Bunded tanks are specially protected tanks used for fuel storage in situations where leakage to the environment would be particularly undesirable. The tanks are called "bunded" because they are effectively a tank within a tank, so that any leakage caused by piercing or overfilling from the inner tank would still be contained within the outer. The outer tank must hold 110 % of the capacity of the inner tank.
Bunded tanks come in all shapes and sizes, and are used in a wide variety of situations.
Please visit www.bundedtanks.com for more information about bunded tanks.