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Interagency Modeling and Atmospheric Assessment Center

This page provides an overview of the Interagency Modeling and Atmospheric Assessment Center (IMAAC) and is intended for anyone who is interested in learning more about the IMAAC products.

The Interagency Modeling and Atmospheric Assessment Center coordinates and disseminates Federal atmospheric dispersion modeling and hazard prediction products. These products provide the Federal position during actual or potential incidents involving hazardous material releases. Through plume modeling analysis, the IMAAC provides emergency responders with predictions of hazards associated with atmospheric releases to aid in the decision making process to protect the public and the environment.


Led by the Federal Emergency Management Agency (FEMA), the IMAAC is a partnership among seven Federal agencies, each with supporting capabilities and/or responsibilities for plume modeling. These agencies include:

Access to IMAAC Products

The IMAAC products are available on the Homeland Security Information Network (HSIN) IMAAC page.  To open a HSIN account, please contact the HSIN Helpdesk at 1-866-430-0162 (available 24/7) or send an email to requesting a HSIN account and access to the IMAAC community of interest.

Activation for Emergency Support

The IMAAC provides plume models for real-world emergencies involving significant hazardous atmospheric releases.  To request IMAAC support; state, local, and federal officials should contact the IMAAC Technical Operations Hub, managed by the Defense Threat Reduction Agency at (703) 767-2003 or submit an email to

Exercise Support

The IMAAC also provides atmospheric modeling support for National Level Exercises and local exercises.  To request the IMAAC support an exercise, send an email to

Contact Information

For general inquiries, please send an email to

Last Updated: 
01/18/2018 - 09:40