Certain Azo Disperse Dyes - information sheet

Updated September 5, 2020:

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 is summarized in this information sheet and has not changed. The section in this information sheet entitled "Preventive actions and reducing risk" has been revised to communicate the following update:

• Publication of the Release Guidelines for Disperse Yellow 3 and 25 other Azo Disperse Dyes in the Textile Sector

On this page

• Overview
• About these substances
• Human and ecological exposures
• Key health and ecological effects (hazard)
• Risk assessment outcomes
  • Screening assessment conclusions
• Preventive actions and reducing risk
  • Additional considerations
• Related information

Overview

• 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 the Canadian Environmental Protection Act, 1999 (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 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.
  • More information on assessing risk can be found in the Overview of Risk Assessment and related fact sheets, particularly on Types of Risk Assessment Documents and the Risk Assessment Toolbox.
• As a result of the screening assessment, it was concluded that 73 of the 74 Azo Disperse Dyes are not harmful to human health or the environment at levels of exposure considered in the assessment. Disperse Yellow 3 was concluded to be harmful to the environment, but not to human health at levels of exposure considered in the assessment.

About these substances

• Seventy-four substances were included in the assessment of Certain Azo Disperse Dyes, as a subgroup of the Aromatic Azo and Benzidine-based Substance Grouping.
• Of these 74 substances, 1 substance (Disperse Yellow 3, also known as Solvent Yellow 77 with the CAS RN 2832-40-8) was also included in the assessment of Certain Azo Solvent Dyes. Disperse Yellow 3 was evaluated in the 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 for other uses of this dye.
• 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 CEPA 1999. That assessment identified a potential ecological concern with respect to new uses for these substances; however, the subgroup assessment described on this page concluded that 32 of these substances are no longer a concern for the environment.
• Azo Disperse Dyes are human-made chemicals. They are not expected to occur naturally in the environment. They are used primarily in the dyeing of textiles (mainly synthetic fibres).

Human and ecological exposures

• Canadians may be exposed to 12 of the 74 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 (potential to cause cancer) and genotoxicity (potential to adversely affect genetic material) were the important or critical effects considered for characterizing the risk to human health in the assessment. These effects were considered due to the potential for azo bond cleavage and release of aromatic amines that have 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

• For the 13 substances (including Disperse Yellow 3) for which exposure of Canadians was expected, a comparison of levels to which Canadians may be exposed to these substances, and levels associated with health effects, showed that the risk to human health is low.
• All 74 substances were proposed to be harmful to the environment at the draft screening assessment stage for the Certain Azo Disperse Dyes subgroup. New hazard information received after that publication led to a change in the ecological conclusion in the final screening assessment described on this page.
• Results of the final screening assessment indicated 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.
• Eight azo disperse dyes in the assessment and an additional 17 azo disperse dyes, all with molar weights below 360 g/mol, were identified as having potential ecological effects of concern.
• The Government of Canada published the Final Screening Assessment for Certain Azo Disperse Dyes on March 11, 2017.

Screening assessment conclusions

• Through the Certain Azo Disperse Dyes subgroup assessment, as well as the Azo Solvent Dyes subgroup assessment, the Government concluded that the 64 Azo Disperse Dyes (including Disperse Yellow 3) are not harmful to human health at levels of exposure considered in the assessments. Conclusions for the other 10 Azo Disperse Dye substances from the Challenge initiative remain unchanged (not harmful to human health).
• The Government also concluded that 73 of the 74 Azo Disperse Dyes are not entering the environment at levels that are harmful to the environment. It was 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.
• It was also determined that Disperse Yellow 3 meets the persistence criteria but does not meet the bioaccumulation criteria as set out in the Persistence and Bioaccumulation Regulations of CEPA 1999.

Preventive actions and reducing risk

• The Government of Canada published the Risk Management Approach for Disperse Yellow 3 on March 11, 2017. It had a 60-day public comment period that ended on May 10, 2017.
  • On July 11, 2018, Disperse Yellow 3 was added to Schedule 1 of CEPA 1999, also called the List of Toxic Substances.
  • The approach proposed to manage the risk of Disperse Yellow 3 was through a pollution prevention (P2) planning notice.
  • Current reported uses of Disperse Yellow 3 are likely to be phased out in the short term, and new information indicates that remaining facilities still using Disperse Yellow 3 plan to stop importing and using the substance. Therefore, a P2 planning notice is no longer considered to be an option since the preparation and implementation of P2 plans are done over many years.
  • Given new information received on Disperse Yellow 3 usage in Canada, the risk management approach was revisited.
  • Release Guidelines have been selected as the optimal risk management instrument to address the toxicity of Disperse Yellow 3 and the environmental concerns associated with the 25 other azo disperse dyes with molar weights below 360 g/mol.

Additional considerations

• Although they are not a concern at current levels of exposure, some 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.
• A Consultation Document on the Options for Addressing Certain Aromatic Azo and Benzidine-based Substances with Effects of Concern was published concurrently with the assessment. The document describes potential options for information gathering or preventative actions for certain Aromatic Azo and Benzidine-based Substances. Stakeholders provided feedback on the document during the 60-day public comment period that ended on May 10, 2017, and a summary of the comments submitted has been published.
• Significant New Activity (SNAc) provisions were previously applied to certain Azo Disperse Dye substances as a result of earlier assessments and potential ecological concerns with respect to new uses (specifically, 32 in the 2008 assessment of 145 PBiT substances and 1 substance (Disperse Orange 5) originally assessed in a 2009 Challenge assessment).
• As part of the Azo Disperse Dyes subgroup assessment described on this page, these 33 substances are no longer considered to have ecological effects of concern. Therefore, new activities involving these substances are no longer a concern, and the requirements under the SNAc provisions were rescinded in July, 2017. Information regarding SNAc provisions on other Azo substances can be found in the review of current SNAc orders and notices.
• 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.

Related information

• Canadians should follow any safety warnings and directions related to the product and dispose of products responsibly.
• The screening assessment focused on potential risks from exposure of the general population of Canada, rather than occupational exposure. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System. For information concerning workplace health and safety and what steps to take in the workplace, Canadians should consult their employer and/or the Occupational Health and Safety Regulator in their jurisdiction.