Abstract: A low emission multiple sealing system for a floating roof liquid hydrocarbon storage tank is provided. The sealing system utilizes a double sealing arrangement in addition to, in a preferred embodiment, a conventional weather seal. The double sealing arrangement includes two functionally independent generally toroidal shaped sealing elements positioned one above the other and filling the annular gap between the floating roof and the inner surface of the storage tank. In order to provide for increased sealing efficiency and to eliminate the deleterious effects of wind and other ambient conditions, the double sealing elements are configured having effective vapor sealing efficiencies and are separated from one another a distance which will maximize the runback, to the tank, of liquid left on the inner storage tank wall during diurnal contraction and/or on liquid hydrocarbon unloadings.