LSSU study counts 6,453 Great Lakes oil spills in a decade, and finds the St. Marys River among the hot spots

SAULT STE. MARIE, Mich. — Researchers based on the St. Marys River at Lake Superior State University have counted 6,453 reported oil spills across the Great Lakes over a decade, and their study says the river right outside their lab is one of the places where spills cluster.

The review, led by LSSU’s Center for Freshwater Research and Education and published in the peer-reviewed Journal of Great Lakes Research, pulled together U.S. and Canadian spill records from 2015 through 2024, the university said in an Oct. 21 announcement.

What the researchers found. Of the 6,453 incidents, 3,654 were reported in U.S. waters and 2,799 in Canadian waters. Fewer than 6% involved more than 500 liters, about 132 gallons, yet those larger spills made up most of the oil reported. Most incidents were small releases, and many records did not say how much or what kind of oil spilled, according to LSSU.

“We tend to focus on the large spills because of their impacts, but smaller spills happen much more frequently, and their ecological effects remain largely unstudied,” said Dr. Cecilia Heuvel, a postdoctoral research associate at the LSSU center.

Why the St. Marys stands out. The study found that connecting waterways, including the St. Marys, St. Clair and Detroit rivers, had substantially higher spill densities per unit of area than the open lakes. That fits what people in the Soo see every shipping season: narrow channels, the locks and a steady line of freighters. Shipping was the most frequently reported source of spills in U.S. waters, while industrial facilities led in Canada, the university said.

The finding lands as the Army Corps of Engineers builds the New Lock at the Soo, a project meant to keep that freighter traffic moving for decades. The Mitten Daily reported on the project’s progress earlier this month.

The reporting gap. Only 35% of U.S. incidents included a spill volume, and Canadian records had no volume data at all before 2023, which makes it hard to estimate how much oil actually reached the water, according to the study summary. The team recommends that both countries record spill volume, oil type and precise location the same way, so the two sets of records can be compared.

The review was a cross-border effort. Partners included Algoma University across the river in Sault Ste. Marie, Ont., the University of Windsor, the University of Michigan, Memorial University of Newfoundland, the U.S. Coast Guard’s Great Lakes Oil Spill Center of Expertise, Kenneth Lee Research Inc. and LimnoTech. Natural Resources Canada’s Multi-Partner Research Initiative paid for the work.

What it means for you. The study is a count of reported incidents, not a measure of the damage they did. The researchers’ point is that small, frequent spills are the least studied, and better records would show where they add up, including on busy stretches like the St. Marys.

How to report a spill. If you see oil, a sheen or a fuel leak on the water or shore in Michigan, the state’s Department of Environment, Great Lakes, and Energy asks you to call its 24-hour Pollution Emergency Alerting System at 800-292-4706. Spills into the water can also be reported to the federal National Response Center at 800-424-8802, according to EGLE.

Sources:
Lake Superior State University, “LSSU-led Study Documents more than 6,400 Oil Spills across the Great Lakes over a decade,” Oct. 21, 2026 (counts, sources, densities, reporting gaps, Heuvel quote, partners, funding), https://www.lssu.edu/lssu-led-study-documents-more-than-6400-oil-spills-across-the-great-lakes-over-a-decade/
Journal of Great Lakes Research, “A decade of oil spills in the Laurentian Great Lakes,” study page, https://www.sciencedirect.com/science/article/pii/S0380133026002066
WGVU News, “Study from Lake Superior State University documents over 6,400 oil spills across Great Lakes,” Oct. 22, 2026, https://www.wgvunews.org/news/2026-10-22/study-from-lake-superior-state-university-documents-over-6-400-oil-spills-across-great-lakes
Michigan EGLE, “Environmental emergencies” (PEAS hotline and National Response Center numbers), https://www.michigan.gov/egle/contact/environmental-emergencies
Photo: NOAA Great Lakes Environmental Research Laboratory, “Freighter approaching the Soo Locks,” June 26, 2014, Wikimedia Commons, CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0/), cropped and color-adjusted, https://commons.wikimedia.org/wiki/File:Freighter_approaching_the_Soo_Locks_(14659035049).jpg

Sault Ste. Marie

Tags: Sault Ste. Marie · Lake Superior State University · Great Lakes · Oil Spills · St. Marys River · Environment