Regulation overview
DOT Hazardous Materials Regulations (49 CFR Parts 171 to 180)
The Hazardous Materials Regulations (HMR) in Title 49 of the Code of Federal Regulations, Parts 171 to 180, are the US Department of Transportation rules for shipping hazardous materials by road, rail, air and water. They require shippers and carriers to classify, package, mark, label, placard and document shipments, and to train employees. The transport information in SDS Section 14 draws on them, but OSHA does not enforce that section.
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Who it applies to
The HMR apply to anyone who offers hazardous materials for transportation, transports them, or prepares or tests packagings used for them. That includes manufacturers shipping products, distributors, warehouses preparing shipments and carriers. The Pipeline and Hazardous Materials Safety Administration (PHMSA) writes the rules, while enforcement is shared among modal agencies such as the Federal Motor Carrier Safety Administration, the Federal Railroad Administration, the Federal Aviation Administration and the Coast Guard. Hazardous materials are defined as substances or materials that DOT has determined may pose an unreasonable risk to health, safety and property in transport.
How the parts are organized
- Part 171: general information, definitions and incorporated standards.
- Part 172: the Hazardous Materials Table, shipping papers, marking, labeling, placarding, emergency response information and training requirements.
- Part 173: shippers' general requirements, including classification criteria and packaging requirements for specific materials.
- Parts 174 to 177: carriage by rail, aircraft, vessel and public highway.
- Parts 178 to 180: packaging specifications, tank cars and the continuing qualification and maintenance of packagings.
Classes, packing groups and the Hazardous Materials Table
The HMR group hazardous materials into nine hazard classes, such as explosives, gases, flammable liquids, flammable solids, oxidizers and organic peroxides, toxic and infectious substances, radioactive material, corrosives and miscellaneous. Many materials are assigned a packing group (I, II or III) indicating the degree of danger. The Hazardous Materials Table in Section 172.101 lists proper shipping names, hazard class, identification numbers (UN or NA numbers), packing group, label codes and packaging references. Learn the classes on our DOT hazard classes page.
These systems are separate from the GHS. A material can be hazardous under HazCom but not regulated for transport in a given quantity, or the reverse. See Section 14.
Hazard communication in transport
- Shipping papers must describe the material (identification number, proper shipping name, hazard class, packing group, quantity) and include an emergency response telephone number for many shipments.
- Marking and labels on packages: proper shipping name, identification number and hazard class labels (diamond-shaped).
- Placards on vehicles and containers for certain quantities and classes.
- Emergency response information available to carriers and emergency responders.
The emergency number is often provided by the manufacturer or a contracted emergency response service. CHEMTREC (1-800-424-9300 in the US) is a commonly used 24-hour service for chemical transportation emergencies; it is not a substitute for local emergency services. See also the disclaimer page for emergency numbers.
Hazmat employee training
Employers must train and test each "hazmat employee" who performs functions such as loading, packaging, marking, preparing shipping papers or driving. The training covers general awareness, function-specific duties, safety, security awareness and, where a security plan applies, in-depth security training, and the employer must keep training records. Recurrent training is required at least once every three years (Section 172.704). Do not confuse this with HazCom training for workplace hazards; see HazCom training requirements.
Key differences versus OSHA HazCom
- Purpose. HMR protect people during transport; HazCom informs workers in workplaces.
- Classification system. HMR use UN-based transport classes and packing groups with quantity thresholds and exemptions (such as limited quantities); HazCom uses GHS hazard classes.
- Documents. Shipping papers, placards and package labels versus SDSs and GHS labels.
- Enforcement. DOT and its modal agencies versus OSHA.
- International link. HMR align with UN recommendations and incorporate parts of the IMDG Code and ICAO instructions for international shipments. See IATA DGR and IMDG.
Frequently asked questions
What are 49 CFR 171-180?
They are the parts of the US Code of Federal Regulations containing the Department of Transportation's Hazardous Materials Regulations for shipping hazardous materials.
Does the SDS tell me how to ship a chemical?
Section 14 gives transport classification information, but it is not enough by itself. Shipping requires trained personnel and compliance with the current regulations.
How many hazard classes does DOT use?
Nine classes, some subdivided into divisions. See our DOT hazard classes page for details.
Is GHS pictogram the same as a DOT label?
No. GHS pictograms on a product label and DOT hazard class labels on a package are separate systems with different designs and purposes. Some shipments carry both.