There are brethren who have made UDSs from drums containing VOCs (Volatile Organic Compounds) - Gasoline, Fuel, Solvents, etc. Their consumers have not croaked or gotten ill.
There are brethren who have built UDSs from drums that contained cooking oil or fruit juice. Their consumers have not gotten ill.
Using a drum that contained VOCs should be washed thoroughly with soap and/or Simple Green *before* performing a burnout or liner grind. All it takes is a spark in a dirty drum to ruin your day/life.
Clean, clean, clean is the word for those VOC drums.
Dbl Bbl Smoker, UDS, ECB, Char-Broil gas grill & charcoal grills, SJ - Certified Moink Baller