I see PNC Financial Services with 52,000 employees, PPG Industries with 43,000, Alcoa with 60,000, Westinghouse Electric with 14,500, U.S. Stell with 42,000. I could go on.
Probably should let City-Data know that, since they don’t have them listed as being in Pittsburgh anymore.
http://www.city-data.com/city/Pittsburgh-Pennsylvania.html