Chicago became a city with a specalized industry What industry was it?

Answer 1

Although Chicago became a big part of the steel industry in the second half of the 1800s, you're probably referring to the meatpacking industry. This was aided by the invention of the refrigerated railroad car that allowed the meat to be transported more easily without spoiling. Labor conditions in the Industrial Era were not very good, and this industry was no exception. Later on these conditions led to Upton Sinclair writing his famous book, "The Jungle," which also revealed the horrible condition of the meat itself until the quality was better regulated.