Certain Azo Disperse Dyes – information sheet

Updated July 12, 2017:

The Final Screening Assessment of Certain Azo Disperse Dyes was published on March 11, 2017 as part of the Substance Grouping Initiative of the Chemicals Management Plan (CMP). The assessment summarized in this information sheet (formerly public summary) has not changed (for example, uses, exposures, and conclusions). A new section titled “Key health and ecological effects (hazard)” has been added. The section titled "Preventive actions and reducing risk" has been revised to communicate these two updates:

  • Rescission of the requirements under the Significant New Activity (SNAc) provisions for 33 azo disperse dyes.
  • Closing of the public comment period on the Consultation Document on the Options for Addressing Certain Aromatic Azo and Benzidine-based Substances with Effects of Concern.

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About these substances

  • Seventy-four substances are included in this assessment of Certain Azo Disperse Dyes. These substances were considered in the Substance Groupings Initiative of the CMP.
  • Of the 74 substances included in this assessment of Certain Azo Disperse Dyes, 1 substance (Disperse Yellow 3, also known as Solvent Yellow 77 or CAS RN 2832-40-8) was also included in the assessment of Certain Azo Solvent Dyes.
  • Disperse Yellow 3 was evaluated in this assessment of Certain Disperse Dyes due to ecological concerns when used as a disperse dye in the dyeing of textiles. Disperse Yellow 3 was evaluated in the assessment of Certain Azo Solvent Dyes for human health concerns and other uses of this dye.
  • Twenty-four Azo Disperse Dye substances included in this grouping were previously assessed during the earlier Challenge Initiative of the CMP. At that time, these substances were found not to be harmful to the environment or human health, with the exception of the substance ANMOM, which was not concluded on in the Challenge Initiative.
  • Thirty-three Azo Disperse Dyes were previously assessed in April 2008 as part of an assessment of 145 PBiT (Persistent, Bioaccumulative and inherently Eco-Toxic) substances under the Canadian Environmental Protection Act, 1999 (CEPA 1999). That assessment identified a potential ecological concern with respect to new uses for these substances.
  • Azo Disperse Dyes are industrial chemicals. They are not expected to occur naturally in the environment.
  • Azo Disperse Dyes are used primarily in the dyeing of textiles (mainly synthetic fibres).
  • On the basis of recent data, the 74 Azo Disperse Dyes are not manufactured in Canada; however, some are imported into the country.

Exposure of Canadians and the environment

  • Canadians may be exposed to 12 of these Azo Disperse Dyes as well as to Disperse Yellow 3 from textiles containing these substances. Exposure to the other substances was not expected.
  • These substances may be released to the environment during textile dye formulation and textile dyeing.

Key health and ecological effects (hazard)

  • Carcinogenicity (the ability to cause cancer) and genotoxicity (ability to adversely affect genetic material) were the important or “critical” effects considered for characterizing the risk to human health in this assessment. These effects were considered due to the potential for azo bond cleavage and release of aromatic amines with effects of concern.
  • Non-cancer effects on the spleen were also used for characterizing the risk to human health.
  • Available aquatic toxicity data for Azo Disperse Dyes indicated variable effects on different organisms. Chronic studies showed that fish and aquatic invertebrates were sensitive to Azo Disperse Dyes, particularly smaller sized dyes.

Risk assessment outcomes

  • The Government of Canada conducted a science-based evaluation of Certain Azo Disperse Dyes, called a screening assessment to address the potential for harm to Canadians and the environment.
  • Under CEPA 1999, the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people or to the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.
  • Results of the final screening assessment indicate that these Azo Disperse Dyes are expected to remain in the environment for a long time, under certain conditions, but are not expected to accumulate in organisms.
  • These 74 substances were proposed to be harmful to the environment at the draft screening assessment stage for the subgroup. New hazard information received after that publication led to a change in the ecological conclusion in the final screening assessment.
  • For the 13 substances for which exposure of Canadians was expected, a comparison of levels to which Canadians can be exposed and levels associated with health effects showed that the risk to human health is low.
  • The Government of Canada published the Final Screening Assessment for Certain Azo Disperse Dyes on March 11, 2017.

Screening assessment conclusions

  • The Government concluded that 73 of the 74 Azo Disperse Dyes are not entering the environment at levels that are harmful to the environment. It is also concluded that the remaining substance, Disperse Yellow 3 (CAS RN 2832-40-8), is entering or may enter the environment at levels that are harmful to the environment.
  • The Government also concluded that these 74 Azo Disperse Dyes (including Disperse Yellow 3) are not harmful to human health at current levels of exposure.

Preventive actions and reducing risk

  • The Government of Canada published the Proposed Risk Management Approach for Disperse Yellow 3 on March 11, 2017. The proposed risk management approach was followed by a 60-day public comment period that ended on May 10, 2017.
  • The Government is proposing to develop a Pollution Prevention Planning notice under section 56 of CEPA 1999 to address the ecological risk of Disperse Yellow 3 being released to water from dye formulation and from the dyeing process of synthetic textiles.
  • The Government proposed to add Disperse Yellow 3 to Schedule 1 of CEPA 1999, also called the List of Toxic Substances.
  • Although they are not a concern at current levels of exposure, some of these Azo Disperse Dyes as well as other substances of the Aromatic Azo and Benzidine-based Substance Grouping have health or ecological effects of concern. The Government has investigated options on how best to monitor changes in the use profile of these substances.
  • Therefore, a Consultation Document on the Options for Addressing Certain Aromatic Azo and Benzidine-based Substances with Effects of Concern was published concurrently with this assessment. The document describes potential options for information gathering or preventative actions for certain Aromatic Azo and Benzidine-based Substances. Stakeholders were asked to provide feedback on the document during the 60-day public comment period that ended on May 10, 2017.
  • SNAc provisions were previously applied to 33 Azo Disperse Dye substances. Thirty-two of these 33 substances were included in the 2008 assessment of 145 PBiT substances, and 1 substance (Disperse Orange 5) was assessed in 2009 under Batch 5 of the Challenge. These provisions require that any proposed new manufacture, import or use of the substances be subject to further assessment to determine if any new activities require further risk management consideration.
  • As a result of the Final Screening Assessment of Certain Azo Disperse Dyes, the requirements under the SNAc provisions on these 33 substances were rescinded in July 2017, as the substances are no longer considered to have ecological effects of concern. Therefore, new activities involving these substances are no longer a concern.
  • Further information and updates on risk management actions can be found in the CMP Risk Management Actions table and the Risk Management Activities and Consultations Schedule.

Important to know

  • To protect themselves and the environment, Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
  • Canadians who may be exposed to these substances in the workplace should consult with their employer and an occupational health and safety (OHS) representative about safe handling practices, applicable laws and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
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