Aliphatic Diesters Group – information sheet

Hexanedioic acid, diisodecyl ester (DIDA)
CAS Registry Number 27178-16-1

Publications summarized:

The Government of Canada conducts risk assessments of substances under the Canadian Environmental Protection Act, 1999 (CEPA) to determine whether they present or may present a risk to human health or to the environment.
- The risks posed by a substance are determined by both its hazardous properties (potential to cause adverse human health or ecological effects) and the amount or extent to which people and the environment are exposed.
- When needed, the Government applies risk management measures under CEPA and other federal acts to help prevent or reduce potential harm.
The ecological hazard and exposure potentials of this substance (DIDA) were classified using the Ecological Risk Classification of Organic Substances (ERC) Approach.
The Government concluded that DIDA is not harmful to human health or to the environment at levels considered in the assessment.
DIDA may have hazardous properties; however, the risk to people in Canada is considered to be low. The Preventative actions and risk reduction section below provides links on where to find updates on activities.

The assessment focused on hexanedioic acid, diisodecyl ester, also referred to as DIDA. It is 1 of 2 substances referred to collectively as the Aliphatic Diesters Group. This substance was assessed as part of the Chemicals Management Plan (CMP).
The other substance, called nonanedioic acid, bis(2-ethylhexyl) ester (CAS RN 103-24-2), was determined to be of low concern to both human health and the environment through other approaches. Conclusions for that substance are provided in the Final Screening Assessment for Substances Identified as Being of Low Concern based on the Ecological Risk Classification of Organic Substances and the Threshold of Toxicological Concern (TTC)-based Approach for Certain Substances.
According to information gathered by the Government, DIDA is used as a plasticizer in electrical cables, as a processing aid, and as an ingredient in lubricants and greases in Canada. Lubricant-type products available to consumers in Canada containing DIDA were identified as motor oils, power steering fluids, aerosol lubricants, and lubricant products designed to stop oil leaks. DIDA is also listed as a formulant in registered pesticide products.

People in Canada may be exposed to DIDA from the use of products available to consumers, such as motor oil, and aerosol lubricant.
According to information considered under the ERC Approach, DIDA was identified as having a high ecological exposure potential due to its overall persistence (ability to stay in the environment over time) and large use quantities.

There were limited health effects (hazard) data for DIDA, therefore, a comparative approach using similar chemicals, called read-across, was used for assessing potential health effects.
Using data available on a similar substance, developmental effects were identified as the critical effects for characterizing the risk to human health from DIDA exposure.
According to information considered under the ERC Approach, DIDA was identified as having a moderate level of ecotoxicity.

Based upon a comparison of levels to which people in Canada may be exposed to DIDA and levels associated with health effects, the risk to human health from this substance is low.
Based upon the outcome of the ERC Approach, DIDA is considered unlikely to be causing ecological harm.

The Government concluded that DIDA is not harmful to human health at current levels of exposure.
The Government also concluded that DIDA is not entering the environment at levels that are harmful.

Although DIDA is not considered to be harmful to human health and the environment at levels of exposure considered in the assessment, this substance is considered to have a health effect of concern due to its potential to cause developmental effects. There may be a concern if exposures to this substance were to increase.
Therefore, the Government published a notice of intent to apply Significant New Activity (SNAc) provisions of CEPA to DIDA. During the 60-day public comment period (ending on April 10, 2019), additional acceptable conditions for this substance were identified. Consequently, the scope of the SNAc requirements was amended and an updated notice of intent to apply SNAc provisions of CEPA to DIDA was republished on June 28, 2025.
The SNAc provisions would require that the Government be notified of certain proposed new activities related to DIDA, and that the new activity be assessed for potential risks to human health and the environment before being undertaken.
The notice outlines the proposed definition of a significant new activity in relation to DIDA, as well as the information that would need to be provided to the Government for assessment before the new activity is undertaken.

Updates on actions for DIDA can be found on the timeline for the Aliphatic Diesters Group.
Information on SNAc provisions applied to substances, where applicable, is found in the SNAc publications dataset.
Updates on information gathering initiatives and additional information on the risk management of substances as well as a table of risk management actions for substances addressed under the CMP are available.
Use the Substances Search tool to find substances that are referenced in certain legislative or regulatory instruments or on Government of Canada websites.

DIDA may be found in products available to consumers. Consumers should follow any safety warnings and directions related to the product and dispose of products responsibly.
Assessments conducted under CEPA focus on risks of exposure of the general population, including populations who may be disproportionately impacted. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System (WHMIS). The Government of Canada recognizes that it is the responsibility of the federal, provincial and territorial occupational health and safety organizations to coordinate legislation for the safe use of chemicals in the workplace. We are working to support this role by integrating the information, tools, and/or technical expertise of the CMP and Health Canada's Workplace Hazardous Products Program.

2025-10-24