Certain Azo Direct Dyes and Reactive Dyes of the Aromatic Azo and Benzidine-based substance grouping

What are they?

  • Sixty-nine substances, including sixty-one Azo Direct Dyes and eight Azo Reactive Dyes, are included in this assessment.
  • Certain Azo Direct and Reactive Dyes are industrial chemicals. They are not expected to occur naturally in the environment.

How are they used?

  • Certain Azo Direct Dyes are generally used for the colouring of textile materials, leather and paper products, and some are used in food packaging applications.
  • Certain Azo Reactive Dyes are used primarily in the textiles industry for dying plant-based fibres such as cotton and rayon.
  • Based on the most recent data, none of these Azo Direct and Reactive Dyes are manufactured in Canada; however, seven substances (six Azo Direct Dyes and one Azo Reactive Dye) are imported into Canada.

Why did the Government of Canada assess them?

  • Certain Azo Direct and Reactive Dyes were identified as priorities for assessment based on categorization within the Domestic Substances List, and/or were considered as priority substances based on other human health concerns.
  • Certain Azo Direct and Reactive Dyes were considered in the Chemicals Management Plan (CMP) Substance Groupings Initiative. These substances were included for the screening assessment of potential risks to the environment and to human health.

How are Canadians exposed to them?

  • Exposure of the general population of Canada to Certain Azo Direct and Reactive Dyes via environmental media is considered to be low because there are limited amounts of these dyes used in Canada.
  • Canadians may be exposed to some of these dyes primarily during the use of certain consumer products such as textile materials, leather and paper products.

How are they released into the environment?

  • Certain Azo Direct and Reactive Dyes may be released to the environment as a result of industrial processes to formulate various products and during the use and disposal of products containing some of these substances.

What are the results of the assessment?

  • The Government of Canada has conducted a science-based evaluation of Certain Azo Direct and Reactive Dyes, called a screening assessment.
  • Screening assessments address the potential for harm to the general population of Canada and the environment.
  • Results of the final screening assessment indicate that Certain Azo Direct and Reactive Dyes are expected to remain in the environment for a long time, under certain conditions, but are not expected to accumulate in organisms.
  • Furthermore, the quantity of these substances that may be released to the environment is below the level expected to cause harm to organisms.
  • The Government of Canada is therefore concluding that none of the Certain Azo Direct and Reactive Dyes are entering the environment at levels that constitute a danger to the environment.
  • The Government of Canada is also concluding that none of the Certain Azo Direct and Reactive Dyes are harmful to human health at current levels of exposure.
  • However, given that some of these substances have health effects of concern based on potential carcinogenicity, there may be concerns if exposures were to increase in Canada.
  • Hazards related to chemicals used in the workplace should be classified accordingly under the Workplace Hazardous Materials Information System (WHMIS).

What is the Government of Canada doing?

  • The Government of Canada published the Final Screening Assessment for Certain Azo Direct Dyes and Azo Reactive Dyes on April 4, 2015.
  • Based on the conclusion of the screening assessment, no further action will be taken at this time.
  • Given the health concerns for some of these substances, the Government will investigate options on how best to monitor changes in the use profile of these substances. Stakeholders will have the opportunity to provide feedback on a consultation document, describing potential options for information gathering or preventative actions, to be published once assessments for all of the Aromatic Azo and Benzidine-based Substance Grouping are completed.

What can Canadians do?

  • The health risks associated with a chemical depend on the hazard (its potential to cause health effects) and the dose (the amount of chemical to which you are exposed). Certain Azo Direct and Reactive Dyes are not a concern for the environment or human health at current levels of exposure.
  • As a general precaution, Canadians are reminded when using any product to carefully follow any safety warnings and directions.
  • Canadians who handle these substances in the workplace should consult with their employer and occupational health and safety representative about safe handling practices, applicable laws and requirements under the Workplace Hazardous Materials Information System (WHMIS).
Certain Azo Direct Dyes Assessed by the Government of Canada
CAS RN DSL Name Colour Index Name or Common Name
1325-37-7 C.I. Direct Yellow 11 Direct Yellow 11
1325-54-8 Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis-5-nitro-, disodium salt, reaction products with 4-[(4-aminophenyl)azo]benzenesulfonic acid, sodium salts Direct Orange 39
2829-42-7 Benzoic acid, 3,3′-[carbonylbis(imino-4,1-phenyleneazo)]bis[6-hydroxy-, disodium salt Direct Yellow 26
2870-32-8 Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[5-[(4-ethoxyphenyl)azo]-, disodium salt Direct Yellow 12
3214-47-9 1,5-Naphthalenedisulfonic acid, 3,3′-[carbonylbis[imino(2-methyl-4,1-phenylene)azo]]bis-, tetrasodium salt Direct Yellow 50
3626-36-6 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[4-hydroxy-3-(phenylazo)-, disodium salt Direct Orange 26
3687-80-7 1-Naphthalenesulfonic acid, 4-[[1-hydroxy-6-[[[[5-hydroxy-6-[(2-methoxyphenyl)azo]-7-sulfo-2-naphthalenyl]amino]carbonyl]amino]-3-sulfo-2-naphthalenyl]azo]-, trisodium salt Direct Red 26
4399-55-7 1,5-Naphthalenedisulfonic acid, 3-[[4-[[4-[(6-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-6-sulfo-1-naphthalenyl]azo]-1-naphthalenyl]azo]-, tetrasodium salt Direct Blue 71
5001-72-9 2-Naphthalenesulfonic acid, 7,7′-iminobis[4-hydroxy-3-(phenylazo)-, disodium salt Direct Red 31
5489-77-0 2-Naphthalenesulfonic acid, 3-[[4-[(2,4-dimethyl-6-sulfophenyl)azo]-2-methoxy-5-methylphenyl]azo]-4-hydroxy-7-(phenylamino)-, disodium salt Direct Violet 51
6406-87-7 2-Naphthalenesulfonic acid, 5-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-8-[[4-(phenylazo)-7-sulfo-1-naphthalenyl]azo]-, trisodium salt Not applicable
6420-33-3 1,5-Naphthalenedisulfonic acid, 3,3′-[carbonylbis[imino(5-methoxy-2-methyl-4,1-phenylene)azo]]bis-, tetrasodium salt Direct Yellow 34
6420-41-3 2-Naphthalenesulfonic acid, 4-hydroxy-7-[[[[5-hydroxy-6-(phenylazo)-7-sulfo-2-naphthalenyl]amino]carbonyl]amino]-3-[(6-sulfo-2-naphthalenyl)azo]-, trisodium salt Direct Red 4
6420-43-5 2-Naphthalenesulfonic acid, 4-hydroxy-7-[[[[5-hydroxy-6-[(2-methylphenyl)azo]-7-sulfo-2-naphthalenyl]amino]carbonyl]amino]-3-[(2-methyl-4-sulfophenyl)azo]-, trisodium salt Direct Red 62
6471-09-6 Benzoic acid, 5-[[4-[[4-[[4-[(4-amino-9,10-dihydro-9,10-dioxo-3-sulfo-1-anthracenyl)amino]-2-sulfophenyl]amino]-6-(phenylamino)-1,3,5-triazin-2-yl]amino]phenyl]azo]-2-hydroxy-, trisodium salt Direct Green 28
6476-10-4 2-Naphthalenesulfonic acid, 8-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-5-[[4-(phenylazo)-6-sulfo-1-naphthalenyl]azo]-, trisodium salt Not applicable
10114-47-3 7-Benzothiazolesulfonic acid, 2,2′-(azodi-4,1-phenylene)bis[6-methyl-, disodium salt Direct Yellow 28
10134-33-5 2-Naphthalenesulfonic acid, 8-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-5-[[4-(phenylazo)-7-sulfo-1-naphthalenyl]azo]-, trisodium salt Direct Black 56
10482-42-5 2-Naphthalenesulfonic acid, 5-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-8-[[4-(phenylazo)-6-sulfo-1-naphthalenyl]azo]-, trisodium salt Not applicable
12217-64-0 1,3-Naphthalenedisulfonic acid, 7,7′-[carbonylbis[imino(5-methoxy-2-methyl-4,1-phenylene)azo]]bis-, tetrasodium salt Direct Orange 72
28706-21-0 1,3-Naphthalenedisulfonic acid, 7,7′-[iminobis[carbonyl(2-methyl-4,1-phenylene)azo]]bis-, tetrasodium salt Not applicable
32829-81-5 Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[5-[[4-[(4-sulfophenyl)azo]phenyl]azo]-, tetrasodium salt
38801-08-0 Benzoic acid, 4,4′-[carbonylbis[imino(1-hydroxy-3-sulfo-6,2-naphthalenediyl)azo]]bis-, compd. with 2,2′,2′′-nitrilotris[ethanol] (1:4)
53523-90-3 Benzoic acid, 3,3′-[1,2-ethenediylbis[(3-sulfo-4,1-phenylene)azo]]bis[6-hydroxy-5-methyl-, tetralithium salt
65150-80-3 C.I. Direct Yellow 11, lithium salt Direct Yellow 11 lithium salt
71033-21-1 Benzothiazolesulfonic acid, 2,2′-(azodi-4,1-phenylene)bis[6-methyl-, disodium salt Not applicable
71767-19-6 2-Naphthalenesulfonic acid, 5-[[6-amino-1-hydroxy-3-sulfo-5-[(3-sulfophenyl)azo]-2-naphthalenyl]azo]-6-methoxy-8-[[7-sulfo-4-[(3-sulfophenyl)azo]-1-naphthalenyl]azo]-, pentasodium salt
71873-49-9 Benzoic acid, 4,4′-[1,2-ethenediylbis[(3-sulfo-4,1-phenylene)-ONN-azoxy-4,1-phenyleneazo]]bis-, tetrasodium salt
72139-21-0 Benzoic acid, 3,3′-[(1,4-dioxo-2-butene-1,4-diyl)bis(imino-4,1-phenyleneazo)]bis[6-hydroxy-, disodium salt
72152-50-2 Benzoic acid, 2-[[6-[[4-[[6-(benzoylamino)-1-hydroxy-3-sulfo-2-naphthalenyl]azo]-3-methylbenzoyl]amino]-1-hydroxy-3-sulfo-2-naphthalenyl]azo]-, trisodium salt
72245-49-9 Benzoic acid, 4-[[1-hydroxy-6-[[[[5-hydroxy-6-[(2-methyl-4-sulfophenyl)azo]-7-sulfo-2-naphthalenyl]amino]carbonyl]amino]-3-sulfo-2-naphthalenyl]azo]-, sodium salt
72245-56-8 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4-[[[4-[(2,4-diaminophenyl)azo]phenyl]amino]carbonyl]phenyl]azo]-5-hydroxy-6-(phenylazo)-, sodium salt
72749-87-2 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[4-hydroxy-3-[(2-methylphenyl)azo]-, disodium salt
72749-88-3 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[4-hydroxy-3-[(2-methoxyphenyl)azo]-, disodium salt
72869-93-3 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[4-hydroxy-3-[(6-sulfo-2-naphthalenyl)azo]-, compd. with 2,2′-(methylimino)bis[ethanol] (1:4)
75150-14-0 1,4-Benzenedisulfonic acid, 2-[[4-[[4-[[1-hydroxy-6-(phenylamino)-3-sulfo-2-naphthalenyl]azo]-1-naphthalenyl]azo]-6-sulfo-1-naphthalenyl]azo]-, ammonium sodium salt
75768-93-3 2-Naphthalenesulfonic acid, 7-(benzoylamino)-4-hydroxy-3-[[4-[(4-sulfophenyl)azo]phenyl]azo]-, compd. with 2,2′,2′′-nitrilotris[ethanol] (1:2) Direct Red 81 triethanolamine salt
83221-53-8 Benzoic acid, 5-[[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-1-naphthalenyl]azo]-2-hydroxy-, sodium salt Not applicable
83221-54-9 Benzoic acid, 3-[[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-1-naphthalenyl]azo]-2-hydroxy-, sodium salt
83221-56-1 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[4-hydroxy-3-(phenylazo)-, sodium salt
83221-68-5 2-Naphthalenesulfonic acid, 6-[(2,4-diaminophenyl)azo]-3-[[4-[[4-[[7-[(2,4-diaminophenyl)azo]-1-hydroxy-3-sulfo-2-naphthalenyl]azo]phenyl]amino]-3-sulfophenyl]azo]-4-hydroxy-, trilithium salt
83221-69-6 2-Naphthalenesulfonic acid, 6-[(2,4-diaminophenyl)azo]-3-[[4-[[4-[[7-[(2,4-diaminophenyl)azo]-1-hydroxy-3-sulfo-2-naphthalenyl]azo]phenyl]amino]-3-sulfophenyl]azo]-4-hydroxy-, lithium sodium salt
83221-72-1 2,7-Naphthalenedisulfonic acid, 4-amino-3,6-bis[[4-[(2,4-diaminophenyl)azo]phenyl]azo]-5-hydroxy-, lithium sodium salt
83221-73-2 Benzoic acid, 4,4′-[carbonylbis[imino(1-hydroxy-3-sulfo-6,2-naphthalenediyl)azo]]bis-, sodium salt
83221-74-3 Benzoic acid, 4-[[1-hydroxy-6-[[[[5-hydroxy-6-(phenylazo)-7-sulfo-2-naphthalenyl]amino]carbonyl]amino]-3-sulfo-2-naphthalenyl]azo]-, sodium salt
83232-28-4 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[3-[[4-(acetylamino)phenyl]azo]-4-hydroxy-, sodium salt
83232-29-5 2-Naphthalenesulfonic acid, 3-[[4-(acetylamino)phenyl]azo]-4-hydroxy-7-[[[[5-hydroxy-6-(phenylazo)-7-sulfo-2-naphthalenyl]amino]carbonyl]amino]-, sodium salt
83232-30-8 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[4-hydroxy-3-[(2-methylphenyl)azo]-, sodium salt
83232-31-9 2-Naphthalenesulfonic acid, 7,7′-(carbonyldiimino)bis[4-hydroxy-3-[(2-methyl-4-sulfophenyl)azo]-, sodium salt
83232-32-0 2-Naphthalenesulfonic acid, 4-hydroxy-7-[[[[5-hydroxy-6-[(2-methylphenyl)azo]-7-sulfo-2-naphthalenyl]amino]carbonyl]amino]-3-[(2-methyl-4-sulfophenyl)azo]-, sodium salt
83783-94-2 2,7-Naphthalenedisulfonic acid, 3,3′-[1,2-ethenediylbis[(3-sulfo-4,1-phenylene)azo]]bis[5-amino-4-hydroxy-, lithium sodium salt, compd. with 2,2′-(methylimino)bis[ethanol]
83783-95-3 2-Naphthalenesulfonic acid, 3,3′-[1,2-ethenediylbis[(3-sulfo-4,1-phenylene)azo]]bis[6-amino-4-hydroxy-, lithium sodium salt, compd. with 2,2′-(methylimino)bis[ethanol]
83783-96-4 2,7-Naphthalenedisulfonic acid, 5-amino-3-[[4-[2-[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-2-sulfophenyl]ethenyl]-3-sulfophenyl]azo]-4-hydroxy-, lithium sodium salt, compd. with 2,2′-(methylimino)bis[ethanol]
83783-99-7 Benzoic acid, 3,3′-[1,2-ethenediylbis[(3-sulfo-4,1-phenylene)azo]]bis[6-hydroxy-5-methyl-, lithium sodium salt, compd. with 2,2′-(methylimino)bis[ethanol]
84878-16-0 2,7-Naphthalenedisulfonic acid, 4-amino-6-[[4-[[4-[(2,4-dihydroxyphenyl)azo]phenyl]thio]phenyl]azo]-5-hydroxy-3-[(4-nitrophenyl)azo]-, sodium salt
84878-17-1 2,7-Naphthalenedisulfonic acid, 4-amino-6-[[4-[[[4-[(2,4-dihydroxyphenyl)azo]phenyl]amino]sulfonyl]phenyl]azo]-5-hydroxy-3-[(4-nitrophenyl)azo]-, potassium salt
85169-18-2 Glycine, N-[4-[[2-[4-[[1-amino-8-hydroxy-7-(phenylazo)-3,6-disulfo-2-naphthalenyl]azo]phenyl]-1H-benzimidazol-5-yl]azo]-3-hydroxyphenyl]-, compd. with 2,2′-iminobis[ethanol] (1:3)
85269-31-4 Benzoic acid, 3,3′-[1,2-ethenediylbis[(3-sulfo-4,1-phenylene)azo]]bis[6-hydroxy-5-methyl-, potassium salt, compd. with 2,2′,2′′-nitrilotris[ethanol]
93803-37-3 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3-[[4-[5-[(4-hydroxyphenyl)azo]-1H-benzimidazol-2-yl]phenyl]azo]-6-(phenylazo)-, disodium salt
102082-94-0 2,7-Naphthalenedisulfonic acid, 4-amino-6-[[4-[[[4-[(2,4-diaminophenyl)azo]phenyl]amino]sulfonyl]phenyl]azo]-5-hydroxy-3-[(4-nitrophenyl)azo]-, lithium salt
110152-63-1 Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[5-[(4-hydroxyphenyl)azo]-, lithium sodium salt
Certain Azo Reactive Dyes Assessed by the Government of Canada
CAS RN DSL Name Name
17095-24-8 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-bis[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt Reactive Black 5
59641-46-2 2-Naphthalenesulfonic acid, 7-[[4-chloro-6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[(4-methoxy-2-sulfophenyl)azo]- Not applicable
83399-85-3 1,4-Benzenedisulfonic acid, 2-[[4-[[4-[[(2,3-dichloro-6-quinoxalinyl)carbonyl]amino]-5-sulfo-1-naphthalenyl]azo]-7-sulfo-1-naphthalenyl]azo]-, lithium sodium salt
83400-10-6 1,5-Naphthalenedisulfonic acid, 2-[[8-[[(2,3-dichloro-6-quinoxalinyl) carbonyl]amino]-1-hydroxy-3,6-disulfo-2-naphthalenyl]azo]-, lithium sodium salt
83400-11-7 1,7-Naphthalenedisulfonic acid, 4-(benzoylamino)-6-[[5-[[(5-chloro-2,6-difluoro-4-pyrimidinyl)amino]methyl]-1-sulfo-2-naphthalenyl]azo]-5-hydroxy-, lithium sodium salt         Reactive Black 158
83400-12-8 2,7-Naphthalenedisulfonic acid, 5-(benzoylamino)-3-[[5-[[(5-chloro-2,6-difluoro-4-pyrimidinyl)amino]methyl]-1-sulfo-2-naphthalenyl]azo]-4-hydroxy-, lithium sodium salt Not applicable
85586-78-3 1,5-Naphthalenedisulfonic acid, 3-[[4-[[4-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-7-sulfo-1-naphthalenyl]azo]-7-sulfo-1-naphthalenyl]azo]-, potassium sodium salt       
108624-00-6 2,7-Naphthalenedisulfonic acid, 4-amino-6-[[5-[(5-chloro-2,6-difluoro-4-pyrimidinyl)amino]-2-sulfophenyl]azo]-5-hydroxy-3-[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, lithium sodium salt Reactive Blue 225
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