49 CFR 172.504 – General Placarding Requirements contains the applicability, scope, and general requirements for the use of placards when transporting a hazardous material.  §172.504(a) identifies the five (5) types of packagings and modes of transportation that will require placards, unless excepted.  A closer look at these five defined terms is important since packagings and methods of transportation not included in §172.504(a) will not require a placard. (more…)