Another businessman who shaped the face of modern America was Andrew Carnegie, a Scottish immigrant. Where Rockefeller was interested in oil, Carnegie was interested in another emerging good—steel. Carnegie was an astute businessman who knew that steel would become the lifeblood of the rail industry and therefore become the backbone of transportation across the United States. Where Rockefeller bought out his competitors, Carnegie focused on a strategy of vertical integration or the buying up of all of the industries needed to support his industry. And so, Carnegie bought railroads, coal mines, and steel mills in support of his expansion program. In 1875, Carnegie opened his first steel mill and revolutionized not only the steel industry, but industry in general. Carnegie was obsessed with efficiency and maximizing work (and therefore profit). He realized that it was more cost effective to run his factory continuously all day every day, as the extra work would more than make up for the extra cost of replacing his machines more frequently. However, he treated his workers in a similar fashion. Workers who were not totally efficient and focused despite the horribly inhospitable working conditions were summarily dismissed. Those injured on the job were also dismissed, as there was no protection for them in place at the time. In fact, Carnegie’s treatment of his workers went a long way, pushing workers to organize into labor unions, and these unions would help shape the landscape of industrial America into modern times.