{"data":{"id":"us/40-cfr-721.1660","jurisdiction":"us","citation":"40 CFR 721.1660","heading":"Benzidine-based chemical substances.","body":"(a) Chemical substances and significant new uses subject to reporting. (1) The benzidine-based chemical substances listed in Table 1 and Table 2 of this section are subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this section.\nTable 1—Benzidine-Based Chemical Substances\nCAS or accession No. C.I. name C.I. No. Chemical name\n117-33-9 Not available Not available 1,3-Naphthalenedisulfonic acid, 7-hydroxy-8-[2-[4'-[2-(4-hydroxyphenyl)diazenyl][1,1'-biphenyl]-4-yl]diazenyl]-\n65150-87-0 Not available Not available 1,3,6-Naphthalenetrisulfonic acid, 8-hydroxy-7-[2-[4'-[2-(2-hydroxy-1-naphthalenyl)diazenyl][1,1'- biphenyl]-4-yl]diazenyl]-, lithium salt (1:3)\n68214-82-4 Direct Navy BH 22590 2,7-Naphthalenedisulfonic acid, 5-amino-3-[2-[4'-[2-(7-amino-1-hydroxy-3-sulfo-2- naphthalenyl)diazenyl][1,1'-biphenyl]-4- yl]diazenyl]-4-hydroxy-, sodium salt (1:2)\n72379-45-4 Not available Not available 2,7-Naphthalenedisulfonic acid, 4-amino-5- hydroxy-3-[2-[4'-[2-[2-hydroxy-4-[(2- methylphenyl)amino]phenyl]diazenyl][1,1'- biphenyl]-4-yl]diazenyl]-6-(2-phenyldiazenyl)-\nAccession No. 21808 CAS No. CBI (NA) CBI CBI 2,7-Naphthalenedisulfonic acid, 4-amino-5- hydroxy [[[(substituted phenylamino)] substituted phenylazo] diphenyl]azo-, phenylazo-, disodium salt. (generic name)\nAccession No. 24921 CAS No. CBI CBI 4-(Substituted naphthalenyl )azo diphenylyl azo-substituted carbopolycycle azo benzenesulfonic acid, sodium salt. (generic name)\nAccession No. 26256 CAS No. CBI (NA) CBI CBI 4-(Substituted phenyl)azo biphenylyl azo- substituted carbopolycycloazo benzenesulfonic acid, sodium salt. (generic name)\nAccession No. 26267 CAS No. CBI (NA) CBI CBI 4-(Substituted phenyl)azo biphenylyl azo - substituted carbopolycycle azo benzenesulfonic acid, sodium salt. (generic name)\nAccession No. 26701 CAS No. CBI (NA) CBI CBI Phenylazoaminohydroxynaphthalenylazobiphenylazo substituted benzene sodium sulfonate. (generic name).\nTable 2—Benzidine-Based Chemical Substances\nCAS No. C.I. name C.I. No. Chemical name\n92-87-5 Benzidine Not available [1,1′-Biphenyl]-4,4′-diamine.\n531-85-1 Benzidine · 2HCl Not available [1,1′-Biphenyl]-4,4′-diamine, dihydrochloride.\n573-58-0 C.I. Direct Red 28 22120 1- Naphthalenesulfonic acid, 3,3′-[[1,1′-biphenyl]-4,4′-diylbis(azo)]bis[4-amino-, disodium salt.\n1937-37-7 C.I. Direct Black 38 30235 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′-[(2,4-diaminophenyl) azo][1,1′-biphenyl]-4- yl]azo]-5-hydroxy-6-(phenylazo)-, disodium salt.\n2302-97-8 C.I. Direct Red 44 22500 1-Naphthalenesulfonic acid, 8,8′-[[1,1′-biphenyl]-4,4′-diylbis(azo)]bis[7-hydroxy-, disodium salt.\n2429-73-4 C.I. Direct Blue 2 22590 2,7-Naphthalenedisulfonic acid, 5-amino-3-[[4′-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo][1,1′-biphenyl]-4-yl]azo]-4-hydroxy-, trisodium salt.\n2429-79-0 C.I. Direct Orange 8 22130 Benzoic acid, 5-[[4′-[(1-amino-4-sulfo-2-naphthalenyl) azo][1,1′-biphenyl]-4-yl]azo]-2- hydroxy-, disodium salt.\n2429-81-4 C.I. Direct Brown 31 35660 Benzoic acid, 5-[[4′-[[2,6-diamino-3-[[8-hydroxy-3,6-disulfo-7-[(4-sulfo-1-naphthalenyl)azo]-2- naphthalenyl]azo]-5-methylphenyl]azo][1,1′- biphenyl]-4-yl]azo]-2-hydroxy-, tetrasodium salt.\n2429-82-5 C.I. Direct Brown 2 22311 Benzoic acid, 5-[[4′-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl) azo][1,1′-biphenyl]-4-yl]azo]-2-hydroxy-, disodium salt.\n2429-83-6 Direct Black 4 30245 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′-[(2,4-diamino-5-methylphenyl)azo][1,1′-biphenyl]-4-yl]azo] -5-hydroxy-6-(phenylazo)-, disodium salt.\n2429-84-7 C.I. Direct Red 1 22310 Benzoic acid, 5-[[4′-[(2-amino-8-hydroxy-6-sulfo-1-naphthalenyl)azo][1,1′-biphenyl]-4-yl]azo]-2-hydroxy-, disodium salt.\n2586-58-5 C.I. Direct Brown 1:2 30110 Benzoic acid, 5-[[4′-[[2,6-diamino-3-methyl-5-[(4-sulfophenyl)azo]phenyl]azo][1,1′-biphenyl]-4- yl]azo]-2-hydroxy-, disodium salt.\n2602-46-2 C.I. Direct Blue 6 22610 2,7-Naphthalenedisulfonic acid, 3,3′-[[1,1′-biphenyl]-4,4′-diylbis(azo)]bis[5-amino-4-hydroxy-, tetrasodium salt.\n2893-80-3 C.I. Direct Brown 6 30140 Benzoic acid, 5-[[4′-[[2,4-dihydroxy-3-[(4-sulfophenyl) azo]phenyl]azo][1,1′-biphenyl]-4- yl]azo]-2-hydroxy-, disodium salt.\n3530-19-6 C.I. Direct Red 37 22240 1,3-Naphthalenedisulfonic acid, 8-[[4′-[(4-ethoxyphenyl)azo][1,1′-biphenyl]-4-yl]azo]-7-hydroxy-, disodium salt\n3567-65-5 C.I. Acid Red 85 22245 1,3-Naphthalenedisulfonic acid, 7-hydroxy-8-[[4′-[[4-[[(4-methylphenyl)sulfonyl]oxy]phenyl]azo][1,1′-biphenyl]-4-yl]azo]-, disodium salt.\n3626-28-6 C.I. Direct Green 1 30280 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3-[[4′-[(4-hydroxyphenyl)azo][1,1′- biphenyl]-4- yl]azo]-6-(phenylazo)-, disodium salt.\n3811-71-0 C.I. Direct Brown 1 30045 Benzoic acid, 5-[[4′-[[2,4-diamino-5-[(4-sulfophenyl) azo]phenyl]azo][1,1′ biphenyl]-4- yl]azo]-2-hydroxy-, disodium salt.\n4335-09-5 C.I. Direct Green 6 30295 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-6-[[4′-[(4-hydroxyphenyl)azo][1,1′-biphenyl]-4- yl]azo]-3-[(4-nitrophenyl)azo]-, disodium salt.\n6358-80-1 C.I. Acid Black 94 30336 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3-[[4′-[[4-hydroxy-2-[(2- methylphenyl)amino]phenyl]azo] [1,1′- biphenyl]-4-yl]azo]-6-[(4-sulfophenyl) azo]-, trisodium salt.\n6360-29-8 C.I. Direct Brown 27 31725 Benzoic acid, 5-[[4′-[[4-[(4-amino-7-sulfo-1-naphthalenyl)azo]-6-sulfo-1-naphthalenyl]azo][1,1′-biphenyl]-4-yl] azo]-2- hydroxy-, trisodium salt.\n6360-54-9 C.I. Direct Brown 154 30120 Benzoic acid, 5-[[4′-[[2,6-diamino-3-methyl-5-[(4-sulfophenyl)azo]phenyl] azo][1,1′-biphenyl]-4-yl]azo]-2- hydroxy-3-methyl-, disodium salt.\n8014-91-3 C.I. Direct Brown 74 36300 Benzoic acid, 3,3′-[(3,7-disulfo-1,5-naphthalenediyl)bis [azo(6-hydroxy-3,1-phenylene)azo[6(or7)-sulfo-4,1-naphthalenediyl]azo[1,1′-biphenyl]-4,4′-diylazo]]bis[6-hydroxy-, hexasodium salt.\n16071-86-6 C.I. Direct Brown 95 30145 Cuprate(2-), [5-[[4′-[[2,6-dihydroxy-3-[(2-hydroxy-5-sulfophenyl)azo]phenyl] azo][1,1′- biphenyl]-4-yl]azo]-2-hydroxybenzoato(4-)]-, disodium salt.\n(2) The significant new uses are:\n(i) For each of the chemical substances listed in Table 2 of this section, any use other than use as a reagent to test for hydrogen peroxide in milk; a reagent to test for hydrogen sulfate, hydrogen cyanide, and nicotine; a stain in microscopy; a reagent for detecting blood; an analytical standard; and, additionally for Colour Index (C.I.) Direct Red 28 (Congo Red) (CAS No. 573-58-0), an indicator dye.\n(ii) For the chemical substances listed in Table 1 of this section: Any use.\n(b) Specific requirements. The provisions of subpart A of this part apply to this section except as modified by this paragraph (b).\n(1) Revocation of certain notification exemptions. The provisions of § 721.45(f) do not apply to this section. A person who imports or processes a chemical substance identified in paragraph (a)(1) of this section as part of an article for a significant new use described in paragraph (a)(2) of this section is not exempt from submitting a significant new use notice.\n(2) [Reserved]","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER R—TOXIC SUBSTANCES CONTROL ACT","PART 721—SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES","Subpart E—Significant New Uses for Specific Chemical Substances"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"83dbca960488833dcf7f598b165bf94792affe4697c4829368b27aa4c01d58c9","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-721.1655","next":"us/40-cfr-721.1675"},"notice":"GroundRules: Original legal text. Not legal advice."}