Maryland · Hazardous Materials CDL Practice Test

Placards are diamond-shaped warning signs that communicate hazard class to other drivers, emergency responders, and inspectors.

Federal regulation requires placards on all four sides of the vehicle so the hazard is visible from any approach.

Class 1 covers explosives, divided into divisions 1.1 through 1.6 based on hazard severity.

Class 2 covers gases, including flammable, non-flammable, toxic, and oxygen.

Class 3 covers flammable and combustible liquids such as gasoline, diesel, and many chemicals.

Class 7 covers radioactive materials, with strict packaging, shielding, and labeling requirements.

Class 8 covers corrosive materials such as battery acid and many industrial chemicals.

Class 9 is a catch-all for materials presenting a hazard during transport but not meeting criteria for classes 1-8.

Shipping papers must be on the driver's seat, in a holder mounted on the inside of the driver's door, or in reach when the seat belt is fastened — and clearly identifiable.

When the driver leaves the cab, papers go on the driver's seat or in the door pouch — visible to first responders if the driver is incapacitated.

Shipping papers must include the proper shipping name, hazard class/division, UN/NA identification number, packing group, and total quantity.

The ERG provides initial response guidance based on the UN ID number on the placards or shipping papers. Carry the current edition.

Set parking brakes during loading/unloading to prevent the truck from rolling and to allow the loader to work safely.

Federal regulation prohibits smoking within 25 feet of a placarded vehicle, fueling area, or hazmat storage facility.

A trained person must be in attendance whenever hazmat is being loaded or unloaded.

The Segregation Table at 49 CFR §177.848 lists incompatible material combinations that may not share the same vehicle, container, or storage area.

Explosives have stringent segregation requirements; the Segregation Table prohibits most combinations.

Many tunnels and some bridges restrict hazmat. Check route restrictions in advance and follow alternate routes when required.

Federal regulation requires placarded hazmat vehicles to stop 15-50 feet before all railroad tracks unless specifically exempted (e.g., shunting tracks).

The required stop distance is 15 to 50 feet from the nearest rail, allowing you to see and hear approaching trains while remaining clear of the tracks.

Engine must be shut off during refueling. A person must be in control of the fueling process at all times.

Parking rules vary; generally, placarded vehicles must be at least 5 feet from the road, with an attendant unless certain exceptions apply (e.g., safe haven for explosives).

Explosive loads carry the strictest parking distance requirements: 300 feet from bridges, tunnels, dwellings, and crowded places.

Tire checks at start of trip and at each parking are required for placarded vehicles. Hot tires can be the first sign of a brake or wheel issue that could ignite a load.

Wrong extinguisher type can spread the fire (e.g., water on burning lithium). Refer to the ERG and prioritize personal safety.

Stop, isolate, notify, stay upwind. Refer to the ERG for material-specific guidance.

Carriers must notify their company and may be required to notify the NRC at 1-800-424-8802 for spills meeting reporting thresholds.

TSA reviews the applicant's criminal, immigration, and intelligence background as a condition for the H endorsement.

H endorsement renewals are on a 5-year cycle, with each renewal requiring a fresh TSA threat assessment.

Security awareness training emphasizes vigilance for unusual activity, secure parking, and verification of identities of anyone interacting with the load.

The 1,001-lb aggregate weight threshold triggers placarding for most materials. "Table 1" materials (explosives, poison gases, etc.) require placards in any quantity.

Empty tanks containing hazmat residue must continue to display placards until cleaned and purged of vapor.

Driver responsibility includes refusing improperly prepared shipments — accepting them transfers liability and creates safety risk.

Pre-trip verification of packaging, papers, placards, and securement is the driver's legal responsibility.

Labels are diamond-shaped, smaller than placards, applied to individual packages to communicate hazard class.

Consistency between package marking and shipping papers is essential for first responders to identify the material.

States and municipalities can designate specific routes for placarded hazmat loads, often avoiding tunnels, bridges, and dense populations.

Dispatchers, safety managers, and the FMCSA hazmat routing tool can confirm legal routing for your load.

Standard practice: secure the truck, follow the consignee's safety rules, and supervise unloading.

Accurate manifests are required for every hazmat shipment to ensure first responders can identify materials in an incident.

Notify receivers immediately if any hazmat package is damaged or leaks during transit.

Clear communication about material identity is essential to first responders during any incident.

Division 6.1 covers materials that are toxic to humans through inhalation, ingestion, or skin contact.

Division 6.2 covers infectious substances such as medical waste, cultures, and clinical specimens.

Class 5 has two divisions: 5.1 oxidizers and 5.2 organic peroxides — both promote combustion of other materials.

Class 4 has three divisions: 4.1 flammable solids, 4.2 spontaneously combustible, and 4.3 dangerous when wet.

Loading must prevent shift, fall, or incompatible contact. Use blocking, bracing, dunnage, or load bars as needed.

Tunnel prohibitions vary; many tunnels prohibit placarded hazmat or specific divisions (especially explosives and flammable gases).

Hazmat carriers maintain mileage records and other documentation as required for safety and compliance auditing.

Provide shipping papers and the ERG. These give first responders critical information to manage the incident safely.