All Harlequin oil tanks are bunded. This means that each tank benefits from a 'tank within a tank' design, which protects your valuable heating oil in the event of the inner tank splitting. Older style, single skin oil tanks can be environmentally hazardous as, in the event of the tank splitting, the contents will seep into the surrounding area, causing damage to the environment and potentially resulting in cleanup costs of up to 50,000 pounds for the homeowner. Remember, oil spills may not be covered by home insurance policies, therefore it's wise to 'Buy Safe, Buy Bunded'. Harlequin HQi bunded oil tanks are a no-nonsense option and have been designed for customers who do not require the additional tank technology, as featured on Harlequin 'iTank' oil storage tanks.