All Other Pipeline Transportation (U.S.) — NAICS 486990

A Histometrics industry primer for public- and private-market investors

1. Overview

"All Other Pipeline Transportation" is the residual bucket of the U.S. pipeline sector: pipelines that move something other than crude oil, natural gas, or refined petroleum products. The North American Industry Classification System (NAICS) puts everything left over here — most importantly carbon-dioxide (CO₂) pipelines, plus anhydrous-ammonia (fertilizer) lines, coal-slurry and other slurry lines, and brine.[1]

Two things make this small niche worth understanding. First, the physical asset is a hard-to-replicate corridor — a right-of-way that connects a supply source (a natural CO₂ dome, a capture site, an ammonia plant) to a customer or a storage site. The steel is cheap relative to the land access and permits. Second, the measured industry is tiny in headcount but strategically outsized: roughly 5,300 miles of CO₂ pipeline already crisscross the oil basins of Texas, New Mexico, Wyoming, Oklahoma, Louisiana, Mississippi, Colorado, and North Dakota, feeding CO₂ into aging oil fields to squeeze out more crude.[6][9] That existing network is a stable, toll-road-style cash machine. On top of it sits a high-risk, high-reward growth story: a proposed build-out of new CO₂ pipelines to serve carbon capture and storage (CCS), driven by the federal Section 45Q tax credit and throttled not by money or technology but by permitting and landowner fights.[8][14]

Ways in: there is no pure-play public company in this category. Public-market exposure comes bundled inside diversified energy, midstream, and industrial-gas companies where "other" pipelines are one small line of business. Private-market exposure — infrastructure funds, project companies, and venture-backed developers — is where the frontier CCS action is; the biggest proposed new build (Summit Carbon Solutions) is privately held.

2. What it is and how it is structured

Scope. NAICS 486990 covers establishments primarily engaged in pipeline transportation of goods except crude oil, natural gas, and refined petroleum products. The Census Bureau's illustrative examples are carbon-dioxide, coal-slurry and other slurry, anhydrous-ammonia, and brine pipeline transportation (including booster pumping stations).[1] In practice the real categories today are:

• CO₂ pipelines — the dominant use by mileage and asset value. High-pressure lines (roughly 1,100–2,200 pounds per square inch, or psi) carry CO₂ in a dense "supercritical" state — a fluid that flows like a liquid but fills space like a gas — mostly for enhanced oil recovery (EOR), the technique of injecting CO₂ into a depleted reservoir to mobilize trapped oil, and increasingly for permanent geologic storage.[9]
• Anhydrous-ammonia pipelines — a real but small fertilizer-delivery network (long-haul lines moving ammonia from Gulf Coast production to the Corn Belt).
• Coal-slurry and other slurry pipelines — essentially defunct in the U.S.: the last major one, Peabody's 273-mile Black Mesa coal-slurry line in Arizona, closed at the end of 2005 when the power plant it fed shut down.[9]

What it explicitly excludes — and where most "pipeline" money actually is:

• Crude-oil pipelines → NAICS 486110.
• Natural-gas pipeline transportation → NAICS 486210.
• Refined-petroleum-product pipelines (gasoline, diesel, jet fuel), including liquefied petroleum gas (LPG) → NAICS 486910.
• Field gathering lines at the wellhead → oil/gas extraction (211120/211130); natural-gas distribution → 221210; oil-and-gas pipeline construction → 237120; water supply → Utilities (221310).

A classification nuance investors must keep straight: two products people intuitively call "other pipelines" — natural gas liquids (NGLs) (ethane, propane, butanes) and hydrogen — mostly do not land in 486990. NGL/LPG transportation is generally reported under refined products (486910) or natural gas (486210), and hydrogen lines are small (about 1,600 miles nationally) and typically classified with industrial gases.[7][12] So although these show up when you go looking for exposure to "everything that isn't oil or gas," they sit outside the measured 486990 statistics. That is a big reason the federal numbers below look so small.

3. How big it is

Federal business statistics describe a tiny, extremely concentrated industry. These figures combine two reference years and are not a single-year financial statement.

CR4/CR8 mean the revenue share held by the largest four/eight firms. The market-concentration index (HHI, the Herfindahl-Hirschman Index) is suppressed in the federal data — too few firms to publish without disclosing individual companies — so no HHI value is stated here. But the concentration ratios tell the story: four firms account for roughly 90% of reported revenue, and the top twenty account for all of it.[3]

The undercount is severe — read this before using the size figures. These statistics badly understate the economic weight of "other" pipeline transportation, for four reasons. First, pipelines are capital-heavy and labor-light: a ~5,300-mile CO₂ network worth billions in steel-in-the-ground can be run by a couple hundred people, so headcount and payroll say little about scale.[2][9] Second, County Business Patterns excludes non-employer businesses, the self-employed, and most government facilities, and the Economic Census excludes government-owned establishments — so captive industrial lines and tiny operators fall out.[5] Third, most CO₂-pipeline mileage is owned by diversified companies (ExxonMobil, Kinder Morgan, Occidental) whose primary federal classification sits elsewhere (oil-and-gas extraction, crude pipelines, refining); their CO₂ activity is not captured under 486990.[10][11] Fourth, much CO₂ is sold as a commodity to EOR operators rather than booked as a transportation service, so that revenue lands in other line items.

For physical context only (these do not measure 486990 revenue): PHMSA reported about 5,354 miles in its "CO₂ or other" hazardous-liquid pipeline category in 2022, and the Department of Energy (DOE) counts roughly 1,600 miles of dedicated hydrogen pipelines.[6][7] Treat the $374 million receipts figure as the floor of a residual bucket, not the size of the U.S. CO₂-transport economy.

4. The investable universe

There is no listed pure-play. The former closest thing — Denbury Inc., which called itself the largest owner of CO₂ pipelines in the U.S. — was acquired by ExxonMobil (announced July 2023, closed November 2023, about $4.9 billion) and is no longer public.[10] Exposure today falls into three groups.

Group 1 — CO₂ pipelines (the core of measured 486990). In each, CO₂ is a small segment of a much larger enterprise.

Group 2 — adjacent "other product" pipelines (classified in nearby NAICS codes, but the way investors actually get exposure to non-oil/gas pipeline economics). None is a pure-play; all also own crude, gas, refined-product, processing, storage, or marketing assets.

These firms describe transportation revenue as driven by throughput, reserved capacity, tariffs, or contractual fees in their SEC filings.[24] Air Products and Linde run large Gulf Coast hydrogen systems serving refineries and chemical plants.[25] Note the vehicle: several are master limited partnerships (MLPs) — publicly traded partnerships that pass most taxable income through to unitholders, offering direct infrastructure-cash-flow exposure but with partnership (Schedule K-1) tax reporting.

Group 3 — private owners and developers (where dedicated new capacity is being attempted):

5. How the money works

The economics are those of contracted, toll-road-style infrastructure — heavy upfront capital, then low operating cost and long-lived, fee-based cash flow — not a regulated-utility rate base. Owners earn money through some mix of:

• Transportation tariffs (the toll model). Shippers pay a volumetric fee to move product. For CO₂ this has fallen over the past decade as larger-diameter lines and better compression cut unit costs (industry and policy sources put per-ton transport in the low single digits of dollars per 100 miles, down materially since the mid-2010s).[28]
• Reserved-capacity / take-or-pay and minimum-volume commitments. Customers pay for access whether or not they fully use it; shortfalls can still generate revenue. This is what makes the cash flow durable.
• CO₂ commodity sales. The CO₂ incumbents (ExxonMobil/Denbury, Kinder Morgan, Occidental) don't just move CO₂ — they sell it to EOR operators, often at a price indexed to crude oil. That makes a chunk of their CO₂ revenue oil-price-sensitive, unlike a plain toll.[10]
• EOR oil production. Because the incumbents also operate their own floods, they capture the oil upside directly (Kinder Morgan and Occidental produce Permian oil using their own CO₂).[11]
• Ancillary services — storage, fractionation, terminals, marketing — add returns but also add operating and commodity exposure.

For new-build CCS projects the logic differs: the pipeline is a toll road whose customers are industrial emitters (ethanol, ammonia/fertilizer, gas processing, cement) that capture CO₂ to claim the 45Q credit and sell lower-carbon-intensity products. Here the swing variable is not oil price but policy (45Q) and the ability to actually build the route.[8][14]

The metrics that matter: throughput/utilization (tons or barrels per day against capacity); contract coverage (share under reservation/take-or-pay contracts), tenor, and renewal risk; customer concentration and credit quality; tariff per unit; capital cost per mile and maintenance capex; energy for pumping/compression; incident frequency; and, for CO₂, capture commitments, storage permits, and eligible tax-credit volumes.

6. What drives demand

• Oil-field EOR economics. Historically the great majority of U.S. CO₂ demand is for enhanced oil recovery, which rises and falls with oil prices (higher oil = more floods worth running).[9]
• The 45Q tax credit. Section 45Q of the Internal Revenue Code pays for capturing and storing CO₂. The July 2025 "One Big Beautiful Bill Act" (OBBBA) preserved it and, critically, raised the EOR/utilization credit from $60 to $85 per metric ton — to parity with permanent geologic storage (with direct-air-capture at $180/ton), indexed to inflation from 2027.[14][15] Industry analysts estimate the parity change cuts conventional CO₂-EOR breakeven from roughly $28 to about $16 per barrel — a major demand tailwind for CO₂ throughput.[16]
• Industrial carbon capture. As capture is added at ethanol plants, fertilizer/ammonia, gas processing, and (eventually) power and cement, each new source needs a pipe to a sink; federal projections tie carbon-capture deployment closely to 45Q.[17]
• Depleting natural CO₂ domes. The historic supply — natural underground reservoirs like McElmo Dome and Jackson Dome — is finite, pushing the industry toward captured (anthropogenic) CO₂ over time.[9]
• Low-carbon fuel markets. Demand for low-carbon-intensity ethanol (for sustainable aviation fuel and low-carbon-fuel-standard credits) is a key reason Midwest ethanol producers want CCS pipelines at all.[20]
• NGL production and exports (adjacent-code demand). For the broader "other pipeline" universe, the EIA reported record U.S. natural-gas-plant-liquids exports of about 3.1 million barrels/day in 2025 (up ~7%) — ethane ~579,000 b/d, propane ~1.8 million b/d — which supports pipelines to fractionators, petrochemical plants, and export terminals.[13]

7. Regulation

This code has no single regulator; oversight depends on the product, route, and whether a system is interstate or intrastate. For CO₂ specifically, the framework is unusually fragmented — the single biggest reason projects stall.

• Safety (federal). The Pipeline and Hazardous Materials Safety Administration (PHMSA), part of the U.S. Department of Transportation (DOT), regulates hazardous-liquid and CO₂ pipeline safety under its Part 195 rules. Scrutiny intensified after a February 2020 Denbury CO₂ rupture near Satartia, Mississippi, hospitalized dozens (CO₂ is odorless, heavier than air, and an asphyxiant). PHMSA proposed a stronger CO₂ safety rule in January 2025, but the incoming administration withdrew it in early 2025; as of mid-2026 no new federal CO₂ rule is finalized.[18][19]
• Siting and eminent domain (state). Unlike interstate natural-gas pipelines — which get federal siting authority from the Federal Energy Regulatory Commission (FERC) under the Natural Gas Act — interstate CO₂ pipelines have no equivalent federal siting or eminent-domain framework. Routing, permits, and the power to condemn land are decided state by state, and this is the binding constraint: South Dakota banned eminent domain for carbon pipelines in March 2025, and Iowa, North Dakota, and others have run multi-year contested proceedings.[8][20][23]
• Environmental review. Projects can trigger the National Environmental Policy Act (NEPA), Clean Water Act approvals for water/wetland crossings, state utility approvals, and landowner easements.
• Geologic storage (federal, delegable). Permanent underground CO₂ storage uses Class VI injection wells under the EPA's Underground Injection Control (UIC) program; several states (North Dakota, Wyoming, Louisiana) have won "primacy" to permit these themselves.[22]
• Tax (federal). The IRS administers the 45Q credit that underwrites the CCS build-out.[15]

For investors, permitting and land access are often as decisive as engineering: a technically sound project can fail if it cannot secure rights of way, storage permits, or customer commitments.

8. Competitive dynamics and consolidation

The measured industry is textbook-concentrated (top-4 ≈ 90% of reported revenue) and just got more so.[3] The defining move was ExxonMobil's 2023 acquisition of Denbury, which folded the largest independent CO₂ transport-and-storage network into a supermajor and made Exxon the #1 U.S. CO₂ operator, alongside long-time players Kinder Morgan and Occidental.[10] In the adjacent NGL midstream world, consolidation ran in parallel — ONEOK acquired Magellan Midstream Partners in 2023, and private infrastructure funds have taken pipeline companies private or bolted carbon-management platforms onto existing networks.[24][26]

The durable competitive advantages are scarce rights of way, existing interconnections and hub access, storage/fractionation integration, anchor customers and acreage dedications, regulatory approvals, a clean safety record, and low-cost capital. Competition comes from other pipelines, captive customer-owned lines, rail, trucks, barges, and product substitution.

Barriers to entry cut both ways. They protect incumbents' basin networks, but they have repeatedly stopped newcomers cold: Navigator cancelled its entire 1,300-mile Heartland Greenway in 2023, and Summit has been forced to shrink — dropping counties, cutting roughly 200 miles, and removing hundreds of landowners from its route in 2026 to route around opposition and South Dakota's eminent-domain ban.[20][21] Consolidation and route-attrition, not greenfield expansion, are the current reality.

9. Risks

• Permitting / eminent-domain / social-license risk (the big one). State-level route approval and landowner opposition can delay or kill a project regardless of its economics — proven by Navigator's cancellation and Summit's forced downsizing.[20][21]
• Public safety. CO₂ is a dense, odorless asphyxiant; the Satartia rupture galvanized community resistance and remains a rallying point against new lines.[19]
• Volume / contract risk. Production declines, weak petrochemical demand, competing pipelines, expiring minimum-volume commitments, or counterparty default reduce utilization — and pipelines' high fixed costs make underutilization especially punishing.
• Oil-price sensitivity. For the EOR-linked CO₂ incumbents, both CO₂ sales prices and EOR oil volumes fall when crude falls, so a chunk of "pipeline" revenue is really an oil bet.[10]
• Policy risk. The growth case leans heavily on 45Q; it was strengthened in 2025, but any future rollback — or failure to finalize workable safety and storage rules — would reprice the build-out.[14][18]
• Construction / financing / technology risk. Steel, labor, power, and interest-rate costs can erode returns; CO₂ phase behavior and impurities, hydrogen embrittlement, and storage integrity can affect reliability.
• Stranded-asset risk. Purpose-built CO₂ or slurry lines have few alternative uses if demand or economics shift.
• Classification and disclosure risk. As a standalone category this is a very small, opaque bucket buried inside larger companies — hard to isolate and analyze.[3]

10. How to invest and the outlook

Public routes. There is no clean listed way to own "other pipelines." For CO₂ specifically, the realistic plays are diversified majors and midstream operators where CO₂ is a modest segment — ExxonMobil (XOM), Kinder Morgan (KMI), and Occidental (OXY) — whose valuation, dividend, and cash flow are driven mainly by the parent's core oil, gas, and midstream businesses; CO₂/CCS is optionality, not the thesis. For the broader NGL / hydrogen / industrial-gas exposure that investors also lump under "other pipelines," the vehicles are large midstream partnerships (EPD, OKE, ET, TRGP, MPLX, WMB, PAA) and industrial-gas majors (APD, LIN) — again, small slices of larger businesses. Start with the asset, not the ticker: read filings for the share of revenue from CO₂/NGL/hydrogen/ammonia transport, throughput and utilization, contracted-versus-uncontracted capacity, customer concentration and contract expirations, tariff jurisdiction, capex, leverage, and safety/environmental liabilities.

Private routes. This is where dedicated CO₂-pipeline exposure actually lives: venture- and infrastructure-fund-backed developers such as Summit Carbon Solutions and repurposing plays from operators like Tallgrass (Blackstone-owned), plus platforms like Buckeye/IFM (owner of Elysian Carbon Management) and development-stage Wolf Carbon Solutions. These are illiquid, project-finance-style bets whose returns hinge on construction cost, permitting, rights of way, offtake/storage agreements, 45Q eligibility, and exit liquidity — high dispersion between winners and cancelled projects.

Outlook (forward-looking judgment). The macro setup is unusually favorable on paper: the 2025 lift of the EOR credit to $85/ton parity materially improves throughput economics, and CO₂ transport costs keep falling.[15][16] The mature natural-CO₂-to-EOR network, and the established ammonia and NGL systems tied to constrained hubs, should keep throwing off steady, toll-like cash. But the growth of the industry now turns almost entirely on non-economic gates — state siting decisions, eminent-domain law, PHMSA safety rules, and community acceptance. The reasonable base case is a stable incumbent network with slow, contested expansion of captured-CO₂ capacity: the capital and the tax credits are ready, but the rights-of-way are the bottleneck. The most attractive bets are likely selective expansions around existing networks, not speculative systems dependent on unpermitted storage or a single incentive. Watch headlines out of Iowa, the Dakotas, and PHMSA — not the oil price alone — as the leading indicators for this niche.

---

Sources

1. U.S. Census Bureau. "NAICS 486990 — All Other Pipeline Transportation" (2022 definition and illustrative examples). https://www.census.gov/naics/?details=486990&year=2022
2. U.S. Census Bureau. County Business Patterns, NAICS 486990 (establishments, employment, payroll), 2023. https://www.census.gov/programs-surveys/cbp.html
3. U.S. Census Bureau. Economic Census, concentration statistics for NAICS 486990 (firms, receipts, CR4/CR8/CR20/CR50), 2022. https://data.census.gov/table/ECNSIZE2022.EC2200SIZECONCEN
4. U.S. Small Business Administration. "Table of Small Business Size Standards" (NAICS 486990 = $46.0M), 2023. https://www.sba.gov/document/support-table-size-standards
5. U.S. Census Bureau. "County Business Patterns Methodology" (coverage exclusions). https://www.census.gov/programs-surveys/cbp/technical-documentation/methodology.html
6. PHMSA (U.S. DOT). "Annual Report Mileage for Hazardous Liquid or Carbon Dioxide Systems" (~5,354 miles CO₂/other, 2022). https://www.phmsa.dot.gov/data-and-statistics/pipeline/annual-report-mileage-hazardous-liquid-or-carbon-dioxide-systems
7. U.S. Department of Energy. "Hydrogen Pipelines" (~1,600 miles in the U.S.). https://www.energy.gov/eere/fuelcells/hydrogen-pipelines
8. Congressional Research Service. "Carbon Dioxide (CO2) Pipelines: Safety, Siting, and Eminent Domain" (IN12575), 2025. https://www.congress.gov/crs-product/IN12575
9. ClearPath. "Carbon Dioxide Pipelines 101" (network mileage, EOR, natural CO₂ domes, coal-slurry history). 2024. https://clearpath.org/tech-101/carbon-dioxide-pipelines-101/
10. Oil & Gas Journal / ExxonMobil. "ExxonMobil acquires Denbury" (announced July 2023, closed Nov. 2023, ~$4.9B; largest U.S. CO₂ network). 2023. https://www.ogj.com/general-interest/companies/article/14296369/exxonmobil-acquires-denbury
11. Kinder Morgan. "Carbon Dioxide (CO2) Operations" (Cortez pipeline, ~500 miles, ~1.5 Bcf/d; Permian EOR). https://www.kindermorgan.com/Operations/CO2/Index
12. U.S. Energy Information Administration. "Transporting and Storing Hydrocarbon Gas Liquids" (NGL fractionation). https://www.eia.gov/energyexplained/hydrocarbon-gas-liquids/transporting-and-storing-hydrocarbon-gas-liquids.php
13. U.S. Energy Information Administration. "Natural gas plant liquids exports reached record highs in 2025." 2026. https://www.eia.gov/todayinenergy/detail.php?id=67387
14. Global CCS Institute. "U.S. Preserves and Increases 45Q Credit in the One Big Beautiful Bill Act." 2025. https://www.globalccsinstitute.com/u-s-preserves-and-increases-45q-credit-in-one-big-beautiful-bill-act/
15. Carbon Capture Coalition. "The One Big Beautiful Bill Act of 2025" (45Q values; EOR parity fact sheet). 2025. https://carboncapturecoalition.org/wp-content/uploads/2025/06/OBBB-fact-sheet.pdf
16. American Oil & Gas Reporter. "45Q Tax Credit Parity Significantly Improves CO2 EOR Economics" (breakeven ~$28 → ~$16/bbl). 2025. https://www.aogr.com/web-exclusives/exclusive-story/45q-tax-credit-parity-significantly-improves-co2-eor-economics
17. U.S. Energy Information Administration. "Tax credits drive carbon capture deployment in our Annual Energy Outlook." 2025. https://www.eia.gov/todayinenergy/detail.php?id=65764
18. PHMSA (U.S. DOT). "USDOT Proposes New Rule to Strengthen Safety Requirements for Carbon Dioxide Pipelines" (Jan. 2025). https://www.phmsa.dot.gov/news/usdot-proposes-new-rule-strengthen-safety-requirements-carbon-dioxide-pipelines
19. Mississippi Today. "Trump withdraws new pipeline rules inspired by CO2 leaks in Mississippi, Louisiana" (Satartia context). 2025. https://mississippitoday.org/2025/03/07/trump-withdraws-new-pipeline-rules-inspired-by-co2-leaks-in-mississippi-louisiana/
20. Iowa Capital Dispatch. "South Dakota regulators deny carbon pipeline permit again..." and coverage of the Navigator cancellation and Iowa/South Dakota proceedings. 2023–2025. https://iowacapitaldispatch.com/2025/04/22/south-dakota-regulators-deny-carbon-pipeline-permit-again-but-company-vows-to-reapply/
21. DTN Progressive Farmer. "Summit Carbon Solutions Pipeline Gets New Path Forward After Iowa Permit Change" (route downsizing). July 2026. https://www.dtnpf.com/agriculture/web/ag/news/business-inputs/article/2026/07/02/summit-carbon-solutions-pipeline-new
22. U.S. Environmental Protection Agency. "Class VI Wells Used for Geologic Sequestration of Carbon Dioxide" (UIC program). https://www.epa.gov/uic/class-vi-wells-used-geologic-sequestration-carbon-dioxide
23. South Dakota Searchlight. Coverage of South Dakota HB 1052 (eminent-domain ban for carbon pipelines) and Iowa eminent-domain limits. 2025. https://southdakotasearchlight.com/2025/05/13/senate-passes-bill-restricting-eminent-domain-for-carbon-pipelines/
24. U.S. Securities and Exchange Commission, EDGAR. 2025 Form 10-K filings for Enterprise Products (EPD), Targa (TRGP), ONEOK (OKE, incl. Magellan acquisition), Energy Transfer (ET), MPLX, Kinder Morgan (KMI), Williams (WMB), and Plains All American (PAA). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany
25. Air Products / Linde. Gulf Coast hydrogen-pipeline disclosures. https://www.airproducts.com/company/sustainability/hydrogen-for-mobility
26. Buckeye Partners / Koch Industries. Buckeye acquisition of Elysian Carbon Management; Koch/Flint Hills pipeline operations. https://www.buckeye.com/news/
27. Wolf Carbon Solutions. U.S. project disclosures (development-stage). https://wolfcarbonsolutions.com/
28. Center for Climate and Energy Solutions (C2ES) / U.S. DOE National Energy Technology Laboratory. "Carbon Dioxide Enhanced Oil Recovery" (CO₂ transport and EOR economics). https://www.c2es.org/document/carbon-dioxide-enhanced-oil-recovery-a-critical-domestic-energy-economic-and-environmental-opportunity/