Your FREE CDL Hazmat (H Endorsement) Flashcards 2026 – 250+ Cards

Any material DOT designates as hazardous that must be placarded under 49 CFR 172 subpart F, plus any quantity of a select agent or toxin listed in 42 CFR part 73 (49 CFR 383.5).

The CDL endorsement for driving a CMV that carries hazardous materials as defined in 49 CFR 383.5. It takes a state knowledge test and a TSA security threat assessment.

The CDL code for a driver who holds both the tank vehicle (N) and hazardous materials (H) endorsements (49 CFR 383.153).

TSA's background check for HME applicants. TSA denies the HME for a disqualifying crime, failing the immigration status rules, a security threat finding, or certain mental capacity findings (49 CFR 1572.5).

TSA has found the driver is not a security risk, or the driver holds a valid TWIC. This applies to issuing, renewing, upgrading, and transferring the HME (49 CFR 383.141(b)).

TSA requires new fingerprints each time the HME is renewed (TSA, Hazmat Endorsement).

When a driver uses a TWIC security threat assessment, the HME gets the same expiration date as that TWIC assessment (TSA, Hazmat Endorsement).

States must renew the HME every 5 years or less, so each holder is screened by TSA at least every 5 years (49 CFR 383.141(d)).

At least 60 days before the HME expires, the state must tell the holder that renewal requires a new TSA security threat assessment (49 CFR 383.141(c)).

If TSA has not finished the assessment by the expiration date, the issuing state may extend the HME for 90 days. Any further extension needs TSA approval (49 CFR 1572.13(c)).

Felonies such as espionage, treason, terrorism, murder, and improper transportation of hazardous materials under 49 U.S.C. 5124 disqualify an applicant permanently (49 CFR 1572.103(a)).

Felonies such as arson, robbery, extortion, bribery, and drug distribution disqualify an applicant if convicted within 7 years of applying or released from prison within 5 years (49 CFR 1572.103(b)).

An applicant with certain disqualifying standards can ask TSA for a waiver under 49 CFR 1515.7 (49 CFR 1572.5(d)).

A driver getting the H endorsement for the first time must finish hazmat theory training from a provider listed on FMCSA's Training Provider Registry (49 CFR 380.609(b)).

There is no minimum number of hours. The provider must cover every topic in the hazmat curriculum before the driver can take the state H knowledge test (49 CFR part 380, Appendix E).

The trainee needs an overall score of at least 80 percent on the provider's written theory assessment (49 CFR 380.715).

Drivers issued an H endorsement before February 7, 2022 did not have to complete ELDT for it (49 CFR 380.603(b)).

A first DUI conviction while driving a CMV hauling hazmat disqualifies the driver for 3 years, compared with 1 year in a CMV without hazmat (49 CFR 383.51, Table 1).

Anyone whose work directly affects hazmat transportation safety, including a self-employed owner-operator who hauls hazmat (49 CFR 171.8).

Every hazmat employee must be trained at least once every three years (49 CFR 172.704(c)(2)).

A new or reassigned hazmat employee may work only under direct supervision of a trained employee, and training must be finished within 90 days (49 CFR 172.704(c)(1)).

The employer keeps a record of each hazmat employee's training for the preceding three years, for as long as the person works there and 90 days after (49 CFR 172.704(d)).

Pre-trip inspection, vehicle controls, tunnels, bridges and rail crossings, attendance, parking, smoking, routing, incident reporting, and loading and segregation (49 CFR 177.816).

The hazmat regulations, hazmat handling, operation of emergency equipment, and emergency response procedures (49 CFR 383.121).

The shipper must give the motor carrier the required placards before or when it offers the shipment, unless the vehicle is already placarded for it (49 CFR 172.506(a)).

No motor carrier may transport hazmat in a vehicle unless the required placards are affixed (49 CFR 172.506(a)(1)).

Allowed only in an emergency: with a state or local government escort, with DOT permission, or when needed to protect life or property (49 CFR 177.823).

No one may accept or haul a forbidden material, or hazmat that is not prepared to the regulations (49 CFR 177.801).

Carriers hauling hazmat in vehicles that must be marked or placarded, their supervisors, and each person who drives or is in charge of the vehicle (49 CFR 397.1).

Hazmat vehicles must be driven and parked under the laws of each jurisdiction, unless they conflict with a DOT rule that is stricter (49 CFR 397.3).

Drivers of placarded hazmat loads may not text or use a hand-held mobile phone while driving (49 CFR 177.804(b)).

Required for anyone who ships or hauls certain hazmat, including any quantity of Division 1.1, 1.2, or 1.3 explosives (49 CFR 172.800(b)).

A risk assessment plus measures for personnel security, unauthorized access, and en route security (49 CFR 172.802).

Explosives with a mass explosion hazard, meaning an explosion that affects almost the entire load at once (49 CFR 173.50).

Explosives with a projection hazard but no mass explosion hazard (49 CFR 173.50).

Explosives with a fire hazard and a minor blast or projection hazard, but no mass explosion hazard (49 CFR 173.50).

Explosives with a minor explosion hazard. Effects stay largely inside the package (49 CFR 173.50).

Very insensitive explosives, also called blasting agents (49 CFR 173.2).

Extremely insensitive articles with no mass explosion hazard; the risk is limited to the explosion of a single article (49 CFR 173.50(b)(6)).

Flammable gas (49 CFR 173.115(a)).

Non-flammable, nonpoisonous compressed gas: exerts 200 kPa (29.0 psig) or more at 68 °F (20 °C), or is a liquefied gas or cryogenic liquid, and is not Division 2.1 or 2.3 (49 CFR 173.115(b)).

Gas poisonous by inhalation (49 CFR 173.115(c)).

A flammable liquid has a flash point of not more than 140 °F (60 °C) (49 CFR 173.120(a)).

A liquid that fits no other hazard class and has a flash point above 140 °F (60 °C) and below 200 °F (93 °C) (49 CFR 173.120(b)).

Not regulated by the HMR unless it is a hazardous substance, a hazardous waste, or a marine pollutant (49 CFR 173.150(f)(2)).

Flammable solid: desensitized explosives, self-reactive materials, readily combustible solids, and polymerizing materials (49 CFR 173.124(a)).

Spontaneously combustible material, which includes pyrophoric and self-heating materials (49 CFR 173.124(b)).

A liquid or solid that can ignite within 5 minutes of contact with air, even in small amounts and with no ignition source (49 CFR 173.124(b)).

Dangerous when wet: material that can become spontaneously flammable or give off flammable or toxic gas on contact with water (49 CFR 173.124(c)).

Oxidizer: material that can cause or enhance combustion of other materials, generally by yielding oxygen (49 CFR 173.127).

Organic peroxide: an organic compound containing the -O-O- structure, a derivative of hydrogen peroxide (49 CFR 173.128).

Poisonous material other than a gas, known or presumed to be toxic to humans (49 CFR 173.132).

Infectious substance: material known or reasonably expected to contain a pathogen that can cause disease in humans or animals (49 CFR 173.134).

Radioactive material: material containing radionuclides above set activity levels (49 CFR 173.403).

Corrosive material: causes irreversible damage to human skin, or corrodes steel or aluminum at a severe rate (49 CFR 173.136).

Miscellaneous hazardous material, including elevated temperature materials, hazardous substances, hazardous wastes, and marine pollutants not in another class (49 CFR 173.140).

PG I means great danger, PG II medium danger, and PG III minor danger (49 CFR 171.8).

Class 2, Class 7, and Division 6.2 materials are not assigned packing groups (49 CFR 172.101(f)).

The table in 49 CFR 172.101 that lists each material's proper shipping name, hazard class, ID number, packing group, labels, special provisions, packaging, and quantity limits.

Symbols that change how an entry is used: +, A, D, G, I, and W (49 CFR 172.101(b)).

Fixes the proper shipping name, hazard class, and packing group even if the material does not meet that class definition (49 CFR 172.101(b)(1)).

The material is regulated only by air, unless it is a hazardous substance or hazardous waste (49 CFR 172.101(b)(2)).

The material is regulated only by vessel, unless it is a hazardous substance or hazardous waste (49 CFR 172.101(b)(6)).

The proper shipping name is fine for domestic shipments but may not be accepted internationally (49 CFR 172.101(b)(3)).

The proper shipping name is meant for international shipments. A different name may be used for domestic-only trips (49 CFR 172.101(b)(5)).

A technical name for the hazardous material must be added in parentheses with the basic description (49 CFR 172.101(b)(4)).

Hazmat descriptions and proper shipping names. Only words in Roman type, not italics, are part of the proper shipping name (49 CFR 172.101(c)).

The hazard class or division, or the word Forbidden (49 CFR 172.101(d)).

A material marked Forbidden in Column 3 may not be offered or transported (49 CFR 172.101(d)(1)).

The identification number. UN numbers work for domestic and international shipments; NA numbers are not recognized outside the United States (49 CFR 172.101(e)).

The packing group, in Roman numerals I, II, or III (49 CFR 172.101(f)).

The label codes. The first code is the primary hazard and any others are subsidiary hazards (49 CFR 172.101(g)).

Special provisions, explained in 49 CFR 172.102 (49 CFR 172.101(h)).

Packaging sections in Part 173: 8A exceptions, 8B non-bulk packaging, and 8C bulk packaging (49 CFR 172.101(i)).

Quantity limits per package: 9A for passenger aircraft or passenger rail, 9B for cargo aircraft only (49 CFR 172.101(j)).

Vessel stowage locations and other vessel handling codes (49 CFR 172.101(k)).

A shipping order, bill of lading, manifest, or similar document that describes the hazmat as Part 172 subpart C requires (49 CFR 171.8).

ID number, proper shipping name, hazard class or division, and packing group, in that order with nothing in between (49 CFR 172.202(b)).

UN2744, Cyclobutyl chloroformate, 6.1, (8, 3), PG II. The numbers in parentheses are subsidiary hazard classes (49 CFR 172.202(b)).

The total quantity with its unit of measure, such as 200 kg, plus the number and type of packages, such as 12 drums (49 CFR 172.202(a)(5), (a)(7)).

The hazmat must be listed first, printed in a contrasting color, or marked with an X in a column headed HM (49 CFR 172.201(a)(1)).

The X in the HM column may be replaced by RQ when the material is a hazardous substance (49 CFR 172.201(a)(1)(iii)).

The amount of a hazardous substance listed in Appendix A to 172.101. A package holding that much or more makes the material a hazardous substance (49 CFR 171.8).

The letters RQ go before or after the basic description of each hazardous substance (49 CFR 172.203(c)(2)).

The shipping paper must say Poison-Inhalation Hazard or Toxic-Inhalation Hazard and give the hazard zone (49 CFR 172.203(m)).

Added just before the proper shipping name of a liquid elevated temperature material when the name does not already say so (49 CFR 172.203(n)).

If the word waste is not already in the name, the proper shipping name of a hazardous waste starts with Waste, as in Waste acetone (49 CFR 172.101(c)(9)).

EPA Form 8700-22. No one may offer, haul, transfer, or deliver hazardous waste without it (49 CFR 172.205(a)).

The generator and the initial carrier sign and date the original. Each later carrier and the receiving facility sign a copy (49 CFR 172.205(c)-(d)).

The required shipping description may not use codes or abbreviations unless the rules specifically allow them (49 CFR 172.201(a)(3)).

Each page is numbered in order and the first page shows the total, for example Page 1 of 4 pages (49 CFR 172.201(c)).

The shipper certifies on the paper that the materials are properly classified, described, packaged, marked and labeled, and ready for transport under DOT rules (49 CFR 172.204(a)(1)).

Except for hazardous waste, shipments moved entirely by private carriage and bulk loads in a cargo tank supplied by the carrier (49 CFR 177.817(b)).

One year after the carrier accepts the material, or three years for hazardous waste (49 CFR 177.817(f)).

Two years after the initial carrier accepts the material, or three years for hazardous waste (49 CFR 172.201(e)).

Within reach while wearing the lap belt, and either in plain view or in a pouch on the inside of the driver's door (49 CFR 177.817(e)(2)(i)).

In the pouch on the inside of the driver's door, or on the driver's seat (49 CFR 177.817(e)(2)(ii)).

The hazmat paper must be tabbed or placed on top so authorities can find it (49 CFR 177.817(e)(1)).

On each side and each end of the vehicle, freight container, or bulk packaging (49 CFR 172.504(a)).

Materials that need placards in any amount: Divisions 1.1, 1.2, 1.3, 2.3, 4.3, 5.2 Type B temperature controlled, 6.1 poison inhalation hazard, and Class 7 Radioactive Yellow III (49 CFR 172.504(e)).

All other placarded categories, including Divisions 1.4, 1.5, 1.6, 2.1, 2.2, 4.1, 4.2, 5.1, Class 3, combustible liquid, Class 8, and Class 9 (49 CFR 172.504(e), Table 2).

By highway, Table 2 materials need no placards when the vehicle carries less than 1,001 lb aggregate gross weight of them (49 CFR 172.504(c)).

It does not apply to bulk packagings or to materials needing subsidiary placards under 172.505 (49 CFR 172.504(c)).

A non-bulk package holding only residue of a Table 2 material is left out when deciding on placards (49 CFR 172.504(d)(1)).

Can replace separate Table 2 placards when a vehicle carries non-bulk packages of two or more Table 2 categories (49 CFR 172.504(b)).

When 2,205 lb (1,000 kg) or more of one Table 2 category is loaded at one facility, that category's own placard is required, even with a DANGEROUS placard (49 CFR 172.504(b)).

Only the placard for the lowest division number must be shown (49 CFR 172.504(f)(1)).

A material poisonous by inhalation needs a POISON INHALATION HAZARD or POISON GAS placard in addition to any other required placard (49 CFR 172.505(a)).

A material with a dangerous-when-wet subsidiary hazard needs DANGEROUS WHEN WET placards on each side and end, in addition to its other placards (49 CFR 172.505(c)).

Materials with secondary hazards may show subsidiary placards even when the rules do not require them (49 CFR 172.505(d)).

FLAMMABLE GAS (49 CFR 172.504(e), Table 2).

NON-FLAMMABLE GAS (49 CFR 172.504(e), Table 2).

POISON GAS, required in any amount (49 CFR 172.504(e), Table 1).

FLAMMABLE (49 CFR 172.504(e), Table 2).

COMBUSTIBLE. A FLAMMABLE placard may be used instead on a cargo tank or portable tank (49 CFR 172.504(e), (f)(2)).

FLAMMABLE SOLID (49 CFR 172.504(e), Table 2).

SPONTANEOUSLY COMBUSTIBLE (49 CFR 172.504(e), Table 2).

DANGEROUS WHEN WET, required in any amount (49 CFR 172.504(e), Table 1).

OXIDIZER (49 CFR 172.504(e), Table 2).

ORGANIC PEROXIDE. It is a Table 1 placard for Type B, temperature-controlled organic peroxide and Table 2 otherwise (49 CFR 172.504(e)).

POISON, or POISON INHALATION HAZARD (Table 1) for material poisonous by inhalation (49 CFR 172.504(e)).

None. Infectious substances have no placard (49 CFR 172.504(e), Table 2).

RADIOACTIVE, required for packages with a Radioactive Yellow III label (49 CFR 172.504(e), Table 1).

CORROSIVE (49 CFR 172.504(e), Table 2).

Not required for domestic transport, but a bulk packaging must still show the ID number (49 CFR 172.504(f)(9)).

May be used instead of NON-FLAMMABLE GAS for domestic shipments of compressed or refrigerated liquid oxygen (49 CFR 172.504(f)(7)).

When the vehicle also carries flammable gas or oxygen and shows the FLAMMABLE GAS or OXYGEN placard (49 CFR 172.504(f)(3)).

Domestically, when the vehicle already shows a POISON INHALATION HAZARD or POISON GAS placard (49 CFR 172.504(f)(11)).

At least 250 mm (9.84 inches) on each side, set square-on-point like a diamond (49 CFR 172.519(c)(1)).

The hazard class or division number goes in the bottom corner of both primary and subsidiary placards (49 CFR 172.519(b)(4)).

At least 3 inches away from advertising or any marking that could reduce its effect (49 CFR 172.516(c)(4)).

Words or ID numbers on a placard are shown horizontally, reading left to right (49 CFR 172.516(c)(5)).

Clear of ladders, pipes, doors, and tarps, and where possible out of the dirt and water thrown by the wheels (49 CFR 172.516(c)).

May be on the front of the tractor instead of, or as well as, the front of the trailer (49 CFR 172.516(b)).

The carrier must keep placards readable and visible, not damaged, faded, or covered by dirt (49 CFR 172.516(c)(6)).

No placard unless the load is hazmat it represents, and no sign or slogan such as Drive Safely that could be confused with a placard (49 CFR 172.502(a)).

160 mm (6.3 in) high by 400 mm (15.7 in) wide, with the ID number in black numerals 100 mm (3.9 in) tall (49 CFR 172.332(b)).

Shown in black numerals on a white area across the center of the placard (49 CFR 172.332(c)).

RADIOACTIVE, all EXPLOSIVES placards, DANGEROUS, and any subsidiary placard (49 CFR 172.334(a)).

A plain white diamond the same size as a placard. It can show a required ID number instead of an orange panel, including when the ID may not go on the placard itself; it is not a placard (49 CFR 172.336(b)).

The proper shipping name and the ID number with its UN, NA, or ID prefix (49 CFR 172.301(a)).

A non-bulk package with a hazardous substance must be marked RQ next to the proper shipping name (49 CFR 172.324(b)).

Required near the labels or placards on material poisonous by inhalation; on bulk, on two opposite sides (49 CFR 172.313(a)).

Liquid hazmat in combination packages must be packed closures up and marked with arrows on two opposite sides (49 CFR 172.312(a)).

A diamond hazard label is at least 100 mm (3.9 inches) on each side (49 CFR 172.407(c)).

White-I, Yellow-II, or Yellow-III, chosen by the package's surface radiation level and transport index (49 CFR 172.403).

Every package must be secured against shifting during normal transport, and packages with valves loaded to minimize damage (49 CFR 177.834(a)).

No hazmat may be loaded or unloaded unless the handbrake is securely set (49 CFR 177.834(e)).

Smoking on or near the vehicle is forbidden while loading or unloading Class 1, 3, 4, or 5 or Division 2.1 materials (49 CFR 177.834(c)).

No tools likely to damage package closures may be used to load or unload Class 1 explosives (49 CFR 177.834(f)).

The engine must be stopped while Class 1 explosives are loaded or unloaded, except to run certain pumping equipment (49 CFR 177.835(a)).

No bale hooks or metal tools. Do not throw or drop packages, and do not roll them unless they are barrels or kegs (49 CFR 177.835(b)).

No bolts, screws, nails, or other parts may project inward where they could damage explosives packages (49 CFR 177.835(e)).

Tight floors, lined where the load touches with non-metallic material or non-ferrous metal, with listed military exceptions (49 CFR 177.835(f)).

Not allowed if the combination has more than two cargo-carrying vehicles or any vehicle in it is a placarded cargo tank, among other limits (49 CFR 177.835(c)).

Detonators may not ride with Division 1.1, 1.2, or 1.3 materials unless packed in a specification MC 201 container or loaded by a PHMSA-approved method such as IME Standard 22 (49 CFR 177.835(g)).

The heater must be made inoperable by draining or removing its fuel tank and disconnecting its power source (49 CFR 177.834(l)(1)).

A combustion heater is allowed only under listed conditions, including that it cannot heat any cargo above 130 °F (54 °C) (49 CFR 177.834(l)(2)).

Keep the whole load inside the body or under a tarp, close the tailgate, and keep water-sensitive material dry (49 CFR 177.838(a)-(b)).

A vehicle may carry no more than 100 lb (45.4 kg) net of these Division 4.1 materials (49 CFR 177.838(g)).

A package of nitric acid at 50 percent or stronger may not be loaded above any other kind of material (49 CFR 177.839(a)).

Load them so other cargo cannot fall on them, and insulate the terminals against short circuits (49 CFR 177.839(b)).

Secure them upright or horizontal, in racks, or packed in boxes or crates so they cannot shift, tip, or fall out (49 CFR 177.840(a)(1)).

A package bearing a POISON or POISON INHALATION HAZARD label may not ride with food or feed unless overpacked or separated as the rule allows (49 CFR 177.841(e)(1)).

No package labeled POISON, POISON GAS, or POISON INHALATION HAZARD may be carried in the driver's compartment, including the sleeper berth (49 CFR 177.841(e)(2)).

The number on a radioactive label equal to the maximum radiation level in millirem per hour at 1 meter from the package. It tells the carrier how much control the package needs (49 CFR 173.403).

The total transport index of Class 7 packages in one vehicle may not exceed 50, except for exclusive use shipments (49 CFR 177.842(a)).

These packages must be kept a minimum distance, set by total TI, from areas occupied by people or animals and from undeveloped film (49 CFR 177.842(b)).

The two materials may not be loaded, transported, or stored together in the same vehicle (49 CFR 177.848(e)(2)).

The materials may share a vehicle only if separated so they could not mix if a package leaked (49 CFR 177.848(e)(3)).

A blank space, or a class not listed, means no segregation restriction (49 CFR 177.848(e)(1)).

Corrosive liquids may not be loaded above or next to Class 4 or Class 5 materials, whatever separation is used (49 CFR 177.848(e)(3)).

Cyanides may not be loaded with acids if mixing would produce hydrogen cyanide (49 CFR 177.848(c)).

They may not be stored, loaded, or transported together (49 CFR 177.848(c)).

If a subsidiary hazard calls for stricter segregation than the primary hazard, the stricter rule applies (49 CFR 177.848(e)(6)).

Different Class 1 materials follow the separate Class 1 compatibility table, shown by an asterisk in the main table (49 CFR 177.848(e)(4), (f)).

Note A lets ammonium nitrate (UN1942) and ammonium nitrate fertilizer ride with Division 1.1 or 1.5 materials despite the X (49 CFR 177.848(e)(5)).

Allowed only when no other practical way to ship exists, apart from a few listed exceptions. Non-explosive hazmat is then capped at 99 lb per class and 496 lb in total (49 CFR 177.870(b), (e)).

No Class 1 material except small-arms ammunition may be carried where passengers ride (49 CFR 177.870(c)).

A capacity greater than 119 gallons (450 L) with no intermediate containment (49 CFR 171.8).

A net mass greater than 882 lb (400 kg) and a capacity greater than 119 gallons (450 L) (49 CFR 171.8).

A water capacity greater than 1,000 lb (454 kg) (49 CFR 171.8).

A bulk tank for liquids or gases that is attached to the vehicle, or is loaded and unloaded without being removed from it (49 CFR 171.8).

A CMV built to carry liquid or gas in tanks with an individual capacity over 119 gallons and an aggregate capacity of 1,000 gallons or more (49 CFR 383.5).

A rigid or flexible portable packaging, other than a cylinder or portable tank, designed for mechanical handling (49 CFR 171.8).

Placards stay on an emptied bulk packaging until it is cleaned and purged of vapors or refilled with a material that removes the hazard. Narrow exceptions cover Class 9 residue below the RQ and empty IBCs moved under 173.29(d) (49 CFR 172.514(b)).

ID markings stay on until the package is cleaned of residue and purged, or refilled with a material needing different or no markings (49 CFR 172.302(d)).

Shown on each side and each end of the packaging (49 CFR 172.302(a)(1)).

Shown on two opposing sides (49 CFR 172.302(a)(2)).

Required markings on cargo tanks are at least 50 mm (2.0 inches) high (49 CFR 172.302(b)(3)).

The proper shipping name or a common name, such as Refrigerant Gas, on each side and each end in letters at least 2 inches high (49 CFR 172.328(b)).

When compartments hold different materials, the end displays may be left off if the side displays follow the order of the compartments (49 CFR 172.336(c)).

Portable tanks under 1,000 gallons and bulk bags or boxes under 640 cubic feet may be placarded on two opposite sides or labeled instead (49 CFR 172.514(c)).

A bulk packaging of elevated temperature material is marked HOT on two opposing sides (49 CFR 172.325(a)).

A qualified person must attend a cargo tank at all times while it is loaded. The person loading it is responsible (49 CFR 177.834(i)(1)).

The motor carrier must ensure a qualified person attends the whole unloading (49 CFR 177.834(i)(2)).

Staying within 25 feet of the tank, alert, with a clear view of the tank and delivery hose as far as practical. Approved remote camera or sensor monitoring can also count (49 CFR 177.834(i)(3)).

Knows the hazards of the material, has been taught emergency procedures, and is authorized and able to move the cargo tank (49 CFR 177.834(i)(4)).

When delivery is fulfilled, the tank is on the consignee's premises, and the tractor has been removed from the premises (49 CFR 177.834(i)(2)).

All manhole closures must be closed and secured, and all valves and closures in the liquid discharge system closed and free of leaks (49 CFR 177.834(j)).

The engine must be off during loading and unloading unless it runs the pump (49 CFR 177.837(a)).

When loading through an open filling hole, connect the bond wire before opening any hole and leave it until the last hole is closed (49 CFR 177.837(c)(1)).

When the tank is loaded or unloaded through a vapor-tight connection, made before flow starts and broken after it stops (49 CFR 177.837(c)(2)).

Connect the conductor to the container being filled first, then to the container being emptied (49 CFR 177.837(b)).

The attendant may stay within 150 feet of the tank and 25 feet of the hose, checking both at least every five minutes (49 CFR 177.837(d)).

Stop within 50 feet of, and no closer than 15 feet to, the nearest rail, then look and listen both ways (49 CFR 392.10(a)).

Cross in a gear that lets you finish without shifting. Do not shift gears while crossing the tracks (49 CFR 392.10(a)).

Vehicles placarded for the classes listed in 392.10, any vehicle carrying chlorine, and every cargo tank used for hazmat, loaded or empty (49 CFR 392.10(a)).

When a police officer or flagman waves you on, a green traffic signal allows it, the line is marked abandoned, the crossing has an Exempt sign, or at streetcar or industrial switching tracks inside a business district (49 CFR 392.10(b)).

Do not drive onto the crossing unless there is room to drive completely through without stopping (49 CFR 392.12, 177.804(b)).

The vehicle must be attended at all times by the driver or a qualified representative of the carrier (49 CFR 397.5(a)).

Allowed on carrier, shipper, or consignee property if a person who knows the load and the emergency procedures keeps it in view, or in a safe haven. Loads of 50 lb or less may also be left at a construction or survey site (49 CFR 397.5(b)).

On a public street, highway, or shoulder, the driver must attend the vehicle, except while doing duties that are part of the job (49 CFR 397.5(c)).

The person in charge is on the vehicle, awake and not in the sleeper berth, or within 100 feet with a clear view of it (49 CFR 397.5(d)(1)).

An area approved in writing by local, state, or federal officials for parking unattended vehicles carrying Division 1.1, 1.2, or 1.3 explosives (49 CFR 397.5(d)(3)).

A vehicle with Division 1.1, 1.2, or 1.3 material may not park on or within 5 feet of the traveled part of a public road (49 CFR 397.7(a)(1)).

Only with the consent of the person in charge, who must know what the vehicle carries (49 CFR 397.7(a)(2)).

Do not park within 300 feet of a bridge, tunnel, dwelling, or place where people work or gather, except briefly when there is no other choice (49 CFR 397.7(a)(3)).

Do not park on or within 5 feet of the traveled part of a public road except briefly when operations require it (49 CFR 397.7(b)).

Do not drive near an open fire unless you can pass without stopping, and never park within 300 feet of one (49 CFR 397.11).

No smoking or lighted tobacco within 25 feet of a vehicle with Class 1, Class 5, or flammable materials (2.1, 3, 4.1, 4.2), or an empty tank that carried Class 3 or 2.1 (49 CFR 397.13).

Turn the engine off, and someone must control the fueling at the point where the tank is filled (49 CFR 397.15).

Check every tire at the start of each trip and each time the vehicle is parked (49 CFR 397.17(a)).

Repair, replace, or inflate it before driving on. You may drive only to the nearest safe place to do that (49 CFR 397.17(b)).

Remove it and place it a safe distance from the vehicle, and do not drive until the cause is fixed (49 CFR 397.17(c)).

Avoid heavily populated areas, crowds, tunnels, narrow streets, and alleys unless there is no practical alternative or a needed deviation (49 CFR 397.67(b)).

Convenience is never a valid reason to use a route through populated areas or tunnels (49 CFR 397.67(c)).

Required before a vehicle with Division 1.1, 1.2, or 1.3 explosives moves; the carrier gives the driver a copy (49 CFR 397.67(d)).

A copy of the Part 397 rules and written accident or delay instructions. The driver signs a receipt the carrier keeps for one year (49 CFR 397.19).

Radioactive loads at this level must use preferred routes such as Interstates, with a written route plan (49 CFR 397.101).

The driver must have received written training within the two preceding years (49 CFR 397.101(e)).

The power unit needs a fire extinguisher with a UL rating of 10 B:C or more (49 CFR 393.95(a)(1)(i)).

Flame signals may not be carried on vehicles hauling Division 1.1-1.3 or on cargo tanks used for Division 2.1 or Class 3, loaded or empty (49 CFR 393.95(g)).

If flammable liquid or gas is leaking, no flame device may be placed close enough to ignite it (49 CFR 392.22(b)(2)(vi)).

800-424-8802 (toll free) or 202-267-2675 (49 CFR 171.15(a)).

As soon as practical, and no later than 12 hours after the incident (49 CFR 171.15(a)).

Each person in physical possession of the hazmat at the time of the incident (49 CFR 171.15(a)).

When hazmat directly causes a death, a hospital admission, a public evacuation of 1 hour or more, or closure of a major transportation artery for 1 hour or more, among others (49 CFR 171.15(b)).

DOT Form F 5800.1, filed within 30 days of discovering the incident (49 CFR 171.16(a)).

The reporting person keeps a copy for two years at its principal place of business (49 CFR 171.16(b)(3)).

Must be monitored at all times while the hazmat is in transport, by someone who knows the material or can reach that person immediately (49 CFR 172.604(a)).

Not allowed. A number that requires a call back, such as an answering machine or beeper, does not meet the rule (49 CFR 172.604(a)(2)).

Must include the basic description and technical name, immediate health hazards, fire or explosion risks, immediate precautions, fire methods, spill or leak methods, and first aid (49 CFR 172.602(a)).

Printed legibly in English, on paper or in electronic format, and usable away from the package (49 CFR 172.602(b)).

Repair it if safe, or move the material in a salvage packaging to destination or back to the shipper (49 CFR 177.854(b)-(c)).

Guard the vehicle and load, and make a special effort to move it to a place where the hazards can be controlled (49 CFR 177.854(a)).

The Emergency Response Guidebook for first responders, developed by U.S. DOT, Transport Canada, and Mexico's transport secretariat with help from Argentina's Centro de Información Química para Emergencias (CIQUIME). The current edition is ERG2024.

Materials listed by ID number, giving the guide number for each (ERG2024).

Materials listed alphabetically by name, giving the guide number and ID number for each (ERG2024).

The numbered response guides, each with Potential Hazards, Public Safety, and Emergency Response sections (ERG2024).

Table 1 initial isolation and protective action distances, Table 2 water-reactive materials, and Table 3 distances for six common toxic inhalation gases (ERG2024).

The material is a toxic inhalation hazard or water-reactive. With no fire, go to Table 1 for distances and also read the orange guide (ERG2024).

The material may undergo violent polymerization (ERG2024).

Used for a DANGEROUS placard, when the material is unknown, or when hazmat is suspected but no placards can be seen (ERG2024).

Guide 112 for Divisions 1.1, 1.2, 1.3, or 1.5, and Guide 114 for Divisions 1.4 or 1.6 (ERG2024).

Use it only when the ID number or shipping name is not available. Switch to the specific guide once you know the material (ERG2024).

Start with the most conservative guide, the one calling for the most protective action (ERG2024).

Approach from upwind, uphill, or upstream, stay clear of spills, vapors, and smoke, and do not rush in (ERG2024).

Small spill: a release of 208 liters (55 US gallons) or less, generally a single small package such as a drum, a small cylinder, or a small leak from a large package. Large spill: more than 208 liters, usually from a large package or many small ones (ERG2024).

The radius of a zone around the spill, in all directions, where protective clothing and breathing protection are required (ERG2024).

The downwind distance from the spill where people should be evacuated or sheltered in place (ERG2024).

Day is after sunrise and before sunset; night is between sunset and sunrise (ERG2024).

Move people crosswind, perpendicular to the wind direction, and away from the spill (ERG2024).

Use the orange guide's evacuation distances, then protect downwind using Table 1 for any material that is still releasing (ERG2024).