At a petrol station, in the manager’s absence and due to a programming error, a delivery driver transfers 7000 litres of diesel fuel into a tank which can only contain 3000 litres of fuel. The stop valve is defective and the deliveryman does not realise his oversight until the pit containing the tank overflows. Over 3000 litres of diesel are pumped outside the tank, and several tens of litres spill out of the pit.