Requirements for specific materials and packagings transported under the ICAO Technical Instructions, IMDG Code, Transport Canada TDG Regulations, or the IAEA Regulations.

Link to an amendment published at 91 FR 49305, Aug. 4, 2026.#

All shipments offered for transportation or transported in the United States under the ICAO Technical Instructions, IMDG Code, Transport Canada TDG Regulations, or the IAEA Regulations (IBR, see § 171.7) must conform to the requirements of this section, as applicable.#

(a)Conditions and requirements for cylinders and pressure receptacles—(1) Applicability. Except as provided in this paragraph (a), a filled cylinder (pressure receptacle) manufactured to other than a DOT specification or a UN standard in accordance with part 178 of this subchapter, a DOT exemption or special permit cylinder, a TC, CTC, CRC, or BTC cylinder authorized under § 171.12, or a cylinder used as a fire extinguisher in conformance with § 173.309(a) of this subchapter, may not be transported to, from, or within the United States.#

(2)Conditions. Cylinders (including UN pressure receptacles) transported to, from, or within the United States must conform to the applicable requirements of this subchapter. Unless otherwise excepted in this subchapter, a cylinder must not be transported unless—#

(i)The cylinder is manufactured, inspected and tested in accordance with a DOT specification or a UN standard prescribed in part 178 of this subchapter, or a TC, CTC, CRC, or BTC specification set out in the Transport Canada TDG Regulations (IBR, see § 171.7), except that cylinders not conforming to these requirements must meet the requirements in paragraph (a)(3), (4), or (5) of this section;#

(ii)The cylinder is equipped with a pressure relief device in accordance with § 173.301(f) of this subchapter and conforms to the applicable requirements in part 173 of this subchapter for the hazardous material involved;#

(iii)The openings on an aluminum cylinder in oxygen service conform to the requirements of this paragraph, except when the cylinder is used for aircraft parts or used aboard an aircraft in accordance with the applicable airworthiness requirements and operating regulations. An aluminum DOT specification cylinder must have an opening configured with straight (parallel) threads. A UN pressure receptacle may have straight (parallel) or tapered threads provided the UN pressure receptacle is marked with the thread type, e.g. “17E, 25E, 18P, or 25P” and fitted with the properly marked valve; and#

(iv)A UN pressure receptacle is marked with “USA” as a country of approval in conformance with §§ 178.69 and 178.70 of this subchapter, or “CAN” for Canada.#

(3)Pi-marked cylinders. Cylinders with a water capacity not exceeding 150 L and that are marked with a pi mark, in accordance with the European Directive 2010/35/EU (IBR, see § 171.7), on transportable pressure equipment (TPED), and that comply with the requirements of Packing Instruction P200 or P208, and 6.2 of the Agreement Concerning the International Carriage of Dangerous Goods by Road (ADR) (IBR, see § 171.7), concerning pressure relief device use, test period, filling ratios, test pressure, maximum working pressure, and material compatibility for the lading contained or gas being filled, are authorized as follows:#

(i)Filled cylinders imported for intermediate storage, transport to point of use, discharge, and export without further filling; and#

(ii)Cylinders imported or domestically sourced for the purpose of filling, intermediate storage, and export.#

(iii)The bill of lading or other shipping paper must identify the cylinder and include the following certification: “This cylinder (These cylinders) conform(s) to the requirements for pi-marked cylinders found in § 171.23(a)(3).”#

(4)Importation of cylinders for discharge within a single port area. Except as provided in § 171.23(a)(3), a cylinder manufactured to other than a DOT specification or UN standard in accordance with part 178 of this subchapter, or a TC, CTC, BTC, or CRC specification cylinder set out in the Transport Canada TDG Regulations (IBR, see § 171.7), and certified as being in conformance with the transportation regulations of another country may be authorized, upon written request to and approval by the Associate Administrator, for transportation within a single port area, provided—#

(i)The cylinder is transported in a closed freight container;#

(ii)The cylinder is certified by the importer to provide a level of safety at least equivalent to that required by the regulations in this subchapter for a comparable DOT, TC, CTC, BTC, or CRC specification or UN cylinder; and#

(iii)The cylinder is not refilled for export unless in compliance with paragraph (a)(5) of this section.#

(5)Filling of cylinders for export or for use on board a vessel. A cylinder not manufactured, inspected, tested and marked in accordance with part 178 of this subchapter, or a cylinder manufactured to other than a UN standard, DOT specification, exemption or special permit, or other than a TC, CTC, BTC, or CRC specification, may be filled with a gas in the United States and offered for transportation and transported for export or alternatively, for use on board a vessel, if the following conditions are met:#

(i)The cylinder has been requalified and marked in accordance with subpart C of part 180 of this subchapter, or has been requalified as authorized by the Associate Administrator;#

(ii)In addition to other requirements of this subchapter, the maximum filling density, service pressure, and pressure relief device for each cylinder conform to the requirements of this part for the gas involved; and#

(iii)The bill of lading or other shipping paper identifies the cylinder and includes the following certification: “This cylinder has (These cylinders have) been qualified, as required, and filled in accordance with the DOT requirements for export.”#

(6)Cylinders not equipped with pressure relief devices. A DOT specification or a UN cylinder manufactured, inspected, tested and marked in accordance with part 178 of this subchapter and otherwise conforms to the requirements of part 173 of this subchapter for the gas involved, except that the cylinder is not equipped with a pressure relief device may be filled with a gas and offered for transportation and transported for export if the following conditions are met:#

(i)Each DOT specification cylinder or UN pressure receptacle must be plainly and durably marked “For Export Only”;#

(ii)The shipping paper must carry the following certification: “This cylinder has (These cylinders have) been retested and refilled in accordance with the DOT requirements for export.”; and#

(iii)The emergency response information provided with the shipment and available from the emergency response telephone contact person must indicate that the pressure receptacles are not fitted with pressure relief devices and provide appropriate guidance for exposure to fire.#

(b)Conditions and requirements specific to certain materials—(1) Aerosols. Except for a limited quantity of a compressed gas in a container of not more than 4 fluid ounces capacity meeting the requirements in § 173.306(a)(1) of this subchapter, the proper shipping name “Aerosol,” UN1950, may be used only for a non-refillable receptacle containing a gas compressed, liquefied, or dissolved under pressure the sole purpose of which is to expel a nonpoisonous (other than Division 6.1, Packing Group III material) liquid, paste, or powder and fitted with a self-closing release device (see § 171.8). In addition, an aerosol must be in a metal packaging when the packaging exceeds 7.22 cubic inches.#

(2)Safety devices for vehicles, vessels or aircraft, e.g. air bag inflators, air bag modules, seat-belt pretensioners, and pyromechanical devices. For each safety device, the shipping paper description must conform to the requirements in § 173.166(c) of this subchapter.#

(3)Chemical oxygen generators. Chemical oxygen generators must be approved, classed, described, packaged, and transported in accordance with the requirements of this subchapter.#

(4)Class 1 (explosive) materials. Prior to being transported, Class 1 (explosive) materials must be approved by the Associate Administrator in accordance with § 173.56 of this subchapter. Each package containing a Class 1 (explosive) material must conform to the marking requirements in § 172.320 of this subchapter.#

(5)Hazardous substances. A material meeting the definition of a hazardous substance as defined in § 171.8, must conform to the shipping paper requirements in § 172.203(c) of this subchapter and the marking requirements in § 172.324 of this subchapter:#

(i)The proper shipping name must identify the hazardous substance by name, or the name of the substance must be entered in parentheses in association with the basic description and marked on the package in association with the proper shipping name. If the hazardous substance meets the definition for a hazardous waste, the waste code (for example, D001), may be used to identify the hazardous substance;#

(ii)The shipping paper and the package markings must identify at least two hazardous substances with the lowest reportable quantities (RQs) when the material contains two or more hazardous substances; and#

(iii)The letters “RQ” must be entered on the shipping paper either before or after the basic description, and marked on the package in association with the proper shipping name for each hazardous substance listed.#

(6)Hazardous wastes. A material meeting the definition of a hazardous waste (see § 171.8) must conform to the following:#

(i)The shipping paper and the package markings must include the word “Waste” immediately preceding the proper shipping name;#

(ii)The shipping paper must be retained by the shipper and by each carrier for three years after the material is accepted by the initial carrier (see § 172.205(e)(5)); and#

(iii)A hazardous waste manifest must be completed in accordance with § 172.205 of this subchapter.#

(7)Marine pollutants. Except for marine pollutants (see § 171.8) transported in accordance with the IMDG Code, marine pollutants transported in bulk packages must meet the shipping paper requirements in § 172.203(l) of this subchapter and the package marking requirements in § 172.322 of this subchapter.#

(8)Organic peroxides. Organic peroxides not identified by technical name in the Organic Peroxide Table in § 173.225(c) of this subchapter must be approved by the Associate Administrator in accordance with § 173.128(d) of this subchapter.#

(9)[Reserved]#

(10)Poisonous by inhalation materials. A material poisonous by inhalation (see § 171.8) must conform to the following requirements:#

(i)The words “Poison-Inhalation Hazard” or “Toxic-Inhalation Hazard” and the words “Zone A,” “Zone B,” “Zone C,” or “Zone D” for gases, or “Zone A” or “Zone B” for liquids, as appropriate, must be entered on the shipping paper immediately following the basic shipping description. The word “Poison” or “Toxic” or the phrase “Poison-Inhalation Hazard” or “Toxic-Inhalation Hazard” need not be repeated if it otherwise appears in the shipping description;#

(ii)The material must be packaged in accordance with the requirements of this subchapter;#

(iii)The package must be marked in accordance with § 172.313 of this subchapter; and#

(iv)Except as provided in subparagraph (B) of this paragraph (b)(10)(iv) and for a package containing anhydrous ammonia prepared in accordance with the Transport Canada TDG Regulations, the package must be labeled or placarded with POISON INHALATION HAZARD or POISON GAS, as appropriate, in accordance with Subparts E and F of part 172 of this subchapter.#

(A)For a package transported in accordance with the IMDG Code in a closed transport vehicle or freight container, a label or placard conforming to the IMDG Code specifications for a “Class 2.3” or “Class 6.1” label or placard may be substituted for the POISON GAS or POISON INHALATION HAZARD label or placard, as appropriate. The transport vehicle or freight container must be marked with the identification numbers for the hazardous material in the manner specified in § 172.313(c) of this subchapter and placarded as required by subpart F of part 172 of this subchapter.#

(B)For a package transported in accordance with the Transport Canada TDG Regulations in a closed transport vehicle or freight container, a label or placard conforming to the TDG Regulations specifications for a “Class 2.3” or “Class 6.1” label or placard may be substituted for the POISON GAS or POISON INHALATION HAZARD label or placard, as appropriate. The transport vehicle or freight container must be marked with the identification numbers for the hazardous material in the manner specified in § 172.313(c) of this subchapter and placarded as required by subpart F of part 172 of this subchapter. While in transportation in the United States, the transport vehicle or freight container may also be placarded in accordance with the appropriate TDG Regulations in addition to being placarded with the POISON GAS or POISON INHALATION HAZARD placards.#

(11)Class 7 (radioactive) materials. (i) Highway route controlled quantities (see § 173.403 of this subchapter) must be shipped in accordance with §§ 172.203(d)(4) and (d)(10); 172.507, and 173.22(c) of this subchapter;#

(ii)For fissile materials and Type B, Type B(U), and Type B(M) packagings, the competent authority certification and any necessary revalidation must be obtained from the appropriate competent authorities as specified in §§ 173.471, 173.472, and 173.473 of this subchapter, and all requirements of the certificates and revalidations must be met;#

(iii)Type A package contents are limited in accordance with § 173.431 of this subchapter;#

(iv)The country of origin for the shipment must have adopted the edition of SSR-6 of the IAEA Regulations referenced in § 171.7.#

(v)The shipment must conform to the requirements of § 173.448, when applicable;#

(vi)The definition for “radioactive material” in § 173.403 of this subchapter must be applied to radioactive materials transported under the provisions of this subpart;#

(vii)Except for limited quantities, the shipment must conform to the requirements of § 172.204(c)(4) of this subchapter; and#

(viii)Excepted packages of radioactive material, instruments or articles, or articles containing natural uranium or thorium must conform to the requirements of § 173.421, § 173.424, or § 173.426 of this subchapter, as appropriate.#

(ix)Packages containing fissile materials must conform to the requirements of § 173.453 to be otherwise excepted from the requirements of subpart I of part 173 for fissile materials.#

(12)Self-reactive materials. Self-reactive materials not identified by technical name in the Self-reactive Materials Table in § 173.224(b) of this subchapter must be approved by the Associate Administrator in accordance with § 173.124(a)(2)(iii) of this subchapter.#