Around 10 a.m., police say a work crew ruptured the 4-inch gas line at West Morgan Street and Watts Street near Brightleaf Square.
Durham Police evacuated businesses on West Main Street between Albemarle Street and North Buchanan Boulevard. Students at the Durham School of the Arts were also evacuated to a field next to the school for much of the morning.
PSNC quickly capped the line, but officials said it took hours for the gas to completely clear from the sewer system because gas seeped into pipes.
The contractor who hit the line told ABC11 he did his homework and called in utility companies to mark lines before he started digging, but he said they did not mark the line he hit.
"Certainly not knocking anybody, but this is the result of one missed line," said Jim Berube with All Star Underground.
The contractor was running a fiber optic line under the street between two Duke University buildings when it happened.
Nearby businesses said they felt the loss of customers.
"The way the economics are, any business you lose, it's terrible," offered Rosana Silva who owns three restaurants in Brightleaf.