Approximately one-third of Stanford’s campus lost power at about 3 p.m. on Wednesday, following an electrical failure at the nearly completed Bass Biology Building. Around 55 buildings were initially affected, though some were left without power longer than others.

Classes and events that had been planned to occur in affected buildings were officially canceled in an AlertSU announcement sent at 5:06 p.m on Wednesday. All affected buildings, aside from Bass, were restored with power by around 10 p.m., after a cable failure was identified at a transformer serving Bass.

In an email sent to CS 107 students on Wednesday afternoon, computer science lecturer Cynthia Lee speculated that an on-campus construction accident was the cause of the outages. Bass was not officially revealed as the construction site in question until a Thursday morning update from the University.

“From what I understand, construction workers next door to the Gates Computer Science building hit a high voltage line and knocked out power to multiple buildings, including Gates and Huang,” Lee wrote. “Thankfully, what I’m hearing is that no one was hurt. I hope that is the case.”

In an email to The Daily on Wednesday, University spokesperson E.J. Miranda wrote that the cause for the power outages had not yet been confirmed. He noted that Stanford’s “focus is on working to restore power.”

“We have no reports of a campus construction project hitting any utility lines,” Miranda added in a second email. “And there was no active digging in [the Gates] area today.”

While some of the affected buildings were powered with backup generators almost immediately after losing power, other buildings experienced longer outages, and those without generators were warned that they might lose services if battery backups ran out. As of 5 p.m. on Wednesday, more than 40 campus buildings were still affected by the outages, according to Stanford Emergency Information.

WiFi connections were also impacted, as the Stanford network rendered temporarily unavailable for an unknown number of students. Staff of the Lathrop Tech Desk described the incident as a “power/wifi outage” in a sign posted on the door of the Lathrop Learning Hub.

“It was scary,” said Royce Wang ’19. “I was doing my grad school apps on Word, thankfully.”

Stanford’s Land, Buildings & Real Estate (LBRE) department began working to restore power within about an hour of the initial outage, according to an AlertSU Emergency Alert sent around campus. It was estimated in the 4:25 p.m. alert that power restoration in affected buildings would take about four hours.

Cecil H. Green Library, one of the affected buildings, closed at 4:20 p.m., and was reopened at 6:20 p.m., as a result of the outage. The Red Hoop Fountain outside of the library was also shut off.

The Lathrop Learning Hub also closed early on Wednesday. Desktop computers both in the Hub and in the nearby 24-hour study space were shut down as a result of the outage, while customers at the basement Lathrop Cafe were temporarily forced to pay with cash for their coffees and baked goods.

Zhi Xin MS ’19 said she tried to go to the Tech Desk after it shut down, only to find the doors locked and a sign on the door saying it wouldn’t reopen until the next morning. Xin, who was attempting to return a camera she borrowed from the Desk for a class, expressed doubt about how the shutdown would impact rental policies.

“My reservation ends this afternoon, so I don’t know how they’ll deal with that,” she said.

Other affected areas included Mudd Chemistry, Gilbert Biology, Bing Concert Hall, the Arrillaga Alumni Center, Hoover Tower, multiple gyms and athletic facilities, the Cantor Arts Center, various research facilities and all of the Graduate School of Business, according to Stanford’s Emergency Information service.

Several students reported outages having occurred in their residences, though Emergency Information noted that all dormitories and dining halls were reportedly powered as of 4:25 p.m.

“I was in Mars,” said JB Horsley ’19. “We lost power for, like, 10 minutes. I just thought someone turned off the lights.”

“Wifi was also down for about 15 minutes,” said CJ Paige ’19, who was in Norcliffe at the time of the outage. “The power came on before the wifi.”

Other students were in class at the time of the outage, and faculty responses to the outage varied. Griffin Koontz ’17 M.S. ’19 noted that ECON 52 professor Monika Piazzesi continued to teach after the class lecture hall — Lathrop’s Bishop Auditorium — lost power.

“I was in Econ 52, and suddenly the lights went out and we could not see the board any longer,” Koontz said. “Then, the back-up lights turned on, and we could vaguely see the board with the help of [Piazzesi]’s phone flashlight. And she continued to lecture … with her phone shining on the board. And then she would write, and we could kind of see what was going on.”

Piazzesi explained that she did this because she is “really determined to teach [her students] this material.”

“Econ 52 is great material to teach, and a small thing like a power outage won’t prevent me from teaching it,” she wrote in an email to The Daily.

Elsewhere, the outage affected research work. Researchers were told to “cease any work with hazardous materials, and secure and leave [their] lab” in an AlertSU Emergency Alert. More detailed lab safety protocols, published online, asked researchers to close biosafety cabinets and fume hood sashes.

Students and researchers were also warned that ventilation may have been impacted by the incident.

As of 8 p.m. Wednesday night, the Anderson Collection, Stauffer I, Stauffer II, the Stanford Outpatient Psychiatry Clinic, Roth Way Garage, Mudd Chemistry, Gilbert Biology, the Paul Allen Building and Chemistry Gazebo were the only buildings still without power, according to a University update regarding the outage.

Bass was the only building still without power on Thursday, according to Emergency Information.

This article has been updated to include comment from economics professor Monika Piazzesi.

The article has also been updated to include information from Emergency Information posts released on Wednesday night and on Thursday, after this article’s initial publication.

Gillian Brassil and Alex Tsai contributed to this report.

Contact Holden Foreman at hs4man21 ‘at’ stanford.edu and Brian Contreras at brianc42 ‘at’ stanford.edu.