San Francisco Mayor Ed Lee today called the power outages that left fans and players in the dark at Monday night's 49ers game at Candlestick Park a "national embarrassment."
Speaking to reporters after an unrelated news conference this morning, Lee said he would "make sure that we've covered every base so this doesn't happen again."
Lee, who was at Monday night's game, said he spoke with PG&E CEO Anthony Earley this morning and was told that the first outage was caused by a splice failure on an overhead line near the stadium, and that the cause of the second outage is under investigation.
The first outage began at 5:19 p.m., shortly before the game against the Pittsburgh Steelers was scheduled to begin. Service was restored 20 minutes later and the game got under way, but the lights went out again at about 6:45 p.m. during the second quarter.
Candlestick Park was the only facility in the area to be affected by the outage. No homes lost power.
The power line that failed arced when it came down, causing a bright flash caught by aerial television cameras that some initially incorrectly believed was a transformer explosion, Lee said.
He said the downed line has already been repaired by PG&E.
PG&E spokesman Jason King confirmed that the cause of the initial outage was a downed power line on Egbert Avenue, a couple of blocks away from the stadium.
Earlier today, King had said there had also been a malfunction in a city-owned automatic transfer switch that is supposed to provide a secondary source of power for the system in case of an outage.
But this afternoon he changed course, saying, "It's not been concluded that there's been an issue with the switch."
San Francisco Public Utilities Commission General Manager Ed Harrington said "the second feed kicked in" but that his agency is looking into "how fast that happened, and did we respond to that appropriately."
Harrington said, "Nothing that we know indicates that the power failure was caused by city equipment ... the power feed was clearly a problem of when their line broke."
He said the age of Candlestick Park -- which opened in 1960 -- could have been a factor in the time it took to restore the lights.
"An older facility has a harder time getting back up," he said.
The cause of the second outage also remains under investigation.
King said there is no indication that outage was caused by PG&E equipment.
Fire Chief Joanne Hayes-White said, "We're looking at it as internal to the stadium."
Lee, who experienced the blackouts in person, was shocked by the outages.
"Of course, 'Oh my God' was the first issue, and certainly I was concerned for the fans," he said. "But police and fire and Rec and Park working alongside security the 49ers had, they all acted very well."
Lee commended the fans for keeping their cool.
"I want to thank the fans, they were very good at keeping themselves calm."
Police Capt. Paul Chignell of the Bayview Station, which handles calls at Candlestick Park, said, "We were very fortunate, despite the intermittent blackouts, that we didn't have anything but a normal number of inebriants and other minor violations."
The citations issued at the stadium included one to a fan who ran onto the field during the second outage, Chignell said.
Police also had to deal with a bomb threat to the stadium that was called in before the game. The threat was found to be without merit.
"It's not unusual in a large gathering to have some bogus threats," Chignell said.
As for speculation that the outages may have been an intentional act, Lee said the investigation has found "no indication that this was anything other than an accident."
The mayor said he planned to meet later today with officials from PG&E, the California Public Utilities Commission and various city agencies to discuss the incident.
"We want to make sure this doesn't happen again," particularly at a possible playoff game, Lee said. The 49ers, who have clinched a playoff spot, are assured of playing at least one playoff game at home in January.
Lee said he isn't concerned about the outages affecting the city's chances of keeping the team in the city.
"It's the electrical service to the stadium that failed," he said. "It's a completely separate issue."
The 49ers have plans to move to a new planned stadium in Santa Clara as soon as 2015, but Lee insisted, "We still stand as a very strong Plan B."
He said, "If you look at other new stadiums across the country, even new stadiums had challenges as well."
Lee said he was "sad and certainly embarrassed to have this happen on the night of our only Monday Night Football game," but added with a smile, "I'm very glad we won."
The 49ers dominated the Steelers, winning 20-3 to move to 11-3 on the season.