It is more than two years since the Buncefield fuel depot in Hertfordshire caused one of the biggest peacetime explosions ever seen in the UK. The implications for safety and environmental standards are still unfolding.
In February a new containment policy was issued on the storage of toxic and flammable liquids at sites controlled by the major accident hazard (COMAH) regulations. The policy was issued jointly by the Environment Agency, its Scottish counterpart SEPA and the Health and Safety Executive, which together make up the competent authority for overseeing the regime.
The policy requires site operators to upgrade their sites or potentially face enforcement action. It applies immediately to new facilities and to existing sites where significant changes in operation are proposed.
Existing sites will be upgraded "as far as it is practicable to do so" in two phases. The first will cover sites storing petrol, similar petroleum products or other fuels. The second will cover facilities storing flammable and toxic liquids in the chemical manufacturing, storage and distribution industries, and will be subject to a separate consultation this summer.
However, the policy states that "to avoid disrupting operations and supplies, the upgrading work will need to be phased in over a significant period of time - which could be 10 to 20 years in some cases."
Operators will have to review their compliance with the measures set out in the policy and prepare plans, including completion dates, for implementing improvements.
In its response to last summer’s consultation on the policy, the Buncefield Major Incident Investigation Board - chaired by former Conservative minister Lord Newton of Braintree - warned that the suggested implementation period of up to 20 years was "overly generous" and "likely to be open to criticism".
Instead it said it "would prefer not to give an impression to operators that long time scales are generally acceptable - they may be in particular cases, but this should in our view be subject to the outcome of a review by the competent authority of site specific proposals…"
According to the regulatory impact assessment accompanying the rules, Britain has 95 COMAH fuel storage sites, including nine in Scotland. Together the sites have 2,200 tanks.
About 690 tanks contain petrol or similar substances likely to be affected by the rules for primary containment covering areas such as alarms and emergency shutdown systems to prevent spillages. But some will already meet parts of the requirements.
The remaining tanks are used to store less volatile fuels such as diesel, oil, aviation fuel and kerosene, so it is less clear how many will require upgrading. The regulatory impact assessment estimates that between 10% and 25% may be affected.
The policy also requires improvements to secondary and tertiary containment systems such as bunds, diversion tanks and flexible booms. The total cost of implementing the improvements over the next 20 years is put at £676-956 million.
Meanwhile, the competent authority has criticised US oil giant Chevron for failure to improve the fire resistance of bund joints at five storage sites in Plymouth, Kingsbury near Tamworth, Roath Dock in Cardiff, Portslade near Brighton and Sunderland. The criticism came as part of a review of the progress made by 50 fuel storage sites on eight priority areas for improvement.
Environment Agency deputy director of operations, David Jordan, said it was "disappointing" that the sites had "failed to match the standards set by their peers… these standards and deadlines were set by the industry themselves in 2006".
The Agency said it was issuing improvement notices under the COMAH regulations to the sites, requiring them to make changes within three to six months or face prosecution.
The review found that almost all other improvements had been made at the other sites. Overall, it shows a major improvement since a review last year found many fuel storage depots were operating at "below good practice" (ENDS Report 387, p 7 ).