Corrosive placards (Class 8 placards) are a numbered DOT placard used to identify corrosive in transit by road, rail or air.  A corrosive placard is black and white in color and on the top corner depicts a spilled test tube and dissolving hand logo.  The center contains a four digit number identifying the corrosive being transported.  A corrosive is a material, either solid or liquid, that causes visible destruction or irreversible damage to human skin or that has a severe corrosion rate on steel or aluminum.