The main federal regulation in the United States regulating the transportation of hazardous materials is the Hazardous Materials Transportation Act (HMTA), which was adopted in 1975. It is administered by the United States Secretary of Transportation and aims to “guard against the dangers to life, property, and the environment that are inherent in the transportation of hazardous material in intrastate, interstate, and overseas trade.”

HMTA authorized the Secretary of Transportation to term any “particular quantity or form” of a material which “may pose an unreasonable risk to health and safety or property” as hazardous material.

According to their intended purpose, rules pertaining to hazardous materials can be broken down into four distinct categories.

1. Procedures and/or Policies 49 CFR Parts 101, 106, and 107
2. Material Designations 49 CFR Part 172
3. Packaging Requirements 49 CFR Parts 173, 178, 179, and 180
4. Operational Rules 49 CFR Parts 171, 173, 174, 175, 176, and 177

The Act was enacted to strengthen the coordination and uniformity of current regulations for carrying hazardous chemicals in order to minimize spills and illicit dumping that endanger the public and the environment.

Compliance orders [49 U.S.C. 1808(a)], civil penalties [49 U.S.C. 1809(b)], and injunctive relief are all tools used to uphold the HMTA (49 U.S.C. 1810). State and local governmental requirements that are inconsistent with the HMTA (Section 112, 40 U.S.C. 1811) are preempted unless the governmental requirement gives equal or greater protection to the public than the HMTA requirement.