AUGUSTA — The underground gas leak that prompted shopping plaza buildings to be evacuated off Western Avenue Wednesday night was among the “largest scale” gas emergencies the city has faced, a top fire official said.

Summit Natural Gas is responsible for the line and had the leak repaired by Thursday morning. A Summit crew on site Thursday afternoon was in front of the SalonCentric beauty supply store at 126 Western Ave., where pipeline inspector Joe Michaud said crews cut out a piece of the line that needed to be repaired. He expected the crew to be done working within a few hours.

Summit officials later determined the leak was caused by an unmarked underground electrical line that burned a hole in the gas line.

The leak prompted a response from the Augusta Fire Department and Augusta police, who cordoned off the parking area after buildings were evacuated as a precaution. Michaud said there was no danger to local buildings once the leak was fixed, and area businesses opened Thursday morning as scheduled.

“We got some pretty high readings,” David Groder, deputy chief of the August Fire Department, said of the gas levels. “We’ve had minor (gas leaks) happen, but this is probably the largest scale I’ve seen in the area. The readings were high enough they got our attention and we reacted based on those.”

There have been a handful of minor Summit gas leaks in recent years. In 2013, an apparent leak blew off a manhole cover and cracked pavement on Arsenal Street in Augusta, while about a year ago gas leaked at a Hallowell school. Both Maine Natural Gas and Summit Natural Gas began installing pipeline in the region to service businesses and residences about four years ago.

The fire department first received a call at 9 a.m. Wednesday from someone reporting the smell of propane or gas in the shopping center area around 150 Western Ave., but fire officials couldn’t smell anything when they arrived, Groder said.

Then, another call came at 8:30 p.m., and firefighters could smell the strong odor of gas emanating from the sewer system, Groder said. They called both Summit Natural Gas and Maine Natural Gas, which is standard procedure for a leak investigation, and then authorities evacuated Applebee’s restaurant, the Pet Life store, Dollar Tree and Shaw’s supermarket. Firefighters, about 15 of them, also checked the buildings to confirm gas was not leaking inside, Groder said, though “they did get high readings behind Applebee’s.”

Meanwhile, the shopping center was closed off with Augusta police and Capitol police blocking off entrances. Gas company officials determined the source of a pinhole-sized natural gas leak with the gas coming from the sewer line, Groder said. The fire department left the scene around 11:30 p.m. as gas officials from both companies worked through the night on the leak. Groder called the response a good “group effort.”

Groder said the high gas readings were enough of a concern that there was the potential for “some kind of reaction” if the gas were ignited.

“I questioned Summit this morning on the volume (of gas that leaked) and they had no idea at this point,” Groder said. “They said it was like a pinhole, but it’s under pressure.”

Keith Lincoln, director of operations for Summit Natural Gas, said in a statement Thursday afternoon that company staff were able to quickly find the source of the leak, secure it and repair it.

“All repairs have been made, and all service has been restored to the area,” Lincoln said. “At Summit Natural Gas of Maine, our top priority is safety — the safety of our system, our customers, our employees, and the communities we serve. We’re happy that this leak was detected and resolved quickly without any incident.”

Staff writer Jason Pafundi contributed to this report.