40 CFR § 721.4140 - Hexachloronorbornadiene.

---
identifier: "/us/cfr/t40/s721.4140"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 721.4140 - Hexachloronorbornadiene."
title_number: 40
title_name: "Protection of Environment"
section_number: "721.4140"
section_name: "Hexachloronorbornadiene."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "R"
subchapter_name: "TOXIC SUBSTANCES CONTROL ACT"
part_number: "721"
part_name: "SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "15 U.S.C. 2604, 2607, and 2625(c)."
regulatory_source: "49 FR 35018, Sept. 5, 1984, unless otherwise noted."
cfr_part: "721"
---


# 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, 2*beta*,2*abeta*,3*alpha*,6*alpha*,6*abeta,* 7*beta*,7*aalpha*)-, 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-, (1*alpha,* 4*alpha,* 4*abeta,* 5*beta,* 8*beta,* 8*abeta*)-, CAS Number 465-73-6.

(2) [Reserved]

[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]