MERC Coal Terminal Closure¶
The Largest Coal Dock on the Great Lakes Is Closing — and No One Has Quantified the Health Impact¶
Closure Date: June 30, 2026 · 54 jobs eliminated · ~4.7 million tons/year removed from port
The Superior Midwest Energy Terminal — operated by Midwest Energy Resources Company (MERC), a wholly owned subsidiary of DTE Energy (NYSE: DTE) — will permanently cease coal-handling operations on June 30, 2026. This is the largest coal transshipment facility on the Great Lakes, and its closure is the single most significant emissions reduction event at any Great Lakes port in 2026.
No published health impact assessment exists for this facility. Port Health Watch's $42.6 million/year health damages estimate for the Duluth-Superior port complex — calculated using EPA's BenMAP-CE methodology — is the only quantified health damage figure in the public record.
Pre-Closure Baseline Window Closing
The June 30 closure creates a hard deadline for pre-closure baseline data collection. Once coal operations cease, the before/after natural experiment window opens — but only if baseline data is captured now. Port Health Watch has filed 19 FOIA/MGDPA requests across 7 agencies to secure this data.
Who Actually Owns What¶
The corporate structure is frequently misreported. MERC is not an Xcel Energy subsidiary.
| Entity | Role | Jurisdiction |
|---|---|---|
| DTE Energy Company (NYSE: DTE) | Ultimate parent — Michigan-based utility holding company | MI |
| DTE Electric Company (fka Detroit Edison) | Direct parent of MERC | MI |
| Midwest Energy Resources Company | Terminal operator — MI corporation incorporated June 5, 1974 | WI operations |
| KM Superior Terminals Inc. (Koch Industries) | Property owner — DTE leases the site | WI |
| Xcel Energy | Customer, not owner — purchased coal through MERC for MN power plants | MN |
The closure results from DTE's decision not to renew its 50-year lease with Koch Industries. The 250-acre site at 2400 Winter Street reverts to Koch upon lease expiration. No new tenant has been publicly announced.1
Why the Xcel Connection Matters
Xcel Energy is listed as a MERC customer on DTE's own website. Xcel's coal fleet retirement — Sherco Unit 2 (retired December 2023), Sherco Unit 1 (2026), Allen S. King (2028), Sherco Unit 3 (2030) — directly contributed to MERC's throughput collapse. The supply chain runs through both utilities' decarbonization timelines.
50 Years of Throughput — Then a 75% Collapse¶
MERC opened in 1976 to solve a Clean Air Act compliance problem: Detroit Edison needed low-sulfur Powder River Basin coal from Wyoming and Montana to replace high-sulfur eastern coal at its Michigan plants. Superior's position at the head of the Great Lakes made it the ideal rail-to-vessel transshipment point.
Terminal Specifications¶
| Attribute | Detail |
|---|---|
| Site | ~250 acres on St. Louis Bay |
| Dock | 1,200 ft — accommodates 1,000-ft superlakers |
| Car dumper | Metso rotary, 5,000 tons/hour (full 123-car train in ~3 hours) |
| Shiploader | 11,500 tons/hour |
| Ground storage | 5 million tons capacity, up to 8 coal types simultaneously |
| Unit train sets | ~15 aluminum sets of 123 cars each |
| Rail service | BNSF Railway, Union Pacific |
| Peak vessel calls | ~450/season (305-day window, late March–mid January) |
The Decline Arc¶
| Year | Throughput (million tons) | Share of Port Tonnage | Key Event |
|---|---|---|---|
| 2008 | 22.3 | ~48% | All-time record — more coal than all other GL terminals combined |
| 2013 | ~15 | ~35% | Ontario's Nanticoke plant closes (was North America's largest coal plant) |
| 2016 | ~12 | ~28% | Minnesota Power's Taconite Harbor shuts down |
| 2019 | ~8 | ~22% | DTE retires River Rouge coal plant |
| 2023 | 5.6 | ~19% | DTE retires St. Clair (1,547 MW) and Trenton Channel (536 MW) |
| 2025 | 4.7 | ~18% | 75% decline from peak — lowest since opening |
MERC's remaining customers are DTE's last two coal plants: Belle River (converting to gas peaking by 2026) and Monroe (3,066 MW — the third-largest CO₂ emitter among U.S. generators, retiring in phases by 2032). When Monroe goes, there is no customer base left.2
The broader Great Lakes coal picture is equally stark: U.S.-flag coal tonnage dropped from 25 million tons in 2006 to under 7 million by 2025. The Port of Duluth-Superior recorded 25.3 million total tons in 2025 — the lowest since 1938.3
The Workforce: 54 Jobs, One WARN Filing, No Transition Plan¶
In early March 2026, MERC filed a federal WARN Act notice with the Wisconsin Department of Workforce Development documenting the permanent elimination of 54 positions.4
| Category | Positions |
|---|---|
| Mobile equipment operators | 9 |
| Utility operators | 8 |
| Mechanics | 6 |
| Electricians | 5 |
| Operations supervisors | 5 |
| Shiploader/car dumper operators | 5 |
| Other | 16 |
| Total | 54 (51 separated June 30; 3 retained through mid-July for wind-down) |
Workers are represented by the International Longshoremen's Association (ILA) Local 1000. DTE stated affected employees could apply for other positions within the company. No specific severance package details, retraining programs, or community transition plans have been publicly disclosed.
Employment had already declined from 92 positions in 2018 to 54 at closure — a 41% workforce reduction paralleling the throughput decline. Combined with the CHS grain terminal closure (September 2025, 23 jobs), the port lost 77 positions in under a year.
What We Don't Know
No city council resolution, Douglas County Board action, or Wisconsin state legislative response to the closure has been identified. No environmental organization has issued a public statement. The community response has been characterized by pragmatic acceptance — Mayor Jim Paine called the closure "not unexpected."
Environmental Contamination: The $44 Million Question¶
WDNR Identifies MERC as Potential Responsible Party¶
On October 20, 2023, the Wisconsin Department of Natural Resources sent a formal letter to MERC (addressed to Paul Omberg, 2400 Winter Street, Superior) identifying the facility as a potential source of contamination in the adjacent Oil Barge Dock Slip. Sediment characterization found elevated levels of:5
- Mercury and lead
- PAHs (polycyclic aromatic hydrocarbons)
- Dioxins
- Coal particles
- Volatile and semi-volatile organic compounds (VOCs/SVOCs)
- Organotin
The DNR cited Wisconsin cleanup statutes (§§ 292.11 and 292.31) and sought MERC's cooperation in providing nonfederal cost share under the Great Lakes Legacy Act.
The Broader Cleanup Context¶
The Oil Barge Dock Slip investigation is part of the Superior Slips Sediment Remediation Project (BRRTS Activity #11-16-591466) — a planned $44 million effort to remove approximately 190,000 cubic yards of contaminated sediment from three slips.6
The MERC site sits within the St. Louis River Area of Concern, one of 43 designated under the 1987 Great Lakes Water Quality Agreement. As of late 2025, approximately 72–83% of required management actions were complete. In 2021, EPA dredged 75,000 cubic yards of sediment contaminated with coal, gasoline, and oil residues from nearby Howards Bay.7
The Remediation Cost Comparable¶
The nearby C. Reiss Coal Company site — a 55-acre former coal dock — required excavating 110,000 cubic yards of contaminated material and cost $22–28 million to rehabilitate.8 The MERC site is roughly five times larger (250 acres vs. 55 acres) and handled significantly higher volumes over a longer period. No Phase I or Phase II Environmental Site Assessment for the MERC property has been publicly released.
FOIA Priority
MERC's response to the October 2023 WDNR letter — and any subsequent cost-sharing negotiations — is a priority target for our ongoing FOIA campaign. This contamination finding directly connects the terminal to the multi-million-dollar harbor remediation effort.
The Health Assessment Gap¶
No published epidemiological study, BenMAP-CE health impact assessment, or facility-specific air quality monitoring data exists for the MERC terminal. This is the central finding of our research — and the central opportunity.
Douglas County is in attainment for all National Ambient Air Quality Standards. Wisconsin Administrative Code NR 445.10 requires coal-handling facilities to limit off-property respirable coal dust concentrations to below 21.6 μg/m³ for any 24-hour period, but no publicly available monitoring data confirms compliance. MERC maintains dust control systems including 30 water cannons, a water truck fleet, telescoping discharge chutes, a baghouse dust collection system, and an on-site water treatment plant.9
The absence of facility-specific health data means Port Health Watch's analysis fills a void that neither state regulators, the port authority, nor the terminal operator have addressed. Our $42.6 million/year health damages estimate — derived from BenMAP-CE concentration-response functions applied to the Duluth-Superior port complex — is the only monetized health impact figure in the public record.
Vessel Emissions: The 97/3 Scope 3 Reality¶
A 2019 ICCT inventory of Great Lakes vessel emissions found that bulk carriers collectively emitted 921,798 tonnes of CO₂, 637 tonnes of PM2.5, and 19,472 tonnes of NOₓ annually across the entire Great Lakes system.10 At the Duluth-Superior port level, vessel emissions constitute 97.4% of port-attributable CO₂ — the terminal's on-site operational emissions are rounding errors compared to the vessels it services.
This 97/3 split is the single most important structural insight for methodology development: any credible port emissions reduction framework must account for Scope 3 vessel emissions, not just Scope 1 terminal operations.
Emissions Impact: What the Closure Eliminates¶
Estimated MERC Terminal Emissions (~8,500 tonnes CO₂/year)¶
| Source | Estimated Tonnes CO₂/yr |
|---|---|
| Coal dust (fugitive emissions) | ~1,200 |
| Coal-handling equipment (diesel) | ~2,800 |
| Coal carrier vessel at-berth emissions | ~3,500 |
| Facility electricity | ~600 |
| Rail movements within terminal | ~400 |
| Total | ~8,500 |
Beyond CO₂, the terminal generates fugitive coal dust (PM from open-air storage, conveyor transfers, and vessel loading), PM2.5 from diesel equipment, and at-berth vessel emissions from auxiliary engines during loading operations.
Post-Closure Impact¶
| Metric | Before (2025) | After (July 2026+) | Change |
|---|---|---|---|
| MERC CO₂ | ~8,500 t/yr | 0 | −100% |
| Share of port Scope 1 | ~19.6% | 0% | −19.6 points |
| Fugitive coal dust | Active source | Eliminated | — |
| Vessel calls (MERC-specific) | ~100–150/season | 0 | −100% |
The dMRV Opportunity¶
The MERC closure creates a natural experiment with three properties uniquely valuable for digital Measurement, Reporting, and Verification:
1. Clean Before/After Baseline¶
With continuous air quality monitoring at Duluth-WDSE and West Duluth stations, the closure provides:
- Pre-closure baseline: Q1–Q2 2026 monitoring data (shipping season, coal operations active)
- Post-closure comparison: Q3–Q4 2026 monitoring data (same season, minus MERC)
- Confounding control: Weather normalization and vessel call volume tracking isolate the MERC-specific signal
2. SD VISta Health Benefit Quantification¶
The measured PM2.5 reduction attributable to MERC closure translates into avoided health outcomes:
ΔHealth Outcomes = β × ΔPM₂.₅ × Population × Baseline Rate
This provides empirical validation for the concentration-response functions used in the Air Quality Health Units (AQHU) methodology — strengthening the SD VISta submission to Verra.
3. Verra VCS Methodology Pathways¶
The MERC closure establishes:
- Verified baseline emissions for the Duluth-Superior port complex
- Additionality evidence — the closure-driven reduction is counterfactual-ready
- Monitoring protocol validation — proving ambient stations can detect port-specific emissions changes
Potential VCS methodology pathways for maritime at-berth capture credits include VM0049 modules for maritime CO₂ capture — a conversation EcoAsset Lab is actively pursuing with Verra's methodology team.
Site Redevelopment: Koch Industries Holds the Cards¶
The 250-acre site reverts to Koch Industries upon lease expiration. City and port officials strongly favor continued industrial/maritime use.
Port Director Jason Serck has stated that waterfront shipping facilities should be preserved for maritime use. UW-Superior logistics professor Daniel Rust has characterized MERC as a world-class facility likely to attract a new operator. The site's infrastructure — 1,200-foot dock, rail connections, deep-water access — is difficult to replicate.11
Potential reuse scenarios include other bulk commodity handling, wind energy component logistics (nacelles, blades, towers), or mixed industrial development. However, 50 years of coal handling create significant potential for soil contamination requiring environmental assessment before any reuse.
Available Wisconsin remediation tools include the Voluntary Party Liability Exemption (VPLE) program, brownfield redevelopment grants, and Environmental Remediation Tax Incremental Districts. The MERC site is not on the EPA Superfund National Priorities List.
Port Health Watch Service
A MERC site redevelopment assessment provides environmental baseline characterization for the 250-acre site, including soil/groundwater screening, regulatory clearance requirements, and redevelopment scenario analysis. See our Services page for engagement options →
Timeline¶
| Date | Event |
|---|---|
| June 5, 1974 | MERC incorporated as Michigan corporation (Detroit Edison subsidiary) |
| 1976 | Superior Midwest Energy Terminal opens |
| 2008 | All-time throughput record: 22.3 million tons (~48% of port cargo) |
| Oct 31, 2025 | Northern News Now breaks closure confirmation story |
| Nov 17, 2025 | WPR comprehensive closure report (Danielle Kaeding) |
| Q1–Q2 2026 | Pre-closure baseline data collection — 19 FOIA/MGDPA requests filed across federal, MN, and WI jurisdictions |
| March 2026 | WARN Act notice filed: 54 positions permanently eliminated |
| June 30, 2026 | MERC coal operations cease permanently |
| Q3 2026 | Post-closure monitoring begins; before/after comparison window opens |
| Q4 2026 | First before/after emissions comparison available |
| 2027 | Site remediation assessment; Koch Industries redevelopment decision |
| 2027–2028 | SD VISta methodology submission using MERC baseline data |
What This Page Is For¶
This page exists to document — with primary-sourced, publicly available data — the full picture of what is happening at the MERC terminal: who owns it, who profits from it, what it has put into the air and water, and what happens when it stops.
No one else has assembled this picture. The closure announcement generated brief news coverage and pragmatic shrugs. No regulatory proceeding was required. No public hearing was held. No health impact was assessed. The largest coal dock on the Great Lakes is shutting down, and the public record contains no accounting of what 50 years of coal handling did to the community's health or environment.
Port Health Watch is building that accounting. The June 30 closure is not just an event — it is a once-in-a-generation natural experiment that creates an irreplaceable before/after baseline for emissions monitoring and carbon credit methodology validation. The data we capture now will underpin years of analysis.
Last updated: April 2026
Data sources: DTE Energy corporate filings and website, Wisconsin DNR (BRRTS, AOC program, Oct 2023 letter to MERC), WARN Act filings (WI DWD), Duluth Seaway Port Authority tonnage reports, ICCT Great Lakes vessel emissions inventory (2019), WPR, Superior Telegram, Northern News Now, EPA Region 5
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DTE spokesperson Brad Carroll confirmed the lease non-renewal to Northern News Now, October 31, 2025. Koch Industries ownership via KM Superior Terminals Inc. reported by WPR, November 17, 2025. ↩
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DTE Energy CleanVision IRP commits to full coal exit by 2032. Monroe Plant retirement schedule per Michigan PSC proceedings and Utility Dive reporting. ↩
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Duluth News Tribune, reporting on Duluth Seaway Port Authority 2025 season summary. Great Lakes coal tonnage decline from Badger Institute analysis citing USACE waterborne commerce data. ↩
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WARN Act notice filed with Wisconsin Department of Workforce Development, reported by WJFW and Fox 96.9, March 4, 2026. ↩
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Wisconsin DNR letter to MERC (Paul Omberg), October 20, 2023. Document available through WDNR BRRTS system. ↩
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Superior Slips Sediment Remediation Project, BRRTS Activity #11-16-591466. Cost estimate and scope from WDNR AOC program documentation. ↩
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EPA press release on Howards Bay sediment removal; St. Louis River AOC status from WDNR and St. Louis River Alliance. ↩
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C. Reiss Coal Company dock rehabilitation costs reported by Superior Telegram and WPR (May 2025 completion, $28M total project). ↩
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MERC dust control systems described by Coal Age and Martin Engineering case studies. NR 445.10 coal dust standards from Wisconsin Administrative Code. ↩
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ICCT, "A comprehensive inventory of Great Lakes vessel emissions," 2019. Published via Great States Great Lakes Coalition. ↩
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Port Director Jason Serck and Prof. Daniel Rust quoted in WPR's November 2025 closure coverage. ↩