Company lists · Data refreshed September 2026

Top 25 Emissions verification companies based in the United States

RevenueBase identified 282 emissions verification companies headquartered in the United States as of September 2026 and tracks 5,056 professional contacts across them, including 2,367 with verified work emails. Houston is the largest hub.

This list covers emissions verification companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 19, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 19, 2026 86% judged on-target in blind review
282Companies
5,056Contacts tracked
2,367Verified emails
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The 25 largest emissions verification companies based in the United States

Ranked by team size
Top 25 of 282 emissions verification companies based in the United States, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to emissions verification companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceDecatur, AL, United StatesHQ checked Sep 19, 20261,001-5,000956 contacts →

Indirect evidence

“Alliance is a new kind of environmental services company-powered by innovation, focused on service, and committed to client success.”

Source: RevenueBase Database · checked Sep 19, 2026
2Indirect evidenceHouston, United StatesHQ checked Sep 19, 2026501-1,000442 contacts →

Indirect evidence

“SPL is a leading provider of compliance and testing services for Environmental, Energy, and other end markets.”

Source: RevenueBase Database · checked Sep 19, 2026
3Partial evidenceSanta Clara, CA, United StatesHQ checked Sep 19, 2026201-500297 contacts →

Partial evidence

“Reducing emissions, detecting leaks, mitigating risk, optimizing operations, ensuring compliance and advancing research are some of the challenges facing our clients.”

Source: RevenueBase Database · checked Sep 19, 2026
4Indirect evidenceSeabrook, TX, United StatesHQ checked Sep 19, 2026201-500161 contacts →

Indirect evidence

“Automation and Technology Group: Specializing in Analyzer System Integration.”

Source: RevenueBase Database · checked Sep 19, 2026
5Indirect evidencePalatine, IL, United StatesHQ checked Sep 19, 202651-200152 contacts →

Indirect evidence

“Since its founding in 1972, CleanAir has an established reputation for excellence on projects of all sizes, ranging from boiler, APC equipment and cooling tower efficiency testing…”

Source: RevenueBase Database · checked Sep 19, 2026
6Indirect evidenceAustin, TX, United StatesHQ checked Sep 19, 202651-200114 contacts →

Indirect evidence

“Based in Austin, Texas, ESC Spectrum, an Alliance Technical Group company, is a leading provider of products and services for customers in a variety of industries, from Electric…”

Source: RevenueBase Database · checked Sep 19, 2026
7Indirect evidenceOrange, CA, United StatesHQ checked Sep 19, 202651-20097 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
8Indirect evidenceSpring, TX, United StatesHQ checked Sep 19, 202651-20080 contacts →

Indirect evidence

“Insight Environmental is an environmental consulting firm founded on education, experience, and expertise.”

Source: RevenueBase Database · checked Sep 19, 2026
9Indirect evidenceSt Paul, MN, United StatesHQ checked Sep 19, 202651-20073 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
10Indirect evidenceFort Collins, CO, United StatesHQ checked Sep 19, 202651-20070 contacts →

Indirect evidence

“We deliver quality solutions with integrity and expertise, every time.”

Source: RevenueBase Database · checked Sep 19, 2026
11Partial evidenceTulsa, United StatesHQ checked Sep 19, 202611-5068 contacts →

Partial evidence

“AIR HYGIENE is known for providing professional services which include the following:* Providing superior, cost saving services to our clients!* High quality emission testing…”

Source: RevenueBase Database · checked Sep 19, 2026
12Indirect evidenceCollinsville, IL, United StatesHQ checked Sep 19, 2026201-50068 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
13Indirect evidenceHouston, TX, United StatesHQ checked Sep 19, 202651-20063 contacts →

Indirect evidence

“As a leader in the environmental compliance services industry, AARC does more than just meeting the needs of clients today.”

Source: RevenueBase Database · checked Sep 19, 2026
14Indirect evidenceHouston, TX, United StatesHQ checked Sep 19, 2026201-50063 contacts →

Indirect evidence

“Sage ATC Environmental Consulting is now Atlas.”

Source: RevenueBase Database · checked Sep 19, 2026
15Partial evidenceElk City, OK, United StatesHQ checked Sep 19, 202651-20059 contacts →

Partial evidence

“GAS provides Nationwide “Emissions Testing and LDAR” Services.”

Source: RevenueBase Database · checked Sep 19, 2026
16Partial evidenceCharleston, SC, United StatesHQ checked Sep 19, 202651-20052 contacts →

Partial evidence

“GEL Engineering and GEL Engineering of NC provide environmental, engineering, surveying, and emissions testing services to our valued clients throughout the southeast and beyond.”

Source: RevenueBase Database · checked Sep 19, 2026
17Indirect evidenceSaline, MI, United StatesHQ checked Sep 19, 202651-20052 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
18Partial evidenceHouston, TX, United StatesHQ checked Sep 19, 202651-20050 contacts →

Partial evidence

“Conifer Systems designs, manufactures and installs state-of-the-art emissions control systems and provides aftermarket services to enable industries to meet and exceed their…”

Source: RevenueBase Database · checked Sep 19, 2026
19Indirect evidenceRichmond, VA, United StatesHQ checked Sep 19, 202611-5049 contacts →

Indirect evidence

“SanAir Technologies Laboratory, Inc.”

Source: RevenueBase Database · checked Sep 19, 2026
20Indirect evidenceRichardson, TX, United StatesHQ checked Sep 19, 202611-5041 contacts →

Indirect evidence

“Farmer Environmental Group is a national full service environmental consulting firm providing a wide range of services to industries, municipalities, insurance, real estate…”

Source: RevenueBase Database · checked Sep 19, 2026
21Indirect evidenceOakland, CA, United StatesHQ checked Sep 19, 202651-20041 contacts →

Indirect evidence

“Established in 1986, ACC Environmental Consultants, Inc.(ACC) is an employee-owned full service environmental consulting and design firm recognized for its excellent and reliable…”

Source: RevenueBase Database · checked Sep 19, 2026
22Indirect evidenceHelena, MT, United StatesHQ checked Sep 19, 202611-5040 contacts →

Indirect evidence

“Air Quality and Environmental Consulting Bison Engineering, Inc.”

Source: RevenueBase Database · checked Sep 19, 2026
23Indirect evidencePasadena, CA, United StatesHQ checked Sep 19, 202611-5039 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
24Indirect evidenceSan Diego, CA, United StatesHQ checked Sep 19, 202611-5039 contacts →

Indirect evidence

“We are a green environmental testing and consulting firm, dedicated to providing the highest level of customer service available in the industry.”

Source: RevenueBase Database · checked Sep 19, 2026
25Partial evidenceBrea, CA, United StatesHQ checked Sep 19, 202651-20038 contacts →

Partial evidence

“Since 1984, we have been designing, implementing, operating and servicing various types of motor vehicle emissions and technical/safety inspection programs.”

Source: RevenueBase Database · checked Sep 19, 2026

Showing 25 of 282 emissions verification companies based in the United States

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Emissions verification companies based in the United States at a glance

As of Sep 19, 2026
46.8%Verified-email coverage
17.9Average contacts per company
11-50Median size (employees)
2.5%Largest-city concentration · Houston
Sep 19, 2026Page data refreshed

Companies by employee count

1-10
127
11-50
117
51-200
30
201-500
5
501-1,000
1
1,001-5,000
2

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 282 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among emissions verification companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “emissions verification companies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names emissions verification companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among emissions verification companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 2,367 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 19, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names emissions verification companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many emissions verification companies are there based in the United States?

RevenueBase identified 282 emissions verification companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Alliance Technical Group, headquartered in Decatur, tops this list with the largest team on record.

Which city has the most emissions verification companies?

Houston leads with 7 headquartered companies, followed by Huntington Beach (7) and Austin (6).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 2,367 verified decision-maker contacts tracked across these 282 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 19, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.