A cluster of mylar balloons floated into power lines at the intersection of 25th and Mission streets sometime after 3 p.m. Saturday, cutting power to 6,500 customers and service on several Muni lines, according to Robert W. Trumbull, distribution supervisor for Pacific Gas & Electric.

While power was mostly restored by 4:45 p.m., Muni lines 14, 49 and 33 did not resume service until 7:50 p.m. Earlier in the day, a few buses were rerouted to South Van Ness.

Trumbull said the escaped balloons made contact with and burned overhead power lines at the intersection of 25th and Mission streets.

The burned wires fell onto Muni’s 600-volt power line, stopping service on the three Muni lines that run between 16th and Cesar Chavez streets.

“If [the wire] had landed on the street, it would have arced…. If people were in the intersection, it would have been a problem. But no one was injured,” said Division 3 Fire Chief Audry Lee.

Power was out for several hours from 9th and Mission to Cesar Chavez, according to John Scott from the San Francisco Municipal Transportation Agency. Readers also reported outages on San Jose Avenue and in Bernal Heights as far south as Cortland Avenue.

“We are doing all it takes to get the Muni up and running again,” Scott said earlier today.

Police blocked off all traffic on Mission Street between 25th and 26th streets.

By 5 p.m., power had been restored to most of PG&E’s customers, but 212 still had no service late in the day, Trumbull said. The electric-powered Muni lines were still down at 6:30 p.m., but diesel-fueled buses were unaffected by the outage.

It is against the law to sell mylar metallized nylon balloons without weights, because it’s relatively commonplace for the conductive metal balloons to cause power outages, Trumbull said. Balloons are to blame for a number of outages in California each year.

Trumbull urged consumers to buy plastic balloons.

Muni was working this evening to reestablish transportation, and PG&E is going to reinstall the electricity lines.

In addition to blocking traffic, the power outage affected many Mission Street businesses. Walgreens at 23rd Street remained closed until 4:45 p.m. Nearby, Radio Shack reopened after an hour. Jim Lara from Radio Shack said they were in the middle of a sale when the store lost power. “When the lights are out, it gets dangerous. There was no surveillance, there was no security, so we had to close up.”

Miguel Garcia, owner of Taqueria La Corneta, was relieved when his store’s power came back on around 4:30 p.m. “If we would have been without power for another hour, we would have had to throw away all the food!”

Kenneth Siu of the Fresh Meat Market pointed to two fish lying still on the bottom of a tank. “Saturday is the busiest day for us, and we had to close our shop for an hour,” he said. “We lost about $1,000 in sales and these three catfish.”

At the restaurant Rosamunde just south of 24th Street, patrons and servers were unfazed by the outage. “For an hour we weren’t able to serve lunch, but you just make it happen,” said Sarah Miller. “Sorry for the inconvenience,” she called out to a customer.

“No problem,” he said. “The beer made everything OK!”