The leak was discovered last night at the Convenient Mart at Wyoming Avenue and Pringle Street in Kingston.
We are told a contractor who was hired by the store's owner to do a routine inspection found the leak and called the D-E-P.
It's estimated between 500 and 17-hundred gallons of gas seeped into the ground water about 14 feet below street level.
However, it does not appear any gas has seeped into drinking water.
Clean-up and repairs are underway.
The owner of the store had no comment.