I wouldn't dare remove it ... unless you like donating all your hard earned money to the state.
Don't know how rural your area is ... but if that were in my yard, I'd cut the top, toss brush, trash, tires, what have you inside ... then make a gigantic brush pile on top of it so nobody can tell there's a hole under it, then fire it up. No more oil .... or brush.
Cheaper than a $30k fine any way you slice it.
See ... all this militant environmentalism by the government has made criminals out of us honest folks. Sad state of affairs we are in .....
There may ... or may not ... have been an underground tank in this undisclosed location: