Replace oil burner with gas burner, and remove underground tank.
Pros: Eliminates underground tank worry
Cons: Must install LP tank outside on property (no natural gas available). Must replace burner (although some companies will do this for signing up with LP delivery service. Also, I've heard that LP is more expensive than oil.
Replace underground tank with newer underground tank.
Pros: No need to give up basement space.
Cons: May face same problem later. (Are there any newer tank designs that are guaranteed underground?)
Replace underground tank with above ground tank.
Pros: Eliminates worries.
Cons: Lose basement or garage space. (Basement is finished, adding to dilemma).
Thanks in advance!