40 CFR Part 98: Mandatory Greenhouse Gas Reporting

40 CFR Part 98, the EPA’s mandatory greenhouse gas reporting rule, requires large industrial emitters, fuel suppliers, and industrial gas suppliers to measure their annual emissions and file them electronically with the agency every year. The program, known as the Greenhouse Gas Reporting Program (GHGRP), was established under the Clean Air Act and generally covers facilities that emit 25,000 metric tons or more of carbon dioxide equivalent per year, plus certain industries that must report regardless of how much they emit.¹ If your facility is covered, you owe the EPA a signed annual report, a written monitoring plan kept on-site, and at least three years of supporting records.

Which Facilities Have to Report

Section 98.2 sorts covered entities into three groups: facilities in “all-in” source categories that report every year no matter what, facilities in other listed categories that report only if their emissions cross the 25,000 metric ton threshold, and fuel and industrial gas suppliers listed in Table A-5.²

The all-in categories are listed in Table A-3 and include petroleum refineries, cement producers, aluminum smelters, ammonia manufacturers, lime manufacturers, nitric acid plants, and adipic acid producers, among others.³ Beginning with reporting year 2025, coke calciners, calcium carbide producers, and caprolactam production facilities join the list.

For facilities in the Table A-4 categories, the trigger is 25,000 metric tons of CO2 equivalent per year, combining stationary fuel combustion and every applicable listed activity at the site.² A site with modest output across several processes can still cross that line once the totals are added.

Two boundaries worth noting. Research and development activities, as defined in the regulation, are not part of any source category and don’t trigger reporting.² Ordinary agricultural operations are not among the regulated source categories, so a typical farm doesn’t report; but a facility located on agricultural land that contains a listed source category, such as ammonia manufacturing, still does.

Which Gases Count

The regulation covers carbon dioxide, methane, nitrous oxide, and a broad category of fluorinated gases that includes sulfur hexafluoride, nitrogen trifluoride, hydrofluorocarbons, perfluorocarbons, and other fully fluorinated compounds. Ozone-depleting substances already regulated under a separate program and compounds with very low vapor pressures are excluded from the fluorinated gas definition.⁴

Because each gas traps heat at a different rate, everything gets converted to a single unit, carbon dioxide equivalent (CO2e), using Global Warming Potential values assigned in Table A-1 of Subpart A.⁵ Some fluorinated gases carry GWPs in the thousands, so even small releases can move the total meaningfully.

The Written Monitoring Plan

Every reporting facility must maintain a written GHG Monitoring Plan. It doesn’t get filed with the EPA, but it has to be kept on-site and produced on request. The plan must cover the job titles of the people responsible for collecting emissions data, the methods used to gather the data feeding into emission calculations, and the procedures for quality assurance, maintenance, and repair of monitoring instruments, including continuous monitoring systems and flow meters.

The plan can reference existing corporate documents like standard operating procedures rather than duplicate them, provided the required elements are easy to locate. It has to be updated whenever production processes change, monitoring equipment is replaced, or quality assurance procedures are revised.⁶

Data collection itself varies by source category. Part 98 is organized into subparts, each with its own calculation methods, emission factors, and missing-data procedures. Subpart C, covering stationary fuel combustion, generally requires tracking fuel usage through purchase records or flow meter readings.⁷ A facility with multiple listed source categories may need to follow several sets of rules at once.

Flow meters and other measurement instruments used for reporting must meet accuracy standards set out in Subpart A: generally within ±5% error, with orifice, nozzle, and venturi meters allowed up to ±6% total error. Acceptable calibration procedures include the manufacturer’s recommended method, applicable industry standards, or a method specified in the relevant subpart. Fuel billing meters from your utility provider are exempt. Calibration records are part of the recordkeeping obligation.

Filing Through e-GGRT

All annual reports go through the Electronic Greenhouse Gas Reporting Tool (e-GGRT) at ghgreporting.epa.gov.⁸ Paper submissions are not accepted. Registration involves creating a user account, completing an Electronic Signature Agreement, registering the facility, and appointing a Designated Representative. New user registration has to be completed in a single session.

Once data entry is done, e-GGRT runs automated validation checks that flag potential errors so the user can review and correct before final submission. A successful filing generates an electronic confirmation that serves as proof of compliance.⁹

The Designated Representative

Every facility must appoint a Designated Representative (DR) as the legal point of contact for all Part 98 reporting. The DR is chosen through an agreement that binds all owners and operators of the facility. If the facility already reports under 40 CFR Part 75, the acid rain program, the same individual must serve as DR for both.¹⁰

The role carries personal liability. Every annual report includes a certification the DR signs, attesting under penalty of law that they have personally examined the information. False statements can result in fines or imprisonment. Once the EPA receives a complete Certificate of Representation, everything the DR does or fails to do binds each owner and operator, regardless of any private agreements between them.¹⁰

Facilities can also appoint an Alternate Designated Representative and delegate specific tasks to Agents, but neither appointment relieves the DR of ultimate responsibility. If a DR is replaced, all prior actions by the previous representative remain binding on the new one and on all owners and operators.

When Reports Are Due

The standard annual deadline is March 31 for the preceding calendar year’s data.¹¹ The EPA has recently extended that date for specific reporting years: the report for reporting year 2024 was due by May 30, 2025, and the report for reporting year 2025 was extended to October 30, 2026 while the agency considers broader changes to the program.¹² These extensions are one-time changes and don’t alter the default March 31 deadline. Check the EPA’s GHGRP website for any further modifications before assuming the standard date applies.

Missing a deadline can trigger civil penalties under the Clean Air Act. Penalty amounts adjust annually for inflation and can accumulate for every day a violation continues, so the cost of a late filing grows quickly.

What Records to Keep

Facilities must retain all records used to prepare an annual report for at least three years from the submission date. If the EPA requires the facility to use verification software under Section 98.5(b), the retention period extends to five years.⁶ Electronic or hard copy is fine, and off-site storage is fine, as long as records are organized for quick inspection and readily available.

Required records go beyond the final numbers. Facilities must keep a list of every unit, process, and activity for which emissions were calculated, the underlying data broken out by fuel or material type, the calculation methods used, analytical results for any site-specific emission factors, high-heat-value and carbon-content test results, and any operating data that fed into the calculations. The GHG Monitoring Plan itself is a required record.⁶

How the EPA Checks the Data

The agency doesn’t accept submitted data at face value. Every report goes through electronic validation and verification checks. When something is flagged, the EPA notifies the reporter, and the facility can either explain why the data is correct or correct and resubmit.⁹ A clear audit trail makes it much easier to respond quickly and avoid escalation.

For certain sensitive data classified as “inputs to equations,” the EPA uses an electronic Inputs Verification Tool (IVT) instead of collecting raw figures. Facilities enter inputs into the IVT at submission for verification, and the EPA does not retain them. That approach lets the agency check the math without holding competitively sensitive data.

Reported data is subject to Confidential Business Information protections under 40 CFR Part 2, Subpart B. Rather than evaluate confidentiality requests one at a time, the EPA makes broad determinations through rulemaking about which data elements are public and which are protected, and it publishes summary tables listing the status of each reporting element for direct emitters and suppliers.¹³ Reviewing those tables before a first submission is worthwhile if you’re concerned about what will become public.

How to Stop Reporting

Once a facility starts reporting, it must continue every year even if emissions later drop below 25,000 metric tons. Two off-ramps are available:

Five-year off-ramp: if reported emissions stay below 25,000 metric tons of CO2 equivalent for five consecutive years, the facility can notify the EPA and stop reporting. The notification is due by March 31 of the year following the fifth consecutive low-emission year.
Three-year off-ramp: if reported emissions drop below 15,000 metric tons of CO2 equivalent for three consecutive years, the facility qualifies to exit sooner. The same March 31 notification deadline applies.

Under either path, the facility must keep all records from its final reporting years for at least three years after discontinuing. The exit is not permanent: if annual emissions reach 25,000 metric tons or more in any future year, the reporting obligation resumes.¹⁴

1
Congressional Research Service. EPA’s Greenhouse Gas Reporting Program
2
eCFR. 40 CFR 98.2 – Who Must Report
3
eCFR. Table A-3 to Subpart A of Part 98 – Source Categories
4
eCFR. 40 CFR 98.6 – Definitions
5
eCFR. Table A-1 to Subpart A of Part 98 – Global Warming Potentials, 100-Year Time Horizon
6
eCFR. 40 CFR 98.3 – General Monitoring, Reporting, Recordkeeping and Verification Requirements
7
eCFR. 40 CFR Part 98 Subpart C – General Stationary Fuel Combustion Sources
8
Environmental Protection Agency. Introduction to e-GGRT System Overview
9
United States Environmental Protection Agency. GHGRP Methodology and Verification
10
Government Publishing Office. 40 CFR Part 98 – Mandatory Greenhouse Gas Reporting
11
eCFR. 40 CFR 98.3 – General Monitoring, Reporting, Recordkeeping and Verification Requirements
12
Federal Register. Extending the Reporting Deadline Under the Greenhouse Gas Reporting Rule for 2025
13
US EPA. Confidential Business Information for GHG Reporting
14
eCFR. 40 CFR 98.2 – Who Must Report