Company lists · Data refreshed September 2026

Top 25 Environmental compliance consulting companies based in the United States

Name: Environmental compliance consulting companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 19, 2026 3,046 companies tracked

RevenueBase identified 3,046 environmental compliance consulting companies headquartered in the United States as of September 2026 and tracks 62,162 professional contacts across them, including 27,121 with verified work emails. Houston is the largest hub.

This list covers environmental compliance consulting 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

3,046Companies

62,162Contacts tracked

27,121Verified emails

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The 25 largest environmental compliance consulting companies based in the United States

Ranked by team size

Top 25 of 3,046 environmental compliance consulting 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 environmental compliance consulting 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Swca Environmental Consultants	Strong evidence	Phoenix, AZ, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,629 contacts →
	Strong evidence “Founded on a commitment to sound science and creative solutions, SWCA is a leader in environmental and management consulting services.” Source: RevenueBase Database · checked Sep 19, 2026
2	Montrose Environmental Group	Partial evidence	Little Rock, AR, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,529 contacts →
	Partial evidence “Onterris (formerly Montrose Environmental Group) was one of the first to see environmental responsibility as not just an imperative but as a strategic asset.” Source: RevenueBase Database · checked Sep 19, 2026
3	Apex Companies	Indirect evidence	Rockville, MD, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,137 contacts →
	Indirect evidence “Who is Apex?” Source: RevenueBase Database · checked Sep 19, 2026
4	Barr Engineering CO	Strong evidence	Minneapolis, MN, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,088 contacts →
	Strong evidence “Barr provides engineering and environmental consulting services to clients across the Midwest, throughout the Americas, and around the world.” Source: RevenueBase Database · checked Sep 19, 2026
5	Triumvirate Environmental	Partial evidence	Somerville, MA, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,068 contacts →
	Partial evidence “Triumvirate Environmental provides sustainable environmental solutions to leading companies in the Life Sciences, Healthcare, Education, and Advanced Manufacturing markets.” Source: RevenueBase Database · checked Sep 19, 2026
6	IEA	Strong evidence	Brooklyn Park, MN, United StatesHQ checked Sep 19, 2026	n/a	982 contacts →
	Strong evidence “The Institute for Environmental Assessment, Inc.(IEA) is small business committed to providing trusted environmental safety consulting services for private and public…” Source: RevenueBase Database · checked Sep 19, 2026
7	Trinity Consultants	Strong evidence	Dallas, TX, United StatesHQ checked Sep 19, 2026	1,001-5,000	961 contacts →
	Strong evidence “Trinity Consultants is a global team of experts helping organizations solve complex challenges in environmental compliance, ecological protection, infrastructure performance, and…” Source: RevenueBase Database · checked Sep 19, 2026
8	Alliance Technical Group	Partial evidence	Decatur, AL, United StatesHQ checked Sep 19, 2026	1,001-5,000	956 contacts →
	Partial 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
9	ATC Group Services LLC	Indirect evidence	Lafayette, LA, United StatesHQ checked Sep 19, 2026	1,001-5,000	865 contacts →
	Indirect evidence “ATC Group Services LLC is now Atlas.” Source: RevenueBase Database · checked Sep 19, 2026
10	Environmental Science Associates	Strong evidence	San Francisco, CA, United StatesHQ checked Sep 19, 2026	501-1,000	732 contacts →
	Strong evidence “ESA is a 100% employee-owned environmental consulting firm.” Source: RevenueBase Database · checked Sep 19, 2026
11	Antea Group USA	Strong evidence	St Paul, MN, United StatesHQ checked Sep 19, 2026	1,001-5,000	658 contacts →
	Strong evidence “Antea Group is an international engineering and environmental consulting firm specializing in full-service solutions in the fields of environment, health and safety, and…” Source: RevenueBase Database · checked Sep 19, 2026
12	Trihydro Corporation	Strong evidence	Laramie, WY, United StatesHQ checked Sep 19, 2026	501-1,000	577 contacts →
	Strong evidence “Headquartered in Laramie, Wyoming, Trihydro provides environmental consulting, engineering and surveying, air quality and process management, information technology, and water and…” Source: RevenueBase Database · checked Sep 19, 2026
13	EBI Consulting	Indirect evidence	Burlington, MA, United StatesHQ checked Sep 19, 2026	501-1,000	535 contacts →
	Indirect evidence “For 35 years we have been helping investors, lenders, owners, developers, contractors, and property managers reduce risk and optimize their built facilities, infrastructure and…” Source: RevenueBase Database · checked Sep 19, 2026
14	VLS Environmental Solutions, LLC	Partial evidence	Houston, TX, United StatesHQ checked Sep 19, 2026	1,001-5,000	481 contacts →
	Partial evidence “At VLS, we address your company’s most significant hurdles with waste management and compliance through sustainable solutions.” Source: RevenueBase Database · checked Sep 19, 2026
15	Rincon Consultants	Strong evidence	Ventura, CA, United StatesHQ checked Sep 19, 2026	501-1,000	479 contacts →
	Strong evidence “Rincon Consultants is a multi-disciplinary environmental sciences, planning, and engineering consulting firm that provides quality professional services to government and industry.” Source: RevenueBase Database · checked Sep 19, 2026
16	Enhesa	Partial evidence	Arlington, VA, United StatesHQ checked Sep 19, 2026	201-500	474 contacts →
	Partial evidence “At Enhesa we empower the world’s largest businesses to achieve compliance, manage risk, and drive sustainability with clear, actionable insights.” Source: RevenueBase Database · checked Sep 19, 2026
17	Groundwater & Environmental Services, INC	Partial evidence	Wall Township, NJ, United StatesHQ checked Sep 19, 2026	201-500	447 contacts →
	Partial evidence “We are Groundwater & Environmental Services, Inc, better known as GES.” Source: RevenueBase Database · checked Sep 19, 2026
18	ROUX	Strong evidence	Islandia, NY, United StatesHQ checked Sep 19, 2026	201-500	433 contacts →
	Strong evidence “Founded 40 years ago, Roux is recognized for being a highly effective, client-focused environmental consulting and management firm.” Source: RevenueBase Database · checked Sep 19, 2026
19	P2s	Indirect evidence	Long Beach, CA, United StatesHQ checked Sep 19, 2026	201-500	375 contacts →
	Indirect evidence “P2S has brought forward-thinking, sustainable engineering solutions to California, the Pacific Northwest, and beyond, for over 30 years.” Source: RevenueBase Database · checked Sep 19, 2026
20	LSA	Strong evidence	Irvine, CA, United StatesHQ checked Sep 19, 2026	201-500	332 contacts →
	Strong evidence “LSA is a diversified environmental, transportation, and community planning firm that evolved from a small consulting firm.” Source: RevenueBase Database · checked Sep 19, 2026
21	All4	Strong evidence	Kimberton, PA, United StatesHQ checked Sep 19, 2026	201-500	331 contacts →
	Strong evidence “ALL4 is a global consulting firm committed to shaping a sustainable future through innovative environmental, health, and safety (EHS) and digital solutions.” Source: RevenueBase Database · checked Sep 19, 2026
22	Environmental Consulting & Technology, Inc. ECT	Strong evidence	Gainesville, FL, United StatesHQ checked Sep 19, 2026	201-500	305 contacts →
	Strong evidence “Environmental Consulting & Technology, Inc.(ECT) is a multi-disciplinary environmental and sustainability consulting firm delivering strategy, permitting, design, and management…” Source: RevenueBase Database · checked Sep 19, 2026
23	Ecology And Environment, INC	Indirect evidence	Lancaster, NY, United StatesHQ checked Sep 19, 2026	5,001-10,000	278 contacts →
	Indirect evidence “E&E is now WSP USA.” Source: RevenueBase Database · checked Sep 19, 2026
24	Wetland Studies And Solutions, Inc. Wssi , A Davey Tree Company	Strong evidence	Gainesville, VA, United StatesHQ checked Sep 19, 2026	201-500	268 contacts →
	Strong evidence “For more than 30 years, WSSI has been the trusted partner in environmental, regulatory, cultural resources, and water resources engineering consulting.” Source: RevenueBase Database · checked Sep 19, 2026
25	Merjent	Strong evidence	Minneapolis, MN, United StatesHQ checked Sep 19, 2026	201-500	264 contacts →
	Strong evidence “Merjent is an environmental, restoration, and engineering consulting firm with a long history serving the energy industry.” Source: RevenueBase Database · checked Sep 19, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: environmental compliance consulting companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names environmental compliance consulting companies.
Partial evidence: Its own public description names part of environmental compliance consulting companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental compliance consulting companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 3,046 environmental compliance consulting companies based in the United States

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Environmental compliance consulting companies based in the United States at a glance

As of Sep 19, 2026

43.6%Verified-email coverage

20.4Average contacts per company

1-10Median size (employees)

2.3%Largest-city concentration · Houston

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

1,698

11-50

1,008

51-200

254

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

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 3,046 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 environmental compliance consulting 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 “environmental compliance consulting 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 environmental compliance consulting 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 environmental compliance consulting 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, 27,121 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.

Environmental compliance consulting companies by metro

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 environmental compliance consulting 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 environmental compliance consulting companies are there based in the United States?

RevenueBase identified 3,046 environmental compliance consulting 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?

Swca Environmental Consultants, headquartered in Phoenix, tops this list with the largest team on record.

Which city has the most environmental compliance consulting companies?

Houston leads with 70 headquartered companies, followed by Austin (38) and New York (37).

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 27,121 verified decision-maker contacts tracked across these 3,046 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.