Section 721.9660 - Methylthiouracil(a)Chemical substance and significant new use subject to reporting.(1) The chemical substance methylthiouracil (CAS No. 56-04-2) 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: Manufacture, import, or processing of 10,000 pounds or more per year per facility for any use.(b)Specific requirements. The provisions of subpart A of this part apply to this section except as modified by this paragraph. (1)Recordkeeping. The following recordkeeping requirements are applicable to manufacturers, importers, and processors of this substance, as specified in § 721.125 (a), (b), and (c) .58 FR 63517, Dec. 1, 1993