On This Day In History
Date
[Date of Event]
Location
[Location]
Industry
[Industry]
Substance
[Substance Name]
Cause
[Cause of Event]
Consequence
[Consequence of Event]
Injuries
[Number of Injuries]
Fatalities
[Number of Fatalities]
Lessons Learned
[Lessons Learned]
A major LPG explosion and subsequent fire occurred at the Conoco Humber Refinery (now Phillips 66) in the Saturate Gas Plant (SGP) area.The incident was initiated by the catastrophic failure of an overhead pipe carrying flammable hydrocarbon vapours from the de-ethaniser column.This released a large vapour cloud which ignited, causing a significant explosion and a fire that burned for over three hours, severely damaging the SGP and surrounding units.
April 16, 2001
United Kingdom
Energy (Oil Refining)
Hydrocarbons
The immediate cause was the catastrophic rupture of a 6-inch diameter carbon steel pipe elbow (Line P4363) in the de-ethaniser overheads circuit. This failure resulted from severe internal erosion-corrosion. A water injection point, added years earlier to prevent downstream fouling but located just 67cm upstream of the elbow without a proper dispersion device, continuously washed away the protective internal iron sulphide layer. This allowed corrosive agents in the stream (H2S, chlorides etc.) to aggressively attack the exposed pipe wall, reducing its thickness from ~7.1mm to as little as 0.3mm in places. Root causes identified by the Health and Safety Executive (HSE) investigation included:
- Inadequate Pipework Inspection Regime: The refinery’s inspection system failed to identify the severely corroded state of the pipework.
- Insufficient Management of Change (MoC): The potential impact of installing and operating the water wash point on upstream pipework integrity was not adequately assessed or managed.
- Weaknesses in Corrosion Management: Systems and resources for identifying, assessing, and mitigating corrosion threats (particularly location-specific ones like downstream of injection points) were insufficient.
- Large Vapour Cloud Explosion (VCE) followed by a major fire lasting over 3 hours.
- Extensive damage leading to the write-off of the Saturate Gas Plant (SGP).
- Significant damage to adjacent units (e.g., Coker closed blowdown system) and widespread lesser damage across the site, including administration buildings, canteens, and stores (damaged cladding, glazing, minor structural damage).
- Damage to off-site properties (mainly broken windows, some minor structural damage) up to 1.5km away in South Killingholme and Immingham, with 370 separate damage reports received.
- Temporary shutdown of the entire refinery operations.
- Release of asbestos due to damage to lagging materials.
- Minor injuries on site; remarkably few considering the scale, attributed to it being a Bank Holiday with reduced staffing (~185 on site vs. ~800 normally) and timing near shift change.
1 minor on-site injury and 2 minor off-site injuries
(Note: An IChemE paper notes 71 subsequent civil claims for injury were pursued by workers and members of the public.)
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- Mechanical Integrity: The critical need for robust, risk-based inspection (RBI) programs for pipework that specifically address potential degradation mechanisms (like erosion-corrosion) and identify high-risk locations (e.g., downstream of injection points).
- Management of Change (MoC): Rigorous assessment of all process and plant modifications is essential to identify and mitigate potential unintended consequences, including impacts on material degradation.
- Corrosion Management: Effective corrosion management requires dedicated systems, expertise, sustained resources, and clear communication to ensure potential threats are understood and controlled throughout the plant lifecycle. Understanding the interaction between process fluids, materials, and operating conditions (including additions like water wash) is crucial.
- Hazard Identification: Recognising and assessing specific hazards introduced by operational practices or modifications is vital for prevention.
