Company lists · Data refreshed September 2026

Top 25 Hazardous materials consulting firms based in the United States

Name: Hazardous materials consulting 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 28, 2026 2,121 companies tracked

RevenueBase identified 2,121 hazardous materials consulting firms headquartered in the United States as of September 2026 and tracks 53,741 professional contacts across them, including 18,391 with verified work emails. Houston is the largest hub.

This list covers hazardous materials consulting 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 28, 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 28, 2026 86% judged on-target in blind review

2,121Companies

53,741Contacts tracked

18,391Verified emails

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The 25 largest hazardous materials consulting firms based in the United States

Ranked by team size

Top 25 of 2,121 hazardous materials consulting firms based in the United States, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to hazardous materials consulting 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	Clean Harbors	Indirect evidence	Norwell, MA, United StatesHQ checked Sep 28, 2026	10001+	8,924 contacts →
	Indirect evidence “Clean Harbors is North America’s leading provider of environmental and industrial services.” Source: RevenueBase Database · checked Sep 28, 2026
2	Montrose Environmental Group	Indirect evidence	Little Rock, AR, United StatesHQ checked Sep 28, 2026	1,001-5,000	1,529 contacts →
	Indirect 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 28, 2026
3	US Ecology Inc., A Republic Services Company	Indirect evidence	Boise, ID, United StatesHQ checked Sep 28, 2026	1,001-5,000	1,360 contacts →
	Indirect evidence “US Ecology is a Republic Services company.” Source: RevenueBase Database · checked Sep 28, 2026
4	Clean Earth	Indirect evidence	King Of Prussia, PA, United StatesHQ checked Sep 28, 2026	1,001-5,000	1,275 contacts →
	Indirect 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 28, 2026
5	Triumvirate Environmental	Indirect evidence	Somerville, MA, United StatesHQ checked Sep 28, 2026	1,001-5,000	1,068 contacts →
	Indirect 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 28, 2026
6	IEA	Partial evidence	Brooklyn Park, MN, United StatesHQ checked Sep 28, 2026	n/a	982 contacts →
	Partial 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 28, 2026
7	Crystal Clean	Indirect evidence	Hoffman Estates, IL, United StatesHQ checked Sep 28, 2026	1,001-5,000	899 contacts →
	Indirect evidence “Crystal Clean is a national leader in the environmental services market, providing the smart alternative.” Source: RevenueBase Database · checked Sep 28, 2026
8	Antea Group USA	Partial evidence	St Paul, MN, United StatesHQ checked Sep 28, 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 28, 2026
9	ROUX	Partial evidence	Islandia, NY, United StatesHQ checked Sep 28, 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 28, 2026
10	CTEH	Indirect evidence	North Little Rock, AR, United StatesHQ checked Sep 28, 2026	201-500	336 contacts →
	Indirect evidence “CTEH, LLC's purpose is preparing for and responding to a company's or community’s worst day.” Source: RevenueBase Database · checked Sep 28, 2026
11	All4	Partial evidence	Kimberton, PA, United StatesHQ checked Sep 28, 2026	201-500	331 contacts →
	Partial 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 28, 2026
12	MPS Group	Indirect evidence	Farmington Hills, MI, United StatesHQ checked Sep 28, 2026	1,001-5,000	331 contacts →
	Indirect evidence “When it comes to managed professional services, there’s one company that puts the latest technologies, quality processes, and innovative management techniques to work for you –…” Source: RevenueBase Database · checked Sep 28, 2026
13	Actenviro, A Republic Services Company	Indirect evidence	San Jose, CA, United StatesHQ checked Sep 28, 2026	501-1,000	313 contacts →
	Indirect evidence “ACT Enviro is a Republic Services company.” Source: RevenueBase Database · checked Sep 28, 2026
14	Sevenson Environmental Services INC	Indirect evidence	Niagara Falls, NY, United StatesHQ checked Sep 28, 2026	501-1,000	277 contacts →
	Indirect evidence “Sevenson Environmental Services, Inc.” Source: RevenueBase Database · checked Sep 28, 2026
15	Ironclad Environmental Solutions	Indirect evidence	Houston, TX, United StatesHQ checked Sep 28, 2026	201-500	263 contacts →
	Indirect evidence “Ironclad Environmental Solutions is the leading provider of custom waste management solutions, supported by the largest national fleet of innovative, top-quality specialty assets.” Source: RevenueBase Database · checked Sep 28, 2026
16	GSI Environmental INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 28, 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 28, 2026
17	Enviri	Indirect evidence	Philadelphia, PA, United StatesHQ checked Sep 28, 2026	10001+	251 contacts →
	Indirect evidence “We believe in doing what is right - for our customers, our people, our communities and the environment.” Source: RevenueBase Database · checked Sep 28, 2026
18	Ancon Services	Indirect evidence	Los Alamitos, CA, United StatesHQ checked Sep 28, 2026	501-1,000	248 contacts →
	Indirect evidence “Founded in 1968, Ancon Services has expanded our services to cover virtually all of our clients industrial and environmental needs.” Source: RevenueBase Database · checked Sep 28, 2026
19	ACV Enviro, A Republic Services Company	Indirect evidence	Rahway, NJ, United StatesHQ checked Sep 28, 2026	501-1,000	241 contacts →
	Indirect evidence “ACV Enviro is a Republic Services company.” Source: RevenueBase Database · checked Sep 28, 2026
20	Environmental Works, INC	Indirect evidence	Springfield, MO, United StatesHQ checked Sep 28, 2026	201-500	238 contacts →
	Indirect evidence “Environmental Works, Inc.(EWI) offers truly comprehensive environmental solutions for a variety of industries, businesses, and municipalities.” Source: RevenueBase Database · checked Sep 28, 2026
21	Metiri Group	Indirect evidence	Clovis, CA, United StatesHQ checked Sep 28, 2026	n/a	233 contacts →
	Indirect evidence “Appl Inc is an environmental services company based out of 908 N Temperance Ave, Clovis, CA, United States.” Source: RevenueBase Database · checked Sep 28, 2026
22	Patriot Environmental Services	Indirect evidence	Signal Hill, CA, United StatesHQ checked Sep 28, 2026	201-500	223 contacts →
	Indirect evidence “Patriot Environmental Services, a Crystal Clean company, is a leading environmental service provider with clients throughout the Southwestern United States.” Source: RevenueBase Database · checked Sep 28, 2026
23	Labelmaster	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 28, 2026	201-500	212 contacts →
	Indirect evidence “For more than five decades, Labelmaster has been the go-to source for companies – big and small – to navigate and comply with the complex, ever-changing regulations that govern…” Source: RevenueBase Database · checked Sep 28, 2026
24	August Mack Environmental, INC	Indirect evidence	Indianapolis, IN, United StatesHQ checked Sep 28, 2026	51-200	210 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 28, 2026
25	Hillmann Consulting, LLC	Indirect evidence	Union, NJ, United StatesHQ checked Sep 28, 2026	201-500	209 contacts →
	Indirect 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 28, 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: hazardous materials consulting 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 hazardous materials consulting firms.
Partial evidence: Its own public description names part of hazardous materials consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name hazardous materials consulting 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 2,121 hazardous materials consulting firms based in the United States

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Hazardous materials consulting firms based in the United States at a glance

As of Sep 28, 2026

34.2%Verified-email coverage

25.3Average contacts per company

11-50Median size (employees)

3.3%Largest-city concentration · Houston

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

1,051

11-50

752

51-200

229

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 2,121 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 hazardous materials consulting 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 “hazardous materials consulting 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 hazardous materials consulting 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 hazardous materials consulting 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, 18,391 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 28, 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.

Hazardous materials consulting firms by metro

Hazardous materials consulting firms in Houston69

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 hazardous materials consulting 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 hazardous materials consulting firms are there based in the United States?

RevenueBase identified 2,121 hazardous materials consulting 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?

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

Which city has the most hazardous materials consulting firms?

Houston leads with 69 headquartered companies, followed by San Diego (24) and Indianapolis (21).

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 18,391 verified decision-maker contacts tracked across these 2,121 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 28, 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.