Company lists · Data refreshed September 2026

Top 25 Environmental monitoring firms based in the United States

Name: Environmental monitoring 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 2,117 companies tracked

RevenueBase identified 2,117 environmental monitoring firms headquartered in the United States as of September 2026 and tracks 41,087 professional contacts across them, including 14,825 with verified work emails. Houston is the largest hub.

This list covers environmental monitoring 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

2,117Companies

41,087Contacts tracked

14,825Verified emails

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The 25 largest environmental monitoring firms based in the United States

Ranked by team size

Top 25 of 2,117 environmental monitoring 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 monitoring 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	Pace Analytical Services	Indirect evidence	Minneapolis, MN, United StatesHQ checked Sep 19, 2026	1,001-5,000	2,228 contacts →
	Indirect evidence “Pace® Science and Technology Company makes the world a safer, healthier place.” Source: RevenueBase Database · checked Sep 19, 2026
2	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
3	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
4	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
5	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
6	Mesa Laboratories, INC	Partial evidence	Lakewood, CO, United StatesHQ checked Sep 19, 2026	501-1,000	323 contacts →
	Partial evidence “Mesa Labs helps you monitor and maintain higher standards in any environment – from the air we breathe to the critical moments of life-saving care.” Source: RevenueBase Database · checked Sep 19, 2026
7	Picarro	Indirect evidence	Santa Clara, CA, United StatesHQ checked Sep 19, 2026	201-500	297 contacts →
	Indirect evidence “Reducing emissions, detecting leaks, mitigating risk, optimizing operations, ensuring compliance and advancing research are some of the challenges facing our clients.” Source: RevenueBase Database · checked Sep 19, 2026
8	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
9	Alpha Analytical	Indirect evidence	Westborough, MA, United StatesHQ checked Sep 19, 2026	501-1,000	254 contacts →
	Indirect evidence “Since 1987, Alpha Analytical, Inc.” Source: RevenueBase Database · checked Sep 19, 2026
10	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
11	Metiri Group	Partial evidence	Clovis, CA, United StatesHQ checked Sep 19, 2026	n/a	233 contacts →
	Partial evidence “Appl Inc is an environmental services company based out of 908 N Temperance Ave, Clovis, CA, United States.” Source: RevenueBase Database · checked Sep 19, 2026
12	OTT Hydromet	Indirect evidence	Sterling, VA, United StatesHQ checked Sep 19, 2026	201-500	231 contacts →
	Indirect evidence “OTT HydroMet works to deliver customer outcomes by providing decision makers with vital insights they trust.” Source: RevenueBase Database · checked Sep 19, 2026
13	Patriot Environmental Services	Partial evidence	Signal Hill, CA, United StatesHQ checked Sep 19, 2026	201-500	223 contacts →
	Partial 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 19, 2026
14	Dickson	Partial evidence	Addison, IL, United StatesHQ checked Sep 19, 2026	51-200	223 contacts →
	Partial evidence “Since 1923, the Dickson Company has helped numerous organizations monitor their most sensitive environments.” Source: RevenueBase Database · checked Sep 19, 2026
15	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
16	Rees Scientific	Partial evidence	Trenton, NJ, United StatesHQ checked Sep 19, 2026	51-200	210 contacts →
	Partial evidence “Rees Scientific provides continuous automated monitoring to a limitless number of applications in a wide range of industries.” 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	Ysi, INC	Strong evidence	Yellow Springs, OH, United StatesHQ checked Sep 19, 2026	201-500	194 contacts →
	Strong evidence “YSI is the maker of environmental, laboratory, and municipal monitoring instruments, sensors, software, systems, and data collection platforms for water quality monitoring and…” Source: RevenueBase Database · checked Sep 19, 2026
19	GEL Laboratories, LLC	Partial evidence	Charleston, SC, United StatesHQ checked Sep 19, 2026	201-500	190 contacts →
	Partial evidence “Since 1981, GEL Laboratories has been a leading provider of comprehensive and reliable analytical services to the environmental industry including chemical, radiochemical…” Source: RevenueBase Database · checked Sep 19, 2026
20	Normandeau Associates, INC	Indirect evidence	Bedford, NH, United StatesHQ checked Sep 19, 2026	201-500	189 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 19, 2026
21	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
22	BAY West LLC	Partial evidence	St. Paul, MN, United StatesHQ checked Sep 19, 2026	201-500	187 contacts →
	Partial 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
23	VMC Group	Partial evidence	Bloomingdale, NJ, United StatesHQ checked Sep 19, 2026	51-200	187 contacts →
	Partial evidence “We design & build solutions that allow customers to better manage the negative environmental effects of air, noise, seismic, vibration, & shock.” Source: RevenueBase Database · checked Sep 19, 2026
24	Enviroscience, INC	Partial evidence	Stow, OH, United StatesHQ checked Sep 19, 2026	51-200	176 contacts →
	Partial evidence “EnviroScience is a team of over 150 expert biologists, commercial divers, environmental engineers, and environmental scientists that provides biomonitoring, environmental…” Source: RevenueBase Database · checked Sep 19, 2026
25	LWS Lighthouse Worldwide Solutions	Indirect evidence	White City, OR, United StatesHQ checked Sep 19, 2026	201-500	175 contacts →
	Indirect evidence “When you need to monitor your cleanroom for contamination, Lighthouse is your premier solution provider.” 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 monitoring 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 monitoring firms.
Partial evidence: Its own public description names part of environmental monitoring firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental monitoring 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 2,117 environmental monitoring firms based in the United States

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Environmental monitoring firms based in the United States at a glance

As of Sep 19, 2026

36.1%Verified-email coverage

19.4Average contacts per company

1-10Median size (employees)

2.5%Largest-city concentration · Houston

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

1,063

11-50

775

51-200

216

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 2,117 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 monitoring 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 monitoring 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 monitoring 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 monitoring 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, 14,825 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 monitoring firms by metro

Environmental monitoring firms in Houston52
Environmental monitoring firms in New York27

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 monitoring 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 monitoring firms are there based in the United States?

RevenueBase identified 2,117 environmental monitoring 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?

Pace Analytical Services, headquartered in Minneapolis, tops this list with the largest team on record.

Which city has the most environmental monitoring firms?

Houston leads with 52 headquartered companies, followed by New York (27) and Seattle (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 14,825 verified decision-maker contacts tracked across these 2,117 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.