Previously authorized packaging.

Link to an amendment published at 91 FR 49345, Aug. 4, 2026.#

(a)When the regulations specify a packaging with a specification marking prefix of “DOT,” a packaging marked prior to January 1, 1970, with the prefix of “ICC” may be used in its place if the packaging otherwise conforms to applicable specification requirements.#

(b)[Reserved]#

(c)After July 2, 1982, a seamless aluminum cylinder manufactured in conformance with and for use under DOT special permit (SP) or exemption (E) 6498, 7042, 8107, 8364 or 8422 may be continued in use if marked before or at the time of the next retest with either the specification identification “3AL” immediately above the special permit or exemption number, or the DOT mark (e.g., DOT 3AL 1800) in proximity to the special permit or exemption marking.#

(d)Cylinders (spheres) manufactured and marked under DOT special permit (SP) or exemption (E) 6616 prior to January 1, 1983, may be continued in use if marked before or at the time of the next retest with the specification identification “4BA” near the special permit or exemption marking.#

(e)After October 1, 1984, cylinders manufactured for use under special permit (SP) or exemption (E) 6668 or 8404 may be continued in use, and must be marked “DOT-4LXXXYY” (XXX to be replaced by the service pressure, YY to be replaced by the letters “AL”, if applicable) in compliance with Specification 4L (§ 178.57 of this subchapter) on or before January 1, 1986. The “DOT-4LXXXYY” must appear in proximity to other required special permit or exemption markings.#

(f)An MC 331 cargo tank motor vehicle must conform to structural integrity requirements in § 178.337-3 or to corresponding requirements in effect at the time of manufacture.#

(g)A non-bulk packaging manufactured, tested, marked, and certified on or before September 30, 1996, in accordance with the applicable provisions of subparts L and M of part 178 of this subchapter in effect on September 30, 1995, may be used as authorized by this subchapter if the packaging conforms to all requirements applicable at the time of manufacture. In addition, such a packaging may be reused as authorized by § 173.28 without a nominal thickness marking, if it conforms to the minimum thickness criteria prescribed in § 173.28(b)(4).#

(h)A packaging that is permanently marked with a special permit number, “DOT-SP” or “DOT-E,” for which the provisions of the special permit have been incorporated into this subchapter may continue to be used for the life of the packaging without obliterating or otherwise removing the special permit number.#

(i)An exemption packaging or shipping paper that is permanently marked “DOT-E” prior to October 1, 2007, may continue in use as long as the exemption or special permit remains valid, unless otherwise specified in the exemption or special permit.#

Editorial Note:For Federal Register citations affecting § 173.23, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.#