The spectacular fire at Buncefield on 11th December 2005 was extremely fortunate in that there were no fatalities, but it did result in significant loss of containment during the fire, allowing firewater to affect local land and groundwater.

Buncefield has been considered to have had a large enough adverse impact on the environment to require reporting to the European Union as a Major Accident To The Environment (MATTE).

Several bunds failed, or leaked eg where pipes passed through bund walls, and this allowed firewater containing PFOS (perfluoroctane sulphonate), unburnt fuel and combustion residues to enter local drains, and ultimately a nearby chalk aquifer. The Competent Authority reviewed these losses of containment, and found that many of them could have been prevented.

In particular, the following findings were made:

► Although the bunds generally remained standing, their integrity was seriously compromised
► Unburnt fuel and firefighting foams floated on top of the firewater in many bunds, but there was no safe method of removing the firewater while retaining the fuel and foam – in effect this meant that the firewater caused foam and fuel to overspill the bunds
► Pipework penetration through bund walls was a significant weak point
► Expansion and construction joints in concrete bund walls formed other significant weak points
► Tertiary containment systems failed to work, mainly due to loss of power to pumps, allowing firewater to flow off site (harder to control)
► The chalk aquifer below the site was affected due to man-made pathways (boreholes and drains) which penetrated the clay layer immediately below the site
As a direct result of the findings from the Buncefield investigation, the Environment Agency has produced a new containment policy which will be rolled out throughout the COMAH regulated industries.

Initially, the guidance is mandatory for petrol and fuel COMAH installations, and will be extended to “establishments storing flammable and toxic liquids in the chemical manufacturing, storage and distribution industries” within the COMAH envelope. (There is likely to be a consultation on this second phase in the summer of 2008).

The new standards are considerably more stringent than previous containment guidance, and it is recognised that it will take years to bring COMAH-regulated industry up to the improved level.

This guidance sets a new standard for bunding and containment, and we believe that eventually it will spread out to the non-COMAH chemical manufacturing and using sector. For example, the new requirements are likely to become BAT “Best Available Technique” for anyone with an Environmental Permit (PPC permit as was).

We therefore strongly recommend to all our clients that if you are considering improving any containment, or putting in new bunds etc, that the work should be done to the new standard, or as close as is practicable. This may seem a bit more expensive up-front, but will be a lot cheaper than having to make major changes in a couple of years time. To download the EA’s new guidance on containment, click here. There is also guidance on secondary and tertiary containment here.

News article 1st June 2008