It used to be steel mills but now I really don't think there is just one main business in Pittsburgh anymore.
steel mills
Penguins
Ben Roethlisberger
1998
What is the main industry in Malaysia
Wilkes Barre/Scranton Penguins, Pittsburghs AHL Affiliate
The main industry of France is tourism.
what is the main industry and product of Belgium
The main industry of Georgia is poultry.
The main industry is production of coins
What is the main industry in Washington?
the air industry
The main industry is Mining, but others include forestry and farming.