HSE publishes investigation report into major incident at ConocoPhillips' Humber refinery

E159:05 1 December 2005

The Health and Safety Executive (HSE) today published a report on the investigation into a major explosion and fire at ConocoPhillips Limited's Humber Refinery on 16 April 2001 [PDF 926kb] .

Announcing the report, Kevin Allars, Head of HSE's Hazardous Installations Chemical Industries Division, said: "The fire and explosion at the Humber refinery was a very serious event and could have been catastrophic. It shows the potential harm that arises from major hazard plant. Our investigation revealed that as well as failing to inspect pipework at its site adequately, the company's management had not correctly analysed the effects of an operating change, nor recorded it. This led to operators, inspection and monitoring staff not having a common understanding of the actual operating arrangements at the plant."

The report describes the causes of the incident when 170 tonnes of highly flammable Liquefied Petroleum Gas (LPG) was released from ConocoPhillips' (then Conoco Ltd) Saturate Gas Plant at its oil refinery in South Killingholme, North Lincolnshire. Due to the failure of a pipe a gas cloud developed which was then ignited causing a massive explosion. As the fire burned it caused failures of other pipework resulting in further fires.

The report is the result of a joint investigation (led by HSE) with the Environment Agency. It emphasises the vital need for companies that operate high-hazard sites, such as oil refineries and chemical plants, to ensure they have in place robust and appropriate systems for inspecting pipework to detect corrosion and other defects. In particular, the key messages for the chemical and refinery industries are:

• Effective pipework inspection systems are essential major accident prevention measures for high-hazard pipework. Decisions on inspection intervals must be informed by suitable and sufficient information on process conditions and previous inspection findings;
• Systematic and thorough arrangements are necessary for the effective management of corrosion. Such arrangements should ensure that any information on relevant corrosion degradation mechanisms is identified and acted on. Sufficient resources, including relevant expertise, should be applied to ensure that adequate standards are achieved and maintained; and
• Effective communication is an important element of any safety management system. Accurate recording and effective sharing of information and data relevant to plant corrosion is essential for major accident prevention.

Kevin Allars added: "The report seeks to reassure the public that a thorough and detailed investigation into the cause of the incident has been carried out by all parties concerned. It also demonstrates that a number of lessons have been learned, both by ConocoPhillips and by the regulators, and actions have been taken to improve safety performance at the refinery complex.

"Although the report is primarily aimed at operators of COMAH sites who are asked to carefully consider its contents, it should also be viewed by a wider audience, including safety professionals and trade union representatives involved in major hazard industries."

Notes to editors

• The refinery is subject to the Control of Major Accident Hazards Regulations 1999 (COMAH) and HSE and the Environment Agency are the joint Competent Authority for these regulations. HSE has carried out a thorough investigation into what was a complex incident.
• The public report into the incident is designed to summarise the events and the investigations carried out by the Competent Authorities and by ConocoPhillips Limited. A full description of all the investigative work and the detailed incident specific findings and legal work are not presented in the report.
• On 16 December 2004 at Grimsby Crown Court ConocoPhillips Limited pleaded guilty to breaches of sections 2 and 3 of the Health and Safety at Work etc Act 1974 in relation to the incident. The company was also fined for matters relating to a separate incident and were fined a total of £895,000 with £218,854 costs at Grimsby Crown Court on 29 June 2005.
• The fire and explosion at the Humber Refinery was a very serious event and had the potential to be catastrophic. The immediate area of the refinery was devastated, many other buildings on site were badly damaged and there was widespread damage to surrounding properties. Fatalities and serious injuries were avoided only because the incident occurred on a Bank Holiday and at shift changeover time when there were very few people on site.
• HSE and EA are continuing to monitor ConocoPhillips' performance to ensure the safety issues identified by the investigation are adequately managed.

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