49 CFR 173.4b: De minimis exceptions for small hazardous material quantities
Last reviewed: October 14, 2026
This section says certain small quantities of hazardous materials are not hazardous materials under § 171.8 when packaged as the section requires. It also excepts non-infectious specimens in small amounts of alcohol or formaldehyde solution. Both exceptions have packaging, marking, and documentation conditions.
Applies toPacking Group I materials of Division 6.1 (no inhalation hazard), and Packing Group II and III materials of Class 3, Divisions 4.1, 4.2, 4.3, 5.1, 6.1, Class 8, and Class 9, plus certain non-infectious specimens.
What it says
Packing Group I Division 6.1 materials with no inhalation hazard, and Packing Group II and III materials of the listed classes and divisions, are not hazardous materials and not subject to this subchapter when packaged as this section requires.
49 CFR 173.4b(a)“the following materials do not meet the definition of a hazardous material in § 171.8 of this subchapter and, therefore, are not subject to the requirements of this subchapter”
Each inner receptacle may hold no more than 1 mL (0.03 ounce) of an authorized liquid or 1 g (0.04 ounce) of an authorized solid material.
49 CFR 173.4b(a)(1)(i)“One (1) mL (0.03 ounce) for authorized liquids; and”
The completed package must withstand each listed free drop from a height of 1.8 m (5.9 feet) onto a solid unyielding surface without breakage or leakage from any inner receptacle and without a substantial reduction in the effectiveness of the package.
49 CFR 173.4b(a)(5)(i)“without breakage or leakage from any inner receptacle and without a substantial reduction in the effectiveness of the package”
A package may not exceed 100 g (0.22 pounds) of solids or 100 mL (3.38 ounces) of liquids in aggregate hazardous material, and its gross mass may not exceed 29 kg (64 pounds).
49 CFR 173.4b(a)(7)“The aggregate quantity of hazardous material per package does not exceed 100 g (0.22 pounds) for solids or 100 mL (3.38 ounces) for liquids;”
For transportation by aircraft, material packed under this section may not be carried in checked or carry-on baggage.
49 CFR 173.4b(a)(10)(ii)“Material packed in accordance with this section may not be carried in checked or carry-on baggage.”
The outer package of excepted specimens must be legibly marked with the stated scientific research specimens statement.
49 CFR 173.4b(b)(5)“The outer package must be legibly marked “Scientific research specimens, 49 CFR 173.4b applies.””
For transport by vessel, no shipping paper is required, but the Dangerous Cargo Manifest must include the specimen statement and the number of packages indicated.
49 CFR 173.4b(b)(6)(iii)“the Dangerous Cargo Manifest must include the statement “Scientific research specimens, 49 CFR 173.4b applies” and the number of packages indicated.”
Common questions
How much liquid can each inner receptacle hold under the de minimis exception?
Each inner receptacle or article is limited to 1 mL (0.03 ounce) for authorized liquids. For authorized solid materials the limit is 1 g (0.04 ounce).
“The maximum quantity of material per inner receptacle or article is limited to—”
What is the maximum weight of a de minimis package?
The gross mass of the completed package must not exceed 29 kg (64 pounds).
“The gross mass of the completed package does not exceed 29 kg (64 pounds);”
Is a shipping paper needed for scientific specimens shipped by vessel?
No shipping paper is required for transport by vessel. The Dangerous Cargo Manifest must include the specimen statement and the number of packages indicated.
“For transport by vessel, a shipping paper is not required; however, the Dangerous Cargo Manifest must include the statement”
How much flammable liquid can one outer packaging of specimens contain?
The aggregate net quantity of flammable liquid in one outer packaging may not exceed 1 L.
“The aggregate net quantity of flammable liquid in one outer packaging may not exceed 1 L; and”
The text of 49 CFR 173.4b
Electronic Code of Federal Regulations (eCFR), current as of March 31, 2026 · Read it on eCFR
De minimis exceptions
(a) When packaged in accordance with this section, the following materials do not meet the definition of a hazardous material in § 171.8 of this subchapter and, therefore, are not subject to the requirements of this subchapter: Packing Group I materials of hazard Division 6.1 (no inhalation hazard), and Packing Group II and III materials of hazard Class 3, Division 4.1, Division 4.2, Division 4.3, Division 5.1, Division 6.1, Class 8, and Class 9.
(1) The maximum quantity of material per inner receptacle or article is limited to—
(i) One (1) mL (0.03 ounce) for authorized liquids; and
(ii) One (1) g (0.04 ounce) for authorized solid materials;
(2) Each inner receptacle with a removable closure has its closure held securely in place with wire, tape, or other positive means;
(3) Unless equivalent cushioning and absorbent material surrounds the inside packaging, each inner receptacle is securely packed in an inside packaging with cushioning and absorbent material that:
(i) Will not react chemically with the material, and
(ii) Is capable of absorbing the entire contents (if a liquid) of the receptacle;
(4) The inside packaging is securely packed in a strong outer packaging;
(5) The completed package is capable of sustaining—
(i) Each of the following free drops made from a height of 1.8 m (5.9 feet) directly onto a solid unyielding surface without breakage or leakage from any inner receptacle and without a substantial reduction in the effectiveness of the package:
(A) One drop flat on bottom;
(B) One drop flat on top;
(C) One drop flat on the long side;
(D) One drop flat on the short side; and
(E) One drop on a corner at the junction of three intersecting edges; and
(ii) A compressive load as specified in § 178.606(c) of this subchapter. Each of the tests in this paragraph (a)(5) may be performed on a different but identical package; that is, all tests need not be performed on the same package.
(6) Placement of the material in the package or packing different materials in the package does not result in a violation of § 173.21;
(7) The aggregate quantity of hazardous material per package does not exceed 100 g (0.22 pounds) for solids or 100 mL (3.38 ounces) for liquids;
(8) The gross mass of the completed package does not exceed 29 kg (64 pounds);
(9) The package is not opened or otherwise altered until it is no longer in commerce; and
(10) For transportation by aircraft:
(i) The hazardous material is authorized to be carried aboard passenger-carrying aircraft in Column 9A of the § 172.101 Hazardous Materials Table; and
(ii) Material packed in accordance with this section may not be carried in checked or carry-on baggage.
(b) Non-infectious specimens, such as specimens of mammals, birds, amphibians, reptiles, fish, insects and other invertebrates containing small quantities of Ethanol (UN1170), Formaldehyde solution, flammable (UN1198), Alcohols, n.o.s. (UN1987) and Isopropanol (UN1219) are not subject to the requirements of this subchapter provided the following packaging, marking and documentation provisions, as applicable, are met:
(1) The specimens are:
(i) Wrapped in a paper towel or cheesecloth moistened with alcohol, an alcohol solution, or a formaldehyde solution and placed in a plastic bag that is heat-sealed. Any free liquid in the bag must not exceed 30 mL; or
(ii) Placed in vials or other rigid containers with no more than 30 mL of alcohol, an alcohol solution, or a formaldehyde solution. The containers are placed in a plastic bag that is heat-sealed;
(2) The bagged specimens are placed in another plastic bag with sufficient absorbent material to absorb the entire liquid contents inside the primary receptacle. The outer plastic bag is then heat-sealed;
(3) The completed bag is placed in a strong outer packaging with sufficient cushioning material that conforms to subpart B of part 173;
(4) The aggregate net quantity of flammable liquid in one outer packaging may not exceed 1 L; and
(5) The outer package must be legibly marked “Scientific research specimens, 49 CFR 173.4b applies.”
(6) Documentation. (i) For transportation by highway or rail, no shipping paper is required.
(ii) For transport by air, a shipping paper is not required, except that, if a document such as an air waybill accompanies a shipment of specimens containing hazardous materials excepted under the terms of this section, the document must include the statement “Scientific research specimens, 49 CFR 173.4b applies” and the number of packages indicated.
(iii) For transport by vessel, a shipping paper is not required; however, the Dangerous Cargo Manifest must include the statement “Scientific research specimens, 49 CFR 173.4b applies” and the number of packages indicated. Vessel stowage is the same as for hazardous materials in excepted quantities.
(7) Training. Each person who offers or transports excepted quantities of hazardous materials must know about the requirements of this section.
(8) Restrictions. Except as provided in § 175.10, for transportation by aircraft, hazardous material packaged in accordance with this section may not be carried in checked or carry-on baggage by a passenger or crew member.
Sections it refers to
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of March 31, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.