At the close of the 19th century, electricity was introduced into the factory and steam power was abandoned. The image below depicts an early 20th century factory that has changed over to electricity. Notice the power lines running across the front of the image.
After 1911, reinforced concrete factories were constructed with concrete slab floors. The use of interior lighting decreased the need for large exterior windows. Factories grew into sprawling, one-story buildings with expansive interior space and moved farther into the outskirts of town onto campuses with access to major highways.