Drawing on previously unpublished material held back until the criminal prosecution was completed and the appeals processes exhausted, The Buncefield explosion: Why did it happen? identifies several failings including:
Systems for managing the filling of industrial tanks of petrol were both deficient and not fully implemented
An increase in the volume of fuel passing through the site put unsustainable pressure on those responsible for managing its receipt and storage, a task they lacked information about and struggled to monitor. The pressure was made worse by a lack of necessary engineering support and other expertise.
A culture developed where keeping operations going was more important than safe processes, which did not get the attention, resources or priority status they required.
Inadequate arrangements for containment of fuel and fire-water to protect the environment.