All regulations begin with a law and the Hazardous Material Regulations (HMR) of the PHMSA/USDOT is no exception.  The Federal hazardous materials transportation law (49 USC 5101 et seq.) directs the Secretary of Transportation to establish regulations for the safe and secure transportation of HazMat in commerce, as the Secretary considers appropriate.  The applicability of the HMR (to whom and to what materials it applies and when) is defined by regulation at 49 CFR 171.1 and explained in this article. (more…)