Toluene Diisocyanates (TDI) - information sheet

Benzene, 2,4,-diisocyanato-1-methyl- (2,4-TDI)
CAS Registry Number 584-84-9

Benzene, 1,3,-diisocyanato-2-methyl-  (2,6-TDI)
CAS Registry Number 91-08-7

Benzene, 1,3,-diisocyanatomethyl-  (TDI mixed isomers)
CAS Registry Number 26471-62-5

Updated February 15, 2019:

The Final Screening Assessment for toluene diisocyanates (TDIs) was published on July 5, 2008 under the Challenge Initiative of the Chemicals Management Plan (CMP). The assessment is summarized in this information sheet (formerly public summary) and has not changed. The section in this information sheet entitled "Preventive actions and reducing risk" communicates updates in risk management activities, namely:

• Publication of a final pollution prevention planning notice.

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
• Related information

Overview

• The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and to the environment from toluene diisocyanates (TDIs).
• 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 and 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, TDIs were concluded to be harmful to human health, but not to the environment, at levels of exposure at the time of the assessment.

About these substances

• This screening assessment focused on 3 substances referred to collectively as TDIs. The substances addressed were 2,4-TDI, 2,6-TDI, and TDI mixed isomers. They were assessed as part of Batch 1 of the Challenge Initiative of the CMP.
• TDIs are industrial chemicals that are used to manufacture certain products.
• At the time of the assessment, about 86% of TDIs were used in the manufacture of polyurethane foam in Canada. Polyurethane foam is used in household furniture and automotive upholstery, mattresses, pillows, packaging and carpet underlay.
• TDIs may also be used in sealants, coatings, adhesives, some alkyd paints (automotive and marine paint), wood varnish, floor treatment, and wire and powder coating. TDIs had limited applications in food packaging and food processing, with no expected human exposure from food-related uses.

Human and ecological exposures

• The assessment indicated that Canadians may be exposed to TDIs mainly through inhalation during the use of non-foam products available to consumers. In addition, exposures can be elevated near certain industrial facilities where TDIs are used.
• Releases to the environment in Canada from industrial processes were mainly to air. Exposure of the environment to TDIs was considered to be low.
• Current exposures may be different from the time the assessment was published.

Key health and ecological effects (hazard)

• At the time of the assessment, the important or "critical" effects used for characterizing the risk to human health from TDIs were carcinogenicity (ability to cause cancer), and respiratory effects (breathing problems).
• International agencies have also classified TDIs for carcinogenicity. For example, the International Agency for Research on Cancer (IARC) classified TDIs as "possibly carcinogenic to humans" (Group 2B). TDIs have also been classified as a dermal and respiratory sensitizer. Sensitization can result in breathing problems or effects on the skin.
• TDIs were considered to have low potential for ecological effects.

Risk assessment outcomes

• Based upon a comparison of levels to which Canadians can be exposed to TDIs and levels associated with health effects, it was determined that TDIs may pose a risk to human health.
• TDIs are not expected to remain in the environment for a long period of time or accumulate in organisms. Considering all the information presented, it was determined that TDIs are unlikely to cause ecological harm in Canada.
• The Government of Canada published the Final Screening Assessment for Toluene Diisocyanate (TDI) on July 5, 2008.

Screening assessment conclusions

• As a result of the screening assessment, the Government concluded that TDIs are harmful to human health at levels of exposure current at the time of the assessment.
• The Government also concluded that TDIs are not entering the environment at levels that are harmful to the environment.

Preventive actions and reducing risk

• The proposed Risk Management Approach for Toluene Diisocyanates (TDIs) was published on July 5, 2008 and had a 60-day public comment period. The approach focused on addressing the risks identified in the assessment, specifically, industrial releases of TDIs from foam production. In accordance with the approach, the Government took steps to reduce or manage the risks associated with the substance. These steps are listed below.
• TDIs were added to Schedule 1 of CEPA 1999, also called the List of Toxic Substances.
• In June 2010, TDIs were added to Health Canada's List of Prohibited and Restricted Cosmetic Ingredients (referred to as the Cosmetic Ingredient Hotlist). The Hotlist is used to communicate that certain substances may not be compliant with requirements of the Food and Drugs Act or provisions of the Cosmetic Regulations.
• On February 16, 2019, a Final pollution prevention (P2) planning notice in respect of TDIs was published. This notice replaces the P2 planning notice for TDIs used in the polyurethane and other foam sector (except polystyrene) that was published in 2011.
• Releases of TDIs will continue to be reported to the National Pollutant Release Inventory (NPRI). Reporting requirements have been modified to capture additional sources of these pollutants.
• Further information and updates on risk management actions for substances managed under the CMP can be found in the risk management actions table and the two year rolling risk management activities and consultations schedule. Actions for TDIs can also be found in the risk management action milestones for Batch 1 table.

Related information

• TDIs may be found in certain products available to consumers. Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
• Canadians who may be exposed to TDIs 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).