CCDL Permit Prep

Hazardous Materials · page 7 of 8

Hazardous Materials questions 121–140

Part of the 159-question Hazardous Materials pool. Each answer cites the FMCSA CDL Manual or the federal rule it comes from.

Practise these as a timed set

  1. A DOT 3A480 chlorine cylinder has a leak in its valve. Which action is allowed under the special temporary-repair rule?

    • AA trained person uses an authorized Chlorine Institute Kit A method for a one-way trip to a proper facilityCorrect
    • BAny driver wraps the valve and continues normal transport
    • CLoad it valve-side up and finish the delivery
    • DUse no repair kit if the leak appears small

    This narrow rule applies to a qualifying DOT 3A480 or 3AA480 cylinder containing chlorine or sulfur dioxide with a valve or fusible-plug leak. A trained person may use the specified Kit A method, subject to its limits, and the cylinder may make a single one-way trip by private or contract carrier from discovery to a proper facility for discharge and examination. It is not permission for an untrained driver to repair or continue normal transport.

    eCFR 49 CFR 173.3 · 173.3(e)(1): temporary repair of qualifying chlorine or sulfur dioxide cylinders · verified 2026-09-07

  2. What must be done to a cargo heater before a motor vehicle transports Class 1 explosive materials?

    • ADrain or remove its fuel tank and disconnect its power sourceCorrect
    • BSet it to its lowest heat setting
    • CUse it only while the vehicle is parked
    • DKeep it on to protect the load from moisture

    A motor vehicle equipped with any cargo heater may transport Class 1 explosives only after the heater is rendered inoperable by draining or removing its fuel tank and disconnecting its power source. Merely switching it off or lowering its setting does not meet this rule.

    eCFR 49 CFR 177.834 · 177.834(l)(1): cargo heaters with Class 1 explosive materials · verified 2026-09-07

  3. For a placarded hazmat load outside a non-radioactive hazmat routing designation, what areas must the carrier avoid unless a stated exception applies?

    • AEvery state boundary
    • BAll divided highways
    • CHeavily populated areas, crowds, tunnels, narrow streets, and alleysCorrect
    • DAll rural two-lane roads

    The rule lists heavily populated areas, places where crowds assemble, tunnels, narrow streets, and alleys. It also gives limited exceptions for no practicable alternative, specified reasonable deviations, and emergency conditions.

    eCFR 49 CFR 397.67(b) · 397.67(b): routing outside NRHM designations · verified 2026-09-07

  4. Which public forms may be used for non-radioactive hazmat routing designations?

    • ABy the shipper's invoice
    • BBy radio broadcast each morning
    • CBy markings on the placards
    • DMaps, lists, road signs, or a combination of themCorrect

    States and Indian tribes must make information on non-radioactive hazardous-material routing designations available to the public through maps, lists, road signs, or a combination of those forms.

    eCFR 49 CFR 397.73(a) · 397.73(a): public NRHM routing information · verified 2026-09-07

  5. Before and during a Class 3 liquid transfer between containers that are not in metallic contact, what static-control step is required?

    • AProvide a metallic bond or ground conductor to neutralize possible static chargesCorrect
    • BWarm the receiving container
    • COpen all nearby vents
    • DIncrease the transfer pressure

    For the stated non-metallic-contact transfer, a metallic bond or ground conductor must neutralize possible static charges before and during transfer. Cargo-tank rules include defined closed-connection exceptions, so do not apply this item outside its stated condition.

    eCFR 49 CFR 177.837 · 177.837(b)–(c): bonding and grounding · verified 2026-09-07

  6. Under 49 CFR 172.519(c)(1), what shape is a standard hazardous-materials placard?

    • AA circle with a border
    • BA rectangle lying flat
    • CA diamond standing on a pointCorrect
    • DA triangle pointing down

    49 CFR 172.519(c)(1) specifies each diamond (square-on-point) placard prescribed in the subpart. It also sets a minimum size of 250 mm (9.84 inches) on each side.

    eCFR 49 CFR 172.519 · 172.519(c)(1): Placard shape and size · verified 2026-09-07

  7. When 49 CFR 172.332 requires an identification-number marking, what may an orange panel display?

    • AShowing the carrier's name
    • BMarking the fuel filler
    • CIndicating the trailer length
    • DDisplaying the identification numberCorrect

    When an identification-number marking is required, 49 CFR 172.332 allows that number to be displayed on an orange panel, subject to the rule's display conditions.

    eCFR 49 CFR · 49 CFR 172.332(a)-(b): Identification number markings · verified 2026-09-08

  8. What does the signed shipper's certification on a hazardous-materials shipping paper state?

    • AThe shipper prepared the shipment according to applicable regulationsCorrect
    • BThe freight charges are paid
    • CThe driver inspected the load
    • DThe route has been approved

    FMCSA Sections 9.3.4 and 9.3.6 say the signed shipper's certification states that the shipper prepared the hazardous-materials shipment according to the applicable rules.

    FMCSA Commercial Driver License Manual · Sections 9.3.4 and 9.3.6: Shipping Paper and Shipper's Certification · verified 2026-09-08

  9. Under 49 CFR 172.101(a), what does the Hazardous Materials Table provide for each listed material?

    • AIts emergency response phone number, shipper name, and required route
    • BIts hazard class or forbidden status, proper shipping name, and referenced requirementsCorrect
    • CIts maximum shipping weight per vehicle and the required placard size
    • DIts reportable quantity alone, with no packaging or labeling references

    49 CFR 172.101(a) says the table identifies each listed material's hazard class or forbidden status and gives or directs the user to the proper shipping name. It also specifies or references labeling, packaging, aircraft quantity-limit, and vessel-stowage requirements.

    eCFR 49 CFR 172.101 · 172.101(a): Purpose and use of the Hazardous Materials Table · verified 2026-09-29

  10. How many identical placards must a placarded vehicle have?

    • AAt least four: one on the front, rear, and each sideCorrect
    • BOne on the driver's door only
    • CTwo on the rear only
    • DAs many as fit on the cargo area

    FMCSA Section 2.23.3 says a placarded vehicle must have at least four identical placards on the front, rear, and both sides; placards must be readable from all four directions.

    FMCSA Commercial Driver License Manual · Section 2.23.3: Lists of Regulated Products · verified 2026-09-08

  11. A driver plans to park a vehicle carrying Division 1.2 explosives 150 feet from a place where people work. Under the federal rule, when may that location be used?

    • AOnly for a brief operational necessity when no other parking place is practicableCorrect
    • BWhenever the driver remains with the vehicle
    • CWhenever the property owner agrees
    • DFor any personal break under 30 minutes

    49 CFR 397.7 normally bars parking a vehicle containing Division 1.1, 1.2, or 1.3 explosives within 300 feet of a place where people work, congregate, or assemble. The narrow exception requires a brief operational necessity and no other practicable parking place.

    eCFR 49 CFR 397.7 · 397.7(a)(3): 300-foot explosive-parking rule and normal-course exception · verified 2026-09-07

  12. Under 49 CFR 177.870(b), apart from its listed exceptions, when may hazardous materials be transported on a motor vehicle carrying passengers for hire?

    • AOnly when no other practicable means of transportation is availableCorrect
    • BWhenever every passenger wears a seat belt
    • CWhenever the driver authorizes it
    • DWhenever the trip is short

    49 CFR 177.870(b) says that, except for listed exceptions, hazardous materials are not authorized on passenger-for-hire motor vehicles where other practicable transportation is available.

    Electronic Code of Federal Regulations · 49 CFR 177.870(b): Passenger-carrying vehicles · verified 2026-09-08

  13. Under 49 CFR 171.8, what does a packing group tell you about a hazardous material?

    • AThe size of its container
    • BIts relative degree of dangerCorrect
    • CThe number of packages shipped
    • DThe carrier handling it

    49 CFR 171.8 defines a packing group as a grouping by degree of danger: Group I is great danger, Group II is medium danger, and Group III is minor danger.

    eCFR 49 CFR · 49 CFR 171.8: Packing group · verified 2026-09-08

  14. During the required tire examination, a tire is flat, leaking, or improperly inflated. What must the driver do before operating the placarded vehicle?

    • ACause the tire to be repaired, replaced, or properly inflated; move only to the nearest safe place if needed for that workCorrect
    • BContinue until the next scheduled rest break
    • CReduce speed and rely on the other tires
    • DOperate only in daylight until the tire can be checked later

    A flat, leaking, or improperly inflated tire must be repaired, replaced, or properly inflated before the vehicle is driven. The vehicle may be driven only to the nearest safe place to complete that work.

    eCFR 49 CFR 397.17 · 397.17(a)-(c): tire examination, defect response, and overheating · verified 2026-09-07

  15. A placarded vehicle carrying hazardous materials other than Division 1.1, 1.2, or 1.3 explosives must park within 5 feet of a traveled public highway. When can the federal exception apply?

    • AWhenever the shoulder is wide enough
    • BOnly for a brief period when operating necessity requires it and parking elsewhere is impracticableCorrect
    • CWhenever the driver turns on hazard flashers
    • DOnly after 50 feet of clearance has been measured

    The normal rule bars parking on or within 5 feet of the traveled portion of a public street or highway. For hazardous materials other than Division 1.1, 1.2, or 1.3 explosives, the exception is limited to a brief period when operating necessity requires parking there and another place is impracticable.

    eCFR 49 CFR 397.7 · 397.7(b): five-foot parking rule and brief operational-necessity exception for non-Division 1.1, 1.2, or 1.3 hazardous materials · verified 2026-09-07

  16. The hazardous cargo inside a trailer is burning. Which action should the driver avoid?

    • ACalling emergency services from a safe place
    • BMoving clear of the hazard
    • COpening the cargo doors to investigateCorrect
    • DWarning bystanders to stay away and upwind

    Do not open the doors or try to fight an established hazardous-cargo fire. Call for help and keep clear. This differs from a minor vehicle fire that can be addressed safely before it spreads to cargo.

    Oregon DMV Commercial Driver Manual · 9.7.2–9.7.3 · verified 2026-09-07

  17. Under the federal hazardous materials regulations, in what order must a shipping paper show the basic description?

    • AProper shipping name, packing group, identification number, hazard class
    • BHazard class, packing group, proper shipping name, identification number
    • CPacking group, hazard class, identification number, proper shipping name
    • DIdentification number, proper shipping name, hazard class, packing groupCorrect

    The basic description is shown in sequence as identification number, proper shipping name, hazard class or division, and packing group when applicable. No additional information is interspersed in that sequence, except as otherwise provided.

    eCFR 49 CFR 172.202 · 49 CFR 172.202(a)-(b): basic description sequence · verified 2026-09-08

  18. On a hazardous-material shipping paper, what does RQ beside the basic description mean?

    • AThe shipment contains a reportable quantity of a hazardous substanceCorrect
    • BThe cargo requires refrigeration
    • CThe cargo is prohibited from every tunnel
    • DThe load has been returned to the shipper

    RQ identifies a hazardous substance at its reportable quantity for shipping-paper purposes. Place the letters before or after the basic description. The marking is not a placard threshold and does not by itself mean that a release has occurred.

    eCFR 49 CFR · 172.203(c)(2) · verified 2026-09-07

  19. Under the general 49 CFR 177.848 segregation-table meaning, what does an 'X' in a cell mean?

    • AThe materials may not be loaded, transported, or stored together in the same transport vehicle or storage facility during transportationCorrect
    • BThey may share a vehicle if separated by another load
    • CThey require an extra placard when loaded together
    • DThey must be loaded within ten feet of each other

    An 'X' means the listed materials may not be loaded, transported, or stored together in the same transport vehicle or storage facility during transportation. Read the table with the section's other provisions and notes; do not replace the table rule with a packaging guess.

    eCFR 49 CFR 177.848 · 177.848(d)(2)-(3): X and O segregation-table meanings · verified 2026-09-07

  20. Under the 49 CFR 177.848 segregation table, what does an 'O' in a cell mean?

    • AThey may travel together without any separation
    • BThey may be together only when separated so normal leakage cannot commingle the hazardous materialsCorrect
    • CThey require an extra placard when loaded together
    • DThey may travel together only inside bulk packaging

    An 'O' means the materials may not be loaded, transported, or stored together in the same transport vehicle or storage facility during transportation unless they are separated so leakage under normal transportation conditions cannot cause commingling.

    eCFR 49 CFR 177.848 · 177.848(d)(2)-(3): X and O segregation-table meanings · verified 2026-09-07