Emergency responders were called to the scene about 6:15 p.m. after some workers complained of feeling sick.
The store was evacuated as a precaution, Little said. No one was treated for serious illness, however.
Firefighters cleared out the store's ventilation and removed the faulty equipment by 8:30 p.m., making it safe for people to enter.
Since the mall closes at 9 p.m., however, the JC Penny manager told everyone to go home.
The store was expected to reopen Tuesday.
No other stores in the mall were affected, Edie Johnson, director of marketing for Cary Towne Center, said.