Ellwood City, PA, United States
Seamless Tube Industry. A block away was the plant in which Ralph C. Stiefel, the Swiss-born engineer, invented the rotary piercing process for making steel tubing, 1895. He helped found Ellwood Weldless Tube Co., which became a nucleus for National Tube Div. of U.S. Steel.
Listen to the audio guide for Blue plaque № 29110 Free on WIP — starts by itself when you arrive, even with the screen off