Contributory Factors: Component Malfunction

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

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

The incident occurred when workers were weighing a barrel of 4-hydroxybenzohydrazide. There was a short circuiting in the weighing scale which led to an explosion.

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: Survival Technologies

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

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 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 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

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)