Certain Azo Disperse Dyes of the Aromatic Azo and Benzidine-based Substance Grouping
What are they?
- Seventy-four substances are included in this assessment of Certain Azo Disperse Dyes.
- Azo Disperse Dyes are industrial chemicals. They are not expected to occur naturally in the environment.
How are they used?
- Azo Disperse Dyes are used in the dyeing of textiles (mainly synthetic fibres).
- Based on the most recent data, 74 Azo Disperse Dyes are not manufactured in Canada; however, some are imported into the country.
Why did the Government of Canada assess them?
- Azo Disperse Dyes were identified as priorities for assessment through the categorization of substances on the Domestic Substances List and/or because they were associated with environmental or human health concerns.
- Furthermore, these Azo Disperse Dyes were considered in the Substance Groupings Initiative. These substances were included for the screening assessment of potential risks to the environment and to human health.
- Of the 74 substances included in this assessment of Certain Azo Disperse Dyes, one 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 the assessment of Certain Disperse Dyes due to ecological concerns when used as a disperse dye. 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 Chemicals Management Plan (CMP). At that time, these substances were found not to be harmful to the environment or human health.
- Thirty-three Azo Disperse Dyes were previously assessed in April 2008 as part of an assessment of 145 PBiT (Persistent, Bioaccumulative and inherently Toxic) substances under the Canadian Environmental Protection Act, 1999. That assessment identified a potential ecological concern with respect to new uses for these substances.
How are Canadians exposed to them?
- Exposure of Canadians to these substances through environmental media is not expected.
- Canadians may be exposed to 12 of these Azo Disperse Dyes as well as Disperse Yellow 3 during the use of textiles.
How are they released to the environment?
- These substances may be released to the environment during textile dye formulation and textile dyeing.
What are the results of the assessment?
- The Government of Canada conducted a science-based evaluation of Certain Azo Disperse Dyes, called a screening assessment.
- Screening assessments address the potential for harm to the general population of Canada and the environment. More information on types of approaches used to address substances can be found in the Risk Assessment Toolbox fact sheet.
- 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 initially concluded to be harmful to the environment at the draft screening assessment stage for the subgroup. New information received after that publication has led to a change in the ecological conclusion in the final screening assessment.
- It is therefore concluded that 73 of the 74 Azo Disperse Dyes are not entering the environment at levels that constitute a danger to the environment. It is concluded that the remaining substance, Disperse Yellow 3 (CAS RN 2832-40-8), is entering or may enter the environment at levels that constitute a danger to the environment.
- It is also concluded that these 74 Azo Disperse Dyes (including Disperse Yellow 3) are not harmful to human health at current levels of exposure.
What is the Government of Canada doing?
- The Government of Canada published the Final Screening Assessment for Certain Azo Disperse Dyes and the Proposed Risk Management Approach for Disperse Yellow 3 on March 11, 2017. The Proposed Risk Management Approach will be followed by a 60-day public comment period, ending May 10, 2017.
- The government is proposing to develop a Pollution Prevention Planning Notice under section 56 of the Canadian Environmental Protection Act, 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.
- 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 has been 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 are asked to provide feedback on the document during the 60-day public comment period.
- In addition, Significant New Activity (SNAc) provisions were applied to 33 Azo Disperse Dye substances, following their 2008 assessment of 145 PBiT substances. These provisions require that any proposed new manufacture, import or use be subject to further assessment to determine if any new activity required further risk management consideration.
- As a result of this new assessment, it is proposed to remove the SNAc provisions on these 33 substances, as they are no longer considered to have health or ecological effects of concern and therefore new activities are no longer a concern.
What can Canadians do?
- The health risks associated with a substance depend on the hazard (its potential to cause health effects) and the amount of substance to which a person is exposed.
- 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.
- Canadians who may be exposed to these substances in the workplace should consult with their employer and occupational health and safety (OHS) representatives about safe handling practices, applicable laws and requirements under the OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).