Section 721.4140 - Hexachloronorbornadiene(a)Chemical substance and significant new uses subject to reporting.(1) The chemical substance 1,2,3,4,7,7-hexachloronorbornadiene, CAS Number 3389-71-7, 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: Use other than as an intermediate in the production of isodrin or endrin.(b)Specific requirements. The provisions of subpart A of this part apply to this section except as modified by this paragraph. (1)Definitions. In addition to the definitions in § 721.3 , the following definitions apply: (i) "Endrin" means the pesticide 2,7:3,6-Dimethanonaphth[2,3-b]oxirene, 3,4,5,6,9,9-hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-, (1a alpha, 2beta,2abeta,3alpha,6alpha,6 abeta, 7beta,7aalpha)-, CAS Number 72-20-8.(ii) "Isodrin" means the pesticide 1,4:5,8-Dimethano-naphthalene,1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-, (1alpha, 4alpha, 4abeta, 5beta, 8beta, 8abeta)-, CAS Number 465-73-6.50 FR 47538, Nov. 19, 1985. 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