Impact: HUMAN (Offsite Injuries)

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 International Biosynthetics (IBIS) plant was, at the time of the accident, a wholly owned subsidiary of Shell UK Ltd. and employed some 250 people in the manufacture of fine chemicals.

The release occurred on the phosgene plant at 11:27 hours on 7 December 1991. The batch reaction involved the phosgenation of dimethyl aniline (DMA) in a toluene solution. The process involved the addition of 1 tonne of recycled toluene to the reactor, then as no more recycled toluene was available fresh toluene was to be added. Attempts were made to fill the reactor with 2 tonnes of fresh toluene. The flow indicator showed that the required amount of toluene had been added to the reactor, however a control valve between the pump and the vessel was closed and none of the toluene had been added. A level measurement was available for the vessel but as the process appeared to be proceeding normally this was not checked.

The next stage was to add 20 kg of phosgene to check if any water was present in the reactor. This would have resulted in a temperature rise of the solution. Because there was insufficient toluene in the vessel, the temperature indicator was not in the solution and therefore showed no temperature rise. As there appeared to be no water in the reactor, 0.8 tonnes of phosgene were then added to the vessel. After a shift changeover the next steps in the process were carried out. These were to add 1.6 tonnes of DMA and heat to 65°C. The operating temperature was reached but the temperature continued to rise to well above 100°C. As the pressure increased the pressure control valve, pressure relief valve and bursting disc all operated as designed and relieved the vessel to a scrubbing column. The reaction was more violent than had been predicted and the relief system had insufficient capacity to deal with the pressure rise. This resulted in a connection on the condenser line failing and releasing the contents of the vessel to atmosphere. Fortunately the phosgene had been consumed in the reaction. However, the vapour cloud drifted for 4 km affecting about 60 people and staining some property blue.

KEY ISSUES:
• CONTROL SYSTEMS
• REACTION / PRODUCT TESTING
• RELIEF SYSTEMS / VENT SYSTEMS

Report: https://www.icheme.org/media/13702/release-of-chemicals-from-international-biosynthetics-ltd.pdf

Image Credit: HSE

In the early hours of Sunday 11th December 2005, a number of explosions occurred at Buncefield Oil Storage Depot, Hemel Hempstead, Hertfordshire. At least one of the initial explosions was of massive proportions and there was a large fire, which engulfed a high proportion of the site.

Over 40 people were injured; fortunately there were no fatalities. Significant damage occurred to both commercial and residential properties in the vicinity and a large area around the site was evacuated on emergency service advice. The fire burned for several days, destroying most of the site and emitting large clouds of black smoke into the atmosphere.

KEY ISSUES:
• SYSTEMATIC ASSESSMENT OF SAFETY INTEGRITY LEVEL REQUIREMENTS
• PROTECTING AGAINST LOSS OF PRIMARY CONTAINMENT
• ENGINEERING AGAINST ESCALATION OF LOSS OF PRIMARY CONTAINMENT
• ENGINEERING AGAINST THE LOSS OF SECONDARY AND TERTIARY CONTAINMENT
• OPERATING WITH HIGH RELIABILITY ORGANISATIONS
• DELIVERING HIGH PERFORMANCE THROUGH CULTURE AND LEADERSHIP

HSE Reports:
MIIB Final Report Vol 1: https://www.icheme.org/media/13707/buncefield-miib-final-report-volume-1.pdf
MIIB Final Report Vol 2a: https://www.icheme.org/media/13923/buncefield-miib-final-report-volume-2a.pdf
MIIB Final Report Vol 3a: https://www.icheme.org/media/13923/buncefield-miib-final-report-volume-2a.pdf
Land Use Planning – Recommendations: https://www.icheme.org/media/10694/recommendations-on-land-use-planning.pdf
Land Use Planning – Model: https://www.icheme.org/media/13709/illustrative-model-of-a-risk-based-lup-system_repaired.pdf
Explosion Mechanism: https://www.icheme.org/media/10696/buncefield-explosion-mechanism-advisory-group-report.pdf
BSTG Final Report: https://www.icheme.org/media/10697/safety-and-environmental-standards-for-fuel-storage-sites.pdf
Emergency Preparedness: https://www.icheme.org/media/10698/recommendations-on-emergency-preparedness.pdf
Design & Operation: https://www.icheme.org/media/10699/recommendations-on-the-design-and-operation-of-fuel-storage-sites.pdf
Initial Report: https://www.icheme.org/media/10700/buncefield-initial-report.pdf
Investigation – Progress Report: https://www.icheme.org/media/10705/buncefield-first-progress-report.pdf
Investigation – 2nd Progress Report: https://www.icheme.org/media/10703/buncefield-second-progress-report.pdf
Investigation – 3rd Progress Report: https://www.icheme.org/media/10702/buncefield-third-progress-report.pdf
Why did it happen?: https://www.icheme.org/media/10706/buncefield-report.pdf

Image Credit: Hertfordshire County Council

On 4 January 1977, a serious fire and explosion occurred at the Braehead Container Clearance Depot at Renfrew in Scotland.

The fire and explosion, which originated at a warehouse occupied by James Kelman Transport and Storage, completely wrecked that warehouse and the adjacent whisky bonded warehouse occupied by Clyde Container Services Ltd and also caused widespread window and roof damage to domestic, commercial, industrial and public property within a radius of a mile of the premises. The cost of the damage is estimated at some £6 000 000.

It was fortunate that, despite the extent of the damage, only twelve members of the public and one watchman were treated for shock and minor injuries. After investigation had eliminated one cause of fire after another it was discovered that it had accidently been started by three boys who had lit a fire to warm themselves at a den which they had made, during the New Year holiday, from cardboard cartons stacked beside the warehouse.

Subsequent experimental work tended to suggest that explosions of this nature and severity can be caused by the involvement of commercially pure sodium chlorate under the intense heat conditions of an industrial fire.

Report: https://www.icheme.org/media/13693/the-fire-and-explosion-at-braehead-container-depot-renfrew.pdf

Image Credit: HSE

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

At about 8.23 pm on 1 February 1994 there was a release of reactor solution from a recirculating pump near the base of a 25 tonne ethyl chloride (EC) reactor vessel at the factory of The Associated Octel Company Ltd, Ellesmere Port, Cheshire. The reactor solution was highly flammable, corrosive and toxic, mainly consisting of ethyl chloride, a liquefied flammable gas, mixed with hydrogen chloride a toxic and corrosive gas, and small quantities of solid catalyst, aluminium chloride. A dense, white cloud soon enveloped the plant and began to move off-site.

The on-site and external emergency services were called in accordance with pre-arranged procedures for major incidents involving chemical release. Over the next one and a half hours action was taken to isolate the leak, to suppress the further release of vapour and to prevent the cloud spreading.

In spite of these attempts a pool of liquid continued to collect and at 10.08 pm the flammable vapours of ethyl chloride ignited, causing a major pool fire which was most intense at the base of the reactor. As the incident developed there were also fires at flanges damaged in the fire, including jet flames at the top of two large process vessels on the plant. Although these vessels and the reactor were protected by a fire resistant coating, there was concern at one stage that the vessels might explode and the damage extend to chlorine storage vessels on the adjacent plant.

The leak occurred at a point between fixed pipework and the discharge port of a pump recirculating liquids to the reactor, as a direct consequence of either (a) the failure of a corroded securing flange on the pump working loose; or (b) the failure of a PTFE flexible connection (‘bellows’) connecting the pump discharge to the pipe. The HSE believes the first of these possible causes was the more likely. The most likely source of ignition was an electrical control box to a compressor nearby.

KEY ISSUES:
• CORROSION / SELECTION OF MATERIALS
• DESIGN CODES – PIPEWORK
• MAINTENANCE PROCEDURES
• ISOLATION

Report: https://www.icheme.org/media/13705/the-chemical-release-and-fire-at-the-associated-octel-company-limited.pdf

Image Credit: HSE

Employees at the plant were carrying out their normal duties when two chemical compounds came into contact. An explosion occurred releasing a toxic cloud into the air. Toxic cloud

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

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

An accident occurred at a methylcellulose manufacturing facility. An explosion occurred and was followed by a fire, which was extinguished about seven hours later. A total of 17 people working at the site were injured in this accident; three critically, five seriously, and nine with minor injuries. There was one minor injury off site. Ignition of the methylcellulose powder is though to have been due to static electricity, resulting in a powder dust explosion. All methylcellulose operations were suspended for two months before sequentially restarting.

[ Property Damage $240 Million. Estimated Current Value $306 Million ]

Image credit: Shin-Etsu