The FIRST U.S. use of Thermite

On February 24th, 1925, thermite was used for the first time in the United States to break up a massive ice jam on the St. Lawrence River near Waddington, New York. Roughly 250,000 tons of ice began to shift only hours after three 90‑pound thermite charges were ignited.

Thermite—a mixture of finely divided magnesium and red iron oxide—produces an intense, molten‑iron reaction when ignited. This method was developed by Howard Turner Barnes of McGill University and patented under U.S. Patent No. 1,562,137.

Barnes, a leading researcher on the physical properties of ice and the engineering challenges it posed to hydroelectric intakes along the St. Lawrence, continued refining his techniques. The following year, he assisted in breaking up another major ice gorge on the Allegheny River, further demonstrating the practical value of his thermite‑based approach.

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