2 years on - Chevron Pembroke refinery explosion

2 years on - Chevron Pembroke Refinery Explosion

03 June 2013

It is now 2 years since an explosion and fire at the Chevron Pembroke Refinery, 2 June 2011, killed 4 workers and very seriously injured another. Subsequently the HSE issued the alert set out below. During the last 2 years Unite has been trying to obtain more detail from the HSE about the suspected cause of the explosion so that refineries elsewhere are able investigate their own procedures and, if necessary, to take precautionary measures. However, HSE is still unwilling, or unable, to provide any additional information.
Based on information received from the United States, Unite believes that the primary cause of the explosion may be related to electrostatic earthing (bonding), though it should be stressed that HSE is unwilling to confirm or deny this.
Reminder of the Risks and Precautions Associated with Tank Cleaning Operations by Ron De Cort. Head of Operations, Wales and West of England, Hazardous Installations Directorate, HSE
Following the incident at the Chevron Pembroke Refinery on 2nd June HSE, on behalf of the COMAH Competent Authority, would like to remind site operators of the dangers associated with this type of operation and of the guidance available to ensure the work is undertaken safety.

Tank cleaning operations were in progress within the amine recovery unit at the refinery site when there was an explosion and subsequent fire. The incident led to the death of four people and serious injuries were sustained by another person. The joint police and COMAH Competent Authority investigation team is working to establish the cause of the incident.

.The risks associated with tank cleaning are widely recognised in the major hazard industries and there are well established control measures. These are outlined in:
•    Safe maintenance, repair and cleaning procedures, Dangerous Substances and Explosive Atmospheres Regulations 2002. Approved Code of Practice and Guidance, L137, HSE

•    Guidance on permit-to-work systems: A guide for the petroleum, chemical and allied industries, HS(G)250, HSE, and

•    Code of Safe Practice Part 16 - Tank Cleaning Safety Code.Energy Institute, 20085
Site operators should review their arrangements for cleaning tanks that contain hazardous substances and ensure that they meet current good practice.

Further information
The refinery is a top tier establishment under the Control of Major Accident Hazards Regulations 1999 (as amended). The Environment Agency (EA) in England and Wales, Scottish Environment Protection Agency (SEPA) in Scotland, and the Health and Safety Executive (HSE) are jointly responsible (as the Competent Authority) for regulating major hazardous industrial sites in the UK under the Control of Major Accident Hazard Regulations 1999 (COMAH).

COMAH requires operators of major hazard sites subject to the Regulations to take all measures necessary to prevent major accidents and limit their consequences to persons and the environment. Operators of top tier COMAH sites are also required to submit written safety reports to the Competent Authority; and to prepare emergency plans to deal with the consequences of a major accident. Operators and others (including contractors, designers and suppliers) also have relevant duties under the Health and Safety at Work etc Act 1974 and under other environmental legislation to protect land, air and water, including the Water Resources Act 1991.

The incident occurred on Thursday 2 June, 2011 and is still under investigation by Dyfed-Powys Police and HSE. HSE has stated that it may publicise further details at the appropriate time but not before the investigation is completed and any potential legal proceedings have been considered and, if appropriate, concluded.

Advice to Unite Reps
Unite reps employed within refineries, or involved in tank operations, are advised to approach their employers to ensure that all possible steps have been taken to comply with the HSE statement, and the Codes of Practice and Guidance referred to above. In light of the information received from the US, this should involve particular emphasis on electrostatic earthing (bonding) issues.