Company lists · Data refreshed September 2026

Top 25 Environmental consultant firms based in Houston, United States

Name: Environmental consultant firms based in Houston, United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 109 companies tracked

RevenueBase identified 109 environmental consultant firms headquartered in Houston, United States as of September 2026 and tracks 5,045 professional contacts across them, including 2,801 with verified work emails. Houston is the largest hub.

This list covers environmental consultant firms headquartered in Houston, 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 21, 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 21, 2026 86% judged on-target in blind review

109Companies

5,045Contacts tracked

2,801Verified emails

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The 25 largest environmental consultant firms based in Houston, United States

Ranked by team size

Top 25 of 109 environmental consultant firms based in Houston, United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to environmental consultant 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	LJA	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,932 contacts →
	Indirect evidence “Employee-Owned.” Source: RevenueBase Database · checked Sep 21, 2026
2	Bge, INC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,112 contacts →
	Indirect evidence “Ranked No.” Source: RevenueBase Database · checked Sep 21, 2026
3	GSI Environmental INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 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 21, 2026
4	Shah Smith & Associates, INC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	134 contacts →
	Indirect evidence “Shah Smith & Associates, Inc.(SSA) is a 120+ employee Mechanical, Electrical, and Plumbing (MEP) consulting engineering firm with offices in Houston, Austin & Dallas.” Source: RevenueBase Database · checked Sep 21, 2026
5	Edge Engineering And Science, LLC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	116 contacts →
	Indirect evidence “Edge Engineering & Science, LLC (EDGE) is a privately owned professional services firm headquartered in Houston, Texas.” Source: RevenueBase Database · checked Sep 21, 2026
6	Perennial Environmental Services	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	102 contacts →
	Partial evidence “Perennial Environmental Services, LLC, has been providing technical environmental solutions and management with fresh perspectives and unparalleled efficiency since 2003.” Source: RevenueBase Database · checked Sep 21, 2026
7	Aarc Environmental	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	63 contacts →
	Partial evidence “As a leader in the environmental compliance services industry, AARC does more than just meeting the needs of clients today.” Source: RevenueBase Database · checked Sep 21, 2026
8	RCP INC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	63 contacts →
	Indirect evidence “RCP is the regulatory compliance and risk management expert for pipelines, facilities, and terminal operations.” Source: RevenueBase Database · checked Sep 21, 2026
9	Sage ATC Environmental Consulting	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	201-500	63 contacts →
	Partial evidence “Sage ATC Environmental Consulting is now Atlas.” Source: RevenueBase Database · checked Sep 21, 2026
10	Spirit Environmental Montrose Environmental Group	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	54 contacts →
	Indirect evidence “In July of 2024, Spirit was acquired by Onterris.” Source: RevenueBase Database · checked Sep 21, 2026
11	Pilko & Associates	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	50 contacts →
	Indirect evidence “We are the trusted Advisor to corporate officers and boards on mitigating Operational/EHS Risks and unlocking value for global energy, chemical and industrial companies.” Source: RevenueBase Database · checked Sep 21, 2026
12	Riner Engineering, Inc., A UES Company	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	47 contacts →
	Indirect evidence “Riner Engineering became part of the UES family of companies in June 2023, combining our local expertise with UES’s nationwide presence and resources.” Source: RevenueBase Database · checked Sep 21, 2026
13	International Safety Systems, INC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	46 contacts →
	Indirect evidence “International Safety Systems, Inc.(ISS) is a consulting company providing cost effective and high quality industrial hygiene and safety services to 35+ countries from its offices…” Source: RevenueBase Database · checked Sep 21, 2026
14	RSB Environmental, An Alliance Technical Group Company	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	38 contacts →
	Partial evidence “RSB Environmental, an Alliance Technical Group company, is a full-service environmental engineering consulting firm, specializing in environmental health and safety services and…” Source: RevenueBase Database · checked Sep 21, 2026
15	Phase Engineering, LLC	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	34 contacts →
	Partial evidence “Phase Engineering, LLC, was founded in 1993 and is a leading engineering and environmental consulting firm, serving clients nationwide to deliver trusted environmental solutions.” Source: RevenueBase Database · checked Sep 21, 2026
16	Hollaway Environmental Communications Services, INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	33 contacts →
	Partial evidence “Hollaway Environmental + Communication Services, an SBE/DBE/WBE/HUB firm, bridges two worlds that are uniquely connected: Environmental Services and Communications Services.” Source: RevenueBase Database · checked Sep 21, 2026
17	UES Professional Solutions 64, LLC	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	31 contacts →
	Partial evidence “Environmental Consulting and Engineering InControl Technologies was established in 1997 to provide high-end quality environmental consulting services to owners of commercial and…” Source: RevenueBase Database · checked Sep 21, 2026
18	Ikon Environmental Solutions, LP	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	24 contacts →
	Partial evidence “IKON Environmental Solutions, LP (IKON) provides clients with unique solutions to environmental needs.” Source: RevenueBase Database · checked Sep 21, 2026
19	HSE International LLC	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	23 contacts →
	Partial evidence “HSE International provides environmental, social, safety and strategic advisory services to the energy, infrastructure, extractive, financial and government sectors.” Source: RevenueBase Database · checked Sep 21, 2026
20	Acorn International, LLC	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	22 contacts →
	Partial evidence “Acorn International, LLC delivers environmental and social risk management consulting services to international industry and investors.” Source: RevenueBase Database · checked Sep 21, 2026
21	TGE Resources, INC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	21 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 21, 2026
22	SIA Solutions, LLC	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	51-200	19 contacts →
	Partial evidence “SIA Solutions LLC (SIA) has merged with Salas O'Brien and continues to focus on program and project-specific engineering and technical solutions in Environmental Consulting…” Source: RevenueBase Database · checked Sep 21, 2026
23	Environmental Operational Solutions Eosolutions	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	19 contacts →
	Indirect evidence “At EOSolutions, we know you want your operations to stay in compliance.” Source: RevenueBase Database · checked Sep 21, 2026
24	ERC Environmental & Construction Services	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	18 contacts →
	Partial evidence “ERC is a Professional Services Firm in Environmental Consulting and Construction.” Source: RevenueBase Database · checked Sep 21, 2026
25	Paradigm Consultants, Inc., A CMT Company	Partial evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	11-50	14 contacts →
	Partial evidence “Paradigm Consultants, Inc.” Source: RevenueBase Database · checked Sep 21, 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 consultant 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 consultant firms.
Partial evidence: Its own public description names part of environmental consultant firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental consultant 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 109 environmental consultant firms based in Houston, United States

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Environmental consultant firms based in Houston, United States at a glance

As of Sep 21, 2026

55.5%Verified-email coverage

46.3Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · Houston

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

1,001-5,000

Email recency for this list is measured across the whole United States list rather than for Houston, so it is reported there. Company counts and contact totals on this page are exact for Houston, over 109 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 consultant 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 Houston, United States whose own description of what they do matches “environmental consultant 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 consultant 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 consultant firms, and records with no verified work email. Companies headquartered outside Houston 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, 2,801 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 21, 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 consultant firms by metro in the United States

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 consultant 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 consultant firms are there based in Houston, United States?

RevenueBase identified 109 environmental consultant firms headquartered in Houston, 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?

LJA, headquartered in Houston, tops this list with the largest team on record.

Which city has the most environmental consultant firms?

Houston leads with 109 headquartered companies, followed by New York (72) and Seattle (57).

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 2,801 verified decision-maker contacts tracked across these 109 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 21, 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.