GHG emissions rankings

The facility-span mix above is a different cut of the same parent table: it counts how many parents report from a single site versus multi-site footprints, and does not restate the CO₂e ranking. A parent with many facilities can still sit mid-table on latest Scope 1 if each site is modest; a single-site parent can lead a sector when that one plant is large. Read the span bands with the top-emitter chart, not instead of it. The CSV download on this page carries the state aggregates behind the same GHGRP vintage; company detail pages keep the facility list and yearly series used to build both views.

How we build these rankings

Every ranking on PlainCarbon is built from raw EPA Greenhouse Gas Reporting Program (GHGRP) submissions. Each U.S. facility emitting 25,000 metric tons of CO2-equivalent or more per year is required to file an annual return. We aggregate those filings up to the parent-company level using the GHGRP's "Parent Company" linkage so that a company operating dozens of facilities shows up once on a company ranking, not dozens of times.

The top-emitter ranking uses each covered facility's latest available report in the EPA dataset. Year-over-year reductions (used in the biggest-reducers ranking) compare the company's earliest reported year against its most recent reported year, calculated only for companies with at least three years of continuous reporting so that reduction figures reflect operational change rather than reporting boundary shifts.

What the rankings reveal

The largest reported emitters are dominated by integrated electric utilities, major refining companies, and petrochemical producers, the sectors that ran the largest U.S. industrial footprints during the 2010s. Coal-heavy utilities appear high on the top-emitters list and also high on the biggest-reducers list: these are companies that retired coal capacity and switched to natural gas or renewables over the past decade, so a latest-report ranking and a year-over-year reduction ranking answer different questions. Reading the two rankings side by side is more informative than either in isolation.

Methane-specific rankings (in addition to combined CO2-equivalent) call out oil-and-gas systems and landfill operators where methane is the dominant gas. Methane's higher 100-year global warming potential (29.8 per the IPCC AR6 value used by EPA) means that even modest methane reductions show up as large CO2-equivalent reductions on the headline charts. The methane-only view decouples that lever, useful when evaluating sector-specific methane mitigation programs.

Verification and methodology

Every facility and company on a ranking links to its detail page, which in turn links back to the underlying EPA FLIGHT records and includes the company's sector mix, top facilities, and reporting-year coverage. Where a company's legal name has changed (mergers, divestitures, spin-offs), we use the GHGRP's current legal-entity name and note prior reporting names on the detail page so longitudinal comparisons remain traceable. Companies that exit the federal threshold (sell all reporting facilities or shut them down) drop off future rankings when the facility's latest available report is older; those records are not a substitute for a full historical cumulative total.

Industry sector classifications follow EPA subpart designations (Subpart D for electricity, Subpart W for petroleum & natural gas, Subpart H for cement, etc.), not NAICS economic codes. The two overlap substantially but are not identical; on each company page we surface the EPA subpart mix and link to NAICS where the company has registered one. This dual labeling keeps the rankings aligned with how the EPA itself organizes the dataset while preserving comparability to broader economic statistics published by the Census Bureau and Bureau of Labor Statistics.