Company lists · Data refreshed September 2026

Top 25 Environmental contracting companies based in the United States

Name: Environmental contracting 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 4,289 companies tracked

RevenueBase identified 4,289 environmental contracting companies headquartered in the United States as of September 2026 and tracks 121,795 professional contacts across them, including 47,219 with verified work emails. Houston is the largest hub.

This list covers environmental contracting 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

4,289Companies

121,795Contacts tracked

47,219Verified emails

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest environmental contracting companies based in the United States

Ranked by team size

Top 25 of 4,289 environmental contracting 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 contracting 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	Clean Harbors	Partial evidence	Norwell, MA, United StatesHQ checked Sep 19, 2026	10001+	8,924 contacts →
	Partial evidence “Clean Harbors is North America’s leading provider of environmental and industrial services.” Source: RevenueBase Database · checked Sep 19, 2026
2	APTIM	Partial evidence	Baton Rouge, LA, United StatesHQ checked Sep 19, 2026	1,001-5,000	2,639 contacts →
	Partial evidence “APTIM enhances the quality of the environment, wellbeing of people, resilience of communities, and opportunity for employees to make a difference, not just a living.” Source: RevenueBase Database · checked Sep 19, 2026
3	Brown And Caldwell	Indirect evidence	Walnut Creek, CA, United StatesHQ checked Sep 19, 2026	1,001-5,000	2,473 contacts →
	Indirect evidence “Headquartered in Walnut Creek, Calif, Brown and Caldwell is an employee-owned firm with 2,100+ professionals serving clients locally and globally from 52 locations.” Source: RevenueBase Database · checked Sep 19, 2026
4	Geosyntec Consultants	Partial evidence	Boca Raton, FL, United StatesHQ checked Sep 19, 2026	1,001-5,000	2,393 contacts →
	Partial evidence “Geosyntec is a consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural…” Source: RevenueBase Database · checked Sep 19, 2026
5	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
6	ECC	Partial evidence	Burlingame, CA, United StatesHQ checked Sep 19, 2026	n/a	2,040 contacts →
	Partial evidence “ECC is an employee-owned company that consistently ranks among the top construction and environmental companies in the world.” Source: RevenueBase Database · checked Sep 19, 2026
7	Swca Environmental Consultants	Partial evidence	Phoenix, AZ, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,629 contacts →
	Partial 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
8	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
9	Weston Solutions, INC	Partial evidence	West Chester, PA, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,441 contacts →
	Partial evidence “Weston Solutions, Inc.(Weston) is a 100% employee-owned environmental and infrastructure services firm committed to safety and providing measurable client value.” Source: RevenueBase Database · checked Sep 19, 2026
10	US Ecology Inc., A Republic Services Company	Indirect evidence	Boise, ID, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,360 contacts →
	Indirect evidence “US Ecology is a Republic Services company.” Source: RevenueBase Database · checked Sep 19, 2026
11	PMI	Indirect evidence	Irvine, CA, United StatesHQ checked Sep 19, 2026	n/a	1,308 contacts →
	Indirect evidence “Training and Development Solutions” Source: RevenueBase Database · checked Sep 19, 2026
12	Clean Earth	Partial evidence	King Of Prussia, PA, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,275 contacts →
	Partial evidence “Veolia has completed the acquisition of Clean Earth, bringing together two organizations with a shared commitment to environmental stewardship, safety and operational excellence.” Source: RevenueBase Database · checked Sep 19, 2026
13	Verdantas	Partial evidence	Tampa, FL, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,139 contacts →
	Partial evidence “At Verdantas, we blend engineering and environmental science together with advanced technology and world-renowned labs to create solutions with the big picture in mind.” Source: RevenueBase Database · checked Sep 19, 2026
14	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
15	Barr Engineering CO	Partial evidence	Minneapolis, MN, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,088 contacts →
	Partial 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
16	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
17	Asrc Energy Services, LLC	Indirect evidence	Anchorage, AK, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,016 contacts →
	Indirect evidence “ASRC Energy is the largest service provider on the North Slope.” Source: RevenueBase Database · checked Sep 19, 2026
18	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
19	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
20	Crystal Clean	Partial evidence	Hoffman Estates, IL, United StatesHQ checked Sep 19, 2026	1,001-5,000	899 contacts →
	Partial evidence “Crystal Clean is a national leader in the environmental services market, providing the smart alternative.” Source: RevenueBase Database · checked Sep 19, 2026
21	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
22	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
23	The Foth Companies	Indirect evidence	De Pere, WI, United StatesHQ checked Sep 19, 2026	501-1,000	781 contacts →
	Indirect evidence “By combining science, engineering, and technology with a true collaborative spirit, Foth has delivered innovative solutions to our clients since 1938.” Source: RevenueBase Database · checked Sep 19, 2026
24	Environmental Science Associates	Partial evidence	San Francisco, CA, United StatesHQ checked Sep 19, 2026	501-1,000	732 contacts →
	Partial evidence “ESA is a 100% employee-owned environmental consulting firm.” Source: RevenueBase Database · checked Sep 19, 2026
25	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

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 contracting 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 contracting companies.
Partial evidence: Its own public description names part of environmental contracting companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental contracting 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 4,289 environmental contracting companies based in the United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 47,219 reachable decision-makers.

Free signup · no credit card

View the full list →

Environmental contracting companies based in the United States at a glance

As of Sep 19, 2026

38.8%Verified-email coverage

28.4Average contacts per company

11-50Median size (employees)

2.0%Largest-city concentration · Houston

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

1,747

11-50

1,628

51-200

648

201-500

151

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 4,289 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 contracting 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 contracting 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 contracting 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 contracting 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, 47,219 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 contracting 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 contracting 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 contracting companies are there based in the United States?

RevenueBase identified 4,289 environmental contracting 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?

Clean Harbors, headquartered in Norwell, tops this list with the largest team on record.

Which city has the most environmental contracting companies?

Houston leads with 87 headquartered companies, followed by New York (55) and Denver (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 47,219 verified decision-maker contacts tracked across these 4,289 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.

Ready to reach these companies? Verified emails and direct dials for all 4,289 environmental contracting companies based in the United States. Start with a free account, no credit card.

Download this list →

Related lists

Environmental contracting companies by geography

Browse the directory

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.