An interruption in service occurred Thursday at about 9 p.m. Piedmont Natural Gas spokeswoman Loree Elswick says it's believed that worker conducting routine maintenance mistakenly left a gas valve turned off. Now, Piedmont crews must go through a time-consuming process to restore gas service. "Our service technicians are turning natural gas service off at the meter at every single customer in this area," Elswick says. "As soon as that is complete, our service technicians will start at the beginning and go house by house, customer by customer and turn the natural gas back on, check the pilot light and any equipment to make sure everything is in proper working order." Elswick says customers must be home to have service restored. Customers out of town over the Labor Day weekend likely won't have service restored until at least Wednesday.