It was the refinement of the Bessemer process, first used in the United States in the 1860s, that allowed for the major advance in skyscraper construction. As steel is stronger and lighter in weight than iron, the use of a steel frame made possible the construction of truly tall buildings.
True, the US Congress was active in implementing labor related legislations. President Theodore Roosevelt gave importance to the labor unions are needed to help on the collective bargaining agreements between employers and employees. The effects of The Great Depression were hard for the workers, it is a call of their duty to act on it.
Give me liberty or give me death