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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 application 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 to meet requirements for the following programs: 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, shared data could be reported just once for use across multiple programs.


Combined emissions reporting will reduce redundancy in reporting air emissions and associated facility data, as well as review time for EPA, state, local, and tribal programs on data quality assurance and data reconciliation among programs.

  • Regulated Community: CAER will decrease the reporting burden for facilities by reducing duplicative data entry 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.


CAERS Version 2 deployed in March 2021 for the NEI 2020 reporting cycle and is being used by more than 300 facility reporters in Georgia, by the District of Columbia Department of Energy and Environment, and by the local authorities of Pima, Arizona.

CAERS Version 3 deployed in February 2022 and was used by Rhode Island facilities to report inventory year 2021 data.  The Georgia Department of Natural Resources reported significant time savings in the process of review and submission of NEI data to EPA, having submitted that data to EIS four months before the actual deadline.


  • Begin use of CAERS by Maine and Idaho in February of 2023.
  • Build additional CAERS functionality to meet new NEI program requirements and refine the data that can be made available to TRI to provide more information to TRI reporters about CAERS data.
  • Establish data workflows with CEDRI and GHGRP.
  • Work with partners from Arizona, Minnesota, Montana, and Rhode Island.
  • Develop several shared services to support CAERS. These services will also be available as stand-alone products for use by state, local, and tribal partners not using CAERS.


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.

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.

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

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.

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.