During World War I, the Semet-Solvay Process Company, re-tooling for the war effort as many companies did, turned its limestone quarry at Split Rock into a munitions factory, producing highly explosive TNT. On the night of July 2nd, 1918, it is believed that an overheated gear in a grinding machine started a fire in the No. 1 TNT building. Workers fought the blaze until the hoses lost water pressure. The resulting explosion rocked the landscape, killing an estimated 50 men and injuring 50 others. A stone crusher, built in 1903, is the only significant structure on the site.