Section 721.4925 - Methyl n-butyl ketone(a)Chemical substance and significant new use subject to reporting.(1) The chemical substance methyl n-butyl ketone, CAS Number 591-78-6, is subject to reporting under this section for the significant new use described in paragraph (a)(2) of this section.(2) The significant new use is any use.(b)Specific requirements. The provisions of subpart A of this part apply to this section except as modified by this paragraph. (1)Persons who must report. Section 721.5 applies to this section except for § 721.5(a)(2) . A person who intends to manufacture, import, or process for commercial purposes the substance identified in paragraph (a)(1) of this section and intends to distribute the substance in commerce must submit a significant new use notice.52 FR 11825, Apr. 13, 1987. Redesignated at 53 FR 2845, Feb. 2, 1988. Further redesignated at 58 FR 29946, May 24, 1993, as amended at 58 FR 34204, June 23, 1993