Company lists · Data refreshed September 2026

Top 25 Industrial hygiene consultancies based in the United States

Name: Industrial hygiene consultancies 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 2,130 companies tracked

RevenueBase identified 2,130 industrial hygiene consultancies headquartered in the United States as of September 2026 and tracks 35,225 professional contacts across them, including 14,172 with verified work emails. Houston is the largest hub.

This list covers industrial hygiene consultancies 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

2,130Companies

35,225Contacts tracked

14,172Verified emails

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The 25 largest industrial hygiene consultancies based in the United States

Ranked by team size

Top 25 of 2,130 industrial hygiene consultancies 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 industrial hygiene consultancies: 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	Total Safety	Indirect evidence	Pasadena, TX, United StatesHQ checked Sep 28, 2026	1,001-5,000	2,650 contacts →
	Indirect evidence “Total Safety is the world's premier provider of integrated safety and compliance services and the products necessary to support them, including gas detection, respiratory…” Source: RevenueBase Database · checked Sep 28, 2026
2	Exponent	Indirect evidence	Menlo Park, CA, United StatesHQ checked Sep 28, 2026	1,001-5,000	1,560 contacts →
	Indirect evidence “In an era of accelerating change, Exponent is the only premium engineering and scientific consulting firm with the depth and breadth of expertise to solve our clients’ most…” Source: RevenueBase Database · checked Sep 28, 2026
3	Apex Companies	Indirect evidence	Rockville, MD, United StatesHQ checked Sep 28, 2026	1,001-5,000	1,137 contacts →
	Indirect evidence “Who is Apex?” Source: RevenueBase Database · checked Sep 28, 2026
4	Barr Engineering CO	Indirect evidence	Minneapolis, MN, United StatesHQ checked Sep 28, 2026	1,001-5,000	1,088 contacts →
	Indirect 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 28, 2026
5	IEA	Indirect evidence	Brooklyn Park, MN, United StatesHQ checked Sep 28, 2026	n/a	982 contacts →
	Indirect 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
6	ATC Group Services LLC	Indirect evidence	Lafayette, LA, United StatesHQ checked Sep 28, 2026	1,001-5,000	865 contacts →
	Indirect evidence “ATC Group Services LLC is now Atlas.” Source: RevenueBase Database · checked Sep 28, 2026
7	Antea Group USA	Indirect evidence	St Paul, MN, United StatesHQ checked Sep 28, 2026	1,001-5,000	658 contacts →
	Indirect 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
8	Trihydro Corporation	Indirect evidence	Laramie, WY, United StatesHQ checked Sep 28, 2026	501-1,000	577 contacts →
	Indirect 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 28, 2026
9	Rincon Consultants	Indirect evidence	Ventura, CA, United StatesHQ checked Sep 28, 2026	501-1,000	479 contacts →
	Indirect 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 28, 2026
10	Ensafe	Indirect evidence	Memphis, TN, United StatesHQ checked Sep 28, 2026	201-500	463 contacts →
	Indirect evidence “Innovation is not happenstance at EnSafe Inc.” Source: RevenueBase Database · checked Sep 28, 2026
11	ROUX	Indirect evidence	Islandia, NY, United StatesHQ checked Sep 28, 2026	201-500	433 contacts →
	Indirect 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
12	All4	Indirect evidence	Kimberton, PA, United StatesHQ checked Sep 28, 2026	201-500	331 contacts →
	Indirect 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
13	GSI Environmental INC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 28, 2026	201-500	259 contacts →
	Indirect 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
14	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
15	Hillmann Consulting, LLC	Partial evidence	Union, NJ, United StatesHQ checked Sep 28, 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 28, 2026
16	Forensic Analytical Consulting Services, INC	Indirect evidence	Hayward, CA, United StatesHQ checked Sep 28, 2026	51-200	172 contacts →
	Indirect evidence “With a staff of over 150 employees in the San Francisco, Sacramento, Los Angeles, San Diego, Modesto, Bakersfield, Fresno, Portland, Chicago, and Grand Rapids offices, Forensic…” Source: RevenueBase Database · checked Sep 28, 2026
17	Environmental Health & Engineering	Indirect evidence	Newton, MA, United StatesHQ checked Sep 28, 2026	51-200	170 contacts →
	Indirect 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 28, 2026
18	Gradient	Indirect evidence	Boston, MA, United StatesHQ checked Sep 28, 2026	51-200	159 contacts →
	Indirect evidence “Gradient is an environmental and risk science consulting firm renowned for our specialties in Toxicology, Epidemiology, Risk Assessment, Product Safety, Contaminant Fate and…” Source: RevenueBase Database · checked Sep 28, 2026
19	Keramida INC	Indirect evidence	Indianapolis, IN, United StatesHQ checked Sep 28, 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 28, 2026
20	Cleanair Engineering	Indirect evidence	Palatine, IL, United StatesHQ checked Sep 28, 2026	51-200	152 contacts →
	Indirect evidence “Since its founding in 1972, CleanAir has an established reputation for excellence on projects of all sizes, ranging from boiler, APC equipment and cooling tower efficiency testing…” Source: RevenueBase Database · checked Sep 28, 2026
21	Mostardi Platt	Indirect evidence	Elmhurst, IL, United StatesHQ checked Sep 28, 2026	51-200	140 contacts →
	Indirect 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 28, 2026
22	Ensolum, LLC	Indirect evidence	Dallas, TX, United StatesHQ checked Sep 28, 2026	51-200	136 contacts →
	Indirect 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 28, 2026
23	Safe T Professionals, LLC	Indirect evidence	Chandler, AZ, United StatesHQ checked Sep 28, 2026	51-200	130 contacts →
	Indirect evidence “We are a successful environment health and safety staffing/staff augmentation and consulting firm with services available worldwide.” Source: RevenueBase Database · checked Sep 28, 2026
24	Ensero Solutions	Indirect evidence	Fort Collins, CO, United StatesHQ checked Sep 28, 2026	51-200	129 contacts →
	Indirect evidence “Ensero Solutions is an environmental consulting and remediation business with specific expertise in environmental assessments and permitting solutions, mine water management…” Source: RevenueBase Database · checked Sep 28, 2026
25	Secorp Industries	Partial evidence	Lafayette, LA, United StatesHQ checked Sep 28, 2026	501-1,000	126 contacts →
	Partial evidence “Secorp Industries began in 1972 and is a safety company providing Respiratory Protection, Gas Monitoring and Detection, Rescue Services, Safety/Medical Consultants and Training to…” 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: industrial hygiene consultancies. 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 industrial hygiene consultancies.
Partial evidence: Its own public description names part of industrial hygiene consultancies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name industrial hygiene consultancies. 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 2,130 industrial hygiene consultancies based in the United States

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Industrial hygiene consultancies based in the United States at a glance

As of Sep 28, 2026

40.2%Verified-email coverage

16.5Average contacts per company

1-10Median size (employees)

3.5%Largest-city concentration · Houston

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

1,236

11-50

657

51-200

190

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 2,130 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 industrial hygiene consultancies, 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 “industrial hygiene consultancies”. 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 industrial hygiene consultancies), 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 industrial hygiene consultancies, 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, 14,172 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.

Industrial hygiene consultancies 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 industrial hygiene consultancies, 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 industrial hygiene consultancies are there based in the United States?

RevenueBase identified 2,130 industrial hygiene consultancies 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?

Total Safety, headquartered in Pasadena, tops this list with the largest team on record.

Which city has the most industrial hygiene consultancies?

Houston leads with 74 headquartered companies, followed by Chicago (26) and New York (24).

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 14,172 verified decision-maker contacts tracked across these 2,130 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.