Edward M. Harrington (1866-1933) was a chemist and expert on blasting cap design. He held several positions at the Aetna Powder Company, eventually becoming superintendent of the dynamite works at Aetna, Indiana. Harrington then went on to work for the DuPont Company at various plants in the Operating Department until his retirement in 1921. Images in this collection are of dynamite and other explosive plants, including Aetna Powder Company plants in Newport, Rhode Island (electric blasting caps) and Aetna, Indiana, and DuPont Company plants in Repauno, New Jersey; Hopwell, Virginia, and many other locations. Photographs show buildings, office and plant interiors, many with workers, employee groups, housing, and recreation.