Which two men are largely credited with establishing the steel and oil industries in the united states?

Andrew Carnegie and John D. Rockefeller not only established the steel and oil sectors of business, but they dominated them in the late 1800's. The steel industry experienced expansion and robust growth due to the introduction of the Bessemer converter which increased the amount of steel that could be produced tremendously. Rockefeller is often credited with the monopolization of the refinery of oil which introduced vertical integration.

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