(a) Except as otherwise provided in paragraphs (b), (c), (d) and (e) of this section, each package containing a Class 1 material must be marked with the EX-number for each substance, article or device contained therein.
(b) Except for fireworks approved in accordance with § 173.56(j) of this subchapter, a package of Class 1 materials may be marked, in lieu of the EX-number required by paragraph (a) of this section, with a national stock number issued by the Department of Defense or identifying information, such as a product code required by regulations for commercial explosives specified in 27 CFR part 555, if the national stock number or identifying information can be specifically associated with the EX-number assigned.
(c) When more than five different Class 1 materials are packed in the same package, the package may be marked with only five of the EX-numbers, national stock numbers, product codes, or combination thereof.
(d) The requirements of this section do not apply if the EX-number, product code or national stock number of each explosive item described under a proper shipping description is shown in association with the shipping description required by § 172.202(a) of this part. Product codes and national stock numbers must be traceable to the specific EX-number assigned by the Associate Administrator.
(e) The requirements of this section do not apply to the following Class 1 materials:
(1) Those being shipped to a testing agency in accordance with § 173.56(d) of this subchapter;
(2) Those being shipped in accordance with § 173.56(e) of this subchapter, for the purposes of developmental testing;
(3) Those which meet the requirements of § 173.56(h) of this subchapter and therefore are not subject to the approval process of § 173.56 of this subchapter;
(5) Those that are transported in accordance with § 173.56(c)(2) of this subchapter and, therefore, are covered by a national security classification currently in effect.