Company lists · Data refreshed September 2026

Top 25 Environmental site assessment firms based in the United States

Name: Environmental site assessment firms 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 2,154 companies tracked

RevenueBase identified 2,154 environmental site assessment firms headquartered in the United States as of September 2026 and tracks 47,795 professional contacts across them, including 23,063 with verified work emails. Houston is the largest hub.

This list covers environmental site assessment firms 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

2,154Companies

47,795Contacts tracked

23,063Verified emails

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The 25 largest environmental site assessment firms based in the United States

Ranked by team size

Top 25 of 2,154 environmental site assessment firms 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 site assessment firms: 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	Providence	Partial evidence	Baton Rouge, LA, United StatesHQ checked Sep 19, 2026	n/a	2,232 contacts →
	Partial evidence “Providence is an employee-owned engineering and environmental consulting firm.” Source: RevenueBase Database · checked Sep 19, 2026
2	Langan Engineering & Environmental Services	Partial evidence	Parsippany, NJ, United StatesHQ checked Sep 19, 2026	1,001-5,000	2,177 contacts →
	Partial evidence “Langan's client-focused, highly entrepreneurial culture cultivates an environment of opportunities in which career growth and teamwork flourish.” Source: RevenueBase Database · checked Sep 19, 2026
3	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
4	Partner Engineering & Science, INC	Partial evidence	Torrance, CA, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,358 contacts →
	Partial evidence “Partner Assessment Corp.” Source: RevenueBase Database · checked Sep 19, 2026
5	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
6	Trinity Consultants	Partial evidence	Dallas, TX, United StatesHQ checked Sep 19, 2026	1,001-5,000	961 contacts →
	Partial 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
7	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
8	GZA Geoenvironmental, INC	Indirect evidence	Norwood, MA, United StatesHQ checked Sep 19, 2026	501-1,000	880 contacts →
	Indirect evidence “Founded in 1964 as a soils and foundations specialty consultant, GZA GeoEnvironmental, Inc.(GZA) has grown into a full-service company providing its clients with highly…” 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	Emsl Analytical, INC	Partial evidence	Cinnaminson, NJ, United StatesHQ checked Sep 19, 2026	501-1,000	719 contacts →
	Partial evidence “As the nation's leading environmental testing firm, EMSL's network of nationwide laboratories has been providing quality analytical services since 1981.” Source: RevenueBase Database · checked Sep 19, 2026
11	Antea Group USA	Partial evidence	St Paul, MN, United StatesHQ checked Sep 19, 2026	1,001-5,000	658 contacts →
	Partial 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	Raba Kistner, INC	Indirect evidence	San Antonio, TX, United StatesHQ checked Sep 19, 2026	501-1,000	582 contacts →
	Indirect evidence “Founded in 1968, Raba Kistner Inc.” Source: RevenueBase Database · checked Sep 19, 2026
13	Trihydro Corporation	Partial evidence	Laramie, WY, United StatesHQ checked Sep 19, 2026	501-1,000	577 contacts →
	Partial 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
14	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
15	Nova Engineering And Environmental, LLC	Partial evidence	Kennesaw, GA, United StatesHQ checked Sep 19, 2026	501-1,000	518 contacts →
	Partial evidence “Established in 1996, NOVA was originally founded to provide Environmental Consulting, Geotechnical Engineering, and Construction Materials Testing and Inspection services to the…” Source: RevenueBase Database · checked Sep 19, 2026
16	Anchor QEA	Partial evidence	Seattle, WA, United StatesHQ checked Sep 19, 2026	501-1,000	479 contacts →
	Partial evidence “Headquartered in Seattle, Washington, Anchor QEA is a nationally recognized environmental science and engineering consulting firm specializing in aquatic, shoreline, and water…” Source: RevenueBase Database · checked Sep 19, 2026
17	Rincon Consultants	Partial evidence	Ventura, CA, United StatesHQ checked Sep 19, 2026	501-1,000	479 contacts →
	Partial 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
18	Ensafe	Indirect evidence	Memphis, TN, United StatesHQ checked Sep 19, 2026	201-500	463 contacts →
	Indirect evidence “Innovation is not happenstance at EnSafe Inc.” Source: RevenueBase Database · checked Sep 19, 2026
19	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
20	ROUX	Partial evidence	Islandia, NY, United StatesHQ checked Sep 19, 2026	201-500	433 contacts →
	Partial 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
21	AEI Consultants	Strong evidence	Walnut Creek, CA, United StatesHQ checked Sep 19, 2026	201-500	433 contacts →
	Strong evidence “AEI Consultants provides building, environmental, land and sustainability assessment and consulting services throughout North America.” Source: RevenueBase Database · checked Sep 19, 2026
22	EDR	Partial evidence	Shelton, CT, United StatesHQ checked Sep 19, 2026	201-500	353 contacts →
	Partial evidence “Serving the property due diligence industry since 1990 With over two decades of experience delivering the most comprehensive environmental risk data in the United States, EDR…” Source: RevenueBase Database · checked Sep 19, 2026
23	Froehling & Robertson, INC	Indirect evidence	Richmond, VA, United StatesHQ checked Sep 19, 2026	201-500	312 contacts →
	Indirect evidence “Established in 1881, Froehling & Robertson, Inc.” Source: RevenueBase Database · checked Sep 19, 2026
24	Environmental Restoration LLC	Strong evidence	Saint Louis, MO, United StatesHQ checked Sep 19, 2026	201-500	273 contacts →
	Strong evidence “Environmental Restoration LLC (ER) is 100% employee-owned and provides Environmental Site Remediation, Construction and Emergency Response services for hazardous waste materials…” Source: RevenueBase Database · checked Sep 19, 2026
25	Merjent	Partial evidence	Minneapolis, MN, United StatesHQ checked Sep 19, 2026	201-500	264 contacts →
	Partial 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 site assessment firms. 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 site assessment firms.
Partial evidence: Its own public description names part of environmental site assessment firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental site assessment firms. 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 2,154 environmental site assessment firms based in the United States

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Environmental site assessment firms based in the United States at a glance

As of Sep 19, 2026

48.3%Verified-email coverage

22.2Average contacts per company

1-10Median size (employees)

1.9%Largest-city concentration · Houston

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

1,088

11-50

802

51-200

199

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 2,154 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 site assessment firms, 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 site assessment firms”. 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 site assessment firms), 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 site assessment firms, 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, 23,063 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 site assessment firms 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 site assessment firms, 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 site assessment firms are there based in the United States?

RevenueBase identified 2,154 environmental site assessment firms 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?

Providence, headquartered in Baton Rouge, tops this list with the largest team on record.

Which city has the most environmental site assessment firms?

Houston leads with 40 headquartered companies, followed by New York (32) and Seattle (26).

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 23,063 verified decision-maker contacts tracked across these 2,154 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.