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Assessing and Managing Chemicals under TSCA

Risk Management for Methylene Diphenyl Diisocyanate (MDI) and Related Compounds

What is TDI?

Diisocyanates are well known dermal and inhalation sensitizers in the workplace and have been documented to cause asthma, lung damage, and in severe cases, fatal reactions. Worker exposures are already subject to protective controls in occupational settings.  TDI is chemically similar to MDI and presents similar hazard and exposure concerns, but is reportedly used in a different range of products. EPA has developed a separate Action Plan for Toluene Diiscyanate (TDI) and its related compounds.

Why is EPA concerned?

EPA is concerned about potential health effects that may result from exposures to the consumer or self-employed worker while using products containing uncured (unreacted) MDI and its related polyisocyanates (e.g., spray-applied foam sealants, adhesives, and coatings) or incidental exposures to the general population while such products are used in or around buildings including homes or schools.

What action is EPA taking?

Based on EPA’s screening-level review of hazard and exposure information, including information indicating uncured MDI and its related polyisocyanates are used in a range of consumer and commercial products as well as in products intended only for an industrial market, EPA intends to:

  1. Issue a data call-in for uncured MDI under TSCA section 8(c) to determine if there are allegations of significant adverse effects and initiate a TSCA section 8(d) rulemaking for one-time reporting of relevant unpublished health and safety studies for uncured MDI.
  2. Consider initiating a TSCA section 4 test rule to require exposure monitoring studies on uncured MDI and its related polyisocyanates in consumer products and exposure monitoring studies in representative locations where commercial products with uncured MDI and its related polyisocyanates would be used.
  3. Consider initiating rulemaking under TSCA section 6 for
    1. Consumer products containing uncured MDI, and
    2. Commercial uses of uncured MDI products in locations where the general population could be exposed.
  4. Consider identifying additional diisocyanates and their related polyisocyanates that may be present in an uncured form in consumer products that should be evaluated for regulatory and/or voluntary action.

Previous Actions:

Read about the ongoing federal partnership activities for safer use of spray polyurethane foam containing MDI and related compounds.

Current Actions:

Download the complete Methylene Diphenyl Diisocyanate (MDI) Action Plan (PDF)

Access the public comment docket for the Methylene Diphenyl Diisocyanate (MDI) Action Plan (Docket ID EPA-HQ-OPPT-2011-0182) on