Skip to main content

The Combined Air Emissions Reporting (CAER) project seeks to streamline the way industry reports air emissions to meet EPA, state, local, and tribal program requirements. The CAER System (CAERS) is an electronic reporting tool that allows facilities to report to more than one program via a single data submission.


Various federal, state, local, and tribal programs require industry to report air pollutant emissions to separate systems at different times of the year. These systems include the National Emissions Inventory (NEI), the Toxics Release Inventory (TRI), the Greenhouse Gas Reporting Program (GHGRP), the Compliance and Emissions Data Reporting Interface (CEDRI), and partner-specific systems. This leads to duplication of effort for both industry and government. While each program collects different data, some data (specifically, input data) is the same and could be reported just once for use across multiple programs.


    • Regulated Community: CAER will reduce the reporting burden for facilities by preventing duplicative efforts across programs and improving both the reporting experience and efficiencies.
    • Public: CAER will improve data availability, timeliness, transparency, consistency, and quality for users.
    • Regulators: EPA, states, tribes, and local governments will spend less time reviewing, compiling, and reconciling data, and the most timely and high-quality data will be available to decisions makers.


CAER partnered with the Georgia Department of Natural Resources (DNR) and 12 of its regulated facilities to develop and pilot the “Common Emissions Form,” now known as the CAER System (CAERS). The Minimum Viable Product of CAERS was released in April 2020 and is currently being used by Georgia facilities to report National Emissions Inventory (NEI) 2019 inventory year emissions. Data reported there are also available for industry use in reporting air emissions to the Toxics Release Inventory (TRI). CAERS is the result of a truly collaborative effort between EPA, state members of the CAER Product Design Team, and Georgia DNR.


  • Continue work with Georgia DNR in 2020 to enhance CAERS as state, local, and tribal partners prepare for an NEI triennial reporting year (2020).
  • Build additional CAERS functionality in order to meet new NEI program requirements and to refine the data that can be made available to TRI.
  • Onboard Washington, DC to CAERS in 2020 to enable industry to report 2020 inventory year emissions beginning in January 2021.
  • Begin work with the Compliance and Emissions Data Reporting Interface and the Greenhouse Gas Reporting Program.
  • Onboard additional state, local, and tribal partners to work with EPA toward adoption of the common form. Many environmental programs have their own reporting systems, and for those interested, CAERS will focus on how best to integrate their systems.
  • Develop several shared services to support CAER. These services will also be available as stand-alone products for use by state, local, and tribal partners not using CAERS.


For more information, please visit the CAER Project Website. To join the CAER listserv, send an email to


CAER Factsheet

State/Local/Tribal (SLT), National Emission Inventory (NEI), Toxic Release Inventory (TRI) Mapping

Research consistency and possible workflows for sharing of emissions data between TRI, SLTs and NEI. This will include creating a crosswalk for pollutants between programs, figuring out how to handle each program’s terminology (e.g. facility, unit) and emission sources covered by reporting, and identifying where guidance needs to be harmonized, among other things.

Phase 1 – Final Report

TRI/NEI Pollutant Crosswalk

Quality Assurance / Quality Control (QA/QC)

Identification and evaluation of a common set of emissions data QA/QC procedures for potential use in a shared emission reporting system.

Phase 1 – Final Report

Data Model for the Common Emissions Form (CEF)

Document a data model with the emissions-related data elements needed to support a common emission form (CEF) reporting structure in a shared emissions platform. Identify and include state-specific data elements sufficient to allow for broad usage by states and EPA CAER

Phase 1 – Final Report

Appendix A – Data Model Survey Results

Appendix B – Additional Pollutants

Appendix C – Additional Data Fields

SCC-WebFIRE for the Common Emissions Form (CEF)

Scoping study for identifying problems and solutions with SCCs and WebFIRE that will meet SLT, NEI, NATA, and CEDRI/ERT requirements under the CAER project.

Phase 1 – Final Report

State Greenhouse Gas Reporting Program (GHGRP) to National GHGRP Mapping

This will be a pilot study to map emission data in the national GHGRP to state GHGRP programs. The goal of the study is to understand which data elements state mandatory reporting programs have in common with GHGRP required data elements. This will help us understand what would be necessary to share data between the programs.

Phase 1 – Final Report

Appendix A – GHG PDT Dad Element Comparison