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Wyoming Data Analysis

A statewide look across all of the Wyoming data, covering every record, including samples that are not shown on the map.

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Pennsylvania Data Analysis

A statewide look across all of the Pennsylvania data, covering every record, including samples that are not shown on the map.

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Ohio Data Analysis

A statewide look across all of the Ohio data, covering every record, including samples that are not shown on the map.

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West Virginia Data Analysis

A statewide look across all of the West Virginia data, covering every record, including samples that are not shown on the map.

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Oklahoma Data Analysis

A statewide look across all of the Oklahoma data, covering every record, including samples that are not shown on the map.

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New Mexico Data Analysis

A statewide look across all of the New Mexico data, covering every record, including samples that are not shown on the map.

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CO Reporting Quality

CH₄ Distribution by Equipment Group ⓘ

▮ Count of sites in range · ▮ Bin contains flagged site · ● Top flagged sites (up to 5 shown) · | Group median (p50)

Statewide Emissions Trend (raw totals vs. outlier-adjusted) ⓘ

Top Flagged Facilities click a row to open site

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Colorado Oil & Gas Basins

County boundaries shown exactly. Basins are defined by which counties belong to each.

🔍 Zoom: 100%

▮ DJ Basin

Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Elbert, Jefferson, Larimer, Logan, Morgan, Phillips, Sedgwick, Washington, Weld, Yuma

▮ Piceance Basin

Garfield, Moffat, Mesa, Rio Blanco

▮ San Juan Basin

Archuleta, Conejos, La Plata, Mineral, Montezuma, Rio Grande, San Juan

▮ Arkansas River Basin

Bent, Crowley, Fremont, Kiowa, Otero, Prowers

▮ Raton Basin

Las Animas

How CO Reporting Quality Works

Methodology reference for the anomaly detection shown in this panel

Data Source

All figures come from Colorado's Oil and Natural Gas Atmospheric Emissions Inventory Report (ONGAEIR), submitted annually to CDPHE. Facilities report CH₄, CO, NOx, VOC, and CO₂e across 18 equipment categories. TetraSoft ingests each year's raw submissions as they become available and assigns each facility a stable site identifier, so the same physical location can be tracked across years even when its facility ID changes.

What the Analysis Does

For each facility and reporting year, CH₄ values are measured against the full population of facilities in the same equipment category, year, and site type. The score used for comparison is a modified z-score.

A standard z-score measures distance from the mean in units of standard deviation. That is sensitive to extreme values: a few very large reporters can inflate the baseline and make everyone else look normal. The modified version replaces the mean and standard deviation with the median and the median absolute deviation (MAD). The MAD is the typical gap between individual values and the group median. Because it is calculated from the middle of the distribution, a handful of outliers cannot shift the scale. A score of 0 means the record sits exactly at the group median. A score of 10 means it is ten MAD-units above it.

Not all equipment categories get the same treatment. Categories with fundamentally different operating patterns use different detection logic, described in the tier section below.

Warning vs. Critical

Warning: score above 3.5 and CH₄ above the category minimum floor. The record is statistically unusual. Worth a second look, but not far enough out to call definitively wrong.

Critical: score above 7.0 and CH₄ above the category critical floor (varies by tier, described below). At that level the record is well outside its peer group in both statistical and absolute terms. Critical records from Tier 1 categories are removed from the Adjusted CH₄ trend.

Equipment Category Tiers

Not all 18 ONGAEIR equipment categories behave the same way statistically. Treating them identically would produce misleading flags. The analysis uses three tiers.

Tier 1: Standard peer comparison

Tanks, Separators, Stationary Engines or Turbines, NR Internal Combustion Engines, Pneumatic Controllers, Amine Units, Combustion Control Devices, and all categories not listed in Tiers 2 or 3.

Each facility is scored against same-category, same-year peers in the same site type. Critical threshold: z-score above 7.0 and CH₄ above 5 times the category's 99th percentile. These are the categories where volumes are large enough that a genuine outlier represents a real data quality question. Only Tier 1 critical records are subtracted from the Adjusted trend line.

Tier 2: Peer comparison with absolute floor

Heaters or Boilers (5 MT floor), Loadout (5 MT), Well Bradenhead (5 MT), Pneumatic Pumps (5 MT), Dehys (5 MT), Flowback or Completions (10 MT), Pipeline (10 MT), Drill Mud (2 MT).

Same z-score logic as Tier 1, with one addition: critical severity also requires CH₄ above a fixed floor. These categories have very tight distributions. A heater reporting 2 MT can score a z-score above 40 simply because most heaters report under 0.1 MT. That statistical signal is real, but 2 MT is not the kind of emission that warrants an audit review. Below the floor, severity stays at Warning regardless of z-score. Tier 2 critical flags appear in the table but are not subtracted from the Adjusted trend.

Tier 3: Site-historical spike detection

Fugitives, Venting or Blowdowns, II.G Well Maintenance.

Peer comparison does not apply here. These categories exist to capture non-routine operational events: a fugitive emission, a series of planned blowdowns, maintenance activity. A midstream operator running many blowdowns in a year is supposed to report high values. Scoring them against a peer average would flag accurate reporting as anomalous.

Each site is compared against its own history instead. A year is flagged when the site's total for that category exceeds three times its own prior peak. Sites with no prior history are flagged at Warning if the value exceeds 10 MT. The goal is to catch something genuinely new at a specific site, not to penalize consistent high-volume operators.

Tier 3 flags never reduce the Adjusted trend. These are real emissions.

The Adjusted CH₄ Trend

The trend chart shows two lines. Raw is the total reported CH₄ across all CO ONGAEIR facilities for that year. Adjusted is the same total after removing critical Tier 1 records (SEVERE_OUTLIER flags in Tanks, Separators, Stationary Engines, and similar high-volume categories).

The gap between the lines shows how much of the statewide number comes from a small number of extreme records. A wide gap does not mean those records are wrong. Some are genuine large emission events. The Adjusted line answers one specific question: what does the trend look like if we set the statistical extremes aside?

Peer Groups and Site Types

Colorado ONGAEIR facilities report under four site types: Production (wellpads, the largest group at around 19,000 sites), Midstream (compressor stations, processing plants), Pre-Production (drilling sites), and UIC (injection wells). A wellpad and a compressor station handle very different operations, and treating them as one population would produce comparisons with no useful signal. Each site is scored against others in the same site type, equipment category, and year. When fewer than ten facilities exist for a given combination, the comparison expands to the full statewide population.

A note on Colorado's emissions reporting

Colorado ONGAEIR is among the most detailed oil and gas emissions reporting frameworks in the country. CDPHE has built a dataset that other states have looked to as a model, and that reflects years of sustained effort from both the agency and the operator community.

TetraSoft's founders have worked with this dataset since its early years. That history is what makes this analysis possible, and it is also why we read the flags carefully. The patterns surfaced here are statistical. They are starting points for review, not findings. A flagged record may turn out to be a legitimate large-emission event reported exactly as required. Others may reflect reporting conventions or edge cases in submitting software. We flag them so you can look, not so you can conclude.

This tool is for informational use only. Nothing here constitutes a regulatory finding, compliance determination, or audit result. Verify any flagged record against the original ONGAEIR submission before drawing conclusions.

What are EPA FRS Sites?

A quick guide to the Facility Registry Service overlay on the Wyoming map

What FRS is

Think of FRS as the EPA's master list of facilities it keeps an eye on. A site lands on this list because an environmental program regulates it or it has to report to one, not just because it happens to be operating out there. What you see on the map is the Wyoming oil and gas slice of that list: production batteries, gas plants, compressor stations, pipelines, and refineries.

Why a facility shows up

Every one of the 9,137 Wyoming oil and gas facilities here is on file for at least one environmental reason. Most of the time that reason is an air permit, usually a small one, not greenhouse gas reporting. A facility can be on file for several reasons at once, so the numbers below add up to more than the total.

Why it is on file	Facilities
Air permit, minor source	8,331
Registered in a state program	6,411
Compliance and emissions reporting	208
Air permit, major source	178
OSHA establishment	146
Hazardous waste (small-quantity generator)	140
Risk Management Plan (RMP) reporter	73
Air permit, synthetic minor	71
Criteria air pollutant, major	65
TSCA submitter	49
Greenhouse Gas Reporter (GHGRP)	44

What it is not

It is not a full list of everything out there. If a facility has never needed a permit and does not report to any state or federal program, it will not be here.

It is not the same as GHGRP. GHGRP only counts the big emitters (roughly 25,000 metric tons of CO₂e a year or more), and only 44 of these 9,137 make that cut. FRS casts a far wider net, since any air permit, waste registration, or program record is enough to be listed.

It is not the well list. These are regulated facilities, which is a different thing from the wells in the Wells layer (WOGCC's active wells plus its plugged and abandoned wells).

Source: EPA Facility Registry Service (FRS), Wyoming state combined file. Counts reflect the current data.

What are AIRS Facilities?

A quick guide to the AIRS overlay on the Colorado map

What AIRS is

AIRS is the facility registry behind Colorado's air-quality program, run by the state Air Pollution Control Division (part of CDPHE). Anything that holds an air permit or has to report air emissions gets an AIRS ID and a record in this system, so it covers far more than just oil and gas. The AIRS ID is the key you use to pull a facility's permit file from the CDPHE records portal.

What this overlay shows

Colorado's air program has 19,681 registered facilities. Of those, 15,730 already line up with sites in Atlas's oil and gas (ONGAEIR) layer, so we fold them in there. This overlay shows the remaining 3,951 that did not match an ONGAEIR site, so you can see the air-permitted facilities that the oil and gas layer alone would miss.

Where the state assigns an industry code, the largest groups are oil and gas:

Kind of facility	Facilities
Natural gas extraction	1,161
Natural gas pipelines	85
Crude oil pipelines	14
Other pipeline transport	12
Crude petroleum extraction	3

The other 2,676 do not carry an industry code in the source data, and they are a real mix. Some are midstream operators like gas processors, but plenty are not oil and gas at all: cell-tower backup generators, convenience stores and fuel stops, food processing, cement and aggregate plants, auto body shops, and the odd school or city facility. So treat this overlay as "everything else with an air permit," not as a clean midstream list.

What it is not

It is not the full oil and gas picture. The upstream production sites already live in the ONGAEIR layer. This overlay is the leftover air-permitted facilities, not a replacement for that layer.

It is not only midstream and processing. It does include those, but it also sweeps in a long tail of other permitted sources that have nothing to do with oil and gas.

It is not a list of big emitters. An air permit is enough to land here, no matter how small. Holding an AIRS record says a facility is regulated for air quality, not that it is a major source.

Source: Colorado CDPHE Air Pollution Control Division (AIRS), cross-referenced against the ONGAEIR oil & gas inventory. Counts reflect the current data.

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