Assessing and Managing Chemicals under TSCA
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Fact Sheet: Toluene Diisocyanate (TDI) and Related Compounds

Q1. What are TDI and related compounds?

Tolulene diisocyanates (TDI) and related compounds are generally high production volume chemicals, meaning they are produced or imported in to the United States in quantities of 100 million pounds or more each year. These chemicals are predominantly used in the production of polyurethanes and consumer products, such as coatings, elastomers, adhesives, and sealants.

Q2. What action is EPA taking?

EPA is proposing a Significant New Use Rule (SNUR) under the Toxic Substances Control Act (TSCA). This proposed SNUR would require manufacturers (including importers) and processors of TDI and related compounds in consumer products to notify EPA at least 90 days before starting or resuming uses of these chemicals. This notification allows EPA the opportunity to evaluate the intended use and, if necessary, take action to prohibit or limit the activity. For this proposed SNUR, EPA will have the opportunity to evaluate new or resumed use of the chemicals at greater than 0.1% in coatings, adhesives, elastomers, binders, and sealants in consumer products including imported consumer products. For all other uses in consumer products, EPA would have the opportunity to evaluate new or resumed use of the chemicals at any level.

Q3. Why is EPA concerned about TDI and related compounds?

Exposure to TDI and related compounds is well known to result in skin and lung sensitization among workers and has been documented to cause asthma, lung damage, and in severe cases, fatal reactions.

While the majority of polyurethane products containing TDI and related compounds undergo “curing” (hardening) prior to reaching the consumers, some polyurethane products such as coatings, sealants and adhesives may be sold and used in an uncured form, increasing exposure risks for consumers.

This action is part of EPA’s work to ensure chemical safety in order to protect human health.

Q4. What chemicals are in the proposed SNUR?

There are seven TDI and related compounds in this proposed SNUR:

  • Toluene diisocyanate trimer (Benzene, 1,3-diisocyanatomethyl-, trimer, CASRN 9019-85-6)
  • Poly(toluene diisocyanate) (Benzene, 1,3-diisocyanatomethyl-,homopolymer, CASRN 9017-01-0)
  • Toluene diisocyanate dimer (1,3-Diazetidine-2,4-dion3e,1,3bis(3-isocyanatomethylphenyl)-, CASRN 26603-40-7)
  • Toluene diisocyanate “cyclic” trimer (1,35-Triazine-2,4,6(1H,3H,5H)trione, 1,3,5-tris(3-isocyanatomethylphenyl)-, CASRN 26603-40-7)
  • 2,6-Toluene diisocyanate (Benzene, 1,3-diisocyanato-2-methyl-, CASRN 91-08-7)
  • 2,4-Toluene diisocyanate (Benzene, 2,4-diisocyanato-1-methyl-, CASRN 584-84-9)
  • Toluene diisocyanate unspecified isomers (Benzene, 1,3-diisocyanatomethyl-, CASRN 26471-62-5)

Q5. What products containing TDI and related compounds are available to consumers?

Consumers could be exposed to these chemicals while using products containing uncured or unhardened TDI and its related compounds. These chemicals are used in spray-applied sealants and coatings. Prior to complete curing, consumers could be exposed through both skin contact and inhalation.

Consumer products, such as coatings, elastomers, adhesives, and sealants, may contain TDI in residual amounts (less than or equal to 0.1 percent by weight). EPA believes that the use of any of these chemical substances in consumer products above current levels could significantly increase human exposure, and that such increase should not occur without opportunity for EPA review and control as appropriate.

Q6. Is there an easy way for consumers to avoid using products with TDI and related compounds?

Consumers should review Safety Data Sheets (PDF) and other technical product information, including product labels, to determine whether a manufacturer reports the use of TDI. Consumers should also use caution when considering products that are labeled “For Professional Use.”   As professional products, they may contain high levels of isocyanates, the family of chemicals that includes TDI and related compounds.

Q7. Are importers and processors of these chemical substances as part of articles (manufactured goods) included in this proposed SNUR?

Yes. The proposed notification requirement would apply to importers and processors of these chemical substances as part of articles (manufactured goods).

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Last updated on March 7, 2023