The Hazardous Materials Transportation Regulations (HMR) are the U.S. Department of Transportation rules in 49 CFR Parts 171 through 180 that govern how hazardous materials are classified, packaged, documented, marked and moved in commerce. They protect workers, emergency responders and the public along every route a shipment travels.
The HMR reach far beyond tanker fleets. Any business that ships, loads or hauls regulated materials, from fuel and compressed gases to paints and batteries, has duties under these rules, and training and documentation sit at the center of compliance.
What Are the Hazardous Materials Regulations?
The HMR are issued by the Pipeline and Hazardous Materials Safety Administration (PHMSA) under the federal hazardous materials transportation law, 49 U.S.C. 5101 and following. Enforcement is shared across DOT agencies by mode, with the Federal Motor Carrier Safety Administration (FMCSA) enforcing them for highway carriers. Part 171 holds definitions and incident reporting, Part 172 covers hazard communication, training and security, Part 173 sets shipper and packaging rules, Parts 174 to 177 cover each mode of transport and Parts 178 to 180 set packaging specifications.
Under 171.8, a hazardous material is one DOT has found can pose an unreasonable risk to health, safety and property in transport. It includes hazardous substances, hazardous wastes, marine pollutants and materials listed in the Hazardous Materials Table (172.101).
The nine hazard classes
- Class 1: Explosives (Divisions 1.1 to 1.6)
- Class 2: Gases (2.1 flammable, 2.2 non-flammable, 2.3 poison gas)
- Class 3: Flammable liquids, with combustible liquids treated separately
- Class 4: Flammable solids (4.1), spontaneously combustible (4.2) and dangerous when wet (4.3)
- Class 5: Oxidizers (5.1) and organic peroxides (5.2)
- Class 6: Poisonous (toxic) materials (6.1) and infectious substances (6.2)
- Class 7: Radioactive materials
- Class 8: Corrosives
- Class 9: Miscellaneous hazardous materials
Who Must Comply?
The HMR reach everyone in the transportation chain:
- Offerors (shippers): anyone who classifies, packages, marks, labels or prepares shipping papers for hazmat, or tenders it to a carrier.
- Carriers: for-hire and private motor carriers, railroads, airlines and vessel operators, including loading, unloading and storage in transit.
- Hazmat employers: any person, including a government body, that uses at least one hazmat employee.
- Hazmat employees: full-time, part-time, temporary or self-employed workers whose duties directly affect hazmat transportation safety, including drivers, loaders and shipping clerks.
Many companies are both offeror and carrier. Some states adopt the HMR for intrastate movements, sometimes with their own variations, so check your state rules as well.
Key Requirements
Shipping papers (Part 172, Subpart C)
Under 172.202 the basic description must appear in a fixed order: identification number, proper shipping name, hazard class or division (with any subsidiary hazard in parentheses) and packing group. Under 172.204 the offeror signs a certification that the shipment is properly classified, packaged, marked and labeled. The person who provides the shipping paper must keep a copy for two years after the initial carrier accepts the material, or three years for hazardous waste (172.201(e)).
Marking, labeling and placarding
Marking (Subpart D) puts the proper shipping name, identification number and other required markings on packages. Labeling (Subpart E) uses the diamond-shaped hazard labels named in column 6 of the Hazardous Materials Table.
Placarding (Subpart F) applies to vehicles, freight containers, rail cars and bulk packagings, with placards on each side and each end (172.504(a)). Table 1 materials, such as Division 1.1 to 1.3 explosives, poison gas, dangerous when wet materials and poison inhalation hazards, require placards in any quantity. For Table 2 materials moving by highway or rail, placards are not required when the vehicle carries less than 1,001 pounds (454 kg) aggregate gross weight of Table 2 materials in non-bulk packages. That exception never applies to bulk packagings.
Emergency response information (Subpart G)
Shipments must carry emergency response information covering health hazards, fire risks, immediate precautions, spill handling and first aid. Shippers must also list an emergency telephone number monitored at all times while the material is in transit by someone knowledgeable about it or with immediate access to such a person. Answering machines and call-back numbers are not allowed.
Security plans (172.800)
Offerors and carriers of certain high-risk materials must have and follow a written transportation security plan. Examples include any quantity of Division 1.1 to 1.3 explosives or poison inhalation hazard materials and large bulk quantities (more than 3,000 kg or 3,000 L in one packaging) of several other classes. Under 172.802 the plan must include a risk assessment and address personnel security, unauthorized access and en route security. It must be reviewed at least annually.
PHMSA registration (Part 107, Subpart G)
Under 107.601, offerors and carriers must register with PHMSA and pay a fee if they handle any placarded quantity of hazmat (with a limited farmer exception) or certain other listed materials and quantities. For the 2026 to 2027 registration year, PHMSA lists a one-year fee of $275 for small businesses and nonprofits and $2,600 for other registrants, including a processing fee. Under 107.620, motor carriers must carry the current certificate or registration number in each truck and truck tractor used for covered hazmat.
FMCSA rules for highway carriers
Motor carriers hauling placarded or marked hazmat must also follow Part 397, which covers vehicle attendance, parking, a 25-foot no-smoking zone, tire checks at the start of each trip and whenever the vehicle is parked, and routing away from heavily populated areas where practicable. Carriers of the highest-risk materials, such as highway route-controlled quantities of radioactive material or more than 55 pounds of Division 1.1 to 1.3 explosives, need a Hazardous Materials Safety Permit under Part 385, Subpart E. CDL drivers who haul placarded hazmat must hold a hazmat endorsement, which requires a TSA security threat assessment. See our guide to CDL requirements.
Incident reporting (171.15 and 171.16)
The person in physical possession of the material must call the National Response Center as soon as practical, and no later than 12 hours, after incidents such as a death, a hospitalization, a public evacuation or a major artery closure lasting one hour or more (49 CFR 171.15). A written DOT Form F 5800.1 is due within 30 days of discovering any reportable incident, including most unintentional releases. Copies are kept for two years.
Hazmat Employee Training Requirements
Section 172.704 requires each hazmat employer to train, test and certify every hazmat employee in:
- General awareness and familiarization with the HMR and how to recognize hazmat
- Function-specific training for the employee's actual duties
- Safety training on emergency response information, self-protection and accident avoidance
- Security awareness training on recognizing and responding to security threats
- In-depth security training when the employer must have a security plan
New employees and those changing job functions must complete training within 90 days and may work only under direct supervision of a trained employee until then. Recurrent training is required at least once every three years. Records must cover the preceding three years and include the employee's name, the most recent training date, a description or location of the materials, the trainer's name and address and a certification that the employee was trained and tested. Keep them while the person is a hazmat employee and for 90 days afterward. See PHMSA's training page.
Common Violations and Penalties
- Training lapses: no records, missing test certification or recurrent training past three years
- Shipping papers with entries out of order, missing emergency phone numbers or unsigned certifications
- Wrong or missing placards, or applying the 1,001-pound exception to bulk packagings
- Expired PHMSA registration or no registration document in the truck
Civil penalties are set in 49 CFR 107.329 and are adjusted periodically for inflation. They are assessed per violation, with a higher maximum when a violation causes death, serious illness, severe injury or substantial property destruction, and a set minimum for training violations. Check PHMSA's current figures before quoting amounts.
How to Comply: Step by Step
- Inventory your hazmat. Use safety data sheets and the Hazardous Materials Table to confirm each material's class, shipping name and packing group.
- Identify hazmat employees. Include drivers, dock staff, shipping clerks and anyone who signs shipping papers.
- Train, test and certify. Finish within 90 days of hire or job change and schedule recurrent training before the three-year mark.
- Standardize shipping papers. Use templates with the correct sequence, certification and emergency number.
- Check placarding at loading. Use a pre-trip checklist to confirm placards, markings and labels match the load.
- Register and renew. Confirm whether you must register with PHMSA, and whether you need a safety permit or security plan.
- Prepare for incidents. Assign who calls the National Response Center and track 30-day report deadlines.
How SMS360 Helps
The SMS360 DOT Compliance module helps fleets keep hazmat records organized alongside other DOT requirements. Teams can track hazmat employee training dates and receive reminders before recurrent training is due, store training certifications, registration certificates and security plans, and use digital checklists for pre-trip and placarding checks. Incidents can be documented and their corrective actions assigned and tracked. It fits alongside each driver's driver qualification file and your safety data sheet library.
Frequently Asked Questions
How often is DOT hazmat training required?
Hazmat employees must complete initial training within 90 days of hire or a change in job function and recurrent training at least once every three years. Until initial training is complete, they may perform hazmat functions only under the direct supervision of a trained employee.
When does a truck need hazmat placards?
Table 1 materials, such as Division 1.1 to 1.3 explosives and poison inhalation hazards, require placards in any amount. Table 2 materials generally require placards once the vehicle carries 1,001 pounds or more aggregate gross weight in non-bulk packages. Bulk packagings generally must be placarded whatever the quantity.
Do I need to register with PHMSA?
You must register if you offer or transport any quantity of hazmat that requires placarding, or certain other listed materials such as highway route-controlled radioactive material. A limited exception applies to farmers supporting their own farming operations.
How long must hazmat shipping papers be kept?
The person who provides the shipping paper must keep a copy or electronic image for two years after the initial carrier accepts the material. For hazardous waste, the period is three years.
