Combined Air Emissions Reporting System

CAERS is a free, web-based reporting system developed by the Environmental Protection Agency (EPA) to assist facilities with their annual air emissions reporting requirements.

User Registration and Electronic Signature Agreement

Every facility must have a responsible official registered as the Certifier to submit the inventory. The Certifier also designates those individuals who will help prepare the inventory as Preparers. Facilities register these users by submitting the agreement below.

CAERS User Registration and Electronic Signature Agreement (pdf)

NOTE: This form must be completed before anyone can use and submit data through CAERS. Maine DEP must receive the original signed agreement before adding, creating, or removing existing users. FAX and e-mail copies are not acceptable. Certified mail is recommended. Please mail the completed form with original ink signature to:

Sierra Allen, DEP CAERS Administrator
Department of Environmental Protection
Bureau of Air Quality
17 State House Station
Augusta, ME 04333-0017

Here are some User Registration and Electronic Signature Agreement Frequently Asked Questions (pdf)

Use this form if the Certifier is staying the same and only the Facility Preparers need to be updated: CAERS User Registration for New Facility Preparers Only (pdf)

If you have questions about your registration or account, contact Sierra Allen at 207-815-7684.

CAERS Training

EPA has created a user guide and many training videos demonstrating the steps necessary to complete an annual emissions inventory using CAERS. These resources can be found on the CAERS training website.

Emission Factors

EPA has linked Webfire to CAERS to allow easy access to emission factors.

In addition, Maine has generated a list of default factors for most Hazardous Air Pollutants (HAPs) for the inventory years when they are required. Facilities may use the default factors or their own factors, with proper documentation. The spreadsheet linked below sources each of DEP's default emission factors for HAPs.

If you have any questions about the default factors, please contact Sierra Allen 207-815-7684.

Default HAP Emission Factors (excel)

We are here to help

To ensure that your questions will be addressed as promptly as possible, please email us at