective hazard communication practices in place to recognize the potential flammability hazard of each shipment of BS&W, nor did it implement safe handling practices when offloading flammable liquid onto the mud disposal and washout pad area.

Image Credit: CSB

On January 16, 2002, highly toxic hydrogen sulfide gas leaked from a sewer manway at the Georgia-Pacific Naheola mill in Pennington, Alabama. Several people working near the manway were exposed to the gas. Two contractors from Burkes Construction, Inc., were killed. Eight people were injured–seven employees of Burkes Construction and one employee of Davison Transport, Inc. Choctaw County paramedics who transported the victims to hospitals reported symptoms of hydrogen sulfide exposure.

KEY ISSUES:
• REACTIVE HAZARD IDENTIFICATION
• HYDROGEN SULFIDE SAFETY
• EMERGENCY RESPONSE

ROOT CAUSES:
1. Good engineering and process safety practices were not followed when joining the drain from the truck unloading station and the oil pit to the acid sewer.
2. There was no management system to incorporate hazard warnings about mixing sodium hydrosulfide (NaSH) with acid into process safety information.

Image Credit: CSB

On January 21, 1997, an explosion and fire occurred at the Hydrocracker Unit of the Tosco Refinery at Martinez, California, resulting in one death, 46 worker injuries and precautionary sheltering-in-place for the surrounding community. The accident involved the release and autoignition of a mixture of flammable hydrocarbons and hydrogen under high temperature and pressure. EPA undertook an investigation into the causes and underlying circumstances associated with this accident because of its serious consequences (fatality, injuries and offsite concern), the potential for greater impacts, and the opportunity to learn from this accident how similar accidents could be prevented

Image Credit: EPA

On January 22, 2018, a blowout and rig fire occurred at Pryor Trust 0718 gas well number 1H-9, located in Pittsburg County, Oklahoma. The fire killed five workers, who were inside the driller’s cabin on the rig floor. They died from thermal burn injuries and smoke and soot inhalation. The blowout occurred about three-and-a-half hours after removing drill pipe (‘tripping’) out of the well.

The cause of the blowout and rig fire was the failure of both the primary barrier (hydrostatic pressure produced by drilling mud) and the secondary barrier (human detection of influx and activation of the blowout preventer) which were intended to be in place to prevent a blowout.

KEY ISSUES:
• POOR BARRIER MANAGEMENT
• UNDERBALANCED OPERATIONS PERFORMED WITHOUT PROPER PLANNING, PROCEDURES, OR NEEDED EQUIPMENT
• SIGNS OF INFLUX EITHER NOT IDENTIFIED OR INADEQUATELY RESPONDED TO
• ALARM SYSTEM OFF
• FLOW CHECKS NOT CONDUCTED
• GAPS IN SAFETY MANAGEMENT SYSTEM
• DRILLER’S CABIN DESIGN
• BOP COULD NOT CLOSE DUE TO BURNED HYDRAULIC HOSES
• LACK OF SAFETY REQUIREMENTS BY REGULATION

ROOT CAUSES:
1. Failure of primary barrier – hydrostatic pressure produced by drilling mud.
2. Failure of secondary barrier – human detection of influx and activation of the blowout preventer.

Image & AcciMap Credit: CSB

Image credit: CSB

On January 22 and 23, 2010, three separate incidents at the DuPont plant in Belle, WV, involving releases of methyl chloride, oleum, and phosgene, triggered notification of outside emergency response agencies. The incident involving the release of phosgene gas led to the fatal exposure of a worker performing routine duties in an area where phosgene cylinders were stored and used.

Operators discovered the first incident, the release of methyl chloride, the morning of January 22, 2010, when an alarm sounded on the plant’s distributed control system monitor. They confirmed that a release had occurred and that methyl chloride was venting to the atmosphere. Managers assessing the release estimated that more than 2,000 pounds of methyl chloride may have been released over the preceding 5 days.

The oleum release, the second incident, occurred the morning of January 23, 2010. Workers discovered a leak in an overhead oleum sample pipe that was allowing a fuming cloud of oleum to escape to the atmosphere. The plant fire brigade, after donning the appropriate personal protective equipment, closed a valve that stopped the leak about an hour after it was discovered. No injuries occurred, but the plant called the Belle Volunteer Fire Department to assist.

The third incident, a phosgene release, occurred later that same day when a hose used to transfer phosgene from a 1-ton cylinder to a process catastrophically failed and sprayed a worker in the face while he was checking the weight of the cylinder. The employee, who was alone when exposed, was assisted by co-workers who immediately responded to his call for help. Initial assessments by the plant’s occupational health nurse indicated that the worker showed no symptoms of exposure prior to transport to the hospital for observation and treatment. A delayed onset of symptoms, consistent with information in phosgene exposure literature, occurred after he arrived at the hospital. His condition deteriorated over the next day and he died from his exposure the next night.

KEY ISSUES:
• MECHANICAL INTEGRITY
• ALARM MANAGEMENT
• OPERATING PROCEDURES
• COMPANY EMERGENCY RESPONSE & NOTIFICATION

ROOT CAUSES:

Methyl Chloride Incident (January 22, 2010)
1. DuPont management, following their Management of Change process, approved a design for the rupture disc alarm system that lacked sufficient reliability to advise operators of a flammable methyl chloride release.

Oleum Release Incident (January 23, 2010)
1. Corrosion under the insulation caused a small leak in the oleum pipe.

Phosgene Incident (January 23, 2010)
1. DuPont’s phosgene hazard awareness program was deficient in ensuring that operating personnel were aware of the hazards associated with trapped liquid phosgene in transfer hoses.
2. DuPont relied on a maintenance software program that was subject to changes without authorization or review, did not automatically initiate a change-out of phosgene hoses at the prescribed interval, and did not provide a back-up process to ensure timely change-out of hoses.
3. DuPont Belle’s near-miss reporting process was not rigorous enough to ensure that the near failure of a similar phosgene transfer hose, just hours prior to the exposure incident, would be immediately brought to the attention of plant supervisors and managers.
4. DuPont lacked a dedicated radio/telephone system and emergency notification process to convey the nature of an emergency at the Belle plant, thereby restricting the ability of personnel to provide timely and quality information to emergency responders.

Image credit: CSB

The massive explosion fatally injured two workers and caused extensive damage to nearby structures.

Image credit: CSB

During the early morning hours of January 25, ASCO employees filled cylinders with purchased acetylene. At approximately 9:30 am, with the depletion of the supply of purchased acetylene, they began to produce acetylene from calcium carbide in the generator.

Because of heavy snowfall, workers were shoveling snow in the area south of the decant tanks near the loading dock. At 10:36 am, an explosion occurred, centered in the shed. Two of the workers immediately south of the shed were killed instantly. A third worker farther south, closer to the loading dock, was severely injured and was pronounced dead shortly after arriving at the Newark Medical Center. A fourth worker who was in the loading dock/lime pit area was very seriously injured by the blast. .

KEY ISSUES:
• OPERATING PROCEDURES
• STAFF TRAINING
• DRAIN & VENT TO SAFE LOCATION
• BUILDINGS TO BE DESIGNED FOR ACETYLENE CONTAINMENT
• MECHANICAL INTEGRITY
• POSITIVE ISOLATION

ROOT CAUSES:
1. At ASCO, a line that could potentially contain acetylene drained into an enclosed wooden shed.
2. The shed in this incident was not designed or constructed in accordance with NFPA 51A.
3. At ASCO the check valve was relied upon to prevent backflow. The check valve and block valve that failed at ASCO and allowed backflow were not on a testing or inspection schedule. The single block valve on the recycle water line, which was found closed after the explosion, leaked during post-incident testing.
4. Operators did not use either written operating procedures or check lists for start up of the acetylene generator or recycled water system at this facility.

Image Credit: CSB

The Space Shuttle Challenger disaster was a fatal incident in the United States space program that occurred on Tuesday, January 28, 1986, when the Space Shuttle Challenger (OV-099) broke apart 73 seconds into its flight, killing all seven crew members aboard. The crew consisted of five NASA astronauts, one payload specialist, and a civilian schoolteacher. The mission carried the designation STS-51-L and was the tenth flight for the Challenger orbiter.

The spacecraft disintegrated over the Atlantic Ocean, off the coast of Cape Canaveral, Florida, at 11:39 a.m. EST (16:39 UTC). The disintegration of the vehicle began after a joint in its right solid rocket booster (SRB) failed at liftoff. The failure was caused by the failure of O-ring seals used in the joint that were not designed to handle the unusually cold conditions that existed at this launch. The seals’ failure caused a breach in the SRB joint, allowing pressurized burning gas from within the solid rocket motor to reach the outside and impinge upon the adjacent SRB aft field joint attachment hardware and external fuel tank. This led to the separation of the right-hand SRB’s aft field joint attachment and the structural failure of the external tank. Aerodynamic forces broke up the orbiter.

Image Credit: NASA

On January 29, 2003, an explosion and fire destroyed the West Pharmaceutical Services plant in Kinston, North Carolina, causing six deaths, dozens of injuries, and hundreds of job losses. The facility produced rubber stoppers and other products for medical use. The fuel for the explosion was a fine plastic powder, which accumulated above a suspended ceiling over a manufacturing area at the plant and ignited.

KEY ISSUES:
• HAZARD RECOGNITION & COMMUNICATION
• GOOD ENGINEERING PRACTICE
• LOCAL AMENDMENTS TO FIRE CODES

ROOT CAUSES:
1. West did not perform adequate engineering assessment of the use of powdered zinc stearate and polyethylene as antitack agents in the rubber batchoff process.
2. West engineering management systems did not ensure that relevant industrial fire safety standards were consulted.
3. West management systems for reviewing material safety data sheets did not identify combustible dust hazards.
4. The Kinston plant’s hazard communication program did not identify combustible dust hazards or make the workforce aware of such.

Image Credit: CSB

On Wednesday, January 29, 2020, a gas well explosion fatally injured three contractors. The gas well was operated by Chesapeake Energy.

Image credit: CSB

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.

Image credit: CSB

The United States flag tanker “Edgar M. Queeny” rammed the Greek tanker “Corinthos,” while the latter was discharging 400,000 bbl of crude oil at a refinery jetty at Marcus Hook on the Delaware River. A huge initial explosion, and subsequent explosions and fires, occurred on the Greek ship as a result.

Twenty-five crew members were killed on board the vessel, in addition to a crewman from the flag tanker. The Corinthos sank shortly afterwards and was later removed for scrapping.

This incident occurred at Synthron, LLC’s Morganton, North Carolina, facility. The company manufactured a variety of powder coating and paint additives by polymerizing acrylic monomers in a 1,500 gallon reactor.

The company had received an order for slightly more of an additive than the normal size recipe would produce. Plant managers scaled up the recipe to produce the required larger amount of polymer, and added all of the additional monomer needed into the initial charge to the reactor. This more than doubled the rate of energy release in the reactor, exceeding the cooling capacity of the reactor condenser and causing a runaway reaction.

The reactor pressure increased rapidly. Solvent vapors vented from the reactor’s manway, forming a flammable cloud inside the building. The vapors found an ignition source, and the resulting explosion killed one worker and injured 14. The blast destroyed the facility and damaged off-site structures.

KEY ISSUES:
• REACTIVE HAZARDS & SAFEGUARDS
• CORPORATE OVERSIGHT
• SAFE OPERATING LIMITS
• EVACUATION PLANNING & DRILLS

ROOT CAUSES:
1. A lack of hazard recognition.
2. Poorly documented process safety information & ineffective control of product recipe changes.
3. Lack of automatic safeguards to prevent or mitigate the effects of loss of control over the reaction.
4. Improper manway bolting practices and poor operator training.
5. Inadequate emergency plans drills.
6. Inadequate corporate oversight of process safety.

Image credit: CSB

Three combustible dust incidents over a six month period occurred at the Hoeganaes facility in Gallatin, TN, resulting in fatal injuries to five workers. The facility produces powdered iron and is located about twenty miles outside of Nashville.

KEY ISSUES:
• HAZARD RECOGNITION AND TRAINING
• ENGINEERING CONTROLS
• FIRE CODES/ENFORCEMENT
• REGULATORY OVERSIGHT

ROOT CAUSES:
1. Hoeganaes facility management were aware of the iron powder combustibility hazard two years prior to the fatal flash fire incidents but did not take necessary action to mitigate the hazard through engineering controls and housekeeping.
2. Hoeganaes did not institute procedures – such as combustible gas monitoring – or training for employees to avoid flammable gas fires and explosions

Image credit: CSB

The Space Shuttle Columbia disaster was a fatal incident in the United States space program that occurred on February 1, 2003, when the Space Shuttle Columbia (OV-102) disintegrated as it re-entered the atmosphere, killing all seven crew members. The disaster was the second fatal accident in the Space Shuttle program, after the 1986 breakup of Challenger soon after liftoff.

During the launch of STS-107, Columbia’s 28th mission, a piece of foam insulation broke off from the Space Shuttle external tank and struck the left wing of the orbiter. Similar foam shedding had occurred during previous shuttle launches, causing damage that ranged from minor to nearly catastrophic, but some engineers suspected that the damage to Columbia was more serious. Before re-entry, NASA managers had limited the investigation, reasoning that the crew could not have fixed the problem if it had been confirmed. When Columbia re-entered the atmosphere of Earth, the damage allowed hot atmospheric gases to penetrate the heat shield and destroy the internal wing structure, which caused the spacecraft to become unstable and break apart.

Image Credit: NASA

On February 2, 2001, a fire occurred at Bethlehem Steel Corporation’s Burns Harbor mill in Chesterton, Indiana. One Bethlehem Steel millwright and one contractor supervisor died. Four Bethlehem Steel millwrights were injured, one seriously. Workers were attempting to remove a slip blind and a cracked valve from a coke oven gas line leading to a decommissioned furnace. During removal of the valve, flammable liquid was released and ignited.

KEY ISSUES:
• MAINTENANCE JOB PLANNING
• FACILITY WINTERIZATION & DEADLEGS
• LINE & EQUIPMENT OPENING
• DECOMMISSIONING & DEMOLITION

ROOT CAUSES:
1. Management systems for the supervision, planning, and execution of maintenance work were inadequate.
2. The Burns Harbor facility did not have a system for monitoring and controlling hazards that could be caused by changes in COG condensate flammability or accumulation rates.

Image Credit: CSB

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

Six workers were fatally injured during a planned work activity to clean debris from natural gas pipes at Kleen Energy in Middletown, CT. To remove the debris, workers used natural gas at a high pressure of approximately 650 pounds per square inch. The high velocity of the natural gas flow was intended to remove any debris in the new piping. During this process, the natural gas found an ignition source and exploded.

KEY ISSUES:
• SIMILAR NATURAL GAS BLOW INCIDENTS
• INDUSTRY PRACTICES AND SAFER ALTERNATIVE METHODOLOGIES
• HAZARDS OF RELEASING NATURAL GAS NEAR WORK AREAS
• CODES AND STANDARDS

ROOT CAUSES:
1. Natural gas blows are common
2. Workers remained in building during gas blow

Image credit: CSB

On February 7, 2008, at about 7:15 p.m., a series of sugar dust explosions at the Imperial Sugar manufacturing facility in Port Wentworth, Georgia, resulted in 14 worker fatalities. Eight workers died at the scene and six others eventually succumbed to their injuries at the Joseph M. Still Burn Center in Augusta, Georgia. Thirty six workers were treated for serious burns and injuries – some caused permanent, life altering conditions. The explosions and subsequent fires destroyed the sugar packing buildings, palletizer room, and silos, and severely damaged the bulk train car loading area and parts of the sugar refining process areas.

KEY ISSUES:
• COMBUSTIBLE DUST HAZARD RECOGNITION
• MINIMIZING COMBUSTIBLE DUST ACCUMULATION IN THE WORKPLACE
• EQUIPMENT DESIGN & MAINTENANCE

ROOT CAUSES:
1. Sugar and cornstarch conveying equipment was not designed or maintained to minimize the release of sugar and sugar dust into the work area.
2. Inadequate housekeeping practices resulted in significant accumulations of combustible sugar and sugar dust on the floors and elevated surfaces throughout the packing buildings.
3. Imperial Sugar emergency evacuation plans were inadequate. Emergency evacuation drills were not conducted, and prompt worker notification to evacuate in the event of an emergency was inadequate.

Image credit: CSB

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 Wednesday, February 8, 2017, at approximately 11:05 am, a foul condensate tank, part of a non-condensable gas system, exploded at the Packaging Corporation of America (PCA) containerboard mill in DeRidder, Louisiana. The explosion killed three people and injured seven others. All 10 people were working at the mill as contractors. The explosion also heavily damaged the surrounding process. The foul condensate tank travelled approximately 375 feet and over a six-story building before landing on process equipment.

At the time of the incident, the mill was undergoing its annual planned maintenance outage, also referred to as a shutdown. The foul condensate tank likely contained water, a layer of flammable liquid turpentine on top of the water, and an explosive vapor space containing air and flammable turpentine vapor.

KEY ISSUES:
• PROCESS SAFETY MANAGEMENT SYSTEM
• INHERENTLY SAFER DESIGN
• PROCESS HAZARD ANALYSIS
• INEFFECTIVE SAFEGUARDS
• HOT WORK SAFETY MANAGEMENT

ROOT CAUSES:
1. PCA did not evaluate the majority of the non-condensable gas system, including the foul condensate tank, for certain hazards. The DeRidder mill never conducted a process hazard analysis to identify, evaluate, and control process hazards for the non-condensable gas system.
2. PCA did not expand the boundaries of its process safety management program beyond the units covered by safety regulations.
3. PCA did not effectively apply the hierarchy of controls to the selection and implementation of safeguards that the company used to prevent a potential non-condensable gas explosion.
4. PCA did not evaluate inherently safer design options that could have eliminated the possibility of air entering the non-condensable gas system, including the foul condensate tank.
5. PCA did not establish which mill operations group held ownership of, and responsibility for, the foul condensate tank.
6. PCA did not apply important aspects of industry safety guidance and standards.

Image credit: CSB

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

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

A rail car with more than 100 tanks of crude bakken oil derailed in West Virginia, generating a huge fireball, the evacuation of hundreds of people and, a spill into the Kanawha River.

Hundreds evacuated – FRE issued CSX and Sperry Rail Service $25.000 fines each

Proximate causes:
• Inadequate tools, equipment & vehicles (rail defect)

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

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

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 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

A February 20, 2003, dust explosion at the CTA Acoustics, Inc. (CTA) facility in Corbin, Kentucky, killed seven and injured 37 workers. This incident caused extensive damage to the production area of the 302,000-square-foot plant. Nearby homes and an elementary school were evacuated, and a 12-mile section of Interstate 75 was closed. The largest CTA customer, Ford Motor Company, temporarily suspended operations at four automobile assembly plants because CTA had produced acoustic insulation products for those plants, as well as for other industrial and automotive clients.

KEY ISSUES:
• COMBUSTIBLE DUST HAZARD AWARENESS
• WORK PRACTICES
• BUILDING DESIGN
• PRODUCT STEWARDSHIP

ROOT CAUSES:
1. CTA management did not implement effective measures to prevent combustible dust explosions.
2. The CTA cleaning and maintenance procedures for production lines did not prevent the accumulation of unsafe levels of combustible dust on elevated flat surfaces.
3. The CTA incident investigation program did not ensure that all oven fires were investigated and that underlying causes were identified and resolved.
4. The Borden Chemical product stewardship program did not explicitly convey to CTA the explosive hazards of phenolic resins.
5. The original building design and subsequent building modifications did not effectively address the fire and explosion hazards associated with combustible dusts.

Image Credit: CSB

On February 23, 1999, a fire occurred in the crude unit at Tosco Corporation. Avon oil refinery in Martinez, California. Workers were attempting to replace piping attached to a 150-foot-tall fractionator tower while the process unit was in operation. During removal of the piping, naphtha was released onto the hot fractionator and ignited. The flames engulfed five workers located at different heights on the tower. Four men were killed, and one sustained serious injuries.

KEY ISSUES:
• CONTROL OF HAZARDOUS NONROUTINE MAINTENANCE
• MANAGEMENT OVERSIGHT & ACCOUNTABILITY
• MANAGEMENT OF CHANGE
• CORROSION CONTROL

ROOT CAUSES:
1. Tosco Avon refinery’s maintenance management system did not recognize or control serious hazards posed by performing nonroutine repair work while the crude processing unit remained in operation.
2. Tosco’s safety management oversight system did not detect or correct serious deficiencies in the execution of maintenance and review of process changes at its Avon refinery.

Image Credit: CSB

The Rimbey pipeline system in Alberta, Canada transports liquid propane, butane and condensate products in an 8-inch pipeline. On the day of the incident the operating pumps were pumping against a closed valve. The line failed at a pressure of approximately 8000 kPa, which is below the 8372 kPa maximum operating pressure for the pipeline.

Liquid propane erupted violently and formed a pond of boiling propane. The propane quickly formed a ground level flammable gas cloud, which rolled across topsoil until it reached a road where it was ignited by a passing truck. Liquid propane entered a nearby storm sewer catchment basin. The propane spread into adjacent sewer lines. Explosive mixtures were detected over a wide area within the sewer system.

No injuries were recorded, however the incident instigated a large-scale evacuation of 19,000 people while efforts were made to eliminate the explosive danger.

A combination of water flushing, ventilation and nitrogen gas blanketing successfully eliminated the danger about 23 hours after the original fracture. Maintenance crews plugged the pipeline either side of the fracture to stop the flow of leaking gas

KEY ISSUES:
• EMERGENCY RESPONSE / SPILL CONTROL

Image Credit: Provincial Archives Of Alberta