The surge in data center development—with U.S. AI-infrastructure and related investments reaching an estimated $1.15 trillion, according to S&P Global research—generated huge demand for specialized environmental consulting, engineering, permitting, and compliance services to site facilities, said Antea Group CEO Yde Van Hijum. “Legacy industrial site redevelopment remained a reliable revenue stream as developers prioritized repurposing land for logistics and data centers,” he said.

Travis Snyder, HDR project manager for the federal Superfund site remediation of a collapsed 19th century underground silver mine in Creede, Colo. that aims to prevent a feared 22-million-gal release of acidic groundwater into a Rio Grande tributary, observes a formation 7,500 ft below the surface. The project could cost up to $25 million.
Photo courtesy of HDR

 About 60% of hyperscale facilities using at least 100 MW of power are sited on undeveloped land, according to recent Washington Post reporting based on satellite imagery and research firm Clean Data. “Formal regulatory requirements became unavoidable. This sustained core revenue in compliance, environmental auditing and risk management, Van Hijum said.

 The data center surge is likely a key factor in driving Top 200 revenue for private sector clients to $95 billion on this year’s list from $87.3 billion last year. DLZ Corp. also cited more brownfield redevelopment for affordable housing spurring environmental services. But said Van Hijum, “higher interest rates throughout the year tightened corporate budgets. Clients focused on ‘quick-payback’ efficiency measures, which limited the appetite for large-scale, long-term strategic environmental consulting engagements.”

 Ron Thalacker, CEO of CMPM firm Cascade Environmental LLC, said its U.S. environmental services revenue “reflected a market shaped by regulatory uncertainty, shifting client priorities and uneven project timing” that slowed some remediation work and dropped the firm ranking to No. 102 But he also cited the firm's added investment in patented technology, cybersecurity and compliance infrastructure as well as moves into Canada and South America cleanup markets.

 Despite 2025 described by one Top 200 firm as a “pivot year,” others saw major list gains. Burns & McDonnell rose to No. 11 on the ranking from No. 28 last year, with 2025 environmental services revenue at $3.6 billion, up from $1.3 billion the previous year. It has boosted market share in key hubs such as St. Louis, tripling regional environmental billings last year to $93.3 million, said local business media. “Our clients are advancing increasingly complex infrastructure projects while navigating evolving environmental requirements,” said Steve Haler, who leads environmental services in Houston.

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 Contractor ECC rose to No. 21 from No. 50 following a similar movement on last year’s list. “Global environmental services revenue in 2025 significantly exceeded plan, driven by strong execution” of backlog, new disaster response awards, “sustained activity” in federal remediation in North America and PFAS work, it said, “with a robust pipeline of pending and upcoming procurements.”

 The billion-dollar revenue club expands to 33 firms in 2026, including ECC, PCL Construction Enterprises Inc. and list newcomer Republic Services, a No. 25-ranked waste management firm which reported $1.76 billion in environmental services revenue. “[That] was supported by disciplined pricing, increased landfill business, targeted acquisitions and growth in sustainability offerings,” the firm said. Two more Top 200 firms also passed the $2-billion revenue mark on the 2026 list: Garney (No. 15) with $2.32 billion and McCarthy Holdings (No. 17), with $2.1 billion.

 A renamed list participant is Baker Water LLC (No. 127), now the water treatment division of Dugan & Meyers Construction Enterprises LLC that is owned by Baker Construction. Axia Environmental (No. 129) also is the listed firm this year for unit Earth Systems.

 Growth through acquisition spurred a record level of M&A deals involving AE and environmental firms, surpassing 500 in 2025, says industry consultant Morrissey Goodale. More were driven last year not by private equity firms or other financial buyers, but by industry peers to add immediate workforce capacity, technical synergies and market growth. Hazardous waste contractor Clean Earth, ranked No. 33 on the 2025 list, departs after a $3-billion purchase by sector leader Veolia. Also gone is NV5 Global Inc., ranked No. 67 on the 2025 list but bought by nondestructive testing giant Acuren for $1.7 billion.

 The sector also remains a key target for non-U.S. buyers seeking to enter or grow domestic infrastructure markets. That includes France-based Egis Group, with revenue from its 2025 purchase of Chicago water and transportation engineer H.W. Lochner helping lift the new parent’s ranking to No. 56. “We are ... aligning our U.S. teams with the broader environmental, water and sustainability expertise Egis has developed around the world,” says CEO Laurent Germain, noting its work in 70 countries.“Environmental services are not a separate offering added to an engineering project,” he said.

 Concern over environmental resources in burgeoning energy markets has amplified need for Top 200 firm expertise, with the list’s clean air quality and clean energy market continuing to edge out hazardous waste cleanup as the leading market revenue generator (see p.24). “Demand associated with siting and permitting high-voltage transmission and battery energy storage systems was particularly strong and offset declines for wind and solar projects, driving growth in environmental planning and land use permitting,” said HDR. But the firm also predicts that “continued uncertainty” in federal funding and environmental regulations may delay future investments in new transportation infrastructure projects.

 Top 200 firms noted continued growth from states in driving their own environmental policies, with Onterris citing methane services in states with independent regulations such as California, Colorado, Texas and Pennsylvania.

 “As regulatory leadership increasingly shifts to the states, owners and developers face a patchwork of requirements that vary significantly across markets in which they operate and build,” Pepper Construction said, complicating permitting and compliance for those with facilities in multiple jurisdictions.

 The shifting priorities appear to be reflected in Top 200 list 2025 revenue totals by owner—with state and local work generating $74 billion, up from $64.6 billion one year earlier and federal agencies flat at $27 billion.

 Even so, No. 51-ranked Sevenson Environmental Services, a long-time federal contractor on Superfund and U.S. Dept. of Defense remediation projects, expects revenue to remain strong, making up about one-half of its Top 200 total this year, said Chief Financial Officer Bill McDermott. The firm won in March an estimated $180-million cleanup contract in New Jersey tied to legacy U.S. Army chemical weapons and munitions production and testing, described as one of DOD’s largest such awards.

 Revenue rose last year in both water and wastewater supply and treatment sectors but their proportions of the overall Top 200 total did not grow significantly. Market participants had mixed assessments.

 Crossland Heavy Contractors rose on the list from No. 85 in 2025 to No. 34 this year, with President Dan Thompson also noting that its total backlog grew from $917 million to $1.02 billion mostly in work in the two sectors. a trend he expects to continue through this year. “Environmental revenue will be nearly 90% of [Crossland’s] total in the next 12 months, with four of our six offices strictly in the environmental sector, since road work has tapered off. Burgess & Niple reports, however, that strong growth last year in its other environment services “was not enough to overcome the drop” in water-wastewater treatment revenue.

 “Rising costs continue to have a major impact on water related work with many projects coming in significantly over budget and not having sufficient funding to proceed,” said Wade Leonard, president of No. 73-ranked Water Resources Group’s key unit Rice Lake Construction Group. “This leaves many communities only getting a portion completed of necessary upgrades and repairs required.” He is hopeful for better results ahead, since “the engineers we work with on a regular basis are all busy.”

 Brown & Caldwell Chairman and CEO Rich D’Amato said the firm is monitoring inflation impacts and curtailing of funding derived from the Biden-era Inflation Reduction Act and the Infrastructure Investment and Jobs Act. Said No. 150-ranked contractor MB Kahn Construction: “For the remainder of 2026 and moving into 2027, we expect some slowdown while municipalities seek alternatives other than the feds for financing their capital improvement projects.”

 Looking forward, Top 200 firms say unpredictable climate change impacts will continue to create work for environmental services providers, despite what the current administration says to the contrary. “With the Super El Niño prediction in North America in 2026, we expect continued growth in global environmental services revenue. The broader trend of climate volatility—including more intense precipitation events and shifting hydrologic patterns—will continue to elevate risks to infrastructure,” says John M. Hower, Geo-Logic Associates Inc. senior vice president. “We anticipate sustained demand for geotechnical services related to slope stability, foundation design, and climate resilience, particularly in regions prone to landslides, coastal erosion and post-wildfire impacts.”

 No. 169-ranked EHS Support, which rose 18 spots on the list, is concerned that “loss of institutional knowledge” due to staff reductions at federal environmental agencies will hurt advancement of complex U.S. remediation programs.

 “Given continued cost pressures, clients remain highly focused on efficiency, predictability and value,” the firm said, with more demand for strategies and tools to lower costs and improve decision-making.

 A stalled effort for project permit reform took a step forward Sept. 30 with release of the bipartisan Senate bill that sponsors hope to pass soon after the Nov. 3 election and reconcile with a House-approved version by year’s end. CLICK HERE for more detail.

 “Removing these barriers would unlock greater investment and growth. Manufacturers are ready to build,” National Association of Manufacturers CEO Jay Timmons said.

Canada-based Dillon Consulting Ltd., ranked at No. 154, cites greater integration of AI, automated geospatial analysis and customized large-scale digital workflows in its project delivery to “support complex, risk-based decision-making in multi-year environmental assessments.”

The technology innovations “allowed our environmental practitioners to complete highly regulated projects with unprecedented efficiency [and] superior consistency across regional offices," the firm contends.

Dillon also transitioned high-volume clients to what it terms “value-based billing models and formalized productized service packages.” The arrangements “better reflect the strategic value of our regulatory insights beyond mere hourly inputs, particularly in engagements with regulatory friction or multi-disciplinary complexities,” the company says. “This strategy enhanced our profitability and improved our alignment with shifting client expectations.”

 With data management assistance by Jon Keller, Rebecca Pence and Annabelle Fister