Which manufacturing sector of the american economy made andrew carnegie a fabulously wealthy man?

Steel

Explanation:

Andrew Carnegie, the king of steel, appointed Henry Clay Frick as president of the steel industry, started preaching a lower price and higher production scales, increased corporate profitability, and disrespected employees, who worked 84 hours a week and had their strikes violently suppressed.

i think the answer is the one about environmental and social health.

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