Learn More About Products Made With DII

Polyurethanes are produced by reacting diisocyanates with polyols. Other non-reactive additives, such as catalysts, surfactants, blowing agents or flame retardants, may be included in the process. Atmospheric emissions of the diisocyanates (MDI and TDI) during isocyanate production are low, as they are typically carried out in closed equipment with controls on all vents.

Under the Toxics Release Inventory (TRI) program, facilities that manufacture, process or otherwise use TDI, MDI or PMDI and exceed the usage threshold limits set by the U.S. Environmental Protection Agency (EPA), are required by EPA to submit a Form A or Form R by July 1st of each year to EPA and the appropriate state agency. To aid those facilities required to submit TRI forms, ACC’s Center of the Polyurethanes Industry (CPI) offers a Regulatory Compliance Assistance Program (RCAP). Intended to provide some assistance to RCAP users, this program has a number of built-in formulas to estimate emissions from typical process applications and activities. For assistance or questions regarding TDI, MDI, PMDI or TRI reporting, contact CPI RCAP Software User Support.

Airborne Emissions Reporting and Testing Resources:

ACC CPI Isocyanate Emissions Resources

  • Occupational Hygiene Air Monitoring for MDI and TDI Guidance
    This guidance document describes workplace air monitoring methods for MDI and TDI, and provides information on personal and area sample collection. Several instruments and derivatization methods for monitoring vapors are presented. (AX-248, 2012)
  • MDI Emissions Estimator*
    This software provides a fast and convenient method to estimate MDI emissions from typical process applications and activities.
  • TDI Emissions Estimator*
    This software provides a fast and convenient method to estimate TDI emissions from typical process applications and activities.

EPA Testing Methods – Emissions and Stack Emissions

EPA has published various test methods relating to environmental monitoring and stack testing. These tests can be used to supplement information during specific evaluations of occupational exposures. The following methods for MDI and TDI are included on EPA's Emissions Measurement Center Test Methods web page.

The following two methods are listed by the EPA as conditional methods:

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