That tank was meant for one thing only. Once fuel was introduced into it the tank's pores began to absorb fuel oil. You will not be sick the next day from eating food prepared in it. The danger comes from prolonged exposure both to the smoke it produces and to food cooked in it. A pregnant woman's fetus and young children are especially vulnerable.
If you want to make that style of smoker by a new unused tank. In this neck of the woods (literally!) they go for about $270.
if there is ever a question of health safety... the safe answer is NO- bds can help ya find good brand new barrels for the expressed use of making a smoker. i didn't see the links but being in the oil field & hazardous waste business i'm sure you'll find my post & explanation there under those.
I had no idea that the oil, or other harmful stuff, actually would seep into the metal like that.
Good info, I bet others would not have thought about that either. The guy I saw said he packed it full of wood and burned it over night. It may have done the job, but I am not willing to take the chance after what I have read here.