Special Report (this report is courtesy of Hazardous Cargo Bulletin)

The initial report of the board set up to investigate last December’s explosion at the Buncefield oil depot in Hertfordshire, UK is released today. The report confirms the findings outlined in the three progress reports already issued, and points to several issues of concern that will be the subject of further investigation.

The board should be congratulated on having done a good job in rapidly determining the causes of the incident, as have been highlighted in the progress reports. However, while the initial report flags up areas for further investigation, industry will perhaps be disappointed that more concrete recommendations have not as yet been forthcoming. There is certainly much that can be done in terms of monitoring and alarms and the question of bunding integrity has only been touched upon.

What the report does identify is a need for action in three areas.

1. Design and operation of storage sites

The Buncefield incident featured a failure of containment, both for the fuel in the storage tanks and the firewater used to extinguish the blaze, at three levels: primary, secondary and tertiary. The paramount need is to ensure that fuel does not escape from its storage tank and further precautions need to be taken to prevent this happening. If it does, then there is a need to inhibit the formation of a flammable vapour.

Improvements to maintaining primary containment must be considered by industry and the competent authorities, the report states. These include:

– electronic monitoring of tanks and pipework and the associated alarms that warn of abnormal conditions

– the detection of flammable vapours in the immediate vicinity of tanks and pipework

– the response to the detection of abnormal conditions, such as automatic closure of tank inlet valves

– the extent to which the exterior construction of tanks, such as tank top design, inhibits or contributes to flammable vapour formation

– the siting and protection of emergency response facilities

– the recording of monitoring, detection and alarm systems for period review.

Industry should also embark on a review of the purpose, specifications, capacity, construction and maintenance of secondary and tertiary containment systems, in particular the bund walls around tank pits. Any such review should lead to the early publication of revised guidance, which should be capable of being insisted on by legislation.

Further ahead, the report identifies a need for research into the human and organisational factors that contribute to the safe operation of major hazard sites, and additional standards for the layout of such sites.

2. Emergency response to incidents

In the light of findings so far, the report says that operators of oil storage depots should review their on-site emergency plans and the adequacy of information they supply to local authorities so that they take account of the potential for a vapour cloud explosion.

A number of separate reviews are currently looking at the effectiveness of the emergency response to the Buncefield incident. Although the report praises the response of fire and police services, it notes that there are lessons that can be drawn from this exceptional event, particularly in view of the high financial cost of the response effort.

While the public health impact of the incident was minimal, it did reveal the importance of prompt, useful advice to first responders and to the public. The investigation board notes that the Health Protection Agency is progressing work in this area.

The board says it is not clear to what extent the interests of local residential and business communities are taken into account in the emergency planning process. A task force has been set up to investigate options for government support in helping communities back to social normality in the aftermath of any future disaster.

3. Planning

One of the starkest issues raised by the Buncefield explosion is the location of major accident hazard sites close to commercial and residential developments. The situation poses a fundamental planning question, the report says. It also notes that the worst credible scenario envisaged by HSE when looking at the permitting of developments near Buncefield was based on a major liquid pool fire rather than a vapour cloud explosion.

Work remains to be done, the report says, on the desirability and feasibility of applying an advisory approach to developments around other Seveso sites, in which the likelihood of major incidents such as the Buncefield explosion could play a more explicit part.

The initial report of the Buncefield investigation board, along with other material relating to the incident, is available at www.buncefieldinvestigation.gov.uk.

The Bulletin will examine the incident report and its findings and implications in greater detail in the upcoming August and September issues.