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MERC Coal Terminal Deep Dive; Research Pages Updated

Two days of site updates bring a substantial expansion to the MERC Coal Terminal Closure research page at the Port of Duluth-Superior, plus sourcing and framing updates across the three research pillar pages.

MERC Coal Terminal — Full Primary-Sourced Analysis

The MERC Coal Terminal Closure page has been rewritten as a full primary-sourced analysis of what is, by throughput, the largest coal dock on the Great Lakes — and, on June 30, 2026, the single most significant emissions reduction event at any Great Lakes port this year.

The expanded page documents:

  • Corporate structure — MERC is a wholly owned subsidiary of DTE Energy; the 250-acre site is owned by KM Superior Terminals Inc. (Koch Industries), not the terminal operator. DTE leases from Koch under a 50-year agreement that is not being renewed.
  • Throughput decline — from 22.3 million tons at the 2008 peak to 4.7 million tons in 2025, a 75% collapse traced through the retirement of specific Detroit-area coal plants and upstream shifts in Midwest utility fuel mix.
  • Workforce impact — a federal WARN Act notice filed in March 2026 documents the permanent elimination of 54 positions, with a breakdown by job category and separation timing.
  • Environmental contamination context — an October 2023 letter from the Wisconsin Department of Natural Resources identified the facility as a potential responsible party for sediment contamination in the adjacent Oil Barge Dock Slip, part of the broader $44M Superior Slips Sediment Remediation Project within the St. Louis River Area of Concern.
  • Health assessment gap — no published epidemiological study, BenMAP-CE health impact assessment, or facility-specific air quality monitoring data exists for the terminal. Our $42.6M/year health damages estimate for the Duluth-Superior port complex remains the only monetized health impact figure in the public record.
  • Vessel emissions context — integration of ICCT's 2019 Great Lakes vessel emissions inventory, which situates MERC's approximately 8,500 t/yr CO2 within the 97/3 Scope 3 reality: at Duluth-Superior, vessel emissions constitute roughly 97% of port-attributable CO2, with terminal-level emissions the minority share.
  • Timeline and footnote chain — an 11-row timeline from MERC's 1974 incorporation through the June 30, 2026 closure and into the post-closure monitoring window, with primary-source footnotes for each major claim.

The closure creates a natural-experiment baseline window for before/after air quality monitoring. The page frames why that window matters and what data capture it requires.

Research Pages — Sourcing and Framing Updates

The three research pillar pages have been revised for sourcing integrity and framing rigor.

The Carbon Credit Gap — technology performance claims now carry explicit verification citations (Yorke Engineering LLC, March–April 2025, under CARB and South Coast AQMD oversight) and identify the operators on the demonstrations referenced. The ICCT analysis on IMO Net-Zero Framework biofuel ILUC emissions is now cited with publication title, author, and date. Methodology development status has been reframed to match the concept-development language used elsewhere on the site.

The Regulatory Gap — operational statistics for CARB-approved capture operations are now attributable to named primary sources. The priority-states table column previously labeled "ICCT Priority" has been renamed "PHW Priority" with a footnote clarifying that the ranking is Port Health Watch's own classification based on ICCT emissions screening data, not an ICCT publication. A footnote has been added acknowledging that Duluth-Superior handles primarily Great Lakes bulk carriers rather than ocean-going vessels, and that CARB's at-berth regulation applies to the latter vessel class only. Shore power statistics — the ~3% global figure, the DNV July 2025 EU AFIR progress assessment, and the Southampton grid-constraint example — now carry citation footnotes.

Air Quality Health Units framework — the page has been reframed as a proposed concept framework rather than a claim of priority. A new "Open Questions" section documents the methodological challenges that remain before submission: DALY valuation anchoring, dispersion-modeling verification standards, attribution in multi-source pollution environments, and the program-structure fit between SD VISta's existing framework and a standalone health-benefit instrument. The MERC closure is referenced as the first empirical validation opportunity for the quantification chain.

Ongoing Work

Source documentation is being applied progressively across the site. The MERC Coal Terminal page is the current template for the full citation standard documented on our Methodology page; other research pages and port assessments will be updated to match as they are revisited. If you encounter a figure that lacks clear sourcing and you need to verify it, write to research@porthealthwatch.org and we will supply the underlying data and calculation.