Trudy Schamberger had just helped a dog recover from anesthesia at Banfield, the Pet Hospital, on Thursday morning when a firefighter commanded everyone to get out because a nearby gas leak was spewing noxious fumes.

"We were definitely worried," said Schamberger, a vet tech at the clinic in the Spruce Tree Center in St. Paul. "As we were told to leave, our first response was to think, 'How do we get out eight pets with three people?'"

A cap on the end of a main gas line under University Avenue at Fry Street in St. Paul blew off about 10:40 a.m. during what was supposed to be routine utility work.

While no one was injured, hundreds were evacuated from about 12 businesses. Traffic was snarled for hours around Snelling and University Avenues, one of the busiest intersections in the Twin Cities, as area roads were closed.

Workers from the businesses waited in a cold parking lot, on a bus or at nearby restaurants. Some took cabs home because they weren't allowed to use their cars.

The strong, rotten-egg odor with the gas wafted for more than two hours, drifting blocks from the leak as authorities worked to shut off underground valves in about 14 locations.

Gas was completely shut off about 12:45 p.m., leaving about 1,200 customers with no service. Xcel Energy said its best forecast was to have everyone back in service by midnight.

Babak Oskoui said he felt light-headed as he evacuated the Spruce Tree Center about 11 a.m. Misty Becken said she was worried because she's pregnant.

"My lungs were burning right away," said Becken, who works at Metro Dental Care. "People just went into [auto-pilot] mode and got out. It was very smooth."

Schamberger and her coworkers had to leave behind the eight dogs and cats recovering from surgery. They boarded a city bus, where they called the animals' owners. Authorities tested gas levels in the clinic to assuage their concerns; the air was safe.

"It was a very interesting day at work," Schamberger said.

Xcel crew members were rerouting a 12-inch-diameter, 20-foot-long section of pipe in preparation for Central Corridor light-rail construction, Xcel spokesman Steve Roalstad said. Workers had capped one end of the pipe, and the cap blew off.

"We're not sure how the cap came off, quite honestly," Roalstad said, adding that it could take days to determine.

University Avenue was closed from Snelling west to Fairview Avenue and reopened about 1:45 p.m. Most workers were able to reenter their businesses at 1:50 p.m., but Pawn America had to be fanned out because of high gas levels, St. Paul police Senior Cmdr. Todd Axtell said.

Fire Marshal Steve Zaccard said that calm winds helped limit the spread of gas.

Xcel called in extra crews to help with the tedious task of going door to door Thursday to inspect appliances and then relight pilot lights.

"If it takes a while, it takes a while," Roalstad said. "We'll get it done. We got the outcome we wanted today, which is nothing happened other than gas blowing in the air."

The state Office of Pipeline Safety has been notified of the leak. • 612-270-4708 • 612-673-4482