Azo basic dyes of the Aromatic Azo and Benzidine-based substance grouping

What are they?

  • Thirty-three substances are included in the Azo Basic Dyes subgroup screening assessment of the Aromatic Azo and Benzidine-based Substance Grouping.
  • These 33 Azo Basic Dyes are industrial chemicals. They are not expected to occur naturally in the environment.

How are they used?

  • These Azo Basic Dyes are generally used in the dying of paper and textiles.
  • They may also be used in pharmaceuticals and cosmetics.
  • Based on the most recent data, none of these 33 Azo Basic Dyes was manufactured in Canada; however, some were imported into Canada.

Why did the Government of Canada assess them?

  • These 33 Azo Basic Dyes were identified as priorities for assessment based on categorization within the Domestic Substances List (DSL), and/or were considered as priority substances based on other human health concerns.
  • These Azo Basic Dyes were considered in the Chemicals Management Plan (CMP) Substance Groupings Initiative and/or the Challenge to Industry. These substances were included for the screening assessment of potential risks to the environment and to human health.
  • One Azo Basic Dye substance included in this grouping was assessed during the Challenge Initiative of the CMP (NDTHPM [CAS RN 71032-95-6]). This substance was found not harmful to the environment or human health; however, NDTHPM is included in this assessment to consider ecological risk. As no significant new information was identified for NDTHPM, the human health risk assessment for this substance has not been updated.

How are Canadians exposed to them?

  • Exposure of the general population of Canada to these 33 Azo Basic Dyes via environmental media is expected to be low because there are limited amounts of these dyes used in Canada.
  • Canadians may be exposed to some of these substances primarily during the use of certain products available to consumers, such as paper products, textiles, drugs and cosmetics.

How are they released to the environment?

  • These 33 Azo Basic Dyes may be released to the environment as a result of industrial processes to formulate various products and via dying of paper and textiles.

What are the results of the assessment?

  • The Government of Canada has conducted a science-based evaluation of Certain Azo Basic 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 these Certain Azo Basic 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 has therefore concluded that none of these 33 Azo Basic Dyes is entering the environment at levels that constitute a danger to the environment.
  • The Government of Canada has also concluded that none of these substances is harmful to human health at current levels of exposure.
  • However, given that some of these substances have health effects of concern, there may be concerns if their 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 Basic Dyes on May 28, 2016.
  • Based on the conclusion of the final screening assessment, the Government of Canada proposes that no further action be taken on these 33 Azo Basic Dyes.
  • Given the health concerns for some of these substances, the Government will investigate options on how best to monitor changes in the use 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 assessment for all of the Aromatic Azo and Benzidine-based Substance Grouping are completed. In addition, the Significant New Activity (SNAc) provisions of the Canadian Environmental Protection Act, 1999 were applied to CAS RN 59709-10-3, following an initial assessment in 2008. These provisions require that any proposed new manufacture, import or use of CAS RN 59709-10-3 be subject to further assessment to determine if any new activity required further risk management consideration. However, as a result of the current assessment, it is proposed to remove the SNAc provisions on this substance.

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). However, none of the Certain Azo Basic Dyes is harmful to the environment or human health at current levels of exposure.
  • Canadians who may be exposed to these Certain Azo Basic Dyes in the workplace should consult with their employer and occupational health and safety (OHS) representative about safe handling practices, applicable laws and requirements under the OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
  • As a general precaution, Canadians are reminded when using any product to carefully follow any safety warnings and directions, and to dispose of the products appropriately.
Azo Basic Dyes Assessed by the Government of Canada (33 Substances)
CAS RN DSL Name C.I. Name or Generic Name
136-40-3 2,6-Pyridinediamine, 3-(phenylazo)-, monohydrochloride N/A
532-82-1 1,3-Benzenediamine, 4-(phenylazo)-, monohydrochloride Basic Orange 2
2869-83-2 Phenazinium, 3-(diethylamino)-7-[[4-(dimethylamino)phenyl]azo]-5-phenyl-, chloride N/A
4608-12-2 Phenazinium, 3-(dimethylamino)-7-[[4-(dimethylamino)phenyl]azo]-5-phenyl-, chloride N/A
4618-88-6 Phenazinium, 3-amino-7-[[4-(dimethylamino)phenyl]azo]-5-phenyl-, chloride N/A
10114-58-6 1,3-Benzenediamine, 4,4'-[1,3-phenylenebis(azo)]bis-, dihydrochloride Basic Brown 1
10189-42-1 Pyridinium, 1-[2-[[4-[[2,6-dichloro-4-[(dimethylamino)sulfonyl]phenyl]azo]phenyl]ethylamino]ethyl]-, chloride N/A
14408-20-9 Pyridinium, 1-[2-[[4-[(2,6-dichloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl]-, chloride N/A
14970-39-9 1H-1,2,4-Triazolium, 5-[[4-(diethylamino)phenyl]azo]-1,4-dimethyl-, trichlorozincate(1-) N/A
23408-72-2 Benzothiazolium, 2-[[4-(dimethylamino)phenyl]azo]-3-ethyl-6-methoxy-, trichlorozincate(1-) N/A
29508-48-3 1H-Pyrazolium, 1,5-dimethyl-3-[(2-methyl-1H-indol-3-yl)azo]-2-phenyl-, methyl sulfate N/A
36986-04-6 Pyridinium, 1-[2-[[4-[(2-chloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl]-, chloride N/A
52769-39-8 1H-1,2,4-Triazolium, dimethyl-3-[[4-[methyl(phenylmethyl)amino]phenyl]azo]-, trichlorozincate(1-) N/A
59709-10-3 Pyridinium, 1-[2-[[4-[(2-chloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl]-, acetate N/A
63589-49-1 1H-Pyrazolium, 2-cyclohexyl-3-[[4-(diethylamino)phenyl]azo]-1-methyl-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
63681-54-9 Benzenesulfonic acid, dodecyl-, compd. with 4-(phenylazo)-1,3-benzenediamine (1:1) N/A
65150-98-3 Thiazolium, 2-[[4-(diethylamino)phenyl]azo]-3-methyl-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
68929-07-7 Benzothiazolium, 2-[[4-[ethyl(2-hydroxyethyl)amino]phenyl]azo]-5-methoxy-3-methyl-, methyl sulfate (salt) N/A
68936-17-4 1H-Imidazolium, 2-[[4-(dimethylamino)phenyl]azo]-1,3-dimethyl-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
69852-41-1 Benzothiazolium, 2-[[4-[ethyl(2-hydroxyethyl)amino]phenyl]azo]-6-methoxy-3-methyl-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
71032-95-6 2-Naphthalenesulfonic acid, 7-[[4,6-bis[[3-(diethylamino)propyl]amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[[4-(phenylazo)phenyl]azo]-, monoacetate (salt) NDTHPM
72361-40-1 Pyridinium, 1-[2-[[4-[(2-bromo-4,6-dinitrophenyl)azo]-3-methylphenyl]ethylamino]ethyl]-, chloride N/A
72379-36-3 1H-1,2,4-Triazolium, 5-[[4-[ethyl(phenylmethyl)amino]phenyl]azo]-1,4-dimethyl-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
72379-37-4 1H-1,2,4-Triazolium, 3-[[4-[ethyl(phenylmethyl)amino]phenyl]azo]-1,2-dimethyl-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
74744-63-1 1H-1,2,4-Triazolium, 3,3'(or 5,5')-[1,2-ethanediylbis[(ethylimino)-4,1-phenyleneazo]]bis[1,4-dimethyl-, (T-4)-tetrachlorozincate(2-) (1:1) N/A
75199-20-1 1,3'-Bipyridinium, 1',2'-dihydro-6'-hydroxy-3,4'-dimethyl-2'-oxo-5'-[[4-(phenylazo)phenyl]azo]-, chloride N/A
75660-25-2 1,3-Benzenediamine, 4-(phenylazo)-, monoacetate N/A
79234-33-6 1,3-Benzenediamine, 4-(phenylazo)-, acetate N/A
83969-13-5 1,3,4-Thiadiazolium, 5-[bis(1-methylethyl)amino]-2-[[4-(dimethylamino)phenyl]azo]-3-methyl-, sulfate (2:1) N/A
85114-37-0 1H-1,2,4-Triazolium, 1,4-dimethyl-3(or 5)-[[4-[methyl(phenylmethyl)amino]phenyl]azo]-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
85480-88-2 Benzothiazolium, 3-(3-amino-3-oxopropyl)-2-[(1-ethyl-2-phenyl-1H-indol-3-yl)azo]-, (T-4)-tetrachlorozincate(2-) (2:1) N/A
93783-70-1 1,3,4-Thiadiazolium, 5-[bis(1-methylethyl)amino]-2-[[4-(dimethylamino)phenyl]azo]-3-methyl-, trichlorozincate(1-) N/A
125329-01-3 Propanoic acid, 2-hydroxy-, compd. with 7-[[4,6-bis[[3-(diethylamino)propyl]amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[[4-(phenylazo)phenyl]azo]-2-naphthalenesulfonic acid (1:1) N/A

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