The Poe Locks, connecting Lakes Huron and Superior, are a potential single point of failure in the iron mining - steel production - manufacturing supply chain.
An unanticipated closure of the Poe Lock would likely result in widespread bankruptcies and dislocations throughout the economy. Over 10 million people in the United States and 2 - 5 million more in Canada and Mexico would lose their jobs and the North American economies would enter a severe recession. The recession impacts would be concentrated in the Great Lakes region though California and Texas would experience some of the largest job losses. Entire manufacturing industries would be debilitated, including: automobiles; appliances; construction, farming, and mining equipment; and railcars and locomotives.