Bulk packaging that contains an elevated temperature material (except molten sulfur or molten aluminum) must have a HOT marking. HOT Markings for Elevated Temperature Materials are printed with HOT and 3256 or 3257 to satisfy the 4-digit number and HOT marking requirements of 49 CFR, Part 172.325(c) and 172.336(b). The HOT 3256 marking must be used with the worded flammable liquid placard.