40 CFR 98: EPA Greenhouse Gas Reporting Program

Regulatory citation: 40 CFR Part 98, Mandatory Greenhouse Gas Reporting

What Is EPA's Greenhouse Gas Reporting Program?

The Greenhouse Gas Reporting Program (GHGRP) in 40 CFR Part 98 requires certain facilities and fuel and industrial gas suppliers to monitor and report their greenhouse gas emissions or supplies to EPA each year. Subpart A sets the general rules on who must report, how to calculate emissions, deadlines and records. Separate subparts set calculation methods for each source category, such as stationary fuel combustion (Subpart C) and petroleum and natural gas systems (Subpart W).

Why Greenhouse Gas Reporting Matters

Once a facility is subject to Part 98, it must keep reporting every year until it qualifies for an off-ramp. Missing the applicability threshold, a deadline or a required record can lead to enforcement under the Clean Air Act.

Core Requirements

1. Determine Whether You Must Report (98.2(a))

Facilities with a source category in Table A-3 must report regardless of emissions. Facilities with a Table A-4 source category must report if their combined emissions are 25,000 metric tons CO2e or more per year. Other facilities must report if their stationary fuel combustion units have an aggregate maximum rated heat input capacity of 30 mmBtu/hr or more and emit 25,000 metric tons CO2e or more per year from combustion. Suppliers listed in Table A-5 have their own thresholds.

2. Calculate Emissions the Right Way (98.2(b) and 98.3(e))

Emissions of CO2, methane, nitrous oxide and fluorinated gases are calculated using the methods in each applicable subpart and converted to CO2e using the global warming potentials in Table A-1. CO2 from biomass combustion is excluded from the threshold calculation, but methane and nitrous oxide from biomass are included. The same calculation method must be used throughout a reporting period unless a written explanation of the change is provided.

3. Appoint a Designated Representative (98.4)

Each reporting facility or supplier must have one and only one designated representative, who certifies and submits reports. One alternate may also be named. EPA will not accept a report until it has a complete certificate of representation, which must be submitted at least 60 days before the first report is due. A new certificate is due within 90 days of a change in owners or operators.

4. Submit the Annual Report on Time (98.3(b))

Reports are generally due by March 31 each year for the previous calendar year and are submitted electronically in the format EPA specifies. For reporting year 2025, EPA moved the deadline to March 10, 2027, through an interim final rule published in October 2026. The report must include a signed certification by the designated representative.

5. Keep a Monitoring Plan and Records (98.3(g))

Facilities must keep a written GHG Monitoring Plan that identifies who collects emissions data, explains the data collection methods and describes quality assurance, maintenance and repair procedures for monitoring equipment. Required records must be kept for at least 3 years from the date of submission, or 5 years where verification software is used.

6. Correct Errors Within 45 Days (98.3(h))

A revised report must be submitted within 45 days of discovering a substantive error, meaning one that affects reported emissions or prevents EPA from verifying the data. If EPA notifies the facility of a substantive error, it has 45 days to resubmit or explain why the error is not substantive.

7. Use the Off-Ramps Correctly (98.2(i))

A facility may stop reporting after five consecutive years below 25,000 metric tons CO2e, or three consecutive years below 15,000 metric tons CO2e, by notifying EPA by March 31 of the following year. A facility that permanently shuts down all covered processes may also stop after notifying EPA. Reporting must resume if emissions later reach 25,000 metric tons CO2e or operations restart.

Common Compliance Approaches

Run an Annual Applicability Check

Recalculate emissions after process changes, production increases or new equipment, since a facility below the threshold must reevaluate after such changes.

Tie Data to Fuel and Meter Records

Pull fuel purchase, meter and production data into one workbook that maps to the subpart equations.

Track Rule Changes

Assign someone to follow EPA's GHGRP rulemakings, since deadlines and scope have been changing.

Example: Greenhouse Gas Reporting in Practice

A food processing plant runs several natural gas boilers with a combined heat input capacity above 30 mmBtu/hr. Its calculated combustion emissions are about 28,000 metric tons CO2e, so it must report under Subpart C. The plant manager is the designated representative and the environmental engineer maintains the monitoring plan, gas meter calibration records and fuel invoices. After finding a meter error, the engineer submits a revised report within 45 days.

Related regulations: EPA Title V Operating Permits, EPA Area Source Boilers (6J), EPA Toxics Release Inventory.

Note: In September 2025, EPA proposed to remove reporting obligations for most source categories and to suspend Subpart W reporting until reporting year 2034. As of the October 2026 interim final rule, that proposal had not been finalized and the current Part 98 requirements still apply. Check EPA's GHGRP pages and the current regulation text before relying on this summary.

Frequently Asked Questions

What is the GHGRP reporting threshold?

For most facilities it is 25,000 metric tons CO2e or more per year. Facilities with Table A-3 source categories must report regardless of emissions.

When is the reporting year 2025 report due?

Under 98.3(b)(6), the annual report for reporting year 2025 must be submitted no later than March 10, 2027.

Can a facility stop reporting?

Yes, after five consecutive years below 25,000 metric tons CO2e, three consecutive years below 15,000 metric tons CO2e, or a permanent shutdown of covered processes, with notice to EPA by March 31 of the following year.