Newark nj - Oil Tank Below Ground

[Michael Smith]

i am leaving in Brooklyn ny and as every know Brooklyn is very pricey when it comes to real estate 

so i start my self looking in to other markets and i find some great place witch is Newark NJ

as i am looking in some deal a agent send me i see this  

Cool:NoCooling

Heat: 1 Unit

Fuel: Oil Tank Below Ground

Service: Cable TV Available , Cable TV

could someone please help me what is 'Oil Tank Below Ground' and did i should be aware of before buying?

thanks a lot every one and for sure bigger pockets