Remediation Services (U.S.) — NAICS 562910

An investor's primer on the industry that cleans up contaminated soil, groundwater, and buildings — relevant to both public-market and private investors.

("NAICS" is the North American Industry Classification System, the U.S. government's standard code set for industries.)

1. Overview

Remediation is the business of making contaminated land, water, and structures safe again: pumping and treating polluted groundwater, digging out and hauling off tainted soil, stripping asbestos and lead paint from old buildings, reclaiming former mines, and decommissioning industrial and nuclear sites. It is a "someone has to pay to fix this" industry — most of the work is driven by law, liability, or a property transaction, not by a customer who wants a nicer product [3].

That gives it an unusual quality: demand is largely non-discretionary and tied to regulation rather than to consumer taste, so a base level of it is recession-resistant. But it is still a project-driven services business — contamination is uncertain until you dig, government procurement is lumpy, and labor, disposal capacity, and weather can all make quarterly results uneven.

Two things make it interesting to investors right now: a genuine secular growth story in "forever chemicals" (PFAS — per- and polyfluoroalkyl substances), and a supplier base that is still overwhelmingly small, private, and owner-operated — a classic setup for consolidation.

Who can invest, and how. The operating market is mostly private and fragmented. Public-market investors generally reach it indirectly, through diversified environmental, engineering, waste-management, and infrastructure companies — there is no large listed pure-play. Private investors have the more direct routes: buy a regional contractor, back or build an acquisition platform, finance treatment assets, or invest in a specialized cleanup technology. Specific names, tickers, and figures are in sections 4 and 10.

2. What it is and how it's structured

Scope. NAICS 2022 code 562910 covers establishments primarily engaged in [3]:

• Remediation and cleanup of contaminated buildings, mine sites, soil, or groundwater;
• Integrated mine reclamation (demolition, soil remediation, wastewater treatment, hazardous-material removal, land contouring, revegetation);
• Asbestos, lead-paint, mold, and other toxic-material abatement.

A typical project runs across several stages — most of which are not all counted in this code:

1. Site investigation, sampling, risk assessment, and regulatory planning;
2. Abatement of asbestos, lead, mold, oil spills, or other hazardous material;
3. Excavation, containment, soil washing, and groundwater or in-situ treatment;
4. Demolition, decommissioning, mine reclamation, revegetation, and site restoration;
5. Transport, treatment, disposal, long-term monitoring, and site closure.

Work is usually delivered by a prime contractor coordinating subcontractors, laboratories, trucking firms, engineers, and permitted treatment or disposal facilities.

What 562910 EXCLUDES — this matters, because a single cleanup is split across several industry codes, and remediation done inside an engineering, construction, waste, or government organization may never show up under 562910 [3]:

So 562910 is specifically the field-execution middle of the value chain: the crews and firms that physically do the cleanup, sitting between the consultants who design it and the disposal sites that take the waste.

Ownership mix. The industry is overwhelmingly small and private. Federal data show 5,826 establishments employing 91,239 people [1] — roughly 16 employees per location. Average revenue works out to about $4.4 million per firm (2022 receipts ÷ 2022 firm count) [2], well under the U.S. Small Business Administration (SBA) size threshold of $25 million in average annual receipts [4]. The federal data do not publish a public-vs-private ownership split, but in practice the field is family-owned regional firms, employee-owned contractors, private-equity-backed platforms, strategic subsidiaries, and a handful of diversified public companies — nearly all of the latter far broader than the NAICS code itself.

3. How big it is

Ground-truth federal figures. Payroll and employment are from the Census Bureau's County Business Patterns (CBP) for 2023; receipts, firms, and concentration are from the 2022 Economic Census.

A private research estimate (IBISWorld) puts the broader "remediation and environmental cleanup services" market at about $26.5 billion in 2025, growing in the low-single-digit percent range [13]; the gap from the Census $22.74 billion reflects both the later year and a slightly wider definition.

What the federal data do NOT give us. There is no industry-wide profit margin, capacity-utilization rate, backlog figure, input-cost index, or public-vs-private ownership split in the official statistics. Any such metric in this primer is company-specific or a third-party estimate, and is flagged as such.

The undercount caveat — important here. The Census $22.74 billion badly understates how much is actually spent cleaning up contamination in America, for several reasons:

1. CBP counts only employer establishments. It excludes non-employer (self-employed) operators and most government employees, so the smallest firms and public-sector crews fall outside the count [5].
2. Government does much of the work directly. The U.S. Department of Energy's (DOE) Environmental Management program — the world's largest environmental cleanup effort, tackling Cold-War nuclear waste at sites like Hanford — runs roughly $8 billion a year on its own [11]. That work flows to contractors but is booked under federal-government and professional-services codes, not "Remediation Services."
3. Big diversified firms bury it elsewhere. When a waste, engineering, oil, or chemical company performs remediation, it is often classified under waste management, engineering, or the parent industry — not 562910.
4. It excludes the design and dig portions of every project (codes 541620 and 238910 above).

Net: treat $22.74 billion as the size of the stand-alone private remediation-contracting industry, and understand that total U.S. remediation activity — federal, in-house, and contracted — is materially larger.

Fragmentation. The industry is extraordinarily fragmented. The top four firms hold just 9.0% of revenue, the top eight 14.3%, the top 20 25.1%, and the top 50 only 37.4% [2]. The Herfindahl-Hirschman Index (HHI, a standard concentration measure that runs up to 10,000) is 43.2 [2] — one of the lowest readings you will see in any industry, meaning no player has anything close to pricing power over the whole market.

4. The investable universe

There is no large pure-play public remediation company and no dedicated exchange-traded fund (ETF); public exposure is a build-your-own basket of a few focused operators plus diversified firms with remediation arms. Do not assign these companies NAICS 562910 market share from their consolidated revenue — each reports substantial adjacent activity.

Private and "other" owners — where most of the industry actually lives:

• Thousands of regional and local contractors — the ~5,100 firms in the Census count, almost all private and small [2].
• Employee-owned specialists such as Weston Solutions, a 100%-employee-owned environmental and infrastructure firm (investigation, remediation, construction, O&M) [25].
• Private-equity-backed platforms, e.g. Triumvirate Environmental (backed by Berkshire Partners, valued ~$1.8B) [26], Crystal Clean (owned by a J.F. Lehman & Company affiliate since 2023) [27], and ERM (environmental consultancy backed by KKR, with remediation/decommissioning/contaminated-site work) [28]. PE buyers are actively forming platforms and bolting on niche specialists in PFAS treatment, wastewater, and brownfields [24].
• Responsible parties doing in-house cleanup — oil, chemical, mining, and manufacturing companies that self-perform or directly manage remediation of their own contaminated sites.
• Federal cleanup contractors — joint ventures (e.g., the Hanford Central Plateau team of AECOM, Fluor, and Atkins) holding multi-billion-dollar DOE contracts [12].

5. How the money works

Remediation economics look like engineering and field-services, not like a product company:

• Backlog and book-to-bill. Revenue visibility comes from signed contracts. Growing backlog (Perma-Fix, for example, reported backlog up ~51% in 2025 [18]) signals future revenue; a book-to-bill above 1.0 means the pipeline refills faster than work burns off.
• Contract type sets the risk. Work is priced as time-and-materials (bill hours plus a markup — lowest risk when contamination is uncertain), cost-reimbursable/cost-plus (costs plus a fee — common on big federal jobs), or fixed-price/unit-price (contractor eats overruns — higher risk, higher potential margin, used when scope is well defined). Federal nuclear cleanup has a long, well-documented history of cost and schedule overruns — a repeated Government Accountability Office (GAO) finding — which is exactly where fixed-price contractors get burned.
• Billable utilization and labor margin. For the labor-intensive field and consulting portions, profit turns on keeping licensed, safety-certified (HAZWOPER-trained) crews billable, and on the spread between what a worker bills out at and what they cost.
• Pass-through and disposal economics. A large chunk of a cleanup budget is subcontracted disposal, trucking, and lab work passed through at little or no margin. Operators who own the downstream disposal — Clean Harbors' incinerators, Republic/US Ecology's hazardous landfills — also capture treatment/tipping-fee margin, and their profit then depends on facility throughput and gate fees. This vertical integration is the main margin advantage the big players hold over pure field contractors; the trade-off is more capital, but also permits and density that are hard to replicate.
• Recurring vs. event-driven. Some revenue is one-off (an emergency spill response, a demolition). But long-term groundwater monitoring, operations-and-maintenance of treatment systems, and multi-year consent-decree cleanups produce annuity-like, multi-year revenue — prized because it is sticky and non-discretionary.
• Working capital. Government and large-corporate clients pay slowly; days sales outstanding (DSO) and the cash tied up in unbilled work matter to returns, especially for smaller firms.

The most useful company-level metrics an investor can actually get are backlog quality and conversion, awarded (funded) work, billable utilization, project gross margin, change-order frequency, safety record, DSO, disposal-cost pass-through, capital spending, environmental-liability reserves, and free-cash-flow conversion. There is no industry-wide capacity-utilization or margin figure — use company disclosures.

6. What drives demand

• Regulation and liability — the base driver. Companies and governments clean up because CERCLA, RCRA, and state programs require it (see section 7). Enforcement intensity moves demand directly.
• Emerging contaminants, above all PFAS. "Forever chemicals" are the industry's biggest secular tailwind. The Environmental Protection Agency (EPA) designated two of them — PFOA and PFOS — as CERCLA hazardous substances in April 2024 (effective July 2024) and retained the designation in 2025 [9], turning thousands of sites (military bases, airports, manufacturing hubs) into cleanup candidates. Third-party forecasters put the still-small PFAS-remediation market at roughly $1.2 billion in 2025 rising toward ~$2 billion by 2030, growing ~10–13% a year [14] — a private estimate, not an official figure.
• Federal funding. The 2021 Infrastructure Investment and Jobs Act (IIJA, also called the Bipartisan Infrastructure Law) put $3.5 billion into Superfund remedial cleanup and more than $1.5 billion into EPA's Brownfields program, and reinstated (through 2031, at roughly double the old rates) the Superfund chemical excise tax that refills the trust fund [10]. DOE's ~$8-billion-a-year Environmental Management program funds the nuclear-cleanup end [11].
• Real-estate redevelopment / brownfields. A buyer or lender won't close on contaminated land until it's remediated, so property transactions and redevelopment trigger cleanup — tying a slice of demand to the commercial-real-estate and construction cycle.
• Industrial and energy activity. New semiconductor, battery, energy, manufacturing, and mining projects generate permitting, due diligence, spills, closures, and eventual decommissioning; downturns cut event-based volumes (Republic Services flagged softer environmental-services volumes as manufacturing cooled in 2025 [20]).
• Emergency response and climate-related events — oil spills, chemical releases, fires, floods, and rail/transport derailments produce episodic surge work.
• Nuclear decommissioning — an aging reactor fleet and Cold-War legacy sites are a decades-long backlog.

7. Regulation

Remediation is downstream of environmental law; the statutes essentially create the industry:

• CERCLA / "Superfund" (Comprehensive Environmental Response, Compensation, and Liability Act, 1980) — the cornerstone. It lets EPA compel cleanup of the worst contaminated sites (the National Priorities List, or NPL) and imposes liability that can be strict, retroactive, and joint-and-several on "potentially responsible parties" (PRPs) — meaning one party can be forced to pay for an entire site when the harm can't be divided [6]. That regime is what makes cleanup non-optional.
• RCRA (Resource Conservation and Recovery Act) — governs hazardous waste "cradle to grave," from generation through transport, treatment, storage, and disposal, and drives corrective-action cleanups at active facilities [7].
• Brownfields program — federal grants to assess and clean up lightly-to-moderately contaminated property for reuse; note that the 2024 PFAS designation complicated using these grants on PFAS-tainted sites [9].
• TSCA (Toxic Substances Control Act) — controls asbestos, lead, and PCBs, feeding abatement demand.
• OSHA HAZWOPER — the Occupational Safety and Health Administration's Hazardous Waste Operations and Emergency Response standard (29 CFR 1910.120) mandates site characterization, safety programs, training, medical surveillance, and protective equipment for cleanup crews — a compliance cost and a barrier to entry [8].
• Air, water, transport, and state programs — projects often need permits under federal and state air, water, and hazardous-material rules; state voluntary-cleanup, dry-cleaner, and underground-storage-tank (UST) programs oversee a large share of routine remediation, and state limits can be stricter than the federal floor.

Regulation cuts both ways for investors: tighter rules and new contaminant listings (PFAS) expand the market, while deregulation or slower enforcement shrinks mandated spending — and rule changes can also alter technologies, scopes, liability allocations, and disposal costs. Both directions are live policy questions, and the PFAS designation itself faces ongoing litigation.

8. Competitive dynamics and consolidation

The defining feature is fragmentation — top-four share of just 9% and an HHI of 43 [2]. Competition is mostly local and project-by-project, won on technical credentials, safety record, local permits, regulatory relationships, emergency-mobilization capability, bonding and insurance capacity, treatment technology, disposal access, and price. Large customers increasingly prefer a single provider that can manage investigation, field work, transport, treatment, documentation, and closure under one contract.

Barriers to entry are moderate but real: engineering know-how, state licensing, HAZWOPER-certified labor, surety bonding, and — critically — the willingness to take on environmental liability. Those barriers plus recurring, regulation-driven revenue are exactly what attract financial buyers. National concentration statistics can understate local competition, because work is awarded by geography, specialty, license, and site history.

Consolidation is the active theme:

• Private equity is rolling up the long tail, forming platforms and bolting on add-ons in PFAS treatment, wastewater, and brownfields; deal volume rose in 2024–2025 after a soft patch [24].
• Strategics are integrating vertically and expanding reach. Recent transactions include Republic Services' $2.2 billion purchase of US Ecology (2022) [20]; Clean Harbors' ~$400 million acquisition of HEPACO, an emergency-response specialist (2024) [21]; Veolia's ~$3 billion completion of the Clean Earth deal, doubling its U.S. hazardous-waste business (2026) [22]; and WSP's ~$4.5 billion acquisition of TRC (2026) [23].
• Federal cleanup is oligopolistic at the top. The multi-billion-dollar DOE nuclear contracts (e.g., the ~$45 billion Hanford tank-waste contract and a Central Plateau cleanup contract) are won by joint ventures of a handful of large E&C and services firms [12].

Likely trajectory: a slowly consolidating middle as PE platforms and strategics acquire regional specialists, while a large tail of small local operators persists because much of the work is inherently local. These deals show strategic appetite for treatment capacity, geographic density, emergency response, and technical talent — but they do not prove every local contractor will fetch an attractive exit multiple.

9. Risks

• Government-funding and political risk. A meaningful share of demand depends on federal appropriations (Superfund, DOE-EM) and enforcement posture, both of which shift with administrations and budgets.
• Regulatory two-sidedness. New contaminant listings (PFAS) grow the market; deregulation or slower enforcement shrinks mandated cleanup — and the PFAS designation itself is in litigation.
• Fixed-price execution risk. Contamination is often less understood than the bid assumes; overruns — chronic in federal nuclear cleanup per repeated GAO findings — can wipe out project margins.
• Safety and incident risk. Handling hazardous and radioactive material carries direct environmental, worker-safety, and legal exposure; a serious incident is a human, reputational, and financial event, and can cost licenses.
• Labor risk. Dependence on scarce, licensed, safety-certified scientists, project managers, operators, and field crews.
• Disposal-capacity risk. Treatment, incineration, trucking, and landfill constraints can raise costs or delay completion.
• Cyclicality and timing. Event-based and redevelopment-linked work tracks industrial activity and real estate; downturns cut volumes [20], and project timing makes quarters lumpy.
• Client and contract concentration. Federal-heavy contractors (Perma-Fix, Amentum, Fluor) lean on a few large customers and programs.
• Acquisition and integration risk. Roll-ups can fail through overpayment, weak integration, customer loss, or excess leverage.
• Working-capital drag. Slow-paying government and corporate clients tie up cash, especially for smaller firms.
• Disclosure risk. Private operators disclose little; public parents give only limited segment detail — so pure-industry visibility is poor.

10. How to invest and the outlook

Public routes. No pure-play large-cap and no dedicated ETF, so it's a build-your-own basket, and the key is the quality of the exposure, not the company label:

• Most focused / liquid: Clean Harbors (CLH) for scale plus owned disposal; Tetra Tech (TTEK) for government-heavy environmental engineering; Onterris/ex-Montrose (ONT) as a smaller, faster-growing focused vehicle; Perma-Fix (PESI) as a micro-cap bet on nuclear waste and PFAS destruction.
• Diversified exposure: Republic Services (RSG) and Waste Management (WM) for waste-plus-remediation; AECOM (ACM), Jacobs (J), Amentum (AMTM), and Fluor (FLR) for federal and nuclear cleanup; Veolia (VIE) and WSP (WSP) for global environmental platforms. In these, remediation is a segment — size the exposure accordingly.

Questions worth asking of any listed name: How much revenue is direct remediation versus engineering, disposal, consulting, or pass-through? Is growth organic or acquisition-driven? What share of backlog is funded and likely to convert? Are margins protected by pricing, contract clauses, or a disposal-network advantage? How large are environmental reserves and obligations? And how dependent is it on federal contracts, industrial customers, or one-off emergency events?

Private routes — the more direct way into the pure industry, since ~5,100 of the firms are private [2]:

• Backing or co-investing in a PE roll-up platform consolidating regional contractors [24];
• Direct ownership of a regional remediation or abatement contractor;
• Specialist plays in the fast-growing PFAS-treatment niche.

Diligence should emphasize permits, insurance, claims history, environmental liabilities, customer concentration, contract terms, backlog quality, worker retention, safety records, disposal relationships, working capital, capital spending, and the true cost of integrating add-ons. The strongest platforms pair local customer relationships with national procurement, centralized compliance, specialized treatment, and recurring monitoring.

Near-term drivers to watch.

• PFAS is the multi-decade tailwind — if the CERCLA designation survives litigation and states keep tightening limits, it could re-rate the whole industry's growth profile [9][14].
• Durability of federal funding — whether Superfund appropriations, the reinstated excise tax, and DOE-EM budgets hold up is the swing factor for the government-linked names [10][11].
• The redevelopment cycle — a recovery in commercial real estate and industrial construction would lift brownfield and transaction-driven cleanup.
• Continued consolidation — expect PE and strategics to keep buying, which supports valuations for private sellers and can drive earnings for the acquisitive public names [24].

Base case: a low-to-mid-single-digit-growth core industry with a genuine higher-growth option embedded in PFAS and emerging contaminants — steady, regulation-anchored demand; a heavily private and consolidating supplier base; and a small, indirect public opportunity set. Not a smooth, recession-proof growth curve, but durable underlying demand with periodic project-driven volatility.

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Sources

1. U.S. Census Bureau, County Business Patterns (2023), NAICS 562910 — establishments (5,826), employment (91,239), annual payroll ($7.057B), Q1 payroll ($1.670B). https://www.census.gov/programs-surveys/cbp.html
2. U.S. Census Bureau, 2022 Economic Census — receipts and concentration, NAICS 562910 — receipts ($22.739B), firms (5,115), CR4 9.0% / CR8 14.3% / CR20 25.1% / CR50 37.4%, HHI 43.2. https://www.census.gov/programs-surveys/economic-census.html
3. U.S. Census Bureau / NAICS, 2022 NAICS 562910 Remediation Services — definition and cross-references. https://www.census.gov/naics/?details=562910&year=2022
4. U.S. Small Business Administration, Table of Size Standards (2023) — $25M receipts standard for 562910. https://www.sba.gov/document/support-table-size-standards
5. U.S. Census Bureau, County Business Patterns — About / coverage (employer establishments only; excludes non-employers and most government). https://www.census.gov/programs-surveys/cbp/about.html
6. Congressional Research Service / U.S. EPA, CERCLA ("Superfund") overview and liability — strict, retroactive, joint-and-several liability; National Priorities List. https://www.epa.gov/superfund/superfund-cercla-overview
7. U.S. EPA, Resource Conservation and Recovery Act (RCRA) Overview — cradle-to-grave hazardous-waste system. https://www.epa.gov/rcra/resource-conservation-and-recovery-act-rcra-overview
8. Occupational Safety and Health Administration, HAZWOPER standards (29 CFR 1910.120). https://www.osha.gov/emergency-preparedness/hazardous-waste-operations/standards
9. U.S. EPA, PFOA and PFOS designated CERCLA hazardous substances (April 2024) and Brownfields FAQs / 2025 retention. https://www.epa.gov/brownfields/faqs-what-epas-designation-pfoa-and-pfos-cercla-hazardous-substances-means-epas
10. U.S. EPA, Infrastructure Investment and Jobs Act — $3.5B Superfund remedial and ~$1.5B Brownfields; Superfund excise tax reinstated (2022–2031). https://www.epa.gov/infrastructure/cleaning-superfund-sites-highlights-infrastructure-investment-and-jobs-act-funding
11. U.S. Department of Energy, FY 2025 Budget in Brief — Environmental Management (~$8B, "largest environmental cleanup program"). https://www.energy.gov/sites/default/files/2024-03/doe-fy-2025-budget-in-brief.pdf
12. ANS Nuclear Newswire / Nuclear Engineering International, DOE Hanford tank-waste (~$45B) and Central Plateau cleanup contract awards. https://www.ans.org/news/article-5832/doe-again-awards-45-billion-hanford-tank-contract-to-h2c/
13. IBISWorld, Remediation & Environmental Cleanup Services in the US, 2025 — ~$26.5B market size. https://www.ibisworld.com/united-states/industry/remediation-environmental-cleanup-services/1517/
14. Virtue Market Research / Exactitude Consultancy, PFAS Remediation Market — ~$1.2B (2025) to ~$2B (2030), ~10–13% CAGR (private forecast). https://virtuemarketresearch.com/report/pfas-remediation-market
15. Clean Harbors, Inc., Third-Quarter 2025 Financial Results (revenue $1.55B) and 2025 Form 10-K; market cap ~$16.6B (StockAnalysis.com). https://ir.cleanharbors.com/news-releases/news-release-details/clean-harbors-announces-third-quarter-2025-financial-results
16. Tetra Tech, Inc., Fourth Quarter and Fiscal 2025 Results — revenue $5.44B. https://investor.tetratech.com/news/news-details/2025/Tetra-Tech-Reports-Strong-Fourth-Quarter-and-Fiscal-2025-Results/default.aspx
17. Onterris, Inc. (formerly Montrose Environmental Group), Montrose Environmental Group Is Now Onterris — NYSE ticker change MEG → ONT effective May 4, 2026; market cap ~$0.9B (Macrotrends). https://www.businesswire.com/news/home/20260420842892/en/Montrose-Environmental-Group-Is-Now-Onterris
18. Perma-Fix Environmental Services, 2025 Results — revenue $61.7M, backlog +~51%. https://ir.perma-fix.com/press-releases/detail/4900/perma-fix-reports-2025-results-as-expanded-capacity-and
19. Amentum Holdings — ~$14B revenue; DOE nuclear-complex remediation history. https://en.wikipedia.org/wiki/Amentum_Holdings
20. Republic Services / Waste Dive — US Ecology acquisition ($2.2B, 2022); Environmental Solutions segment (~11% of revenue) and 2025 volume softness. https://www.wastedive.com/news/republic-services-us-ecology-environmental-solutions/618561/
21. Clean Harbors, Clean Harbors Completes ~$400M Acquisition of HEPACO (2024). https://www.cleanharbors.com/2024/clean-harbors-completes-acquisition-of-hepaco
22. Veolia, Veolia Completes Clean Earth Deal (~$3B, June 2026), Doubling Its U.S. Hazardous-Waste Business. https://www.veolia.com/en/our-media/press-releases/veolia-completes-clean-earth-deal-doubling-its-us-hazardous-waste-business
23. WSP Global, WSP Completes Acquisition of TRC (~$4.5B, Feb 2026). https://www.wsp.com/en-us/news/2026/wsp-completes-acquisition-of-trc
24. Capstone Partners, Industrial & Environmental Services M&A Update — PE roll-ups in PFAS, wastewater, brownfields, 2025. https://www.capstonepartners.com/insights/article-industrial-environmental-services-market-update/
25. Weston Solutions, Remediation / About — 100% employee-owned environmental and infrastructure firm. https://www.westonsolutions.com/solutions/remediation/
26. Berkshire Partners, Triumvirate Environmental Valued at ~$1.8 Billion Following Growth Investment, 2025. https://berkshirepartners.com/triumvirate-environmental-valued-at-1-8-billion-following-growth-investment-from-berkshire-partners/
27. J.F. Lehman & Company, Acquisition of Crystal Clean, 2023. https://www.jflco.com/news-article/155/jf-lehmancompany-enters-into-definitive-agreement-to-acquire-crystal-clean
28. Environmental Resources Management (ERM), Remediation & Regeneration (KKR-backed environmental consultancy). https://www.erm.com/solutions/remediation-regeneration/
29. AECOM, 2025 Form 10-K — Environment end-market (remediation within infrastructure platform). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0000868857&type=10-K