In an operational capacity, limitations in weapons technology and quick British reactions were making it more difficult to achieve strategic effect. Attacking ports, shipping and imports as well as disrupting rail traffic in the surrounding areas, especially the distribution of coal, an important fuel in all industrial economies of the Second World War, would net a positive result. However, the use of delayed-action bombs, while initially very effective, gradually had less impact, partly because they failed to detonate.[c] Moreover, the British had anticipated the change in strategy and dispersed its production facilities making them less vulnerable to a concentrated attack. Regional commissioners were given plenipotentiary powers to restore communications and organise the distribution of supplies to keep the war economy moving.