e-CFR Navigation Aids


Simple Search

Advanced Search

 — Boolean

 — Proximity


Search History

Search Tips


Latest Updates

User Info


Agency List

Incorporation By Reference

eCFR logo

Related Resources

Electronic Code of Federal Regulations

We invite you to try out our new beta eCFR site at https://ecfr.federalregister.gov. We have made big changes to make the eCFR easier to use. Be sure to leave feedback using the Feedback button on the bottom right of each page!

e-CFR data is current as of March 2, 2021


49 CFR--PART 173

View Printed Federal Register page 85 FR 27879 in PDF format.

Amendment(s) published May 11, 2020, in 85 FR 27879

Effective Dates: Jan. 2, 2023

17. Effective January 2, 2023, in §173.21, revise paragraph (f) introductory text and paragraph (f)(1) to read as follows:

§173.21   Forbidden materials and packages.

*   *   *   *   *

(f) A package containing a material which is likely to decompose with a self-accelerated decomposition temperature (SADT) of 50 °C (122 °F) or less, or polymerize at a temperature of 54 °C (130 °F) or less with an evolution of a dangerous quantity of heat or gas when decomposing or polymerizing, unless the material is stabilized or inhibited in a manner to preclude such evolution. The SADT may be determined by any of the test methods described in Part II of the UN Manual of Tests and Criteria (IBR, see §171.7 of this subchapter).

(1) A package meeting the criteria of paragraph (f) of this section may be required to be shipped under controlled temperature conditions. The control temperature and emergency temperature for a package shall be as specified in the table in this paragraph based upon the SADT of the material. The control temperature is the temperature above which a package of the material may not be offered for transportation or transported. The emergency temperature is the temperature at which, due to imminent danger, emergency measures must be initiated.

Table 1 to Paragraph (f)(1)—Method of Determining Control and Emergency Temperature

SADT1Control temperaturesEmergency temperature
SADT ≤20 °C (68 °F)20 °C (36 °F) below SADT10 °C (18 °F) below SADT.
20 °C (68 °F) <SADT ≤35 °C (95 °F)15 °C (27 °F) below SADT10 °C (18 °F) below SADT.
35 °C (95 °F) <SADT ≤50 °C (122 °F)10 °C (18 °F) below SADT5 °C (9 °F) below SADT.
50 °C (122 °F) <SADT(2)(2)

1Self-accelerating decomposition temperature.

2Temperature control not required.

*   *   *   *   *

Need assistance?