Company lists · Data refreshed September 2026

Top 25 Environmental site assessment companies based in the United States

Name: Environmental site assessment 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 1,701 companies tracked

RevenueBase identified 1,701 environmental site assessment companies headquartered in the United States as of September 2026 and tracks 27,839 professional contacts across them, including 13,212 with verified work emails. Houston is the largest hub.

This list covers environmental site assessment 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

1,701Companies

27,839Contacts tracked

13,212Verified emails

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

Ranked by team size

Top 25 of 1,701 environmental site assessment 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 site assessment 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	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
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	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
4	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
5	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
6	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
7	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
8	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
9	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
10	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
11	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
12	Nova Group, GBC	Partial evidence	St. Louis Park, MN, United StatesHQ checked Sep 19, 2026	201-500	264 contacts →
	Partial evidence “Nova Group, GBC is an international, multidisciplinary advising firm providing environmental, engineering and energy services throughout North America and around the globe.” Source: RevenueBase Database · checked Sep 19, 2026
13	GSI Environmental INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 19, 2026	201-500	259 contacts →
	Partial evidence “GSI Environmental, Inc.(GSI), is an environmental engineering and science consulting firm committed to measuring, analyzing, and solving complex environmental problems around the…” Source: RevenueBase Database · checked Sep 19, 2026
14	Cascade Environmental, LLC	Strong evidence	Bothell, WA, United StatesHQ checked Sep 19, 2026	1,001-5,000	248 contacts →
	Strong evidence “CASCADE is the leading provider of environmental and geotechnical drilling, site investigation and environmental remediation.” Source: RevenueBase Database · checked Sep 19, 2026
15	Environmental Works, INC	Partial evidence	Springfield, MO, United StatesHQ checked Sep 19, 2026	201-500	238 contacts →
	Partial evidence “Environmental Works, Inc.(EWI) offers truly comprehensive environmental solutions for a variety of industries, businesses, and municipalities.” Source: RevenueBase Database · checked Sep 19, 2026
16	August Mack Environmental, INC	Indirect evidence	Indianapolis, IN, United StatesHQ checked Sep 19, 2026	51-200	210 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 19, 2026
17	Hillmann Consulting, LLC	Partial evidence	Union, NJ, United StatesHQ checked Sep 19, 2026	201-500	209 contacts →
	Partial evidence “Hillmann has been a well-recognized leader in the Environmental Health & Safety, Due Diligence & Remediation Management, and Construction Services industries since 1985.” Source: RevenueBase Database · checked Sep 19, 2026
18	Kemron Environmental Services	Partial evidence	Atlanta, United StatesHQ checked Sep 19, 2026	201-500	188 contacts →
	Partial evidence “With more than 50 years of excellence, KEMRON Environmental Services, Inc.” Source: RevenueBase Database · checked Sep 19, 2026
19	BAY West LLC	Strong evidence	St. Paul, MN, United StatesHQ checked Sep 19, 2026	201-500	187 contacts →
	Strong evidence “Bay West is an environmental and industrial services provider for site investigations, groundwater and soil remediation, munitions cleanup, hazardous waste management, industrial…” Source: RevenueBase Database · checked Sep 19, 2026
20	Environmental Health & Engineering	Partial evidence	Newton, MA, United StatesHQ checked Sep 19, 2026	51-200	170 contacts →
	Partial evidence “EH & E delivers integrated environmental, engineering, and health and safety solutions that help businesses and institutions safeguard their assets, improve operations and boost…” Source: RevenueBase Database · checked Sep 19, 2026
21	Ecorp Consulting, INC	Indirect evidence	Rocklin, CA, United StatesHQ checked Sep 19, 2026	51-200	166 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 19, 2026
22	Keramida INC	Indirect evidence	Indianapolis, IN, United StatesHQ checked Sep 19, 2026	51-200	152 contacts →
	Indirect evidence “Founded in 1988, KERAMIDA is a multidisciplinary Sustainability, EHS & Engineering consulting firm grounded in evidence-based research and development.” Source: RevenueBase Database · checked Sep 19, 2026
23	Mostardi Platt	Partial evidence	Elmhurst, IL, United StatesHQ checked Sep 19, 2026	51-200	140 contacts →
	Partial evidence “Since the passage of original environmental legislation nearly four decades ago, both private and public industry have turned to Mostardi Platt for guidance in complying with air…” Source: RevenueBase Database · checked Sep 19, 2026
24	Ensolum, LLC	Partial evidence	Dallas, TX, United StatesHQ checked Sep 19, 2026	51-200	136 contacts →
	Partial evidence “OUR MISSION is to combine sustainable environmental solutions with forward-thinking, cost-effective, innovative, and value-added technologies that balance our clients’ economic…” Source: RevenueBase Database · checked Sep 19, 2026
25	Envirotrac LLC	Indirect evidence	Yaphank, NY, United StatesHQ checked Sep 19, 2026	51-200	135 contacts →
	Indirect evidence “EnviroTrac Ltd.” 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 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 site assessment companies.
Partial evidence: Its own public description names part of environmental site assessment companies, 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 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 1,701 environmental site assessment companies based in the United States

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

As of Sep 19, 2026

47.5%Verified-email coverage

16.4Average contacts per company

1-10Median size (employees)

2.2%Largest-city concentration · Houston

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

878

11-50

646

51-200

135

201-500

501-1,000

1,001-5,000

5,001-10,000

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 1,701 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 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 site assessment 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 site assessment 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 site assessment 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, 13,212 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 companies by metro

Environmental site assessment companies in Houston37
Environmental site assessment companies in New York26

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 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 site assessment companies are there based in the United States?

RevenueBase identified 1,701 environmental site assessment 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?

Langan Engineering & Environmental Services, headquartered in Parsippany, tops this list with the largest team on record.

Which city has the most environmental site assessment companies?

Houston leads with 37 headquartered companies, followed by New York (26) and Seattle (17).

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 13,212 verified decision-maker contacts tracked across these 1,701 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.